Thermodynamic and Kinetic study of the removal of Cu2+ and Pb2+ ions from aqueous solution using Fe7S8 nanomaterial

In the present study, pyrrhotite (Fe7S8) was investigated for the removal of Pb2+ and Cu2+ ions from aqueous solution. The Fe7S8 material was prepared through a solvothermal method and was characterized using XRD. The average particle size for the nanomaterial was determined to be 29.86 ± 0.87 nm using XRD analysis and Scherrer\u27s equation. Batch studies were performed to investigate the effects of pH, time, temperature, interfering ions, and the binding capacity of Pb2+ and Cu2+ ions to the Fe7S8 nanomaterial. During the pH profile studies, the optimum pH for the binding of Pb2+ and Cu2+ was determined to be pH 5 for both cations. Isotherm studies were conducted from which the thermodynamics and binding capacities for both Cu2+ and Pb2+ were determined. The binding capacity for Pb2+ and Cu2+ binding to the Fe7S8 were determined to be 0.039 and 0.102 mmol/g, respectively at 25°C. The thermodynamic parameters indicated a ΔG for the sorption of Pb2+ ranged from 5.07 kJ/mol to -2.45 kJ/mol indicating a non-spontaneous process was occurring. Whereas, the ΔG for Cu2+ ion binding ranged from 9.78 kJ/mol to -11.23 kJ/mol indicating a spontaneous process at higher temperatures. The enthalpy indicated an endothermic reaction was occurring for the binding of Pb2+ and Cu2+ to the Fe7S8 nanomaterial with ΔH values of 55.8 kJ/mol and 153.5 kJ/mol, respectively. Furthermore, the ΔS values for the reactions were positive indicating an increase in the entropy of the system after metal ion binding. Activation energy studies indicated the binding for both Pb2+ and Cu2+ occurred through chemisorption

Migrando do Parodox para o Interbase: a experiência do AINFO.

O objetivo do trabalho é relatar a experiência na migração do sistema de automação das bibliotecas da Embrapa - AINFO, em Paradox para o interbase, versào gratuita com código aberto, disponibilizado pela Borland Software Corporation em setembro de 2000. O método utilizado foi o de estudar a viabilidade, performance e aplicação de componentes de acesso nativo Interbase Ex´press (IBX) e Interbase Objects (IBO) que dispensam a Borland Database Engine (BDE) para conexão do sistema ao banco de dados.bitstream/CNPTIA/9205/1/RELATORIOTECNICO12int.pd

Multistate product traceforward investigation to link imported romaine lettuce to a US cyclosporiasis outbreak – Nebraska, Texas, and Florida, June–August 2013

During June–August 2013, 25 US states reported 631 cyclosporiasis cases including Nebraska and Iowa where a regional investigation implicated common-source imported salad mix served in two chain restaurants. At least two common-origin growing fields were likely sources of contaminated romaine lettuce. Using producer- and distributor-provided data, we conducted a grower-specific traceforward investigation to reveal exposures of ill US residents elsewhere who reported symptom onset during 11 June–1 July 2013, the time period established in the Nebraska and Iowa investigation. Romaine lettuce shipped on 2–6 June from one of these Mexico-origin growing fields likely caused cyclosporiasis in 78 persons reporting illness onsets from 11 June to 1 July in Nebraska, Texas, and Florida. Nationwide, 97% (314/324) of persons confirmed with cyclosporiasis with symptom onset from 11 June to 1 July 2013 resided in 11 central and eastern US states receiving approximately two-thirds of romaine lettuce from this field. This grower’s production practices should be investigated to determine potential sources of contamination and to develop recommendations to prevent future illnesses

Artificial Intelligence for Caries Detection: Value of Data and Information.

If increasing practitioners' diagnostic accuracy, medical artificial intelligence (AI) may lead to better treatment decisions at lower costs, while uncertainty remains around the resulting cost-effectiveness. In the present study, we assessed how enlarging the data set used for training an AI for caries detection on bitewings affects cost-effectiveness and also determined the value of information by reducing the uncertainty around other input parameters (namely, the costs of AI and the population's caries risk profile). We employed a convolutional neural network and trained it on 10%, 25%, 50%, or 100% of a labeled data set containing 29,011 teeth without and 19,760 teeth with caries lesions stemming from bitewing radiographs. We employed an established health economic modeling and analytical framework to quantify cost-effectiveness and value of information. We adopted a mixed public-private payer perspective in German health care; the health outcome was tooth retention years. A Markov model, allowing to follow posterior teeth over the lifetime of an initially 12-y-old individual, and Monte Carlo microsimulations were employed. With an increasing amount of data used to train the AI sensitivity and specificity increased nonlinearly, increasing the data set from 10% to 25% had the largest impact on accuracy and, consequently, cost-effectiveness. In the base-case scenario, AI was more effective (tooth retention for a mean [2.5%-97.5%] 62.8 [59.2-65.5] y) and less costly (378 [284-499] euros) than dentists without AI (60.4 [55.8-64.4] y; 419 [270-593] euros), with considerable uncertainty. The economic value of reducing the uncertainty around AI's accuracy or costs was limited, while information on the population's risk profile was more relevant. When developing dental AI, informed choices about the data set size may be recommended, and research toward individualized application of AI for caries detection seems warranted to optimize cost-effectiveness

Increasing Strength and Muscle Mass in HIV+ Men Recovering from Substance Abuse

The combination of substance (drug and/or alcohol) abuse and infection with human immunodeficiency virus (HIV) can result in the development of several co-morbidities, including muscle wasting. Resistance training could, therefore, be an important tool in the treatment of substance addiction/abuse and HIV. PURPOSE: The purpose of this study was to examine the effect of resistance training on measures of muscle mass and strength in the context of co-occurring substance abuse and HIV. METHODS: Seventeen untrained men (Mean ± SD: 42 ± 11 years, 89.7 ± 16.0 kg, 179.7 ± 9.1 cm, 18.9 ± 5.5 %fat) who are infected with HIV and enrolled in an in-patient substance addiction/abuse treatment program completed six weeks of either resistance training (RT) (three sessions per week) or no-exercise prescription (Control). Before (Pre) and after (Post) the 6-week period, anthropometric (e.g., body mass, skinfolds, and circumferences), strength (bench press and isometric squat), and power (vertical jumps) measurements were obtained. RESULTS: Predicted bench press 1-repetition maximum (1-RM) increased significantly (p\u3c0.05) for RT (Pre: 73.4 ± 23.4 kg; Post: 85.0 ± 30.4 kg) but not for Control (Pre: 54.9 ± 24.6 kg; Post: 57.3 ± 27.0 kg). Peak isometric squat force increased significantly for RT (Pre: 2627 ± 1071 N; Post: 2892 ± 1171 N) but not for Control (Pre: 2411 ± 675 N; Post: 2394 ± 592 N). Peak vertical jump power also increased significantly for RT (Pre: 35.9 ± 3.5 W·kg-1; Post: 36.2 ± 5.0 W·kg-1) but not for Control (Pre: 33.9 ± 3.9 W·kg-1; Post: 35.7 ± 4 W·kg-1). Muscle mass increased significantly for RT (Pre: 46.4 ± 8.2 kg; Post: to 50.5 ± 8.1 kg) but not for Control (Pre: 46.9 ± 13.0 kg; Post: 47.8 ± 12.4 kg). Upper arm and forearm circumference increased only for RT. No adverse effects of the resistance training program were observed. CONCLUSION: Resistance training for six weeks increases muscle strength and power, and induces muscle hypertrophy, in men who are infected with HIV and recovering from substance abuse. These findings support the efficacy for including resistance training in the standard of care for men with HIV undergoing in-patient treatment for substance addiction/abuse

25-hydroxyvitamin D concentrations are lower in patients with positive PCR for SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), with a clinical outcome ranging from mild to severe, including death. To date, it is unclear why some patients develop severe symptoms. Many authors have suggested the involvement of vitamin D in reducing the risk of infections; thus, we retrospectively investigated the 25-hydroxyvitamin D (25(OH)D) concentrations in plasma obtained from a cohort of patients from Switzerland. In this cohort, significantly lower 25(OH)D levels (p = 0.004) were found in PCR-positive for SARS-CoV-2 (median value 11.1 ng/mL) patients compared with negative patients (24.6 ng/mL); this was also confirmed by stratifying patients according to age >70 years. On the basis of this preliminary observation, vitamin D supplementation might be a useful measure to reduce the risk of infection. Randomized controlled trials and large population studies should be conducted to evaluate these recommendations and to confirm our preliminary observation

Electrochemically synthesized mesoporous thin films of ZnO for highly efficient dye sensitized solar cells

Abstract In this work, nanostructured thin films of ZnO were electrochemically grown on FTO substrates. The morphology was tuned by modifying the synthesis parameters. The synthesis was carried out by applying Zn(NO3)·6H2O as the sole component of the aqueous electrolyte, avoiding the use of capping agents. The composition and morphology of the prepared ZnO were characterized by energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM), respectively. The as-deposited films were applied as electrodes in dye sensitized solar cells (DSCs). The performance of the cells was investigated by J×V curves and IPCE (incident photon to charge carrier efficiency) measurements. The SEM analysis demonstrated a direct relationship between ZnO morphology and Zn precursor concentration. It has been shown that the lower the concentration is, the more porous the morphology is. Increasing the amount of dye adsorbed on the ZnO decreased the power conversion efficiency of the final DSCs. The best cell presented the following parameters: open circuit voltage VOC=0.59V, short circuit current JSC=7.64mA/cm2, fill factor FF=50.41%, and power conversion efficiency PCE=2.27%

Polystyrene perturbs the structure, dynamics, and mechanical properties of DPPC membranes: An experimental and computational study

Synthetic plastic oligomers can interact with the cells of living organisms by different ways. They can be intentionally administered to the human body as part of nanosized biomedical devices. They can be inhaled by exposed workers, during the production of multicomponent, polymer-based nanocomposites. They can leak out of food packaging. Most importantly, they can result from the degradation of plastic waste, and enter the food chain. A physicochemical characterization of the effects of synthetic polymers on the structure and dynamics of cell components is still lacking. Here, we combine a wide spectrum of experimental techniques (calorimetry, x-ray, and neutron scattering) with atomistic Molecular Dynamics simulations to study the interactions between short chains of polystyrene (25 monomers) and model lipid membranes (DPPC, in both gel and fluid phase). We find that doping doses of polystyrene oligomers alter the thermal properties of DPPC, stabilizing the fluid lipid phase. They perturb the membrane structure and dynamics, in a concentration-dependent fashion. Eventually, they modify the mechanical properties of DPPC, reducing its bending modulus in the fluid phase. Our results call for a systematic, interdisciplinary assessment of the mechanisms of interaction of synthetic, everyday use polymers with cell membranes