Fast Self-Healing at Room Temperature in Diels-Alder Elastomers

Despite being primarily categorized as non-autonomous self-healing polymers, we demonstrate the ability of Diels-Alder polymers to heal macroscopic damages at room temperature, resulting in complete restoration of their mechanical properties within a few hours. Moreover, we observe immediate partial recovery, occurring mere minutes after reuniting the fractured surfaces. This fast room-temperature healing is accomplished by employing an off-stoichiometric maleimide-to-furan ratio in the polymer network. Through an extensive investigation of seven Diels-Alder polymers, the influence of crosslink density on self-healing, thermal, and (thermo-)mechanical performance was thoroughly examined. Crosslink density variations were achieved by adjusting the molecular weight of the monomers or utilizing the off-stoichiometric maleimide-to-furan ratio. Quasistatic tensile testing, dynamic mechanical analysis, dynamic rheometry, differential scanning calorimetry, and thermogravimetric analysis were employed to evaluate the individual effects of these parameters on material performance. While lowering the crosslink density in the polymer network via decreasing the off-stoichiometric ratio demonstrated the greatest acceleration of healing, it also led to a slight decrease in (dynamic) mechanical performance. On the other hand, reducing crosslink density using longer monomers resulted in faster healing, albeit to a lesser extent, while maintaining the (dynamic) mechanical performance.

Calculation of IFT in porous media in the presence of different gas and normal alkanes using the modified EoS

Gas injection can increase oil recovery because the gas-oil interfacial tension is less than the water-oil interfacial tension (IFT) and tends to zero in the miscibility state. However, little information has been provided on the gas-oil movement and penetration mechanisms in the fracture system at the porosity scale. The IFT of oil and gas in the porous medium changes and can control oil recovery. In this study, the IFT and the minimum miscibility pressure (MMP) are calculated using the cubic Peng-Robinson equation of state that has been modified using the mean pore radius and capillary pressure. The calculated IFT and MMP change with the pore radius and capillary pressure. To investigate the effect of a porous medium on the IFT during the injection of CH₄, CO₂, and N₂ in the presence of n-alkanes and for validation, measured experimental values in references have been used. According to the results of this paper, changes in IFT vary in terms of pressure in the presence of different gases and, the proposed model has good accuracy for measuring the IFT and the MMP during the injection of hydrocarbon gases and CO₂. In addition, as the average radius of the pores gets smaller, the interfacial tension tends to lower values. This effect is different with increasing the mean size of interstice in two different intervals. In the first interval, i.e. the R_p from 10 to 5000 nm, the IFT changes from 3 to 10.78 mN/m and in the second interval, i.e. the R_p from 5000 nm to infinity, the IFT changes from 10.78 to 10.85 mN/m. In other words, increasing the diameter of the porous medium to a certain threshold (i.e. 5000 nm) increases the IFT. As a rule, changes in IFT affected by exposure to a porous medium affect the values of the MMP. In general, IFT decreases in very fine porous media, causing miscibility at lower pressures.

Modeling of the movement of rich gas in a porous medium in immiscible, near miscible and miscible conditions

Gas injection is one of the most common enhanced oil recovery techniques in oil reservoirs. In this regard, pure gas, such as carbon dioxide (CO₂), nitrogen (N₂), and methane (CH₄) was employed in EOR process. The performance of pure gases in EOR have been investigated numerically, but till now, numerical simulation of injection of rich gases has been scared. As rich gases are more economical and can result in acceptable oil recovery, numerical study of the performance of rich gases in EOR can be an interesting subject. Accordingly, in the present work the performance of rich gases in the gas injection process was investigated. Methane has been riched in liquefied petroleum gas (LPG), natural gas liquid (NGL), and Naphtha. Afterwards, the process of gas injection was simulated and the effect of injection fluids on the relative permeability, saturation profile of gas, and fractional flow of gas was studied. Our results showed that as naphtha is a heavier gas than the two other ones, IFT of oil-rich gas with naphtha is lower than other two systems. Based our results, gas oil ratio (GOR) and injection pressure did not affect the final performance of injection gas that has been riched in NGL and LPG. However, when GOR was 1.25 MSCF/STB, rich gas with naphtha moved with a higher speed in the domain and the relative permeability of each fluid and fractional flow of gas were affected. The same result was achieved at higher injection pressure. When injection pressure was 2000 psi, movement of gas with higher speed in the domain, alteration of relative permeability and changes in the fractional flow of gas were obvious. Therefore, based on our result, injection of naphtha with low pressure and high GOR was suggested for considered oil.

Cooperative Adaptive Model-Free Control With Model-Free Estimation and Online Gain Tuning

In this article, a distributed adaptive model-free control algorithm is proposed for consensus and formation-tracking problems in a network of agents with completely unknown nonlinear dynamic systems. The specification of the communication graph in the network is incorporated in the adaptive laws for estimation of the unknown linear and nonlinear terms, and in the online updating of the elements in the main controller gain matrix. The decentralized control signal at each agent in the network requires information about the states of the leader agent, as well as the desired formation variables of the agents in a local coordinate frame. These two sets of variables are provided at each agent by utilizing two recently proposed distributed observers. It is shown that only a spanning-tree rooted at the leader agent is enough for the convergence and stability of the proposed cooperative control and observer algorithms. Two simulation studies are provided to evaluate the performance of the proposed algorithm in comparison with two state-of-the-art distributed model-free control algorithms. With lower control effort as well as fewer offline gain tuning, the same level of consensus errors is achieved. Finally, the application of the proposed solution is studied in the formation-tracking control of a team of autonomous aerial mobile robots via simulation results.

Video Game Play Does Not Improve Spatial Skills When Controlling for Speed-Accuracy Trade-Off: Evidence From Mental-Rotation and Mental-Folding Tasks

Researchers have been divided on the efficacy of computerized cognitive training (CCT) for enhancing spatial abilities, transfer of training, and improving malleability of skills. In this study, we assessed the effects of puzzle video game training on subsequent mental rotation (MR) and mental folding (MF) performance among adults with no cognitive impairment. We assessed participants at baseline with the Shepard-Metzler MR test followed by the differential aptitude test: space relations MF test (i.e., far transfer). We ranked participants' skills on these pre-tests and used a matching technique to form two skill groups from which we then randomly assigned members of each skill group either to an experimental group or a wait-list control group. The experimental group played two puzzle video games closely related to two-dimensional and three-dimensional MR tasks during 4-week training sessions (total of 12 hour of video games). Post-training, participants completed the MR and MF tests again. Two months later, we re-assessed only the experimental group's spatial skills to explore the sustainability of the trained performance. In addition to response times (RT) and error scores (ES), reported separately, we combined these variables into rate correct scores (RCS) to form an integrated measure of potential speed-accuracy trade-offs (SAT). As a result, we did not find significant improvements in MR performance from CCT engagement, nor did participants show a transfer of skills obtained by practicing MR-related puzzle games to a MF task. Based on the current findings, we urge caution when proposing a game-based intervention as a training tool to enhance spatial abilities. We argue that separately interpreting individual test measures can be misleading, as they only partially represent performance. In contrast, composite scores illuminate underlying cognitive strategies and best determine whether an observed improvement is attributable to enhanced capacities or individual heuristics and learned cognitive shortcuts.

On admission hemoglobin and albumin, as the two novel factors associated with thrombosis in COVID-19 pneumonia

Introduction: The unrelenting storm of coronavirus disease (COVID-19) since late 2019 has turned into a crucial health matter of the globe. There is increasing evidence in terms of a hypercoagulable state by this infection. Objectives: The current study aims to clarify the association between thromboembolic events in COVID-19 and the patient, the infection and in-hospital related characteristics. Patients and Methods: The current case-control study has been conducted on 243 COVID-19 pneumonia patients including 83 cases with thrombotic events and 160 controls without thrombosis. The thrombotic events included deep venous thrombosis (DVT) (n=9), pulmonary thromboembolism (PTE) (n=48), acute myocardial infarction (AMI) (n=17), cerebrovascular accidents (CVA) (n=4) and arterial thrombosis (n=5). On admission, hemodynamic parameters, on admission laboratory assessments, mobility during hospitalization, type of oxygenation, intensive care unit (ICU) admission requirement and duration of ICU and also hospital stay were recorded in the checklist. Results: According to logistic regression assessment, on admission O2 saturation (OR: 0.97, 95% CI: 0.94-0.99), hemoglobin level (OR: 0.87, 95% CI: 0.77-0.97) and albumin level (OR: 0.53, 95% CI: 0.3-0.86) were independently correlated with thrombosis due to COVID-19. Other factors, including demographic, infection severity, laboratory and in-hospital characteristics, were not significantly associated with thrombotic events. Conclusion: Based on this study’s findings, hemoglobin and albumin levels were the independent factors associated with the thrombotic events in COVID-19 patients.

Hypophosphatemia after hemodialysis and its association with some clinical complications in patients with chronic kidney disease

Background

Beyond the adverse effects of hyperphosphatemia in patients with chronic kidney disease (CKD(, hypophosphatemia has also been proposed as a common challenge after dialysis. Therefore, the present study aimed to evaluate the serum phosphate level immediately after hemodialysis (HD) and its association with some clinical complications in CKD patients.

Methods

The present cross-sectional study was conducted on 54 eligible CKD patients undergoing regular hemodialysis. Blood samples were taken, prior to the start and immediately after the end of hemodialysis to determine the serum levels of urea, creatinine, sodium, potassium, phosphorus, PTH, blood sugar and albumin. Moreover, the clinical complications of patients including muscle cramps, nausea, vomiting, headache, confusion, weakness and inability to speak are assessed by a questionnaire, before and after HD.

Results

As we expected, the mean of serum creatinine, urea and phosphate levels significantly decreased after dialysis. Post-dialysis hypophosphatemia was graded as mild (3.5 > P ≥ 2.5 mg/dl), moderate (2.5 > P ≥ 1 mg/dl), and severe (<1 mg/dl) based on serum phosphate levels. The frequency of mild and moderate hypophosphatemia was 39.2% and 45.1 %, respectively. None of the participants had severe hypophosphatemia and 13.7% had normal phosphate levels. There was a significant correlation between post-dialysis hypophosphatemia and incidence of nausea and confusion after adjusting for confounding factors.

Conclusion

To our knowledge, this is the first time that the possible association of some of the post-dialysis clinical complications with hypophosphatemia was investigated. Future large-scale studies are required to confirm the association of post-dialysis hypophosphatemia with clinical complications.

Atherogenic index of plasma: A valuable novel index to distinguish patients with unstable atherogenic plaques

Background:

Plaque instability is a leading cause of morbidity and mortality in coronary artery disease (CAD) patients. Numerous efforts have been made to figure out and manage unstable plaques prior to major cardiovascular events incidence. The current study aims to assess the values of the atherogenic index of plasma (AIP) to detect unstable plaques.

Materials and Methods:

The current case-control study was conducted on 435 patients who underwent percutaneous coronary intervention due to chronic stable angina (stable plaques, n = 145) or acute coronary syndrome (unstable plaques, n = 290). The demographic, comorbidities, chronic medications, biochemical and hematological characteristics of the patients were entered into the study checklist. The baseline AIP was measured according to the formula of triglycerides/high-density lipoprotein logarithm. Binary logistic regression was applied to investigate the standalone association of AIP with plaque instability. Receiver operating curve (ROC) was depicted to determine a cut-off, specificity, and sensitivity of AIP in unstable plaques diagnosis.

Results:

AIP was an independent predictor for atherogenic plaque unstability in both crude (odds ratio [OR]: 3.677, 95% confidence interval [CI]: 1.521–8.890; P = 0.004) and full-adjusted models (OR: 15, 95% CI: 2.77–81.157; P = 0.002). According to ROC curve, at cut-point level of 0.62, AIP had sensitivity and specificity of 89.70% and 34% to detect unstable plaques, respectively (area under the curve: 0.648, 95% CI: 0.601–0.692, P < 0.001).

Conclusion:

According to this study, at the threshold of 0.62, AIP as an independent biomarker associated with plaque instability can be considered a screening tool for patients at increased risk for adverse events due to unstable atherosclerotic plaques.

Prognostic significance of lung diffusion capacity and spirometric parameters in relation to hemodynamic status in heart transplant candidates

INTRODUCTION

Investigations have described a correlation between the severity of heart failure and the severity of pulmonary function abnormalities. In this study, we investigated the association of resting spirometric parameters, lung diffusion for carbon monoxide (DLCO), and the transfer coefficient (KCO) with hemodynamic variables and outcomes in a cohort of heart transplant candidates.

MATERIAL AND METHODS

Between January 2018 and January 2020, a total of 100 patients with advanced heart failure who were scheduled for right heart catheterization (RHC) as a pre-transplant evaluation measure were enrolled. Spirometry and DLCO were performed in all patients within 24 hours of their RHC. All selected patients were followed for a median (IQR) time of 6 (2-12) months. The end points of interest were heart failure-related mortality and a combined event involving HF-related mortality, heart transplantation (HTX), and need for the placement of a left ventricular assist device (LVAD).

RESULTS

Among 846 patients scheduled for RHC, a total of 100 patients (25% female) with a mean (SD) age of 38.5 (12.8) were enrolled. There was a significant correlation between FEV1/FVC and CVP (r = -0.22, p = 0.02), PCWP (r = -0.4, p < 0.001), mPAP (r = -0.45, p < 0.001), and PVR (r = -0.32, p = 0.001). The cardiac output correlated with DLCO (r = 0.3, p = 0.008). Spirometry parameters, DLCO parameters, and hemodynamic parameters did not correlate with the combined event. Among the several variables, only PVR had an independent association with the combined event.

CONCLUSION

Both mechanical and gas diffusion parameters of the lung were not associated with outcomes in the homogeneous group of heart transplant candidates.

Two-dimensional germanium islands with Dirac signature on Ag2Ge surface alloy

Two-dimensional (2D) Dirac materials have attracted intense research efforts due to their promise for applications ranging from field-effect transistors and low-power electronics to fault-tolerant quantum computation. One key challenge is to fabricate 2D Dirac materials hosting Dirac electrons. Here, monolayer germanene is successfully fabricated on a Ag₂Ge surface alloy. Scanning tunneling spectroscopy measurements revealed a linear energy dispersion relation. The latter was supported by density functional theory calculations. These results demonstrate that monolayer germanene can be realistically fabricated on a Ag₂Ge surface alloy. The finding opens the door to exploration and study of 2D Dirac material physics and device applications.

Cardiac Echinococcosis Associated with Other Organ Involvement: Report of Two Challenging Cases

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Cardiac echinococcosis is a rare but potentially fatal manifestation of hydatid disease.

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Antiparasitic agents with surgical cyst excision is the treatment of choice.

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Heart team decision-based management is warranted in cases of other organ involvement.

Comparison of Cognitive Rehabilitation versus Donepezil Therapy on Memory Performance, Attention, Quality of Life, and Depression among Multiple Sclerosis Patients

BACKGROUND

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system that affects cognitive performance and leads to depression and decreased quality of life (QOL). The current study aims to assess the effects of cognitive rehabilitation versus donepezil therapy on memory, attention, depression, and QOL in MS patients compared to placebo and control groups.

METHODS

Eighty MS patients were randomly selected from parallel randomized trials and divided into four groups: A: cognitive rehabilitation (10 sessions of 120 minutes), B: control (no intervention), C: donepezil (10 mg daily), and D: placebo. Patients received the intervention for three months. They were assessed for cognitive status, depression, and QOL prior to the intervention and immediately after that using abbreviated mental test (AMT), prospective and retrospective memory questionnaire (PRMQ), everyday memory questionnaire (EMQ), digit span, MSQOL-54, and second edition Beck depression inventory (BDI). We compared scores between groups after the intervention, as well as the progression of scores in every single group.

RESULT

s. The cognitive rehabilitation group showed improvement in EMQ, RPMQ, digit span, physical and mental health subscales of MSQOL54, and depression (P < 0.05). We observed the same effect for donepezil except for the digit span test (P = 0.15). Intergroup comparison of scores showed the superiority of cognitive rehabilitation over donepezil in digit span, depression, and mental health scores.

CONCLUSION

Both donepezil and cognitive rehabilitation effectively improve memory performance, attention, depression, and QOL in MS patients. Cognitive rehabilitation is superior altogether. This study is registered with the Iranian registry of clinical trials http://clinicaltrials.gov/ct2/show/IRCT2016042227522N1.

The Association of Sleep Duration and Quality with Heart Rate Variability and Blood Pressure

BACKGROUND

The current study was conducted to evaluate the relation of sleep duration and quality with blood pressure (BP) and heart rate variability (HRV).

MATERIALS AND METHODS

This cross-sectional study was carried out in 2017 among 260 staff of a university hospital in Isfahan, Iran. They were selected by multi-stage random method from different wards. Time domain spectral analysis was used to measure a number of HRV parameters. The long-term components of the HRV were estimated using the standard deviation of the normal-to-normal interval (SDNN). The square root of the mean squared differences of successive NN intervals (RMSSD) was calculated by statistical time domain measurements; SNN50, and PNN50 were measured. Pittsburg sleep quality index (PSQI) questionnaire was used to assess sleep quality.

RESULTS

Higher PSQI score correlated with lower SDANN rise (OR=0.92). Fairly bad to very good subjective sleep quality had association with lower SDANN (OR=0.43). Very high sleep latency to very low sleep latency ratio had association with lower SDANN (OR=0.39) and lower PNN50 (OR= 0.44). Sleep duration and HRV parameters had no significant association. Fairly bad sleep efficiency to very good sleep efficiency ratio was correlated with lower SDANN (OR= 0.29). Very high daytime dysfunction to very low daytime dysfunction ratio had correlation with lower SDANN (OR=0.35). Very bad compared to very good subjective sleep quality had significant correlation with higher Heart rate (HR) (B=0.03). Very high sleep latency compared to no sleep latency was associated with higher HR (B=4.74). Very high compared to very low amount of sleep disturbances correlated with higher SBP levels (B=15.2). Using sleep medication less than once a week compared with no history of taking such drugs was associated with higher HR (B=16.4).

CONCLUSION

Our findings showed that poor sleep quality are adversely associated with HRV, HR and BP. This finding should be considered in clinical and preventive recommendations.

Incidence of psoriasis in patients with active systemic lupus erythematosus

Introduction: Concomitant onset of active systemic lupus erythematosus (SLE) and psoriasis is rare; however, due to the common skin involvement in both and exacerbation of psoriasis with antimalarial medications used for SLE, it is crucial to investigate the concomitant occurrence of both diseases. Objectives: The present study aims to investigate the incidence of psoriasis in people with active SLE. Patients and Methods: The present cross-sectional study was performed on 148 patients with active SLE from 2015 to 2017. Lupus activity was evaluated based on systemic lupus erythematosus disease activity index-2K (SLEDAI-2K), and then, the incidence of psoriasis in patients was investigated. Patients’ demographic information was recorded in the relevant checklist. Results: The mean score of SLEDAI-2K was 14.10±19.77. The duration of SLE was significantly associated with the SLEDAI-2K score (P=0.001, r = 0.294). Psoriasis incidence was remarkably correlated with the gender of patients with SLE (P=0.019). An insignificant association was found between the coincidences of SLE with psoriasis considering the factors, including age, SLE duration, and mean SLEDAI-2K score. Conclusion: Patients’ mean age, SLE duration, and disease activity score were not correlated with concomitant psoriasis among SLE patients; however, we found that males were more prone to concomitant SLE and psoriasis.

Detection of Minimal Hepatic Encephalopathy in Iranian Patients with Cirrhosis

BACKGROUND

Minimal hepatic encephalopathy (MHE) is the mildest type of hepatic encephalopathy in patients with cirrhosis. Patients with MHE have normal clinical and physical examination but they show some neurocognitive dysfunctions that affect their quality of life negatively. The aim of the current study is to diagnose MHE in patients with cirrhosis and its associated factors.

METHODS

This is a cross-sectional study on 120 known cases of cirrhosis referred to hospitals affiliated to Isfahan University of Medical Sciences during 2014-17. The patients’ cirrhosis severity was evaluated using laboratory tests and physical examinations based on MELD (Model for End-stage Liver Disease) and Child-Pugh criteria. The patients’ demographics were filled in a checklist. All included patients with cirrhosis were asked to respond to the questions of Psychometric Hepatic Encephalopathy Score (PHES) test.

RESULTS

Mean age of the patients was 51.2 ± 9.7 years. 62 (51.7%) patients were men and 58 (48.3%) patients were women. The mean score of the patients based on MELD criteria was 14.03 ± 6.09. 26.7% of the patients presented MHE. Mean age of the patients with MHE was statistically less than the patients without MHE (p value < 0.001). Mean score of MELD criteria among the patients with diagnosis of MHE was significantly higher than the other group (p value < 0.001). The patients’ Child class was statistically associated with MHE (p value < 0.001). Men were significantly more affected than women (p value = 0.03).

CONCLUSION

MHE was associated with MELD score and Child class of the patients with cirrhosis. The noticeable point was reversible association of age with MHE. Further studies are recommended.

A case-control study of risk factors for hepatitis B infection: A regional report among Isfahanian adults

Background:

Hepatitis B is one of the major causes of mortality among viral diseases. To reduce morbidity rate and increase knowledge of people about potential risk factors, the aim of this study was to determine the prevalence of hepatitis B among the general population and the risk factors associated with hepatitis B virus (HBV) infection in Isfahan, Iran.

Materials and Methods:

In a case–control study, 314 HBV-infected patients and 557 healthy participants were recruited. Data on demographics, immunization history, medical history, family medical history, life history, therapeutic factors, and behavioral risk factors were collected through a standard checklist. Chi-square and logistic regression were used for univariate and multivariable analyses.

Results:

Our results showed that among sociodemographic variables, higher age, being male, lower economic status, and lower educational attainments increased the risk of affecting by HBV (odds ratio [OR] >1, P < 0.001); furthermore, Iranian and no immigrant people showed higher significant risk of being affected by HBV. Multivariable logistic regression showed among medical, blood, and behavioral risk factors, family history of hepatitis (OR: 10.56; 95% confidence interval [CI]: 4.56–24.86), dental treatment history (OR: 4.30; 95% CI: 1.41–13.10), and hospitalization (OR: 2.94; 95% CI: 1.72–5.00).

Conclusion:

Our results demonstrated that there are still several risk factors for hepatitis B surface antigen infection among the Iranian adult population. Immunization programs should continue and focus on high-risk adults, and interventions should be directed toward to reduce risk factors associated with hepatitis B.

Viscous lidocaine solution versus lidocaine spray for pharyngeal local anesthesia in upper gastroesophageal endoscopy

Background:

Advantage of using local sedation during upper gastrointestinal endoscopy (UGE) is still challenging. In the current study, the effect of lidocaine spray versus lidocaine viscous solution for pharyngeal local anesthesia during UGE has been compared.

Materials and Methods:

This is a randomized clinical trial conducted on 130 patients conducting UGE in 2013. Patients were randomly divided into two groups of viscous lidocaine solution (Group V) and lidocaine spray (Group S). Patients’ tolerance, satisfaction, pain/discomfort, and anxiety (based on 11-point numerical score scale) and ease of endoscopy were compared.

Results:

Ease of procedure, patients’ tolerance, and patients’ satisfaction were not statistically different between two groups (P > 0.05). Patients’ pain/discomfort and anxiety during endoscopy were significantly different between groups (P < 0.05).

Conclusion:

As a conclusion, there was not any difference between two groups except for pain, discomfort, and anxiety that was higher in those who administered spray that might be due to the method of usage.

Effect of Vitamin E in Prevention of Intraventricular Hemorrhage in Preterm Neonates

Background

Germinal matrix-intraventricular hemorrhage (IVH) is the most common brain hemorrhage in preterm neonates. The importance of this hemorrhage lies in its severe complications. There is no definite treatment for IVH in neonates; therefore, the prevention of IVH should be considered. Some studies have shown that Vitamin E can probably decrease the risk of IVH and the other study has not shown its efficacy. The aim of this study is to evaluate the effects of Vitamin E on incidence and severity of IVH in preterm neonates.

Methods

This study is a randomized clinical trial conducted on 76 neonates with gestational age of ≤30 weeks in the Isfahan University of Medical Science. The neonates were divided into two groups. The group one was administered with 10 units of Vitamin E for 3 days and the second group with placebo. In the 4th and 7th days after birth, brain sonography was conducted to evaluate IVH. The presence of sepsis, incidence of necrotizing enterocolitis, and hypotension were examined.

Results

In this study, 76 neonates with the mean age of 28.49 ± 1.46 weeks participated. The incidence of hemorrhage in the 4th day was 26.3% in cases and 42.1% in controls with no significant difference (P = 0.3). The findings of the second sonography reported the incidence of IVH in 17.1% of cases and 36.8% of control group.

Conclusions

Based on findings of the current study, Vitamin E use did not significantly decrease IVH in neonates. Further studies with larger sample size are needed.

Distributed adaptive model-free cooperative control for a network of generic unknown nonlinear systems

In this article, a distributed model-free consensus control is proposed for a network of nonlinear agents with unknown nonlinear dynamics, unknown process disturbances, and white noise measurement disturbances. Here, the purpose of the control protocol is to first synchronize the states of all follower agents in the network to a leader and then track a reference trajectory in the state space. The leader has at least one information connection with one of the follower agents in the network. The design procedure includes adaptive laws for estimating the unknown linear and nonlinear terms of each agent’s dynamics. The salient feature of the proposed control scheme is that each agent’s estimation is a model-free adaptive law, that is, the need for regressor or linear-in-parameter basis is alleviated. In addition, without requiring direct connection to the leader, the leader’s control input can still be reconstructed by virtue of a robust observer which can be defined in a distributed manner in the network. The entire design procedure is analyzed successfully for the stability using Lyapunov stability theorem. In addition, it is shown that the proposed distributed controller includes an optimal term. Besides, a modified Kalman filter is added to eliminate the measurement noise. Finally, the simulation results on three networks of unknown nonlinear systems are presented. Moreover, a comparative study is presented to evaluate the proposed algorithm against a model-based cooperative control algorithm.

Prevalence of cardiometabolic risk factors in a nationally representative sample of Iranian children and adolescents: the CASPIAN-V Study

Introduction: This study presents the prevalence of cardiometabolic risk factors in a nationally representative sample of Iranian children and adolescents. Methods: This multi-centric study was conducted in 2015 among 4200 students aged 7-18 years. They were selected by multistage cluster sampling from 30 provinces of Iran. Anthropometric indices, biochemical and clinical parameters were measured. Results: The mean of weight, height, waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), and fasting blood glucose (FBG) was higher in boys than in girls (P < 0.05). The mean of triglyceride (TG), total cholesterol (TC) and low-density lipoprotein (LDL) levels were higher in girls than in boys (P < 0.05). The mean of weight, height, WC, SBP, DBP, alanine transaminase (ALT) and body mass index (BMI) was higher in urban than in rural residents (P < 0.05). Overall, 16.1%, 9.4% and 11.4% were underweight, overweight and obese. Abdominal obesity was documented in 21.6% of boys and 20.5% of girls. Low HDL-C was the most prevalent abnormality of lipid profile (29.5%) followed by high serum TGs (27.7%). Low HDL-C was more prevalent in boys than in girls (32.7% vs. 26%, respectively, P < 0.05). Prevalence of obesity and overweight were higher in girls than in boys (P < 0.05). The prevalence of obesity and overweight, abdominal obesity, and low HDL-C were higher in urban than in rural residents (P < 0.05). Conclusion: We found considerably high prevalence of some cardiometabolic risk factors including overweight and obesity, low HDL-C and hypertriglyceridemia in Iranian children and adolescents. The current findings underscore the necessity of intensifying health interventions for primordial and primary prevention of non-communicable diseases from early life.

The pathologic and diagnostic in magnetic resonance imaging of brain and cervical spine of patients with neuromyelitis optica spectrum disorder

Background: Neuromyelitis optica spectrum disease (NMOSD) is a chronic inflammatory demyelinating disorder that involves central nervous system (CNS) with high affinity for involvement of optic nerve and spinal cord. In current study, due to high prevalence of NMOSD in Isfahan, Iran, we have aimed to assess brain and spine magnetic resonance imaging (MRI) of patients with NMOSD. Methods: This cross-sectional study was performed on 62 patients with diagnosis of NMOSD, who referred to MS clinic of Kashani hospital, Isfahan City, during 2015-17. Patients' age, age of onset, primary brain and spine MRI findings, and expanded disability status scale (EDSS) were recorded in check list. Patients underwent new brain and spine MRI. Data were analyzed with SPSS software. Descriptive data were reported by mean ± standard deviation (SD). Results: 62 known cases of NMOSD including 9 (14.5%) men and 53 (85.5%) women with mean age of 34.32 ± 10.26 years, mean age of onset of 28.03 ± 12.09 years, and mean EDSS of 2.63 ± 1.55 were assessed. 33.9% of patients were anti-neuromyelitis optica (NMO) antibody seropositive. Longitudinal extensive transverse myelitis (LETM) and segmental spinal lesions were found in 66.1% and 29.0% of patients, respectively. Diagnostic NMO brain lesions and posterior periventricular lesions were seen in 38.7% and 67.7% of patients, respectively. Two patients had tumefactive lesions. Conclusion: In current study, we found high rate of posterior periventricular lesions in brain MRI and segmental lesions in spine MRI of both anti-NMO antibody seropositive and seronegative patients. As these lesions are not in NMOSD diagnosis criteria, more considerations are recommended. In addition, tumefactive lesions in patients with NMOSD were an exciting finding of this study that should be discussed about more.

Evaluation of Thompson's quadricepsplasty results in patients with knee stiffness resulted from femoral fracture

Background:

Posttraumatic and/or postsurgical knee stiffness is one of the orthopedic complications which is difficult to be treated and can affect individual's life negatively. The aim of this study is to investigate the results of quadricepsplasty in patients with knee stiffness resulted from femoral fracture.

Materials and Methods:

This is a cross-sectional study on all patients with femoral fracture which has caused knee flexion limitation referred to Kashani and Al-Zahra Hospitals in Isfahan from January 2010 to March 2013. The type and site of fracture, joint extension, and fracture fixation technique were recorded. Moreover, the range of motion (ROM) before surgery, under general anesthesia, and 3- and 6-month postoperation were measured.

Results:

Among the patients, 13 had a simple fracture (48%) and 14 had a segmental fracture (51.9%). Considering the fracture site, 11, 10, and 6 patients had femoral (40.74%), supracondylar (37.3%), and femoral supracondylar (22.2%) fractures, respectively. The fracture fixation was performed by the plate, external, and Wagner fixation techniques for 24 (88.9%), 2 (7.4%), and 1 (3.7%) patients, respectively. The mean ROM before operation, under general anesthesia, and 3- and 6-month postoperation were determined to be 33.15° ± 24.73°, 122.60° ± 10.22°, 99.63° ± 16.52°, and 100.74° ± 15.67°, respectively. The mean ROM value at various stages was not similar (P < 0.001). The mean changes in the ROM were 79.2° ± 24.6° and 62.1° ± 19.7° in the cases with simple and segmental fractures, respectively. The mean changes in the knee ROM were significantly higher in simple fractures in comparison with the segmental femoral fracture (P = 0.03).

Conclusion:

We found Thompson's quadricepsplasty may successfully increase the range of knee flexion in knee fracture and also regardless of quadriceps time.

Neuromyelitis optica spectrum disease characteristics in Isfahan, Iran: A cross-sectional study

BACKGROUND

Neuromyelitis optica spectrum disease (NMOSD) is a severe autoimmune demyelinating disorder of the central nervous system that throughout epidemiological data, it has not been completely determined. The aim of this study was to assess characteristics of NMOSD patients in Isfahan as one of the most prevalent cities for multiple sclerosis in Iran.

MATERIALS AND METHODS

Forty-five patients diagnosed as neuromyelitis optica (NMO) disease through 5 years enrolled in this study. Demographics and characteristics of disease such as Expanded Disability Status Scale (EDSS) score, disease duration, clinical symptoms, laboratory data, and magnetic resonance imaging findings (including T1, T2, and flair protocols) were recorded. NMO-immunoglobulin G serology assay was done in all of the patients by ELISA test.

RESULTS

Female to male ratio was 5.4:1. The mean age of disease onset was 29.8 ± 11.2 years. NMO antibody was positive in 24.4% of patients. The presenting symptoms were optic neuritis (55.5%), transverse myelitis (40%), and brainstem symptoms (4.5%). The interval between the first and second attack was 19.28 ± 31.27 months (range: 1 month to 17 years). The mean EDSS score of the patients was 2.8 ± 2.25. Frequency of long-extending cervical plaque was higher among men than women (85.7% vs. 57.9%).

CONCLUSION

Based on this study, the mean age of NMOSD onset among Isfahan population was considerably lower than other studies, and there was higher frequency of long-extending cervical lesion among male patients which needs more consideration in further studies.

Possible Role of Common Spices as a Preventive and Therapeutic Agent for Alzheimer's Disease

For centuries, spices have been consumed as food additives or medicinal agents. However, there is increasing evidence indicating the plant-based foods in regular diet may lower the risk of neurodegenerative diseases including Alzheimer disease. Spices, as one of the most commonly used plant-based food additives may provide more than just flavors, but as agents that may prevent or even halt neurodegenerative processes associated with aging. In this article, we review the role and application of five commonly used dietary spices including saffron turmeric, pepper family, zingiber, and cinnamon. Besides suppressing inflammatory pathways, these spices may act as antioxidant and inhibit acetyl cholinesterase and amyloid β aggregation. We summarized how spice-derived nutraceuticals mediate such different effects and what their molecular targets might be. Finally, some directions for future research are briefly discussed.

Increased B Regulatory Phenotype in Non-Metastatic Lymph Nodes of Node-Positive Breast Cancer Patients

Tumour-draining lymph nodes (TDLNs) are centre in orchestrating the immune responses against cancer. The cellularity and lymphocyte subpopulations change in the process of cancer progression and lymph node involvement. B lymphocyte subsets and their function in breast cancer-draining lymph nodes have not been well elucidated. Here, we studied the influence of tumour metastasis on the frequencies of different B cell subsets including naïve and memory B cells as well as those which are known to be enriched in the regulatory pool in TDLNs of 30 patients with breast cancer. Lymphocytes were obtained from a fresh piece of each lymph node and stained for CD19 and other B cell-associated markers and subjected to flow cytometry. Our investigation revealed that metastatic TDLN showed a significant decrease in active, memory and class-switched B cells while the frequencies of B cells with regulatory phenotypes were not changed. However, CD27(hi) CD25(+) and CD1d(hi) CD5(+) B regulatory subsets significantly increased in non-metastatic lymph nodes (nMLNs) of node-positive patients compared with node-negative patients. Our data provided evidence that in breast cancer, metastasis of tumour to axillary lymph nodes altered B cell populations in favour of resting, inactive and unswitched phenotypes. We assume that the lymphatic involvement may cause an increase in a subset of regulatory B cells in non-metastatic lymph nodes.

Germanene termination of Ge2Pt crystals on Ge(110)

We have investigated the growth of Pt on Ge(1 1 0) using scanning tunneling microscopy and spectroscopy. The deposition of several monolayers of Pt on Ge(1 1 0) followed by annealing at 1100 K results in the formation of 3D metallic Pt-Ge nanocrystals. The outermost layer of these crystals exhibits a honeycomb structure. The honeycomb structure is composed of two hexagonal sub-lattices that are displaced vertically by 0.2 Å with respect to each other. The nearest-neighbor distance of the atoms in the honeycomb lattice is 2.5  ±  0.1 Å, i.e. very close to the predicted nearest-neighbor distance in germanene (2.4 Å). Scanning tunneling spectroscopy reveals that the atomic layer underneath the honeycomb layer is more metallic than the honeycomb layer itself. These observations are in line with a model recently proposed for metal di-(silicides/)germanides: a hexagonal crystal with metal layers separated by semiconductor layers with a honeycomb lattice. Based on our observations we propose that the outermost layer of the Ge(2)Pt nanocrystal is a germanene layer.

Analysis of phenolic compounds in Matricaria chamomilla and its extracts by UPLC-UV

Chamomile (Matricaria chamomilla L.) is a widely used medicinal plant possessing several pharmacological effects due to presence of active compounds. This study describes a method of using ultra performance liquid chromatography (UPLC) coupled with photodiode array (PDA) detector for the separation of phenolic compounds in M. chamomilla and its crude extracts. Separation was conducted on C18 column (150 mm × 2 mm, 1.8 μm) using a gradient elution with a mobile phase consisting of acetonitrile and 4% aqueous acetic acid at 25°C. The method proposed was validated for determination of free and total apigenin and apigenin 7-glucoside contents as bioactive compounds in the extracts by testing sensitivity, linearity, precision and recovery. In general, UPLC produced significant improvements in method sensitivity, speed and resolution. Extraction was performed with methanol, 70% aqueous ethanol and water solvents. Total phenolic and total flavonoid contents ranged from 1.77 to 50.75 gram (g) of gallic acid equivalent (GAE)/100 g and 0.82 to 36.75 g quercetin equivalent (QE)/100 g in dry material, respectively. There was a considerable difference from 40 to 740 mg/100 g for apigenin and 210 to 1110 mg/100 g for apigenin 7-glucoside in dry material.

Evaluation of the accuracy of panoramic radiography in linear measurements of the jaws

BACKGROUND/OBJECTIVE

Panoramic radiography has a great place among imaging techniques because of its enormous advantages. One of the characteristics of an ideal imaging technique is to supply precise measurement. The purpose of the current study was to evaluate the accuracy of linear measurements of the jaws on panoramic radiographs.

PATIENTS AND METHODS

In this study, the vertical distances between the metal markers were measured by panoramic radiography in seven sites of two skulls in various head positions. Then the radiographic measurements were compared with the actual values.

RESULTS

Eighty three percent of the measurements were underestimated, 8.5% were overestimated on panoramic radiography and 8.5% of the measurements had no difference with the real measurements. Overestimation was not greater than 1 mm. The difference between actual and radiographic measurements was less in the posterior areas and in the mandible . In all head positions, the greatest difference between actual and radiographic measurements occurred in the anterior area.

CONCLUSION

Based on the results of this study, linear measurements on panoramic radiography are more reliable in the posterior areas and may be used in early clinical measurements.

Melting entropy of nanocrystals: an approach from statistical physics

Considering size effect on the equations obtained from statistical mechanical theories for the entropy of crystal and liquid phases, a new model has been developed for the melting entropy of nanocrystals, including the effects of the quasi-harmonic, anharmonic and electronic components of the overall melting entropy. Then with the use of our suggested new proportionality between the melting point and the entropy temperature (θ(0)), the melting entropy of nanocrystals has been obtained in terms of their melting point. Moreover, for the first time, the size-dependency of the electronic component of the overall melting entropy, arising from the change in the electronic ground-state of the nanocrystal upon melting, has been taken into account to calculate the melting entropy of nanocrystals. Through neglecting the effect of the electronic component, the present model can corroborate the previous model for size-dependent melting entropy of crystals represented by Jiang and Shi. The present model has been validated by the available computer simulation results for Ag and V nanoparticles. Moreover, a fairly constant function has been introduced which couples the melting temperature, the entropy temperature and the atomic density of elements to each other.

Spectrum of childhood nephrotic syndrome in Iran: A single center study

Nephrotic syndrome (NS) is a clinical entity characterized by massive loss of urinary protein (primarily albuminuria) leading to hypoproteinemia (hypoalbuminemia) and its result, edema. Hyperlipidemia, hypercholesterolemia, and increased lipiduria are usually associated. Although not commonly thought of as part of the syndrome, hypertension, hematuria, and azotemia may be present. This prospective cross-sectional study was performed on 44 children (with age of onset up to 14 years) with idiopathic nephrotic syndrome (INS) in our center during 2000-2007. The objectives were to study the clinical and biochemical parameters and the histopathological distribution of different subtypes of INS and drug-response pattern in these patients. The study group included 44 children. There were 29 (66%) boys and 15 girls (34%). The mean age was 4.87 +/- 3.24 years. Facial edema was found in 42 (95%), microscopic hematuria in 10 (23%), gross hematuria in 2 (4.5%), and hypertension in 5 (11.2%) patients. In children who underwent biopsy, focal segmental glomerulosclerosis was the most common pathologic finding (41%). Other subtypes included minimal change disease in three (18%), membranoproliferative glomerulonephritis in one (5.8%), diffuse proliferative glomerulonephritis in two (11.6 %), membranous glomerulonephritis in one (5.8%), and diffuse mesangial proliferation in three (17.5%) cases. At the time of hospitalization peritonitis was present in five (11.4%), pneumonia and upper respiratory infection (sinusitis) in eight (18%), and cellulites in two (4.5%) patients. Twenty nine patients (66%) were steroid sensitive, 9 (20.5%) steroid resistant, and 6 (13.5%) steroid dependent. Among patients with steroid-sensitive NS, 37% were nonrelapsers, 38.8% frequent relapsers, and 26.4% were infrequent relapsers. Differences seems to exist between season of incidence, suitable response to treatment with corticosteroids, and pathologic findings of biopsy in our study and other studies from Iran and other countries.

A province-based surveillance system for the risk factors of non-communicable diseases: A prototype for integration of risk factor surveillance into primary healthcare systems of developing countries

OBJECTIVES

To establish a surveillance system for risk factors of non-communicable diseases, develop a valid tool and methodology for surveillance surveys, and build capacity in 41 provincial surveillance sites to design and conduct the surveys and provide provincially interpretable baseline data.

STUDY DESIGN

Population-based national study.

METHODS

The World Health Organization's STEPwise approach to non-communicable disease surveillance was adapted to design a national risk factor surveillance model. The first national population-based and cross-sectional study was conducted in 2005 in 41 universities of medical sciences in all 30 provinces of Iran. This involved multi-stage cluster sampling from 25-64 year-old Iranians and non-institutionalized populations. A national technical unit at the Ministry of Health and Medical Education supervised all study processes including data management and analysis.

RESULTS

From the national results, the survey estimated that the prevalence of daily current smoking was 17.9%. Of the target population, 5% consumed at least five combined servings of fruit and vegetables per day. The median daily time spent undertaking transport-related physical activity (43.8 min) was significantly higher than the median time spent on work-related physical activity (27.5 min) or recreational physical activity (28.6 min). Overall, 54.7% of the target population were overweight or obese, and waist circumference was greater among women than men. The prevalence of hypertension was 23.8%, with a higher prevalence among women than men. In addition, 6% of the target population had a high fasting blood glucose (> or =126 mg/dl), and 45.1% had a total cholesterol level of at least 200 mg/dl.

CONCLUSION

Integration of province-based surveillance activities into the Iranian primary healthcare system is feasible. Provincial reports could provide a baseline picture of the most important risk factors for non-communicable diseases. There are several important risks with a prominent burden that may cause a progressive epidemic of major non-communicable diseases in the future in the absence of quality interventions.

Multicentric familial cardiac myxoma

Familial cardiac myxoma is a rare syndrome which constitutes approximately 10% or less of all myxomas. We describe a rare case of LA and LV mass simultaneously in a 35-year-old female presenting to our hospital for evaluation of recurrent cardiac myxoma. Echocardiography revealed both LA and LV mass. Surgery was done and histological findings confirmed the diagnosis of myxoma.

The usefulness of F-18 deoxyglucose whole-body positron emission tomography (PET) for re-staging of renal cell cancer

PURPOSE

The use of whole-body PET for re-staging of renal cell carcinoma has not been investigated. The aim of the current study was to examine the diagnostic accuracy and clinical usefulness of whole-body PET imaging for re-staging of renal cell cancer.

PATIENTS AND METHODS

Clinical PET was performed for re-staging in 36 patients with advanced renal cell cancer. Written reports of imaging studies (including CT, MRI, US, plain film and bone scan), patient history, and extensive chart notes were used to define the clinical stage before PET (pre-PET stage). The written PET report was used to define the clinical stage after PET (PET stage). Reports were used to determine the accuracy of PET for re-staging renal cell cancer and for defining biopsy proven lesions. Clinical parameters and biopsy proven lesions served as reference for the accuracy of PET for re-staging renal cell cancer.

RESULTS

PET classified the clinical stage correctly in 32/36 patients (89%) and was incorrect in 4/36 (11%) (sensitivity and specificity: 87% and 100%). In 20 patients, 25 suspicious lesions were biopsied within 3.2 +/- 6.7 months of the PET study. Of these, 17 were malignant and 8 were benign. PET correctly classified 21/25 (84%) of the biopsied lesions (sensitivity and specificity: 88% and 75%).

CONCLUSION

PET re-stages renal cell cancer with a diagnostic accuracy of 89%. Its diagnostic accuracy for classifying biopsy proven anatomic lesions as malignant or benign was 84%. These findings suggest that PET is useful in characterizing anatomic lesions of unknown significance in patients with renal cell cancer.

Conjunctival dysplasia in soldiers exposed to mustard gas during the Iraq-Iran war: scrape cytology

OBJECTIVE

To describe the conjunctival scrape cytology findings in Iraq-Iran war veterans exposed to mustard gas and to detect malignant transformation at an early stage.

STUDY DESIGN

Twenty-two male war veterans (29-54 years old) who were exposed to chemical bombing about 14 years earlier, formed the base of this study. All of them had chronic eye problems, such as dryness, conjunctival scarring and decreased visual acuity. Conjunctival scrape cytology was performed for cytologic study.

RESULTS

Among 22 cases of conjunctival scarring, 9 were diagnosed as dysplasia. Mild inflammation and squamous metaplasia were also noted. Squamous cell carcinoma was not identified.

CONCLUSION

Conjunctival scraping cytology is useful for the diagnosis of dysplasia in soldiers exposed to mustard gas during of the Iraq-Iran war. This method is also effective for follow-up study.

Subclassification of localized Leishmania lymphadenitis in fine needle aspiration smears

OBJECTIVE

To describe the cytologic findings of localized Leishmania lymphadenitis and discuss the differential diagnosis.

STUDY DESIGN

The study group consisted of 133 cases. All of them were diagnosed by fine needle aspiration (FNA) study. The ages ranged between 3 and 80 years, 102 were male and 31 female. Seventy lymph nodes were excised.

RESULTS

The FNA smears revealed a polymorphic population of cells composed of lymphocytes, histiocytes, giant cells, abnormal plasma cells and tingible body macrophages. Leishman-Donovan (LD) bodies were identified in all cases, but their number differed from case to case. Granulomas, dendritic cells, mast cells and lymphoglandular bodies were identified in a substantial number of cases. Depending upon the presence of characteristic cytologic findings, the cases were divided into five major groups: acute inflammation with giant cells, histiocytic granulomas, epithelioid cell granulomas, plasma cell type and mixed histioplasmacytic type.

CONCLUSION

Leishmaniasis is an uncommon cause of cervical lymphadenitis but should be considered in the differential diagnosis of unexplained lymphadenopathy in endemic countries. Demonstration of LD bodies is necessary for the diagnosis of this self-limited condition, for which no treatment is required.