Effect of wood and peanut shell hydrochars on the desiccation cracking characteristics of clayey soils

Soil cracking can significantly alter the water and nutrient migration pathways in the soil, influencing plant growth and development. While biochar usage has effectively addressed soil cracking, the feasibility of using less energy-intensive hydrochars in desiccating soils remains unexplored. This study investigates the impact of wood and peanut shell hydrochars on the desiccation cracking characteristics of clayey soil. A series of controlled environmental laboratory incubations with regular imaging was conducted to determine crack development's dynamic in unamended and hydrochar-amended soils. The results reveal that the addition of wood hydrochar at 2% and 4% dosage reduced the crack intensity factor (CIF) by 22% and 43%, respectively, compared to the unamended control soil. Similarly, the inclusion of peanut shell hydrochar at 2% and 4% lowered the CIF by 22% and 51%, respectively. The presence of hydrophilic groups on the surface of hydrochars, such as O-H, CH, and C-O-C, enhanced the water retention capacity, as confirmed by Fourier-transform infrared analysis. The CIF decrease is attributed to mitigated water evaporation rates, enabled by enhanced water retention within the hydrochar pore spaces. These findings are supported by scanning electron microscopy analyses of the hydrochar morphology. Despite CIF reduction with hydrochar incorporation, the crack length density (CLD) increased across all hydrochar-amended series. In contrast to unamended soil which exhibited pronounced widening of large cracks and extensive inter-pore voids, the incorporation of hydrochar resulted in higher CLD due to the formation of finer interconnecting crack meshes. Consequently, the unamended control soil suffered greater water loss due to heightened evaporation rates. This study sheds new light on the potential of hydrochars in addressing desiccation-induced soil cracking and its implications for water conservation.

The effect of Tween 80 on monochlorobenzene migration in bentonite

Several studies conducted at industrial sites have documented the infiltration of dense non-aqueous phase liquids (DNAPLs) into clay layers, a phenomenon potentially influenced by the coexistence of chemicals like surfactants in some common pollutants. Bentonite (Ben), monochlorobenzene (MCB), and Tween 80 (T80) were selected as reference components to investigate the influences of nonionic surfactants on DNAPLs migration in clays. Results showed that T80 promotes MCB dissolution and encourages MCB adsorption on Ben. This process reduces the hydrophilicity of Ben, resulting in water loss and shrinkage, which creates cracks and facilitates the migration of MCB within the clay. Tw80 notably enhances MCB solubility, as indicated by a molar solubilization ratio of 7.80. The MCB adsorption on Ben (QMCB) displays a linear increase with raising the T80 adsorption on Ben (QT80), especially when QT80 are below the thresholds, e.g., 408.4 mg/g at pH 3 and 339.3 mg/g at pH 7; however, QMCB is decreased with increasing adsorbed T80 further. The average fracture ratio, crack length, and crack width of cracked samples in the cracking experiments were 0.794%, 11.29 mm, and 0.209 mm, respectively. The findings here contribute to understanding the role of surfactants in VOC transport in contaminated sites.

Effect of anisotropy on deformation and crack formation under the brittle removal of 6H-SiC during SPDT process

INTRODUCTION

Monocrystal SiC is representative of the third generation semiconductor materials, the efficient process technology of 6H-SiC wafer have always been a hot topic. Developing a SPDT processing method based on brittle removal mode with controllable surface/subsurface damage is an important approach to solve the processing difficulties of 6H-SiC.

OBJECTIVES

This work aims to analyze the brittle removal process and fully explain the brittle separation behavior and deformation mechanism of 6H-SiC. The micro-scale crack propagation and the effect of anisotropy on crack distribution during machining process are investigated.

METHODS

Large-scale molecular dynamics simulation was used in this work.

RESULTS

Under the condition of brittle removal, shear fracture occurs in the front area of tool tip. Shear plane is high-index surface, independent of slip system. The location of tensile fracture is the cleavage plane of hexagonal system, and the fracture surface is composed of step-like joint planes or perfect plane structures. Cracks with self-healing capability appear in the area behind the tool when the surface to be machined is basal plane. When the surface to be machined is not basal plane, a large number of dislocations or cracks remain in subsurface region. Under brittle removal mode, a large amount of plastic deformation appears as well, and deformation mode is related to processing scheme.

CONCLUSION

The brittle removal behavior of 6H-SiC under SPDT process has obvious anisotropy. Basal plane is more suitable for brittle removal of 6H-SiC without residual damage such as sub-surface cracks. The crack behind the tool generated by cleavage fracture can be repaired by itself. Fracture behavior is not related to dislocation. The processing method parallel to the c-axis can cause the generation of a large number of surface cracks. The (011¯0)/[21¯1¯0] and (112¯0)/[11¯00] mode is the best way to achieve plastic removal of 6H-SiC during SPDT process.

Recent increases in crack injection and associated risk factors among people who inject psychoactive drugs in England and Wales

BACKGROUND

Crack use is higher in the United Kingdom (UK) than other European countries. Crack is a stimulant with a short half-life, requiring frequent injection to maintain its euphoric effects, thus increasing the risk of blood borne viruses (BBVs) and skin and soft tissue infections (SSTIs). We assessed trends in the prevalence of current crack injection among people who inject drugs (PWID) and investigated harms and other factors associated with its use.

METHODS

We used data from the annual Unlinked Anonymous Monitoring Survey of PWID, which recruits people who have ever injected psychoactive drugs through specialist services. Participants provide a biological sample and self-complete a questionnaire. We included participants from England and Wales who had injected in the past month. We examined trends in crack injection over time (2011-2021) and factors associated with crack injection using multivariable logistic regression (2019-2021).

RESULTS

The proportion of people self-reporting crack injection in the past month almost doubled between 2011-2020/21, from 34 % (416/1237) to 57 % (483/850). Crack injection was more frequently reported by males than females (adjusted odds ratio 1.46, 95 % confidence interval: 1.15-1.87) and injected alongside heroin (6.67, 4.06-10.97) more frequently than alone. Crack injection was independently associated with injecting equipment sharing (1.64, 1.30-2.07), groin injection (2.03, 1.60-2.56) in the past month, overdosing in the past year (1.90, 1.42-2.53), homelessness in the past year (1.42, 1.14-1.77) and ever having hepatitis C infection (1.64, 1.31-2.06).

CONCLUSION

Crack injection has increased significantly over the past decade in England and Wales. People injecting crack are more likely to engage in behaviours that increase the risk of BBV and SSTI acquisition, such as needle/syringe sharing, groin injection and polydrug use. Harm reduction and drug treatment services should adapt to support the needs of this growing population of people injecting stimulants.

Distribution and transformation of potentially toxic elements in crack under coal mining disturbance

In China, coal provides about 56.8% of the energy. Most of China's coal mines are shaft mines, which cause the surface to collapse and crack during the mining process. The soil near the cracks changes its physicochemical properties due to the altered stress conditions. This will affect the distribution of PTEs in the soil. We collected 18 samples from a selected crack in the abandoned land. The pH, Eh, and PTE and their fractions of the samples were determined. With the test results, we understand the distribution characteristics of pH, Eh, PTEs, and their fractions at the cracks. Meanwhile, we explored the key factors that contribute to this distribution. It was determined that crack decreases surface soil pH while increasing Eh. The total amount of 7 PTEs is higher in the bottom soil of the main crack and 2 m away from the main crack. The content of reducible fractions of PTEs increases with the increase of soil Eh. The oxidizable and residual fractions of PTEs adsorbed to the clay particles migrate to and enrich the deeper layers of the main crack. This study emphasizes the effect of crack generation on the distribution of PTEs in soil. It provides insights to describe the distribution of PTE throughout the full life cycle of crack.

Crack growth analysis of ultraviolet nanosecond laser scanning glass with acoustic emission

Undesirable crossing crack defects are prone to occur in the laser processing of glass, but a comprehensive analysis of the crack mechanism is absent. We apply an acoustic emission (AE) monitoring technique in the glass's laser scanning to reveal the crack phenomenon. A two-step experiment (single-line and multi-line scanning) is designed to present the crossing crack's occurrence and growth, and the corresponding AE signals are collected and analyzed in different domains. The time-domain AE feature (root mean square) correlates strongly with the laser ablation intensity in the single-line scanning experiment, and the frequency content of 150 ∼ 200 kHz is extracted as the crack characteristic in the multi-line experiment. The crossing crack growth is proved to be generated by the rapid release of thermal stress in the overlapped heat-affected zone by a brief mechanism discussion. This paper interprets the crack behavior in glass's laser scanning and provides a basis for other monitoring research on laser processing.

High levels of interest in access to free safer smoking equipment to reduce injection frequency among people who inject drugs in Seattle, Washington

Background

Drug use route transition interventions promote safer consumption by facilitating a switch from injection to safer routes such as smoking or oral consumption.

Methods

We performed a descriptive analysis using data from questions about "free, clean equipment for smoking" heroin, methamphetamine and/or crack from the Seattle 2018 National HIV Behavioral Surveillance survey of people who inject drugs (N = 555). We estimated the proportion of respondents with access to free safer smoking equipment, and among these participants, the proportion who reported that this access reduced their injection frequency. Among respondents without access to free safer smoking equipment, we described the proportion who were interested in getting access, and whether they thought this access would reduce their injection frequency.

Results

Among participants who reported prior year heroin (n = 495), methamphetamine (n = 372), or crack (n = 88) injection, 11%, 11% and 12% reported access to free safer smoking equipment, respectively. Of those with access, the proportion that reported that access reduced their injection frequency ranged from 12% to 44%. Among participants without access, 28% who used heroin, 45% who used methamphetamine, and 49% who used crack were interested in access. Of interested participants, a majority reported that they thought this access would reduce their frequency of injection.

Conclusions

Access to free safer smoking equipment was limited. Many participants were interested in getting free safer smoking equipment and reported that this access may reduce their injection frequency. Safer smoking equipment is a harm reduction strategy that should be available to reduce risks from opioid and stimulant injection.

Drug use patterns and factors related to the use and discontinuation of medications for opioid use disorder in the age of fentanyl: findings from a mixed-methods study of people who use drugs

BACKGROUND

Medications for opioid use disorder (MOUD; methadone, buprenorphine, naltrexone) are the most effective treatments for OUD, and MOUD is protective against fatal overdoses. However, continued illegal drug use can increase the risk of treatment discontinuation. Given the widespread presence of fentanyl in the drug supply, research is needed to understand who is at greatest risk for concurrent MOUD and drug use and the contexts shaping use and treatment discontinuation.

METHODS

From 2017 to 2020, Massachusetts residents with past-30-day illegal drug use completed surveys (N = 284) and interviews (N = 99) about MOUD and drug use. An age-adjusted multinomial logistic regression model tested associations between past-30-day drug use and MOUD use (current/past/never). Among those on methadone or buprenorphine (N = 108), multivariable logistic regression models examined the association between socio-demographics, MOUD type; and past-30-day use of heroin/fentanyl; crack; benzodiazepines; and pain medications. Qualitative interviews explored drivers of concurrent drug and MOUD use.

RESULTS

Most (79.9%) participants had used MOUD (38.7% currently; 41.2% past), and past 30-day drug use was high: 74.4% heroin/fentanyl; 51.4% crack cocaine; 31.3% benzodiazepines, and 18% pain medications. In exploring drug use by MOUD history, multinomial regression analyses found that crack use was positively associated with past and current MOUD use (outcome referent: never used MOUD); whereas benzodiazepine use was not associated with past MOUD use but was positively associated with current use. Conversely, pain medication use was associated with reduced odds of past and current MOUD use. Among those on methadone or buprenorphine, separate multivariable logistic regression models found that benzodiazepine and methadone use were positively associated with heroin/fentanyl use; living in a medium-sized city and sex work were positively associated with crack use; heroin/fentanyl use was positively associated with benzodiazepine use; and witnessing an overdose was inversely associated with pain medication use. Many participants qualitatively reported reducing illegal opioid use while on MOUD, yet inadequate dosage, trauma, psychological cravings, and environmental triggers drove their continued drug use, which increased their risk of treatment discontinuation and overdose.

CONCLUSIONS

Findings highlight variations in continued drug use by MOUD use history, reasons for concurrent use, and implications for MOUD treatment delivery and continuity.

Street scars: Suicide ideation and suicide attempt among street-involved adolescents and youth in southern Brazil

OBJECTIVE

To measure the prevalence of suicidal ideation and attempts as well as suicide attempts' associated factors among street-involved youth in southern Brazil.

PARTICIPANTS AND SETTING

Cross-sectional study was conducted with street-involved adolescents and children from Porto Alegre and Rio Grande, Brazil.

METHODS

A respondent-driven sampling strategy was used to access this hard-to-reach population quickly and efficiently. Descriptive, bivariate, and multivariate analyses were conducted, with the latter being binary logistic regression.

RESULTS

The prevalence of suicide attempts was 16.3%, while the frequency of suicidal ideation was 30.9%. Most participants were male, aged between 16 and 18 years, with no ties to school and family. Almost half of the sample had been in a street situation for five years or more, and two-thirds reported spending more than seven hours a day on the streets. Variables independently associated with suicide attempts were aged 19-21 years old, with reduced ties with school and family, having had an experience of sexual abuse, and lifetime use of crack.

CONCLUSIONS

Public policies targeting the strengthening ties of street-involved children, adolescents, and youth with school and family might reduce their vulnerability to threats, such as sexual abuse and use of crack, and hence focus on decreasing suicide attempts.

Cross-sectional microstructural analysis to evaluate the crack growth pattern of weathered marine plastics

Fragmentation of degraded plastics and release of smaller secondary microplastics is usually attributed to the growth of environmental stress cracks. Analysis of crack patterns derived from chemical degradation can be useful not only for assessing the cause of plastic fracture and evaluating the useful lifetime of a product, but it can also potentially provide valuable information on the generation of microplastics. However, the literature with respect to microplastics generation is generally limited to surface observations of polypropylene and polyethylene. Here, we used ion-beam milling to prepare cross-sections of fragments of 15 plastic products made from five commodity plastics (polypropylene, polyethylene, polystyrene, polyvinyl chloride, and polyethylene terephthalate) that were collected at two beaches in Japan, and then we examined the microstructures of those cross-sections by means of scanning electron microscopy and energy dispersive X-ray spectroscopy. Crack growth in the depth direction was examined to provide insights into microplastic generation behavior. In all of the polypropylene samples, and some of the low-density polyethylene and polystyrene samples, cracks with a depth exceeding 100 μm from the sample surface were observed. Considering that crack growth causes fracture of degraded plastic and microplastic release, these observations suggest the release of sharp-edged microplastics from the crack fracture surface. In contrast, in the high-density polyethylene and polyvinyl chloride samples, crack growth was limited to within 20 μm of the sample surface, suggesting the release of irregularly shaped microplastics and additive particles. The present results suggest that the degradation behavior of plastic products in the depth direction is dependent on the type of plastic.

Biomechanical perspectives on dentine cracks and fractures: Implications in their clinical management

OBJECTIVES

The present review discussed the biomechanical properties of cracks and fractures in crown and root dentine and attempted to explain why cracked teeth and vertical root fractures are so frequent despite the existence of multiple crack toughening mechanisms in dentine. The implications of this knowledge were used to justify how these defects are managed clinically.

DATA, SOURCES AND STUDY SELECTION

Literature search was conducted on PubMed, Web of Science, and Scopus for a narrative review on fracture mechanics of crown and root dentine as well as the clinical management of cracked teeth and teeth with vertical root fracture.

CONCLUSIONS

Although dentine is tougher and less brittle than enamel, it's facture toughness is considerably lower than most ductile metals. Because the initiation toughness of dentine is very low, cracks initiate from incipient damage under low stress While crack toughening mechanisms exist that enable dentine to resist crack extension, these mechanisms are often inadequate for protecting dentine from crack propagation that ultimately leads to catastrophic failure. Additional factors such as ageing also reduces the resistance of dentine to crack growth. Because dentine cracks are eventually filled with bacteria biofilms upon exposure to oral fluids, they enable rapid bacteria ingress into the dental pulp via open dentinal tubules. To date, treatment options for cracked teeth are limited. While most teeth with vertical root fracture are recommended for extraction, new strategies have been reported that appeared to achieve short-term success in preserving these teeth.

CLINICAL SIGNIFICANCE

Current strategies for the management for dentine cracks and fractures are limited and their long-term effectiveness remain uncertain. Understanding the characteristics, toughening mechanism and weakening factors of tooth cracks is helpful in designing better treatment.

Is There a Relationship between Laser Therapy and Root Canal Cracks Formation? A Systematic Review

Introduction

Crack formation has become an important issue for endodontists, as it can be decisive for the long-term prognosis of the endodontically treated tooth. Since the applicability of laser in endodontics has become frequent, this systematic review aimed to evaluate the association between laser therapy and the formation of cracks in the dentinal structure of the root canal.

Materials and Methods

A search was performed in PubMed, Scopus, Web of Science, and Virtual Health Library, as well as in the gray literature, on September 24, 2021. Studies that evaluated the formation of cracks in human root dentin due to different types of lasers were included. The risk of bias was assessed following the modified version of the Consolidated Standards of Reporting Trials (CONSORT) checklist tool. A meta-analysis was performed to evaluate (i) the total number of crack incidences; (ii) complete crack formation; (iii) incomplete crack formation; (iv) intra-dentinal crack formation between ultrasonic tips and laser use. The mean difference was calculated with a 95% confidence interval in a fixed-effect model, the heterogeneity was tested using the I² index with level of significance of 5%.

Results

Of the 22 studies included in this review, 15 have shown that lasers can form cracks in root dentin, including those that performed baseline assessment of samples. The meta-analysis confirmed no difference in crack formation between ultrasonic tips and laser devices.

Conclusions

Laser therapy has been gaining prominence in endodontics and that irradiation can form and propagate cracks in the dentinal structure of the root canal assessed by in vitro studies. This is a critical concern for endodontists as it affects the strength and longevity of the tooth. Future research is encouraged to seek the standardization of good methodological practices and achieve establishing parameters to minimize harmful effects of laser on dentin.

Correlation between age, location, orientation, loading velocity and delamination strength in the human aorta

Aortic dissection is a biomechanical phenomenon associated with a failure of internal cohesion, which manifests itself through the delamination of the aortic wall. The goal of this study is to deepen our knowledge of the delamination strength of the aorta. To achieve this, 661 peeling experiments were carried out with strips of the human aorta collected from 46 cadavers. The samples were ordered into groups with respect to (1) anatomical location, (2) orientation of the sample, and (3) extension rate used within the experiment. The obtained results are in accordance with the hypothesis that delamination resistance is not sensitive to the extension rates 0.1, 1, 10, and 50 mms^-1. We arrived at this conclusion for all positions along the aorta investigated in our study. These were the thoracic ascending (AAs), thoracic descending (ADs), and the abdominal aorta (AAb), simultaneously considering both the longitudinal (L) as well as the circumferential (C) orientations of the samples. On the other hand, our results showed that the delamination strength differs significantly with respect to the anatomical position and orientation of the sample. The medians of the delamination strength were as follows, 4.1 in AAs-L, 3.2 in AAs-C, 3.1 in ADs-L, 2.4 in ADs-C, AAb-L in 3.6, and 2.7 in AAb-C case (all values are in 0.01·Nmm^-1). This suggests that resistance to crack propagation should be an anisotropic property and that the aorta is inhomogeneous along its length from the point of view of delamination resistance. Finally, correlation analysis proved that the delamination strength of the human aorta significantly decreases with age.

Detection of cocaine crystals dispersed on non- Erythroxylum herbs

This case report deals with an unusual seized drugs case, in which cocaine, more commonly found in powder form or as crack cocaine, was found in herbs similar to those used to deliver synthetic cannabinoids. A comparison with expected physical appearance and chemical results for a genuine coca leaf is also presented.

IL-10 (-819C/T), TNFA (-30G/A) and ENOS (-786T/C) Polymorphisms Modulating the Outcome Related to Mental Disorders in Crack Addicted Users

Background

Cocaine/crack use affects immune system molecules and development of mental disorders has been identified.

Objective

To investigate the relationship of polymorphisms in the TNFA (-308G/A), IL-10 (-819C/T) and ENOS (-786T/C) genes with mental disorders in cocaine and crack users.

Methods

A case-control study was carried out, which included 107 cocaine and crack users and 115 controls who never used healthy cocaine and crack. The SNPs in the TNFA (-308G/A), IL-10 (-819C/T) and ENOS (-786T/C) genes were genotyped by real time PCR.

Results

As for the individuals included in this study, the average age of 31.4 years (± 8.59). We identified that the G/A genotype to TNFA (-308) (OR = 0.24; p = 0.03) and the A allele (OR = 0.30; p = 0.03) were associated with reduced risk for dysthymic disorder. The T allele of the IL-10 (-819) polymorphism was associated with decreased risk of developing panic disorder (OR = 0.44; p = 0.01), while the C allele was correlated with an increased risk for alcohol dependence (OR = 1.97; p = 0.04), alcohol abuse (OR = 1.81; p = 0.04) and psychotic syndrome (OR = 2.23; p = 0.01). C/C genotype was correlated with increased chances of developing current psychotic syndrome (OR = 4.23; p = 0.01).

Conclusion

Our results suggest that genetic polymorphisms promote susceptibility or promote protection for clinical phenotypes of psychiatric comorbidities in cocaine and crack users and be considered as good prognostic markers.

Finite deformation near a crack tip terminated at an interface between two neo-Hookean sheets

A crack terminating at an arbitrary angle to the interface between two neo-Hookean sheets is investigated under plane stress conditions using finite deformation theory. The asymptotic crack-tip deformation and stress fields are analyzed as a function of the ratio of the moduli and the angle of the crack relative to the interface. Full-held numerical calculations and experimental studies validate the analytical results. A stretch-based crack growth criterion is developed using crack-tip held solutions. Such criterion can predict the delay of crack growth through the bi-material interface observed in experiments and can be extended to any heterogeneity and material.

Local defect resonance of a through-thickness crack

In recent years, Local Defect Resonance (LDR) has generated much interest in development and applications of new resonant acoustic modes for non-destructive testing (NDT) and imaging of planar defects in composite materials. The studies and applications are focused at LDR in composites where the most common defects are delaminations and impacts. This paper considers the mechanism of development and the attributes of LDR for through-thickness cracks in plates. The experiments validate that the LDR is caused by the resonance of the edge waves propagating along the crack faces. The edge wave resonance features weak field decay away from the crack, partial as well as high-order LDR and provides clear opportunities for applications in NDT techniques based on acoustic activation of damage.

Associations amongst form of cocaine used (powder vs crack vs both) and HIV-related outcomes

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Among PWH, cocaine use vs no-use was associated with worse HIV treatment outcomes.

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Powder cocaine only users were more likely to be younger, Hispanic, and employed.

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Users of powder + crack cocaine had lower viral suppression than users of either alone.

•

Harm reduction efforts addressing substance use should be a key component of HIV care.

Introduction

Cocaine (including powder and crack) use is common among people with HIV (PWH). We identified socio-demographic and behavioral factors associated with cocaine use (overall and various forms) among PWH; we also examined differences in HIV treatment outcomes across cocaine exposure groups.

Methods

The study sample (N = 1166) was derived from two cohorts of PWH in Florida between 2014 and 2020. Baseline data were linked to the Enhanced HIV/AIDS Reporting System (eHARS) which tracks HIV viral load. Socio-demographics and polysubstance use were compared by cocaine use and the three cocaine use groups (powder only n = 101, crack only n = 91, or both n = 65). The association between the three cocaine use groups, ART adherence, and HIV viral suppression (<200 copies/mL) in the following year was assessed by multivariate logistic regression.

Results

People who used cocaine had lower HIV treatment adherence and viral suppression than those who did not use. People who used powder cocaine only were more likely to be younger, Hispanic/Latinx, and employed than those who used crack only or both. Compared to people who used both powder and crack cocaine, those who used one form of cocaine had 3 + odds of having durable viral suppression in the following year.

Conclusion

The dual use of both powder and crack cocaine was associated with significantly worse HIV outcomes compared to use of only one form of cocaine. Screening for powder and crack cocaine use and timely intervention are needed to improve HIV treatment outcomes among this high-risk population.

Eggshell crack detection based on the transient impact analysis and cross-correlation method

To explore the transient impact process for cracked eggshell detection, an equivalent mechanical model was built based on a self-designed automatic excitation device. Through analysis of power spectrum from dynamic force signal, it was found that the impact speed affects only the impaction energy. In contrast, the material of the impact head and the weight of the excitation rod determine the energy and the cut-off frequency of the impaction. When the weight of impact tup is less than 6.62 g, the cut-off frequency of excitation impact can cover the egg's inherent frequency. Then, an optimized experiment system was designed to acquire the response acoustic signals. The cross-correlation analysis and Bayes classification methods were carried out to detect the cracked eggshell. In the conducted experiments, a crack detection level of 97% and a false rejection level of 1% were achieved. From the findings, it can be concluded that the proposed method will assist in optimizing the impact device and simplifying the classification algorithm for an online detection system.

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An equivalent mechanical model was built to analyze the transient impact process.

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The effective response signal which covers the inherent frequency of the egg was enhanced by the power spectrum analysis.

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The cross-correlation analysis method was proposed to distinguish the intact eggs and cracked eggs.

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In the conducted experiments, a crack detection level of 97% and a false rejection level of 1% were achieved.

Effectiveness of incorporating contingency management into a public treatment program for people who use crack cocaine in Brazil. A single-blind randomized controlled trial

BACKGROUND

Smoked cocaine (i.e., crack use) is a severe health problem in Brazil, with the country being reported as having the largest crack market in the world. The objective of this study was to evaluate the effectiveness of incorporating Contingency Management targeting cocaine abstinence into a public treatment program in Brazil.

METHODS

Single-blind randomized controlled trial conducted at Unidade Recomeço Helvétia (URH), a public ambulatory treatment program for persons who use crack and live in the "Crackland" region in downtown São Paulo, Brazil. In total, 98 treatment-seeking individuals who use crack were randomized to one of two treatment conditions. Participants allocated to the control condition (n = 48) received 12 weeks of the standard treatment provided at URH. Participants allocated to the experimental condition (n = 50) received the same treatment in combination with Contingency Management (URH+CM). In URH+CM, participants were provided with vouchers with monetary value for submission of negative cocaine urinalysis twice weekly.

RESULTS

Compared to the URH group, the URH+CM group was significantly more likely to submit a negative cocaine urinalysis during treatment, with odds ratios ranging from 4.17 to 6.78, depending on how missing data was accounted for (p<0.01). Participants receiving Contingency Management also had higher odds of achieving three or more weeks of continuous abstinence (OR= 8.07; 95% CI [2.48, 26.24]), achieved longer durations of abstinence (B = 2.14; 95% CI [0.67, 3.61]), submitted a higher percentage of negative urinalysis (B = 19.85; 95% CI [6.89, 32.82]), and were retained in treatment for a longer period (B = 3.00; 95% CI [1.04, 4.97]), compared to those receiving URH alone (p<0.01 for all).

CONCLUSIONS

The incorporation of Contingency Management was effective in promoting cocaine abstinence and treatment retention. The large-scale dissemination of Contingency Management may be an effective strategy to treat Brazilians with cocaine use disorders.

Crack pathway analysis in graphene-like BC3 nanosheets: Towards a deeper understanding

Carbon based two-dimensional (2D) nanostructures have exceptional mechanical properties. Analysis of crack pathway in 2D graphenic materials allows for developing crack arrestors. Herein, we serve Molecular Dynamics (MD) to simulate the fracture behavior of 2D graphene-like boron-carbide (BC₃) by manipulating the crack length (10, 20, 30, 40, and 50 Å) and the crack arrestor (circular and square). Young's modulus, the failure stress, failure strain, and fracture toughness of theoretically born BC₃ nanosheets were then captured. The crack arrestors were studied in three different states (constant position, as well as 4 and 6 Å from crack tips). Three factors, i.e. the stress, crack length, and geometry of nanosheets determined crack pathway considering zigzag and armchair directions. Overall, circular arrestors more severely affected the fracture toughness, failure stress and failure strain with respect to square ones; while Young's modulus variation followed an inverse trend. Moreover, the highest Young's modulus was detected for cracks having length of 10 Å. Fracture toughness increased upon increasing the crack length. In conclusion, the crack arrestors were promising for tuning the mechanical properties of 2D nanosheets.

Cumulative Effects of Adding a Small Group Intervention to Social Network Testing on HIV Testing Rates Among Crack Users in San Salvador, El Salvador

The present study evaluates a combination prevention intervention for crack users in San Salvador, El Salvador that included social network HIV testing, community events and small group interventions. We examined the cumulative effects of the social network HIV testing and small group interventions on rates of HIV testing, beyond the increase that we saw with the introduction of the social network HIV testing intervention alone. HIV test data was converted into the number of daily tests and analyzed the immediate and overtime impact of small group interventions during and in the twelve weeks after the small group intervention. The addition of the small group interventions to the baseline of monthly HIV tests resulted in increased rates of testing lasting 7 days after the small group interventions suggesting a reinforcing effect of small group interventions on testing rates.

Finite element analysis on multi-toughening mechanism of microstructure of osteon

The toughening mechanism of cortical bone is closely related to its hierarchical microstructure. Osteon is the most important microstructure of cortical bone. Therefore, it is very important to study the toughening mechanism of the microstructure of osteon. There are three main kinds of cracks in cortical bone: external crack of osteon, internal radial cracks of osteon and microporous damage cracks. Numerical models for these three kinds of cracks are established by XFEM and the progressive damage approach, respectively. The multi-toughening mechanisms of microstructure of osteon are found. The cement line on the outside of osteon is its first toughening mechanism, which can make the crack deflection and improve the fracture resistance of osteon. The resistance of cement line to fracture increases with the decrease of the strength and the increase of the thickness. The second toughening mechanism is elliptical osteocyte lacunae, which can attract the crack into the elliptical lacunae and cause stress redistribution to prevent the crack propagation. The annularly elliptical lacuna structure is an optimized arrangement and shape of microstructure, which is the third toughening mechanism of osteon. This microstructure can determine the location of the crack initiation and make the microcracks propagate along the annular direction rather than penetrating into the haversian cannal to protect the integrity of the osteon. The study of these toughening mechanisms provides new ideas for the research and design of synthetic composite structures.

Scanning acoustic microscopy for material evaluation

Scanning acoustic microscopy (SAM) or Acoustic Micro Imaging (AMI) is a powerful, non-destructive technique that can detect hidden defects in elastic and biological samples as well as non-transparent hard materials. By monitoring the internal features of a sample in three-dimensional integration, this technique can efficiently find physical defects such as cracks, voids, and delamination with high sensitivity. In recent years, advanced techniques such as ultrasound impedance microscopy, ultrasound speed microscopy, and scanning acoustic gigahertz microscopy have been developed for applications in industries and in the medical field to provide additional information on the internal stress, viscoelastic, and anisotropic, or nonlinear properties. X-ray, magnetic resonance, and infrared techniques are the other competitive and widely used methods. However, they have their own advantages and limitations owing to their inherent properties such as different light sources and sensors.This paper provides an overview of the principle of SAM and presents a few results to demonstrate the applications of modern acoustic imaging technology. A variety of inspection modes, such as vertical, horizontal, and diagonal cross-sections have been presented by employing the focus pathway and image reconstruction algorithm. Images have been reconstructed from the reflected echoes resulting from the change in the acoustic impedance at the interface of the material layers or defects. The results described in this paper indicate that the novel acoustic technology can expand the scope of SAM as a versatile diagnostic tool requiring less time and having a high efficiency.

Argyrophilic nucleolar organizer regions in oral mucosa cells of crack and cocaine users: a cross-sectional study

The objective of this study was to analyze and compare the presence of argyrophilic nucleolar organizer regions (AgNORs) in exfoliated cells obtained from the buccal mucosa among crack and cocaine users and non-users by the AgNOR staining technique. Seventy-three males ≥ 18 years were categorized into two groups: 38 crack and/or cocaine users and 35 non-user volunteers. They were interviewed and responded a questionnaire regarding general health and drug addiction. Exfoliative cytology specimens were collected from the clinically intact buccal mucosa, and cytological preparations were fixed and stained by AgNOR technique. The mean number of AgNORs (p = 0.02) and the percentage of epithelial cells with more than 3 (p = 0.01) and 4 (p = 0.04) AgNORs/nucleus were significantly higher in the non-user group. In conclusion, the frequency and diversity of substances present in the drugs-cocaine, crack, and alcohol-consumed by the volunteers of this study may have influenced the number of AgNORs and the response to damage and consequent effect on protein synthesis.

Soil desiccation cracking and its characterization in vegetated soil: A perspective review

The formation and propagation of surface desiccation cracks in vegetated infrastructures involve coupled factors including unsaturated soil mechanics, atmospheric conditions and vegetation parameters. Vegetation induces a "Love-hate" relationship in the development of desiccation cracks due to plant induced suction as well as root reinforcement. The objective of the paper is to provide a state-of-the-art that comprehensively reviews the desiccation process in context of the soil-water-plant interaction together. At first, basic theories of crack initiation and propagation in literature are discussed in the context of unsaturated soil mechanics. Thereafter, influence of vegetation on soil cracking is discussed systematically based on transpiration induced suction, root reinforcement, plantation strategy, root exudate and basic plant traits. Intrusive and non-intrusive measurement approaches of desiccation cracks including lab and field studies are put forward. Various schools of desiccation models have been briefly touched upon. More than 150 studies on desiccation cracks have been tabulated in this review, considering soil types, vegetation cover, drying-wetting cycles, approaches of characterizing cracks, sample size, crack pattern, hydraulic conductivity and water retention. Future scopes involving measurement considerations, usage of geotechnical centrifuge modelling, bio-amendments and plant effects on desiccation cracking have been put forward.

Dataset on the effect of nano-modified additives of concrete mixes technological properties for winter concreting

This article contains data of effect of nano-modified additives on the technological properties of concrete mixes for winter concreting. The nano-modified additive, consisting of naphthalene formaldehyde, nano-modified silicon dioxide, saponified wood resin and sodium nitrate, ensures the manufacturability of the concrete mix, its quality laying and normal curing at low outdoor temperatures. The nano-modified additive allows prevents the phenomenon of segregation of concrete mixes of grade C12/15. The application of nano-modified additive together with sodium nitrate (4 wt.% of cement) ensures normal conditions for the hydration of cement paste at ambient temperatures from +5 °C to –5 °C. This dataset is associated with a research article entitled “Effect of nano-modified additives on properties of concrete mixtures during winter season” [1].

Residual polymerization stresses in human premolars generated with Class II composite restorations

The objective of this study was to assess the influence of filling techniques on residual polymerization stresses in resin composite restorations of the tooth. Flat planes were ground in buccal enamel surfaces of extracted human premolars, followed by preparing Class II cavities. Indentation cracks were introduced in the planes and crack lengths were measured mesio-distally (x-direction) and cervico-incisally (y-direction). Cavities were filled with a resin composite and an adhesive using three methods; one with bulk filling and two with differing incremental filling techniques. The x- and y-tensile stresses were calculated from crack lengths measured repeatedly over 360 min after filling. Elastic modulus and polymerization shrinkage of the composite were also measured. Filling technique and time after fillings were statistically significant only for the y-stress. The incremental techniques generated smaller stresses than the bulk filling. The stresses developed for 60 min after filling, while the modulus and the shrinkage stopped developing within 10 min and 2 min after irradiation, respectively. The incremental technique, in which the proximal portion of the cavity was filled first, was effective in decreasing the residual tensile stress generated by the polymerization of resin composite.

Association of CHRNA5 Gene Variants with Crack Cocaine Addiction

Genome-wide studies provide increasing evidence of association of genetic variants with different behaviors. However, there is a growing need for replication and subsequent characterization of specific findings. In this sense, the CHRNA5 gene has been associated with nicotine (with genome-wide significance), alcohol and cocaine addictions. So far, this gene has not been evaluated in smoked (crack) cocaine. We aimed to analyze the influence of CHRNA5 variants in crack addiction susceptibility and severity. The sample includes 300 crack-addicted patients and 769 non-addicted individuals. The CHRNA5 SNPs evaluated were rs588765, rs16969968, and rs514743. Homozygosity for rs16969968 and rs588765 major alleles was nominally associated with a risk to crack addiction (GG, P = 0.032; CC, P = 0.036, respectively). Haplotype analyses reveal significant associations (rs588765|rs16969968|rs514743 p_{global-corrected} = 7.66 × 10^-5) and suggest a substantial role for rs16969968. These findings corroborate previous reports in cocaine addiction-in line with the expected effects of cocaine in the cholinergic system-and in the opposite direction of significant GWAS findings for nicotine addiction susceptibility. These results are strengthened by the first report of an association of rs588765 with crack addiction and by the haplotype findings. In summary, our study highlights the relevance of the α5 subunit on crack cocaine addiction, replicating previous results relating CHRNA5 with the genetics and pathophysiology of addiction of different drugs.

Interfacial toughening effect of suture structures

Suture interfaces are one of the most common architectural designs in natural material-systems and are critical for ensuring multiple functionalities by providing flexibility while maintaining connectivity. Despite intensive studies on the mechanical role of suture structures, there is still a lack of understanding on the fracture mechanics of suture interfaces in terms of their interactions with impinging cracks. Here we reveal an interfacial toughening effect of suture structures by means of "excluding" cracks away from interfaces based on a dimensionless micro-mechanical model for single-leveled and hierarchical suture interfaces with triangular-shaped suture teeth. The effective stress-intensity driving forces for crack deflection along, versus penetration through, an interface at first impingement and on subsequent kinking are formulated and compared with the corresponding resistances. Quantitative criteria are established for discerning the cracking modes and fracture resistance of suture interfaces with their dependences on sutural tooth sharpness and interfacial toughness clarified. Additionally, the effects of structural hierarchy are elucidated through a consideration of hierarchical suture interfaces with fractal-like geometries. This study may offer guidance for designing bioinspired suture structures, especially for toughening materials where interfaces are a key weakness. STATEMENT OF SIGNIFICANCE: Suture interfaces are one of the most common architectural material designs in biological systems, and are found in a wide range of species including armadillo osteoderms, boxfish armor, pangolin scales and insect cuticles. They are designed to provide flexibility while maintaining connectivity. Despite many studies on the mechanical role of suture structures, there is still little understanding of their role in terms of interactions with impinging cracks. Here we reveal an interfacial toughening effect of suture structures by means of "excluding" cracks away from interfaces based on a dimensionless micro-mechanical model for single-leveled and hierarchical suture interfaces with triangular-shaped suture teeth. Quantitative criteria are established for discerning the cracking mode and fracture resistance of the interfaces with their dependences on sutural tooth sharpness and interfacial toughness clarified.

[Pulmonary complications in cocaine users]

Cocaine can be responsible for many psychiatric and/or somatic disorders. The aim of this systematic literature review of data was to expose relations between cocaine use and pulmonary complications. Cocaine can be responsible for acute respiratory symptoms (cough, black sputum, hemoptysis, dyspnea, wheezing, chest pain) and for various pulmonary disorders including barotrauma (pneumothorax, pneumomediastinum, subcutaneous emphysema, pneumopericardium), airway damage, asthma, bronchiolitis obliterans with organizing pneumonia, acute pulmonary edema, alveolar hemorrhage, alveolar pneumonia with carbonaceous material, bullous emphysema, acute eosinophilic pneumonia, pulmonary granulomatosis caused by talc or cellulose, interstitial pneumonitis and pulmonary fibrosis, vasculitis, pulmonary hypertension, pulmonary embolism and pulmonary infarction, mycotic pulmonary arterial aneurysms, septic emboli, aspiration pneumonia, community-acquired pneumonia, HIV-related opportunistic infections, latent tuberculosis infection, pulmonary tuberculosis, lung cancer and crack lung. Some of these complications are serious and may have a fatal outcome. Pulmonary function tests, thoracic tomodensitometry, bronchial fibroscopy with bronchoalveolar lavage and lung scintigraphy may be an aid to the diagnosis of these pulmonary compications. Cocaine use must be sought in case of respiratory symptoms in young persons.

Study of the distribution of water within a biscuit during cooling; effect on the checking and the breakage

The fragility of biscuits yields checking (cracks) and eventually breakage, which originated mainly from heterogeneity in water distribution in the thickness dimension (surface vs centre) and also to the plan dimension (edge vs centre) of the product. The objective of the BRICE project is to study the impact of the distribution of water on the occurrence of checking and breakage (C&B) in biscuits, considering a round and thick biscuit and a rectangular and thinner biscuit presenting piercing points. C&B counting was performed over 15 days of storage (the time needed to reach stability). A higher C&B occurrence was observed in the round biscuits, while rectangular biscuits had a near-zero C&B rate. The Karl Fischer method was combined with an automated NIR imaging system to monitor the water distribution at the centres and surfaces of the products, as well as the apparition of C&B. The results confirmed that minuscule water gradients are involved.

Anhydroecgonine methyl ester (AEME), a cocaine pyrolysis product, impairs glutathione-related enzymes response and increases lipid peroxidation in the hippocampal cell culture

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AEME and cocaine decreased GPx, GR and GST activities after 3 and 6 h of exposure.

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AEME and cocaine increased MDA after 48 h of exposure.

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AEME-cocaine combination decreased GPx, GR and GST activities after 3 and 6 h.

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AEME-cocaine combination showed an additive effect on MDA after 48 h of exposure.

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A higher neurotoxic effect after crack cocaine use is suggested.

Crack cocaine smokers inhale, alongside with cocaine, its pyrolysis product, anhydroecgonine methyl ester (AEME). We have previously described AEME neurotoxic effect and its additive effect when co-incubated with cocaine. Our aim was to evaluate, the effect of AEME, cocaine and AEME-cocaine combination on glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST) activities after 3 and 6 h of exposure, periods previous to neuronal death. Lipid peroxidation was evaluated through malonaldehyde (MDA) levels at 3, 6, 24 and 48 h of exposure. All treated groups reduced neuronal viability after 24 h of exposure. AEME and cocaine decreased GPx, GR and GST activities after 3 and 6 h, with an increase in MDA levels after 48 h. AEME-cocaine combination decreased the enzymes activities after 3 and 6 h, showing an additive effect in MDA levels after 48 h. These data show that the glutathione-related enzymes imbalance caused by AEME, cocaine or AEME-cocaine combination exposure preceded neuronal death and lipid peroxidation. Moreover, the additive effect on lipid peroxidation observed with AEME-cocaine exposure after 48 h, suggest a higher neurotoxic effect after crack cocaine use when compared to cocaine alone.

Simulation of crack induced nonlinear elasticity using the combined finite-discrete element method

Numerical simulation of nonlinear elastic wave propagation in solids with cracks is indispensable for decoding the complicated mechanisms associated with the nonlinear ultrasonic techniques in Non-Destructive Testing (NDT). Here, we introduce a two-dimensional implementation of the combined finite-discrete element method (FDEM), which merges the finite element method (FEM) and the discrete element method (DEM), to explicitly simulate the crack induced nonlinear elasticity in solids with both horizontal and inclined cracks. In the FDEM model, the solid is discretized into finite elements to capture the wave propagation in the bulk material, and the finite elements along the two sides of the crack also behave as discrete elements to track the normal and tangential interactions between crack surfaces. The simulation results show that for cracked models, nonlinear elasticity is generated only when the excitation amplitude is large enough to trigger the contact between crack surfaces, and the nonlinear behavior is very sensitive to the crack surface contact. The simulations reveal the influence of normal and tangential contact on the nonlinear elasticity generation. Moreover, the results demonstrate the capabilities of FDEM for decoding the causality of nonlinear elasticity in cracked solid and its potential to assist in Non-Destructive Testing (NDT).

Increasing heroin, cocaine, and buprenorphine arrests reported to the Maine Diversion Alert Program

BACKGROUND

The opioid overdose crisis is especially pronounced in Maine. The Diversion Alert Program (DAP) was developed to combat illicit drug use and prescription drug diversion by facilitating communication between law enforcement and health care providers with the goal of limiting drug-related harms and criminal behaviors. Our objectives in this report were to analyze 2014-2017 DAP for: (1) trends in drug arrests and, (2) differences in arrests by offense, demographics (sex and age) and by region.

METHODS

Drug arrests (N=8193, 31.3% female, age=33.1±9.9) reported to the DAP were examined by year, demographics, and location.

RESULTS

The most common substances of the 10,064 unique charges reported were heroin (N=2203, 21.9%), crack/cocaine (N=945, 16.8%), buprenorphine (N=812, 8.1%), and oxycodone (N=747, 7.4%). While the overall number of arrests reported to the DAP declined in 2017, the proportion of arrests involving opioids (heroin, buprenorphine, or fentanyl) and stimulants (cocaine/crack cocaine, or methamphetamine), increased (p<.05). Women had significantly increased involvement in arrests involving sedatives and miscellaneous pharmaceuticals (e.g. gabapentin) while men had an elevation in stimulant arrests. Heroin accounted for a lower percentage of arrests among individuals age >60 (6.6%) relative to young-adults (18-29, 22.3%, p<.0001). Older-adults had significantly more arrests than younger-adults for oxycodone, hydrocodone, and marijuana.

CONCLUSION

Heroin had the most arrests from 2014 to 2017. Buprenorphine, fentanyl and crack/cocaine arrests increased appreciably suggesting that improved treatment is needed to prevent further nonmedical use and overdoses. The Diversion Alert Program provided a unique data source for research, a harm-reduction tool for health care providers, and an informational resource for law enforcement.

Nonlinear ultrasonic test of concrete cubes with induced crack

Second and third harmonic ratios method to evaluate initial damage in concrete have been extensively studied. However, some regularities of this technique still not clear in current stage. In order to better understand the regularity of nonlinear parameters β and γ on micro and macro damage in concrete, the cracks with different damage scales are induced in concrete specimens. Three levels of test voltage are applied to intact concrete specimens, with the purpose to demonstrate the excitation voltage has an unneglectable effect on nonlinear parameters. The regularity of nonlinear parameters on crack orientation is also obtained in this study. The results of the experiment have considerable importance with respect to the method of higher harmonic ratios for concrete and other inhomogeneous materials.

[Asthma and cocaine use]

INTRODUCTION

Cocaine use can be responsible for many respiratory complications including asthma.

OBJECTIVES

Systematic literature review of data on asthma in cocaine users.

DOCUMENTARY SOURCES

PubMed/Medline search, on the period 1980-2017 with the following keywords: "asthma*" or "bronchospasm" and "cocaine" or "freebase*" or "crack", limits "title/abstract"; the selected languages were English or French. Among 108 articles, 43 abstracts underwent dual reading to select 22 studies.

RESULTS

In four case reports of asthma associated with cocaine use including 11 patients (mean age: 28.3 years [22-33 years]; sex-ratio: 2.5 [males: 71.5%]), cocaine was sniffed [snorted] (9%), smoked (36.5%) or both sniffed and smoked (54.5%). A medical history of childhood asthma was observed in 45.4% of the cases. Acute respiratory failure, requiring intubation and mechanical ventilation, was observed in 45.4% of the cases. Outcome was rapidly favorable in 82%; 9/11, progressively favorable in one patient, and fatal in another patient. Other studies included 6 cross-sectional studies, 4 case-control studies and 8 longitudinal studies (7 retrospective studies and one prospective study). The mean age was 36.6 years (women: 44.7%). Twenty percent of the subjects used cocaine exclusively, and 80% used cocaine combined with other addictive drugs (cocaine and heroin: 62%). The prevalence of cocaine users was higher in asthmatic subjects and the prevalence of asthma was higher in cocaine users. Cocaine use can be responsible for asthma onset and acute asthma exacerbation. In the case of asthma exacerbation, cocaine users were more likely to be admitted in intensive care units and to require intubation and invasive ventilation. Asthma exacerbations may be fatal in spite of resuscitation measures. Asthma treatment observance was lower in cocaine users.

CONCLUSION

Cocaine use may be responsible for asthma onset, acute asthma exacerbations (which may require intubation and invasive ventilation) or death related to asthma. Cocaine use must be systematically considered in the case of asthma exacerbation and practitioners must help cocaine users to stop their consumption.

Symptoms Suggestive of Dysphagia and the Quality of Life in Cocaine and/or Crack Users

Users of cocaine and/or crack may present symptoms of dysphagia due to changes in anatomical structures caused by the use of these substances. The objective of this study was to investigate the presence of symptoms suggestive of dysphagia in users of cocaine and/or crack seeking treatment, as well as to investigate the quality of life of these individuals related to their swallowing condition. A cross-sectional study from September 2015 to December 2016, with 121 users of cocaine and/or crack, was conducted. 59 of them called a telemarketing service and 61 sought treatment at the Centro de Atenção Psicossocial Álcool e Drogas in Porto Alegre (Psychosocial Alcohol and Drug Center). Users were screened and asked to fill the Eating Assessment Tool questionnaire. Users who presented themselves at the center were submitted to the Tool Volume-Viscosity Swallow Test. Users with symptoms of dysphagia responded to the Quality of Life in Swallowing questionnaire. Of all the interviewees, 22.3% (n = 27) reported symptoms suggestive of dysphagia and 2% of the individuals, submitted to swallowing test, presented cough in the liquid consistency. The scores showed a negative impact on quality of life, mainly related to fatigue, sleep, feeding duration, and fear of eating. Significant numbers of users of cocaine and/or crack referred to symptoms suggestive of dysphagia and significant impairments in quality of life, which require specific care in feeding this population in order to assist in their rehabilitation.

Intervention Reach and Sexual Risk Reduction of a Multi-level, Community-Based HIV Prevention Intervention for Crack Users in San Salvador, El Salvador

This article examines the effects of a multi-level, community-based HIV prevention intervention for crack users residing in low-income neighborhoods in San Salvador, El Salvador conducted between August 2011 and June 2016. The intervention consisted of three components introduced sequentially: (1) rapid HIV testing in community settings; (2) a social network HIV testing intervention; and (3) small group interventions with crack users who were members of the same social network. The intervention was evaluated with an interrupted time series design in which we used respondent-driven sampling to conduct 7 cross-sectional surveys with crack users along a 3-4 month period for each assessment (total n = 1597). Results revealed a significant increase in exposure to the intervention over time with 50% of the participants reporting exposure to one or more of the three components. Getting an HIV test at the community site was associated with reductions in total times each individual had sex without a condom (p < 0.05) compared to those who had been exposed to no intervention components. Being referred by another crack user through the Social Network HIV intervention was also associated with reductions in total numbers of condomless sex (p < 0.05) The cumulative effect of being exposed to more than one intervention component was associated with reductions in total number of times individuals had condomless sex (p < 0.05). In spite of the high level of intervention reach and that self-reported exposure to intervention components was associated with lower sexual risk, reductions in sexual risk over time were not observed in the full sample, indicating that the penetration of HIV prevention components was not sufficient to produce population level change.

Relapse in involuntary substance treatment: a transversal study

OBJECTIVE

To evaluate the associations between relapse and admissions (voluntary and involuntary) in a sample of patients with substance dependence.

METHODS

This is a cross-sectional study undertaken at a private medical therapeutic community specialised in treating addiction, located in a rural area of São Paulo, Brazil. Sociodemographic characteristics, the University of Rhode Island Change Assessment Scale (URICA), Stages Readiness and Treatment Eagerness Scale (SOCRATES), Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI) and Structured Clinical Interview for DSM-IV-SCID were used.

RESULTS

Relapse was associated with low family income (P=.006) and contemplation motivational stage (P<0.05). Nevertheless, no significant differences between individuals who were admitted involuntarily (64%) and voluntarily (54%) were observed (P=0.683) in terms of relapses.

CONCLUSIONS

In this sample, the relapse outcome in involuntary admissions was no different from the voluntary ones.

Unlocalized crack initiation and propagation in staggered biomaterials

Many types of tissues in living organisms exhibit a combination of different properties to fulfil their mechanical functions in complex environments. Nacre with more than 90% brittle and hard phase and a little protein matrix, exhibits high strength and toughness, which is difficult to achieve in artificial materials. Researchers have shown that the toughness of nacre is related to the cracking process. Most of them, however, assume an obvious pre-existing crack on the model and the initiation of the microscopical pre-existing crack is not considered yet. Based on fracture mechanics with the cohesive zone model, we reveal the mechanism of the crack initiation and propagation pattern in staggered biomaterials without any pre-existing crack. The simulation result shows that there are two crack propagation modes: localized mode and unlocalized mode. A crack initiates and propagates in a small area in the localized mode, while cracks initiate at different points and propagate in various paths in the unlocalized mode. The crack initiation mechanism from the intrinsic properties of the material is clarified using energy based stability analysis. The result shows that the shear interfacial mechanism significantly delays the crack initiation.

Telephone counseling for young Brazilian cocaine and/or crack users. Who are these users?

OBJECTIVE

To describe the users' drug abuse characteristics, problematic behaviors associated with addiction, the motivation of teenagers and young adults to quit cocaine and/or crack abuse, and then compare these characteristics.

METHODS

A cross-section study was conducted with 2390 cocaine/crack users (teenagers from 14 to 19 years of age, and young adults from 20 to 24 years of age); 1471 were young adults and 919 were teenagers who had called a phone counseling service between January 2006 and December 2013. Semi-structured interviews were performed via phone calls. The questionnaires included sociodemographic information; assessment of the characteristics of cocaine/crack abuse; assessment of the problematic behaviors; also, the Contemplation Ladder was used to evaluate the stages of readiness to cease substance abuse.

RESULTS

Participants reported using cocaine (48.2%), crack and other smoking forms (36.7%) and combined consumption of both drugs (15%). Young adults were more prone to using crack or crack associated with cocaine (OR=1.9; CI 95%=1.05-1.57) and they were exposed to substance abuse for longer than two years (OR=3.45; CI 95%=2.84-4.18), when compared to teenagers. On the other hand, they showed higher readiness to quit.

CONCLUSION

Data shows important differences in drug abuse characteristics, problematic behaviors and motivation to cease substance abuse between teenager and young adult cocaine and/or crack users. Behaviors displayed by young adults involve greater physical, mental and social health damages. These findings reinforce the importance of public policy to act on prevention and promoting health, to increase protection factors among teenagers and lower risks and losses during adult life.

Heroin-based crack induces hyperalgesia through β-arrestin 2 redistribution and phosphorylation of Erk1/2 and JNK in the periaqueductal gray area

Continuous use of crack induces hyperalgesia which is related to drug tolerance. Despite cumulative evidence based on the growth rate of crack abuse, no serious study has been focused on the mechanisms of crack-induced hyperalgesia. This study aimed to elucidate whether extracellular signal-regulated kinases (Erk1/2)/β-arrestin pathways are involved in the crack-induced hyperalgesia. Fifty adult male Wistar rats were randomly divided into five groups: normal saline (NS), crack (0.9 mg/kg/day), heroin (1 mg/kg/day), crack + barbadin (100 μM), and heroin + barbadin groups, which received their intraperitoneal (i.p) treatments for four weeks. The thermal sensitivity was assessed using the hot-plate test. Moreover, phosphorylation of the Erk1/2 and JNK, as well as expression of protein kinase C-alpha (PKC-α), Mu-receptor (MOR), and β-arrestin 2 were determined in the whole lysate and membrane fraction using immunoblotting assay in the periaqueductal gray (PAG) area. The results demonstrated that chronic administration of crack and heroin significantly decreased hind-paw withdrawal latency compared to the NS group. Furthermore, crack as well as heroin administration increased phosphorylated Erk1/2 and JNK in the PAG. In addition, membrane β-arrestin 2 and PKC-α were significantly increased in the crack and heroin-received groups, while membrane MOR expression was decreased in the PAG. Nevertheless, co-administration of barbadin, an inhibitor of β-arrestin, and crack or heroin reversed all these changes. Our findings may partially confirm the role of β-arrestin 2 and PKC rearrangements, Erk1/2 and JNK phosphorylation in crack-induced hyperalgesia and provide potential therapeutic targets to attenuate crack-induced hyperalgesia.

Polydrug use among heroin users in Cleveland, OH

BACKGROUND

Since 2000, heroin use patterns have shifted within the United States. How this change may relate to polydrug use among local heroin users is unknown. Although polydrug use has been studied, user perceptions of drug use in terms of health risks, arrest risk, availability, cost, liking, and dependence have not been considered.

METHODS

Data are presented from a brief, face-to-face survey conducted in 2016 of 200 non-in-treatment heroin users from Cleveland, OH. We assessed the use of and attitudes on alcohol, marijuana, methamphetamine, heroin, crack cocaine, powder cocaine, and prescription drugs. We estimated polydrug (concurrent past month) use with cluster analysis and latent profiles. Regression analysis estimated the strength of relationships between attitudes and frequency of use.

RESULTS

We identified five clusters: Cluster 1 used heroin concomitantly with alcohol and occasionally crack; Cluster 2 used heroin and crack cocaine daily; Cluster 3 used heroin daily and almost exclusively; Cluster 4 used heroin and marijuana daily; and Cluster 5 were part-time drug users. Drug use frequency was associated with liking and being anxious when drugs could not be obtained. High perceived availability of heroin and cocaine and low cost facilitated polydrug use.

CONCLUSIONS

Understanding polydrug use clusters among heroin users is important for addressing the larger opioid epidemic. Users' perceptions of a drug's availability and cost appeared to facilitate polydrug use and justify more detailed future research on drug access.

Effects of DRD2 splicing-regulatory polymorphism and DRD4 48 bp VNTR on crack cocaine addiction

There is evidence that dopamine receptors D2 (DRD2) and D4 (DRD4) polymorphisms may influence substance use disorders (SUD) susceptibility both individually and through their influence in the formation of DRD2-DRD4 heteromers. The dopaminergic role on the vulnerability to addiction appears to be influenced by sex. A cross-sectional study with 307 crack cocaine addicts and 770 controls was conducted. The influence of DRD2 rs2283265 and DRD4 48 bp VNTR in exon 3 variants, as well as their interaction on crack cocaine addiction susceptibility and severity were evaluated in women and men separately. An association between the DRD2 T allele and crack cocaine addiction was found in women. In this same group, interaction analysis demonstrated that the presence of DRD2-T allele and concomitant absence of DRD4-7R allele were associated with risk for crack cocaine addiction. No influence of DRD2 and DRD4 variants was observed in men regarding addiction severity. This study reinforces the role of dopaminergic genes in externalizing behaviors, especially the influence of DRD2-DRD4 interaction on SUD. This is the fourth sample that independently associated the DRD2-DRD4 interaction with SUD itself or related disorders. In addition, our findings point out to a potential difference of dopaminergic neurotransmission across sex influencing addiction susceptibility.

A vibration analysis of a cracked micro-cantilever in an atomic force microscope by using transfer matrix method

In this paper, the effects of crack size and its location have been investigated on the free vibration of an atomic force microscopy (AFM) cantilever applying transfer matrix method. By modeling the crack as a torsional spring and considering the boundary conditions at the contact point with sample's surface, the AFM cantilever vibration behavior has been formulated. Afterwards, the characteristic equation has been derived applying the transfer matrix. At the end, the effects of crack size and its location have been investigated on the flexural resonant frequency and sensitivity of the AFM cantilever. The results indicate that the frequency and sensitivity would be maximum when the crack is approximately in the middle of the cantilever. Growing the crack size can result in the variations of either resonant frequency or sensitivity especially for more stiff samples.

Wastewater-based epidemiology in low Human Development Index states: bias in consumption monitoring of illicit drugs

Wastewater-based epidemiology is a promising approach worldwide, and its application is currently being developed in non-advanced economies. This technology, based on known toxicokinetic data initially used to detect illicit drugs in well-managed and maintained local sewer networks, has been extended to assess other products such as pesticides, alcohol, flame retardants, nicotine, and other substances. This technology is also used in countries with non-advanced economies. The present review aims to support future wastewater-based epidemiology in such countries by providing toxicokinetic data for locally used narcotic drugs that are expected or known to be emerging in developed countries, outlining the excretion differences due to human polymorphism, and summarising the practical obstacles due to the coverage, maintenance efficiency, or type of local sewage network.Case study feedback from Martinique is presented as an example; the Martinique field study complies with the Organisation for Economic Co-operation and Development standards for health issues, but not with regard to population and urban dynamics.

The effect of high temperature environment on rock properties-an example of electromagnetic radiation characterization

High temperature causes thermal damage to rock; the macrofracture and microfracture of rock can be produced under the action of temperature treatment. Under the influence of high temperature, the surrounding rock of deep underground engineering will suffer instability damage and cause serious harm to the people. In order to use the electromagnetic radiation (EMR) technology (a non-contact geophysical method) for evaluating the thermal stability of rock in underground thermal engineering applications, we established the EMR testing experimental system of rock under the action of a continuous heat source. The variation of EMR signals of rock under different temperatures was tested, and the EMR signals generates during the process of rock thermal deformation and thermal fracture, which were later analyzed. Under the action of a continuous heat source, the rock materials produced EMR signals with three kinds of frequencies. With the increase of rock temperature, the variation trends of EMR signals varied from the slow growth rate to the rapid growth rate, EMR signals can be divided into five stages. The increase of EMR signals is positively correlated with temperature, the Hurst exponent was higher than 0.7. The thermal stress was responsible for thermal deformation and fracture, thus generating the EMR signals. The research results have important guiding significance for the application of EMR technology to the evaluation of rock thermal stability.

Evaluation of morphology and size of cracks of the Interfacial Transition Zone (ITZ) in concrete containing fly ash (FA)

Interfacial Transition Zone (ITZ) of coarse aggregate cement matrix is commonly regarded as the weakest element of concrete. In this phase - the first cracks in the material are initiated, and the process of destruction of the composite begins. An improvement of the ITZ properties are positively influenced by the mineral additives used for the composite. One of such a substitute for a binder is, potentially hazardous industrial waste, siliceous fly ash (FA). In this paper the ITZ between aggregate and cement paste in concretes containing FA is considered. The paper presents the results of tests on the effect of the addition of FA in the amount of: 0, 20 and 30% by weight of cement on morphology and size of cracks of the ITZ in composites. In matured concretes the smallest cracks occur in composite with the 20% FA additive. It can be concluded that composites with 20% addition of FA are characterized by low permeability and therefore high durability. The results of tests carried out can be helpful in obtaining concrete with the highest possible: strength, durability and reliability of operation. Moreover, such procedures also cause a restriction storage of hazardous materials, i.e. FA - by 160 million tons per year.

Patterns of microcracking in apple fruit skin reflect those of the cuticular ridges and of the epidermal cell walls

Microcracks in the cuticle of developing apples are aligned with ridges on the inner cuticle surface and are indicative of stress-strain concentrations above the anticlinal cell walls. Microcracks occur in cuticles of most fruits. Growth strains are considered causal. In apples (Malus × domestica), microcracks usually form a mesh pattern similar to that formed by cuticular ridges. Ridge patterns are similar to those of the epidermal cells' anticlinal walls. Our aim was to identify the mechanistic bases for these pattern similarities. By quantifying ridge depth, ridge width, and the areas enclosed by ridges, we reveal the presence of major and minor ridges. Major ridges enclose two-to-four epidermal cells, minor ridges only one cell. There are similar and overlying patterns of microcracking on the cuticle's outer surface and of ridges on its inner surface-microcracks generally follow the outlines of the major ridges. In biaxial tensile tests at 20 kPa, strains were low and microcracks shallow, but at > 40 kPa, strains were higher and microcracks deeper. Microcracks traversing the cuticle are usually aligned with the anticlinal walls of the underlying epidermal cells. In general, increased skin strain is associated with increased skin transpiration. Transpiration increases are reversible for low strains but irreversible for high strains. The alignment of cuticular microcracks with the major ridges, and these with the anticlinal cell walls, indicates associated stress/strain concentrations.