Electrochemical determination of metformin via a carbon paste electrode modified with an Ag NPs/Cu2O/CuO-decorated bacterial nanocellulose composite.

Metformin (MET) is widely used in the treatment of diabetes either alone or in combination with other drugs, in drug discovery to evaluate the anti-diabetic potential of other drugs, and usually as a comparison compound in pharmacokinetics/pharmacodynamics studies. Measuring the concentration of this substance is very important both pre-clinically in different species and clinically in the medical monitoring of diabetic patients to prevent toxicity and ensure adherence to described drugs. Therefore, it is very important to develop a sensitive and selective method to measure MET. In this work, a new electrochemical biosensor based on a carbon paste electrode, modified with bacterial nanocellulose, copper oxide, and silver nanoparticles (Ag NPs/Cu2O/CuO/BNC/CPE) was used for high-sensitivity MET determination. The morphology and structure of this bio-nanocomposite were characterized by ATR-IR, FE-SEM, EDS, mapping, XRD, and DRS techniques. Compared with the CPE electrode, the Ag NPs/Cu2O/CuO/BNC/CPE modified electrode showed much higher electrocatalytic activities toward the oxidation of MET. The measurements were carried out by the cyclic voltammetry technique. Surface conductance was evaluated using the impedance technique. The results showed an increase in surface conductivity. The detection limit was obtained at 42.3 nM and two linear ranges 0.1-76 and 76-1000.0 µM were observed. The developed sensor had good features such as high sensitivity, reproducibility and repeatability, low detection limit, and fast response time. The obtained results from the real sample (MET tablets) were completely satisfactory.

WO3/Ag/ZnO S-scheme heterostructure thin film spinning disc photoreactor for intensified photodegradation of cephalexin antibiotic.

The presence of antibiotics in wastes and drinking water has led to serious environmental and health concerns, further necessitating the development of an advanced sustainable strategy to eliminate antibiotics from aquatic media. In this context, the present research reports the successful fabrication of a spinning disc photoreactor (SDPR) supported ZnO/Ag/WO3 S-scheme visible-light-driven thin-film photocatalyst to study the degradation of cephalexin (CPX) as a target pollutant under blue light irradiation. The optical, electrochemical and physicochemical characterization of the as-prepared thin-film samples were carried out by XRD, top-view FE-SEM, EDS-mapping, UV-Vis-DRS, contact angle, EIS, transient photocurrent, mott Schottky and AFM techniques. The rod shape morphology of the samples with moderate surface roughness, desirable hydrophobicity, low bandgap and remarkable band structure alignment confirmed the applicability of as-prepared thin-film with an average photon flux of 1.94 × 10-4-8.61 × 10-5 E's m-2 s-1. The use of a rotating catalytic disc impressively declined the photon propagation distance, decremented the probability of light absorption by the solution, and intensified the mass transfer rate. The maximum throughputs of 98.8% efficiencies for CPX degradation were achieved at a rotational speed of 180 rpm, the solution flow rate of 1.0 L min-1, the light intensity of 11 mW cm-2, and initial CPX concentration of 40 mg L-1, illumination time of 80 min, and pH of 6. Damkohler number (Da) value was found to be 1.23 × 10-2 at the optimum conditions, indicating the negligibility of the external mass transfer resistance in the SDPR. The photocatalytic mechanism was elucidated for finding the most operative radical species, suggesting the crucial role of ·O2- in photodegradation of CPX and a drastic improvement of the charge separation by S-scheme heterostructure and facilitation by Ag mediator. Findings indicated that the developed reusable and robust SDPR benefited from an s-scheme photocatalyst can be a promising technology for degradation of the organic compounds.

Spinning disc photoreactor based visible-light-driven Ag/Ag2O/TiO2 heterojunction photocatalyst film toward the degradation of amoxicillin.

The presence of antibiotics in waste and drinking water is causing increasing concern around the world, thereby an advanced sustainable technology needs to be developed to eliminate the antibiotics from water resources. Hence, an efficient spinning disc photoreactor (SDPR) equipped with visible light-activated Ag/Ag2O/TiO2 heterostructure thin film photocatalyst was assessed for the degradation of amoxicillin (AMX) as a typical antibiotic. The surface morphology, optoelectronic and structural features of Ag/Ag2O/TiO2 heterojunction were characterized by TEM, BET, mott Schottky, FESEM, EDS, AFM, XRD, UV-Vis-DRS, and contact angle measurements. Results confirm that Ag and Ag2O have a significant effect on the photocharge carrier separation and transfer of the as-developed photocatalyst system. The operative variables including illumination time, rotational speed, solution flow rate, aeration rate, pH, and initial AMX concentration were optimized by CCD. The results displayed the maximum AMX photodegradation (97.91%) could be achieved at optimal conditions involving illumination time of 80 min, a rotational speed of 225 rpm, the solution flow rate of 0.6 L/min, aeration rate of 20 L/min, pH = 6, and initial AMX concentration of 20 mg/L. Interestingly, more than 79% COD and 64% TOC were removed under optimum conditions during 80 min illumination time, respectively. Active species tests confirmed the dominant role of ·OH and ·O2- in AMX degradation. finally, the XRD pattern confirmed that the reusability assessments of the heterojunction film could successfully retain its stability for six consecutive photocatalytic degradation runs. This work demonstrates the feasibility of utilizing visible-light-driven thin-film photocatalysts in spinning disc photoreactors in treating the tenacious antibiotic pollutants.

Myocardial deformation assessed among heart failure entities by cardiovascular magnetic resonance imaging.

AIMS: Although heart failure (HF) is a leading cause for hospitalization and mortality, normalized and comparable non-invasive assessment of haemodynamics and myocardial action remains limited. Moreover, myocardial deformation has not been compared between the guideline-defined HF entities. The distribution of affected and impaired segments within the contracting left ventricular (LV) myocardium have also not been compared. Therefore, we assessed myocardial function impairment by strain in patients with HF and control subjects by magnetic resonance imaging after clinically phenotyping these patients. METHODS AND RESULTS: This prospective study conducted at two centres in Germany between 2017 and 2018 enrolled stable outpatient subjects with HF [n = 56, including HF with reduced ejection fraction (HFrEF), HF with mid-range ejection fraction (HFmrEF), and HF with preserved ejection fraction (HFpEF)] and a control cohort (n = 12). Parameters assessed included measures for external myocardial function, for example, cardiac index and myocardial deformation measurements by cardiovascular magnetic resonance imaging, left ventricular global longitudinal strain (GLS), the global circumferential strain (GCS) and the regional distribution of segment deformation within the LV myocardium, as well as basic phenotypical characteristics. Comparison of the cardiac indices at rest showed no differences neither between the HF groups nor between the control group and HF patients (one-way ANOVA P = 0.70). The analysis of the strain data revealed differences between all groups in both LV GLS (One-way ANOVA: P < 0.01. Controls vs. HFpEF: -20.48 ± 1.62 vs. -19.27 ± 1.25. HFpEF vs. HFmrEF: -19.27 ± 1.25 vs. -15.72 ± 2.76. HFmrEF vs. HFrEF: -15.72 ± 2.76 vs. -11.51 ± 3.97.) and LV GCS (One-way ANOVA: P < 0.01. Controls vs. HFpEF: -19.74 ± 2.18 vs. -17.47 ± 2.10. HFpEF vs. HFmrEF: -17.47 ± 2.10 vs. -12.78 ± 3.47. HFrEF: -11.41 ± 3.27). Comparing the segment deformation distribution patterns highlighted the discriminating effect between the groups was much more prominent between the groups (one-way ANOVA P < 0.01) when compared by a score combining regional effects and a global view on the LV. Further analyses of the patterns among the segments affected showed that while the LVEF is preserved in HFpEF, the segments impaired in their contractility are located in the ventricular septum. The worse the LVEF is, the more segments are affected, but the septum remains an outstanding location with the most severe contractility impairment throughout the HF entities. CONCLUSIONS: While cardiac index at rest did not differ significantly between controls and stable HF patients suffering from HFrEF, HFmrEF, or HFpEF, the groups did differ significantly in LV GLS and LV GCS values. Regional strain analysis revealed that the LV septum is the location affected most, with reduced values already visible in HFpEF and further reductions in HFmrEF and HFrEF.

The reliability of rifampicin resistance as a proxy for multidrug-resistant tuberculosis: a systematic review of studies from Iran.

In Iran, patients showing rifampicin (RIF) resistance detected by the Xpert® MTB/RIF assay are considered as candidates for multidrug-resistant tuberculosis (MDR-TB) treatment. Despite the fact that RIF resistance has been used as a proxy for MDR-TB, little is known about the proportion of isoniazid (INH) resistance patterns in RIF-resistant TB. We systematically searched MEDLINE, Embase, and other databases up to March 2017 for studies addressing the proportion of INH resistance patterns in RIF-resistant TB in Iran. The data were pooled using a random effects model. Heterogeneity was assessed using Cochran's Q and I2 statistics. A total of 11 articles met the eligibility criteria. Data analysis demonstrated that 33.3% of RIF-resistant isolates from new TB cases and 14.8% of RIF-resistant isolates from previously treated cases did not display resistance to INH. The relatively high proportion of INH susceptibility among isolates with RIF resistance indicated that RIF resistance may no longer predict MDR-TB in Iran. Therefore, the detection of RIF resistance by the Xpert MTB/RIF assay will require complementary detection of INH resistance by other drug susceptibility testing (DST) methods in order to establish the diagnosis of MDR-TB.

Epidemiological trends of dermatophytosis in Tehran, Iran: A five-year retrospective study.

OBJECTIVE: Dermatophytosis is the most frequent fungal infection all over the world and its frequency is constantly increasing. The aim of this study was to evaluate clinical features and epidemiological trends of dermatophytosis over the years 2010 to 2014 in Tehran, Iran. PATIENTS AND METHODS: A total of 13,312 patients clinically suspected of cutaneous fungal infections were examined. Skin scales, plucked hairs, nail clippings and sub-ungual debris were examined by direct microscopy and culture. Dermatophyte species were identified at the species level by a combination of morphological and physiological criteria. RESULTS: Direct microscopy confirmed a contamination rate of 19.7% (2622/13,312 cases) of which 1535 cases (58.5%) were culture positive distributed in male (1022 cases) and female (513 cases). The most commonly infected age group was the 30-39 years old. Tinea pedis (30.4%) was the most prevalent type of dermatophytosis followed by tinea cruris (29.8%) and tinea corporis (15.8%). Epidermophyton floccosum (31%) was the most prevalent causative agent, followed by Trichophyton rubrum (26.2%) and Trichophyton mentagrophytes (20.3%). CONCLUSION: Our results showed considerable distribution of dermatophytosis from zoophilic, anthropophilic and geophilic species among population with diverse age groups. Although anthropophilic fungi such as T. mentagrophytes, E. floccosum, and T. rubrum were the main etiologic agents of dermatophytosis, the prevalence of T. verrucosum showed a meaningful increase over the years, which highlights the importance of rural dermatophytosis mainly transmitted from large animals. This noticeable information improves our current knowledge about dermatophytosis and assists to establish effective prevention and therapeutic strategies to overcome the disease.

Removal of Pb(II) from aqueous solutions by graphene oxide aerogels.

This paper reports the application of graphene oxide aerogels (GOAs) for adsorption of lead(II) ions from aqueous solutions. The aerogels were fabricated from graphene oxide (GO) colloidal suspensions by unidirectional freeze drying method. The synthesized GO powders, as well as the aerogels, were thoroughly characterized by various techniques. The experimental data showed that the kinetic of adsorption followed a pseudo-second-order model with sharp lead(II) ions uptake within the first 90 min. Kinetic data analysis revealed that the adsorption process was controlled by film diffusion mechanism. The equilibrium data were best fitted to Langmuir model and the qmax was calculated to be as high as 158 mg/g. Thermodynamic analysis demonstrated that the adsorption process was spontaneous and endothermic with increased randomness at the solid-liquid interface. Experiments showed that almost all the adsorbed ions could desorb into the solution only by decreasing the solution pH below the isoelectric point of the adsorbent. In addition to abundant oxygen containing functional groups existing on the surface of GO sheets, high porosity and surface area of the aerogel are believed to be influential factors in the adsorption process.

Distribution of Hepatitis C virus genotypes in city of Mashhad, North-east of Iran.

PURPOSE: Six major hepatitis C virus genotypes have been characterised, which vary in their geographical distribution. The prevalence of hepatitis C virus (HCV) in an area is not constant, and depends on the changes in route of infection, which may change over time. In this study, the distribution of HCV genotypes in Mashhad, the capital of Razavi Khorasan province in north-east of Iran was investigated. Mashhad is a holy city of Shiate Moslems, which attracts more than 20 million tourists and pilgrims every year. MATERIALS AND METHODS: Two hundred and seventy-eight HCV infected subjects (227 males and 51 females) were included in this study. HCV genotypes were analysed by type specific reverse transcriptase polymerase chain reaction (RT-PCR). RESULTS: Genotype 3a was detected in 49.6%, 1a in 36.3%, 1b in 12.6% and 2a in 0.4%. Two HCV genotypes were detected in 1.1% cases; 1a +3a in 1%, 3a + 1b in 0.4%. Genotypes 2b and 3b were not detected in any samples. CONCLUSION: We demonstrated that despite the previous reports on the frequency of HCV genotypes in Iran, 3a is the predominant genotype in Mashhad.

The molecular and antigenic tissue impact of viral infections on liver transplant patients with neonatal hepatitis.

BACKGROUND: Pathogenesis of neonatal hepatitis relates to various underlying causes including viral infections. Both hepatotropic and non-hepatotropic viruses may induce liver failures in infants before birth, during delivery, or shortly after birth. OBJECTIVES: The tissue impact of HCMV, HSV, HBV, HCV, and rotavirus and adenovirus infections was evaluated in studied infants with neonatal hepatitis. METHODS: The history of viral infections was analyzed in paraffin-embedded biopsy and autopsy tissues of 22 infants with neonatal hepatitis between years 1996 and 2007, retrospectively. The tissue molecular presentation of HBV, HCV, HCMV, HSV, adenovirus, and rotavirus was evaluated by different qualitative simple and nested PCR and RT-PCR protocols. Immunohistochemistry (IHC) method was used for studying the antigenic prevalence of HSV-1, 2; HBV, HCMV and adenovirus infections. Also the laboratory liver indices of all patients with neonatal hepatitis were analyzed. RESULTS: The HBV and HSV genomes were detected in 3 (14%) of 22 infants. The rotavirus and HCV-RNA and also the HCMV-DNA were detected separately in 1 (4%) of 26 paraffin-embedded autopsy and biopsy tissues. The HBV and HSV-1 specific antigens were separately diagnosed in 1 (4%) of 26 neonatal samples by IHC protocols. Also the HSV-2 antigen was seen in 5 (23%) of 22 liver autopsy and biopsy specimens. Co-infections with HCMV, HSV, HBV, HCV, and rotavirus were detected in these infants with hepatitis. CONCLUSION: Diagnosis of single and mixed molecular and antigenic traces of HCMV, HSV, HBV, HCV and rotavirus underlines the etiologic role of these viruses in clinical pathogenesis of neonatal hepatitis.

Etiology of DNA virus infections in liver transplant recipients with neonatal hepatitis.

Neonatal hepatitis is a syndrome of symptoms associated with a history that includes any type of infectious, genetic, toxic, or metabolic causation. Various infectious agents have been implicated in hepatic inflammation in neonates including bacterial and viral pathogens, especially DNA viruses. We used molecular and antigenic methods to evaluate the role of DNA viruses, such as hepatitis type B viruses (HBV), human cytomegalovirus (HCMV), herpes simplex virus (HSV), and adenovirus, in neonatal hepatitis complications. Twenty-six paraffin-embedded biopsy and autopsy tissues obtained between 1996 and 2007 from 22 infants with neonatal hepatitis were studied retrospectively. The genome prevalence of HBV, HCMV, HSV, and adenovirus were analysed using qualitative polymerase chain reaction (PCR) protocols. The antigenic presentation of HSV-1, HSV-2, HBV, HCMV, and adenovirus were evaluated using immunohistochemistry (IHC) methods. The HCMV genome was detected separately in 1 of 22 (4.5%) paraffin-embedded autopsy and biopsy tissues. Also 3/22 (13.6%) samples were infected with HBV and HSV genomes. HBV and HSV-1 antigens were present in 1/26 (4.5%) neonatal samples and HSV-2 antigens in 5/26 (22.7%) by IHC protocols, but adenovirus and HCMV antigens were not detected among samples from infants with neonatal hepatitis. Detection of separate co-infections of HSV, HCMV, and HBV genomes in autopsy and biopsy tissues of HBV and HSV-1 or HSV-2 antigens in these patients, showed the importance of these viral infections in clinical neonatal hepatitis.

Clinical value of esophageal motility testing.

Esophageal motility testing is the method of choice in evaluating esophageal motor disorders. Some physicians, however, question the clinical utility of esophageal motility testing, since the results are often normal in symptomatic patients. The clinical utility of esophageal motility testing is reviewed for patients with a complaint of noncardiac chest pain, dysphagia or symptoms of gastroesophageal reflux disease. Esophageal motility testing is particularly useful for evaluating patients with dysphagia, but less so for gastroesophageal reflux disease patients, and has little clinical utility in patients with noncardiac chest pain.

Manometric measurement of anal canal resting tone: comparison of a rectosphincteric balloon probe with a water-perfused catheter assembly.

The purpose of this study was to compare the manometric measurements of a rectosphincteric balloon probe with a water-perfused catheter assembly on anal canal resting tone. Ten normal subjects (9 males, 1 female; mean age: 32 years; range 27-46 years) underwent station pull-through (0.5 cm/3 sec) beginning in the rectum with a water-perfused catheter assembly and a rectosphincteric balloon probe. Both the probe and the catheter were 5 mm in diameter. Three catheter side ports were perfused at 1 ml/min, and the rectal balloon was inflated with 5 ml of air. Measurements were taken on the same day in a counterbalanced manner. Data were analyzed on a computerized system. Mean (+/-SEM) values with the balloon were 82.3 (+/-8.9) mm Hg and 97.1 (+/-9.3) mm Hg with the catheter. These values were not significantly different (P=0.22). A significant order effect (P=0.04) was found where the first measure (101.3+/-10.2 mm Hg) was higher than the second measure (78.1+/-6.6 mm Hg), which was controlled for in the experimental design. A rectosphincteric balloon probe can accurately measure the resting tone of the anal canal compared to a water-perfused catheter assembly. Caution should be used when measuring anal canal resting tone early in an anorectal manometry assessment.

The effect of gravity on oesophageal peristalsis in humans.

Many mammalian species including non-human primates consume water in a body position not aided by gravity and it has been conjectured that oesophageal peristalsis overcomes gravity in humans. The purpose of this study was to determine the effects of gravity on oesophageal peristalsis in humans in response to water swallows. Six females (30-43 years old) and six males (27-46 years old) without oesophageal symptoms underwent oesophageal motility testing with intraluminal microtransducers placed 5, 7.5, 10 and 15 cm above the lower oesophageal sphincter. Subjects received ten 5 mL water swallows every 30 sec in the supine, standing, and head down (30 degrees) prone positions which were counterbalanced. Oesophageal contractile pressure (115, 98, 126 mmHg), duration (3.5, 3.0, 3.7 sec), onset velocity (4.7, 4.9, 4.7 cm sec-1), peak velocity (5.1, 4.8, 4.1 cm sec-1), average upstroke (dP/dT) (78, 75, 84 mmHg sec-1), or maximum upstroke (132, 120, 141 mmHg sec-1) were not significantly different among the head down prone, upright and supine positions, respectively. The frequency of abnormal contractile activity was statistically different among the positions. More abnormal contractions (i.e. simultaneous, retrograde, non-transmitted) occurred in the upright position (26%) when compared to either the supine (12%, P = 0.005) or head down prone (13%, P = 0.013) positions. The oesophagus tends to function normally to water swallows when unassisted by gravity. Oesophageal peristaltic dysfunction to water swallows may be more pronounced when assisted by the force of gravity.