Rapid screening of bacteriostatic and bactericidal antimicrobial agents against Escherichia coli by combining machine learning (artificial intelligence) and UV-VIS spectroscopy

Antibiotics are compounds that have a particular mode of action upon the microorganism they are targeting. However, discovering and developing new antibiotics is a challenging and timely process. Antibiotic development process can take up to 10-15 years and over $1billion to develop a single new therapeutic product. Rapid screening tools to understand the mode of action of the new antimicrobial agent are considered one of the main bottle necks in the antimicrobial agent development process. Classical approaches require multifarious microbiological methods and they do not capture important biochemical and organism therapeutic-interaction mechanisms. This work aims to provide a rapid antibiotic-antimicrobial biochemical diagnostic tool to reduce the timeframes of therapeutic development, while also generating new biochemical insight into an antimicrobial-therapeutic screening assay in a complex matrix. The work evaluates the effect of antimicrobial action through "traditional" microbiological analysis techniques with a high-throughput rapid analysis method using UV-VIS spectroscopy and chemometrics. Bacteriostatic activity from tetracycline and bactericidal activity from amoxicillin were evaluated on a system using non-resistant Escherichia coli O157:H7 by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), and UV-VIS spectroscopy (high-throughput analysis). The data were analysed using principal component analysis (PCA) and support vector machine (SVM) classification. The rapid diagnostic technique could easily identify differences between bacteriostatic and bactericidal mechanisms and was considerably quicker than the "traditional" methods tested.

Separation, reserve estimation and radioactivity responsibility of the economic heavy minerals of East El- Arish black sand, North Sinai, Egypt

Multi-heavy mineral separation techniques like density, magnetic, and electromagnetic techniques are followed by picking, grain counting, and mineralogical examinations conducted with an environmental scanning electron microscope (ESEM). These techniques have been applied to several drill hole (well) composite samples representing beach sand and dunes of East El-Arish area, North Sinai, Egypt. The results explain the remarkable enrichment in total heavy minerals (THM) of beach sand (4.4%) compared to sand dunes (2.6%): this is due to the natural concentration of the currents of the Mediterranean Sea. After characterizing the heavy minerals in terms of the abundance of each mineral species, the mean values of content relative to total economic heavy minerals (TEHM) were determined as 70.03% ilmenite, 3.81% leucoxene, 3.03% magnetite, 8.7% garnet, 10.6% zircon, 3.13% rutile, 0.37% monazite, and 0.31% titanite in the sand dune samples. The total economic heavy minerals in the beach samples were 64.08% ilmenite, 1.6% leucoxene, 2.84% magnetite, 18.16% garnet, 10.4% zircon, 2.18% rutile, 0.61% monazite, and 0.13% titanite. Monazite, thorite, zircon, and apatite are the main radioactive minerals in the study area. The combination of two specific characteristics of the studied monazite (relatively high Th-U content and high frequency) makes monazite the main contributor to radioactivity of the study area.

Radioactive risk assessment of beach sand along the coastline of Mediterranean Sea at El-Arish area, North Sinai, Egypt

Beach sand includes various levels of natural radioactivity, which can cause health effects. The natural radioactivity was measured in the beach sand along the coastline of the Mediterranean Sea at the east of the El-Arish area, Egypt. Using the HPGe spectrometer, the contribution of radionuclides ²²⁶Ra, ²³²Th and ⁴⁰K in the gamma emitted radiation illustrated that the ²²⁶Ra, ²³²Th and ⁴⁰K activity concentrations are 8.8 ± 3.9, 30.8 ± 12.2 and 106.9 ± 46.8 Bq kg^-1, respectively, which is lower than the reported worldwide limit 33, 45 and 412 Bq kg^-1. The radioactive hazards associated with the beach sand along the coastline of the Mediterranean Sea at the east of the El-Arish area were investigated. The obtained results among the radiological hazard parameters, the radium equivalent content (Ra_eq), the absorbed dose rate (D_air), annual effective dose (AED), external (H_ex) and internal (H_in) hazard indices were estimated. Moreover, the excess lifetime cancer risk (ELCR) and the annual gonadal dose equivalent (AGDE) were also computed and illustrated their values less than the recommended levels. Multivariate statistical approaches like Pearson correlation, the principal component analysis (PCA) and the hierarchical cluster analysis (HCA) were applied to investigate the correlation between the radionuclides and the corresponding radiological hazard variables. Based on the statistical analysis, the ²²⁶Ra and ²³²Th mainly contribute to the radioactive risk of beach sand. Finally, no significant risk of the public associated with utilizing beach sand in building materials.

OUP accepted manuscript

Background

Antimicrobial stewardship programmes (ASPs) have been widely implemented in medical practice to improve antimicrobial prescribing and reduce selection for multidrug-resistant pathogens.

Objectives

To implement different antimicrobial stewardship intervention packages in 135 veterinary practices and assess their impact on antimicrobial prescribing.

Methods

In October 2018, general veterinary clinics were assigned to one of three levels of ASP, education only (CON), intermediate (AMS1) or intensive (AMS2). De-identified prescribing data (1 October 2016 to 31 October 2020), sourced from VetCompass Australia, were analysed and a Poisson regression model fitted to identify the effect of the interventions on the incidence rates of antimicrobial prescribing.

Results

The overall incidence rate (IR) of antimicrobial prescribing for dogs and cats prior to the intervention was 3.7/100 consultations, which declined by 36% (2.4/100) in the implementation period, and by 50% (1.9/100) during the post-implementation period. Compared with CON, in AMS2 there was a 4% and 6% reduction in the overall IR of antimicrobial prescribing, and a 24% and 24% reduction in IR of high importance antimicrobial prescribing, attributable to the intervention in the implementation and post-implementation periods, respectively. A greater mean difference in the IR of antimicrobial prescribing was seen in high-prescribing clinics.

Conclusions

These AMS interventions had a positive impact in a large group of general veterinary practices, resulting in a decline in overall antimicrobial use and a shift towards use of antimicrobials rated as low importance, with the greatest impact in high-prescribing clinics.

Photovoltaic Performance of Thin-Film CdTe for Solar Cell Applications

In the current investigation, we report a theoretical study to acquire the highest feasible efficiency of cadmium telluride (CdTe) thin-films. It is well recognized that CdTe crystallizes in cubic zinc-blende structure and its direct band gap of 1.5 eV turned it out as a potential candidate for photovoltaic (PV) applications. Our calculations are founded on Shockley-Queisser (SQ) limit to simulate the open-circuit voltage, current density, and filling factor versus the variation of photon energy up to 4.0 eV. These key parameters of SQ change with the variation of energy between 0.3 to 3.5 eV. This is owing to the strong optical absorption (> 104 cm−1) and direct band gap of 1.5 eV, which make CdTe thin-film suitable for single junction solar cell and ideal for PV applications. It is observed that the optical absorption enhances as the thickness of the absorbed layer increases. This will effectively provide a theoretical support to the industry of global solar energy that is anticipated to be sustainable in the future.

Incidence of presenting complaints and diagnoses in insured Australian dogs

Knowledge of the most common presenting complaints and diagnoses in companion animals is valuable in preparing veterinary students and veterinarians to manage the most frequently observed conditions in clinical practice. Pet insurance databases provide access to large sample populations and have been previously used to describe disease incidence in companion animals. The aim of this study was to determine the incidence of presenting complaints and diagnoses in insured Australian dogs through the use of a pet insurance database. Analysis of a de-identified dataset containing pet insurance claims associated with presenting complaints and diagnoses from 488,472 insured Australian dogs insured in the years 2016 and 2017, was performed. Annual incidence rates of presenting complaints and diagnoses were calculated and expressed as, number of events per 1,000 dog years at risk. The presenting complaints with the highest incidence were vomiting (14.21 events per 1,000 dog years at risk in 2016, 15.80 events per 1,000 dog years at risk in 2017) and pruritus (8.79 events per 1,000 dog years at risk in 2016, 10.30 events per 1,000 dog years at risk in 2017). Presenting complaints affecting the gastrointestinal system were the most common (19.20 events per 1,000 dog years at risk in 2016, 20.77 events per 1,000 dog years at risk in 2017). The diagnoses with the highest incidence were otitis externa (34.12 events per 1,000 dog years at risk in 2016, 34.82 events per 1,000 dog years at risk in 2017) and dermatitis (28.05 events per 1,000 dog years at risk in 2016, 29.99 events per 1,000 dog years at risk in 2017). Diagnoses affecting the integument were the most common (216.56 events per 1,000 dog years at risk in 2016, 219.06 events per 1,000 dog years at risk in 2017). The results from this study can aid in the design of relevant veterinary curricula and may be helpful in prioritising research on common clinical conditions.

Serum leptin and homeostasis model assessment-IR as novel predictors of early liver fibrosis in chronic hepatitis B virus infection

BACKGROUND

The relationship between hepatitis B virus (HBV) infection, leptin and insulin resistance remains unclear. We hypothesised links between serum leptin and insulin resistance in non-diabetic patients with chronic viral hepatitis B infection and their relation to liver fibrosis.

METHODS

We recruited 190 untreated patients with chronic HBV infection and 72 healthy controls. Serum leptin, fasting glucose, insulin, liver function tests (LFTs), C-peptide and Homeostasis model assessment-IR (HOMA-IR) were measured/calculated by ELISA and standard techniques.

RESULTS

Serum leptin, C-peptide (both P < 0.001), HOMA-IR (P = 0.021) and several LFTs were increased in patients with chronic HBV-infection. In multivariate regression analysis, both HOMA-IR (P = 0.003) and leptin (P = 0.002) were significant independent predictors of HBV infection. There were significant positive correlations (P < 0.01) between leptin and HOMA-IR (r = 0.81), between serum leptin and METAVIR activity (r = 0.95), and between HOMA-IR and BMI (r = 0.75), fasting glucose (r = 0.005), and fasting insulin (r = 0.81). Several LFTs, glucose and insulin correlated modestly (r = 0.61-0.69, P < 0.05) with leptin.

CONCLUSION

Serum leptin may be related to the rate of fibrosis progression in nondiabetic patients with chronic HBV infection. Follow-up by serial measurement of serum leptin and HOMA-IR in non diabetic HBV-infected patients may be used as a non-invasive marker of early liver fibrosis.

Stabilized fabrication of anatase-TiO2/FeS2 (pyrite) semiconductor composite nanocrystals for enhanced solar light-mediated photocatalytic degradation of methylene blue

A novel visible light active TiO₂/FeS₂ semiconductor photocatalyst was synthesized by a simple wet chemical process. X-ray diffraction (XRD) was used to analyze the anatase TiO₂ and pyrite structures in FeS₂/TiO₂ nanocrystals. Scanning electron microscopy (SEM) confirmed the spherical morphology of composite nanocrystals. X-ray photoelectron spectroscopy (XPS) identified the Fe²⁺, S¹⁻, Ti⁴⁺, and O²⁻ oxidation states of relevant species. Energy dispersive X-ray (EDX) analysis was performed for compositional analysis. The measured band gap of the TiO₂/FeS₂ nanocomposite system was 2.67 eV, which is smaller than un-doped TiO₂ (3.10 eV) and larger than FeS₂ (1.94 eV). The photocatalytic activity of TiO₂/FeS₂ was significantly higher than pure FeS₂ for degrading methylene blue (MB) under solar light irradiation due to the increase in visible light absorption, reduction in band gap energy, and better election–hole pair separation. The photocatalytic degradation of MB was investigated under the influence of solution pH, dye concentrations, and varied catalyst dosage. The optimum degradation (100%) of MB was observed in 180 min and the photocatalysis of MB reduced as the dye concentrations in the solution increased from 15 to 75 mg L⁻¹. These results prove that the TiO₂/FeS₂ nanocomposite has the stability, recycling, and adaptability for its practical application as a visible light photocatalyst for wastewater treatment. TiO₂/FeS₂ showed increased degradation of the organic pollutant; which is confirmed by the increased rate of chemical reaction following pseudo first-order reaction kinetics with the highest rate constant value of 0.0408 m⁻¹ having highest R² value of 0.9981.

A novel visible light active TiO₂/FeS₂ semiconductor photocatalyst was synthesized by a simple wet chemical process.

Combined Heart and Kidney Transplantation: A 23-Year Experience

BACKGROUND

We report clinical experience with combined heart and kidney transplantation (HKTx) over a 23-year time period.

METHODS

From June 1992 to August 2015, we performed 83 combined HKTx procedures at our institution. We compared the more recent cohort of 53 HKTx recipients (group 2, March 2009 to August 2015) with the initial 30 previously reported HKTx recipients (group 1, June 1992 to February 2009). Pre-operative patient characteristics, peri-operative factors, and post-operative outcomes including survival were examined.

RESULTS

The baseline characteristics of the two groups were similar, except for a lower incidence of ethanol use and higher pre-operative left-ventricular ejection fraction, cardiac output, and cardiac index in group 2 when compared with group 1 (P = .007, .046, .037, respectively). The pump time was longer in group 2 compared with group 1 (153.30 ± 38.68 vs 129.60 ± 37.60 minutes; P = .007), whereas the graft ischemic time was not significantly different between the groups, with a trend to a longer graft ischemic time in group 2 versus group 1 (195.17 ± 45.06 vs 178.07 ± 52.77 minutes; P = .056, respectively). The lengths of intensive care unit (ICU) and hospital stay were similar between the groups (P = .083 and .39, respectively). In addition, pre-operative and post-operative creatinine levels at peak, discharge, 1 year, and 5 years and the number of people on post-operative dialysis were similar between the groups (P = .37, .75, .54, .87, .56, and P = .139, respectively). Overall survival was not significantly different between groups 2 and 1 for the first 5 years after transplant, with a trend toward higher survival in group 2 (P = .054).

CONCLUSIONS

The most recent cohort of combined heart and kidney transplant recipients had similar ICU and hospital lengths of stay and post-operative creatinine levels at peak, discharge, and 1 and 5 years and a similar number of patients on post-operative dialysis when compared with the initial cohort. Overall survival was not significantly different between the later and earlier groups, with a trend toward higher overall survival at 5 years in the more recent cohort of patients. In selected patients with co-existing heart and kidney failure, combined heart and kidney transplantation is safe to perform and has excellent outcomes.

Use of Anti-Thymocyte Globulin for Induction Therapy in Cardiac Transplantation: A Review

The most common causes of death after heart transplantation (HTx) include acute rejection and multi-organ failure in the early period and malignancy and cardiac allograft vasculopathy (CAV) in the late period. Polyclonal antibody preparations such as rabbit anti-thymocyte globulin (ATG) may reduce early acute rejection and the later occurrence of CAV after HTx. ATG therapy depletes T cells, modulates adhesion and cell-signaling molecules, interferes with dendritic cell function, and induces B-cell apoptosis and regulatory and natural killer T-cell expansion. Evidence from animal studies and from retrospective clinical studies in humans indicates that ATG can be used to delay calcineurin inhibitor (CNI) exposure after HTx, thus benefiting renal function, and to reduce the incidence of CAV and ischemia-reperfusion injury in the transplanted heart. ATG may reduce de novo antibody production after HTx. ATG does not appear to increase cytomegalovirus infection rates with longer prophylaxis (6-12 months). In addition, ATG may reduce the risk of lymphoproliferative disease and does not appear to confer an additive effect on acquiring lymphoma after HTx. Randomized, controlled trials may provide stronger evidence of ATG association with patient survival, graft rejection, renal protection through delayed CNI initiation, as well as other benefits. It can also help establish optimal dosing and patient criteria to maximize treatment benefits.

Similar Mortality and Morbidity of Orthotopic Heart Transplantation for Patients 70 Years of Age and Older Compared With Younger Patients

BACKGROUND

The upper age limit of heart transplantation remains controversial. The goal of the present study was to investigate the mortality and morbidity of orthotopic heart transplantation (HT) for recipients ≥70 compared with those <70 years of age.

METHODS

Of 704 adults who underwent HT from December 1988 to June 2012 at our institution, 45 were ≥70 years old (older group) and 659 were <70 years old (younger group). Survival, intraoperative blood product usage, intensive care unit (ICU) and hospital stays, and frequency of reoperation for chest bleeding, dialysis, and >48 hours ventilation were examined after HT.

RESULTS

The older group had 100% 30-day and 60-day survival compared with 96.8 ± 0.7% 30-day and 95.9 ± 0.8% 60-day survival rates in the younger group. The older and younger groups had similar 1-year (93.0 ± 3.9% vs 92.1 ± 1.1%; P = .79), 5-year (84.2 ± 6.0% vs 73.4 ± 1.9%; P = .18), and 10-year (51.2 ± 10.7% vs 50.2 ± 2.5%; P = .43) survival rates. Recipients in the older group had higher preoperative creatinine levels, frequency of coronary artery disease, and more United Network for Organ Sharing status 2 and fewer status 1 designations than recipients in the younger group (P < .05 for all). Pump time and intraoperative blood usage were similar between the 2 groups (P = NS); however, donor-heart ischemia time was higher in the older group (P = .002). Older recipients had higher postoperative creatinine levels at peak (P = .003) and at discharge (P = .007). Frequency of postoperative complications, including reoperation for chest bleeding, dialysis, >48 hours ventilation, pneumonia, pneumothorax, sepsis, in-hospital and post-discharge infections, were similar between groups (P = NS for all comparisons). ICU and hospital length of stays were similar between groups (P = .35 and P = .87, respectively). In Cox analysis, recipient age ≥70 years was not identified as a predictor of lower long-term survival after HT.

CONCLUSIONS

HT recipients ≥70 years old had similar 1, 5, and 10-year survival rates compared with younger recipients. Both patient groups had similar intra- and postoperative blood utilization and frequencies of many postoperative complications. Older and younger patients had similar morbidity and mortality rates following HT. Carefully selected older patients (≥70 years) can safely undergo HT and should not be excluded from HT consideration based solely on age.