Utilization of compressible hydrogels as electrolyte materials for supercapacitor applications.

Utilization of CoO@Co3O4-x-Ag (x denotes 1, 3, and 5 wt% of Ag) nanocomposites as supercapacitor electrodes is the main aim of this study. A new low-temperature wet chemical approach is proposed to modify the commercial cobalt oxide material with silver nanoparticle (NP) balls of size 1-5 nm. The structure and morphology of the as-prepared nanocomposites were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N2 adsorption-desorption measurements. Hydrogels known to be soft but stable structures were used here as perfect carriers for conductive nanoparticles such as carbons. Furthermore, hydrogels with a large amount of water in their network can give more flexibility to the system. Fabrication of an electrochemical cell can be achieved by combining these materials with a layer-by-layer structure. The performance characteristics of the cells were examined by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charge discharge (GCD). Cobalt oxide modified with 5 wt% Ag gave the best supercapacitor results, and the cell offers a specific capacitance of ∼38 mF cm-2 in two-electrode configurations.

Structural studies and selected physical investigations of LiCoO2 obtained by combustion synthesis.

Nanocrystalline powders of LiCoO2 were synthesized using a modified solution combustion method, and the effects of the annealing temperature (450-900 °C) on structure and composition were investigated using various methods, including XRD, SEM, EPR, and electrical studies. It was found that, as the process temperature increases, the value of the specific surface area decreases, and, hence, the size of the crystallites increases. XRD analysis showed that phase-pure LiCoO2 material was maintained without additional phases. EPR studies revealed the presence of two Ni3+ complexes resulting from Ni impurities. The electrical properties of the studied LiCoO2 samples were investigated by using impedance spectroscopy. Comparison of the effect of annealing temperature on electrical conductivity shows a very interesting behavior. As the annealing temperature increases, the DC conductivity value increases, reaching a maximum at a temperature of 500 °C. However, further increase in the annealing temperature causes a steady decrease in the DC conductivity.

Vanadium oxide nanorods as an electrode material for solid state supercapacitor.

The electrochemical properties of metal oxides are very attractive and fascinating in general, making them a potential candidate for supercapacitor application. Vanadium oxide is of particular interest because it possesses a variety of valence states and is also cost effective with low toxicity and a wide voltage window. In the present study, vanadium oxide nanorods were synthesized using a modified sol-gel technique at low temperature. Surface morphology and crystallinity studies were carried out by using scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy analysis. To the best of our knowledge, the as-prepared nanorods were tested with magnesium ion based polymer gel electrolyte for the first time. The prepared supercapacitor cell exhibits high capacitance values of the order of ~ 141.8 F g-1 with power density of ~ 2.3 kW kg-1 and energy density of ~ 19.1 Wh kg-1. The cells show excellent rate capability and good cycling stability.

Macroporous perovskite nanocrystal composites for ultrasensitive copper ion detection.

Accumulation of heavy metal ions, including copper ions (Cu2+), presents a serious threat to human health and to the environment. A substantial amount of research has focused on detecting such species in aqueous solutions. However, progress towards ultrasensitive and easy-to-use sensors for non-aqueous solutions is still limited. Here, we focus on the detection of copper species in hexane, realising ultra-sensitive detection through a fluorescence-based approach. To achieve this, a novel macroporous composite material has been developed featuring luminescent CsPbBr3 nanocrystals (NCs) chemically adhered to a polymerized high internal phase emulsion (polyHIPE) substrate through surface thiol groups. Due to this thiol functionality, sub-monolayer NC formation is realised, which also renders outstanding stability of the composite in the ambient environment. Copper detection is achieved through a direct solution based immersion of the CsPbBr3-(SH)polyHIPE composite, which results in concentration-dependent quenching of the NC photoluminescence. This newly developed sensor has a limit of detection (LOD) for copper as low as 1 × 10-16 M, and a wide operating window spanning 10-2 to 10-16 M. Moreover, the composite exhibits excellent selectivity among different transition metals.

Surface Modification of Nanocrystalline LiMn2O4 Using Graphene Oxide Flakes.

In this work, a facile, wet chemical synthesis was utilized to achieve a series of lithium manganese oxide (LiMn2O4, (LMO) with 1-5%wt. graphene oxide (GO) composites. The average crystallite sizes estimated by the Rietveld method of LMO/GO nanocomposites were in the range of 18-27 nm. The electrochemical performance was studied using CR2013 coin-type cell batteries prepared from pristine LMO material and LMO modified with 5%wt. GO. Synthesized materials were tested as positive electrodes for Li-ion batteries in the voltage range between 3.0 and 4.3 V at room temperature. The specific discharge capacity after 100 cycles for LMO and LMO/5%wt. GO were 84 and 83 mAh g-1, respectively. The LMO material modified with 5%wt. of graphene oxide flakes retained more than 91% of its initial specific capacity, as compared with the 86% of pristine LMO material.

Corrigendum to "Spectroscopic and structural properties of CeO2 nanocrystals doped with La3+, Nd3+ and modified on their surface with Ag nanoparticles" [Heliyon 7 (5) (May 2021) e06958].

[This corrects the article DOI: 10.1016/j.heliyon.2021.e06958.].

Solution combustion synthesis of a nanometer-scale Co3O4 anode material for Li-ion batteries.

A novel solution combustion synthesis of nanoscale spinel-structured Co3O4 powder was proposed in this work. The obtained material was composed of loosely arranged nanoparticles whose average diameter was about 36 nm. The as-prepared cobalt oxide powder was also tested as the anode material for Li-ion batteries and revealed specific capacities of 1060 and 533 mAh·g-1 after 100 cycles at charge-discharge current densities of 100 and 500 mA·g-1, respectively. Moreover, electrochemical measurements indicate that even though the synthesized nanomaterial possesses a low active surface area, it exhibits a relatively high specific capacity measured at 100 mA·g-1 after 100 cycles and a quite good rate capability at current densities between 50 and 5000 mA·g-1.

Spectroscopic and structural properties of CeO2 nanocrystals doped with La3+, Nd3+ and modified on their surface with Ag nanoparticles.

The purpose of this work is to present our efforts focused on applications of chemical synthesis of nanocrystalline cerium dioxide (CeO2) powders doped with La3+ ions and CeO2:Nd3+ modified, on their surface, with Ag nanoparticles (NPs). The synthesized powders were examined by X-ray powder diffraction (XRD), absorption, emission spectroscopy, scanning electron (SEM) and atomic force microscopy (AFM). The relations between crystallographic properties and stability of CeO2 compounds doped by La ions and surface-modified by Ag were studied. XRD patterns revealed that all studied samples are single-phase and crystallized in the cubic fluorite-type structure, in space group Fm-3m. The average crystallite sizes estimated by Rietveld method of series: La-doped CeO2 were in the range of 7-14 nm, and CeO2:1%Nd3+/n-Ag (n: 1- 5wt.%) were found to be in the range of 29-34 nm, respectively. The lattice parameter a for La-doped CeO2 powders varying from 5.416 to 5.482 Å with increasing content of La3+ ions from 0 to 20wt.%, respectively. For series of CeO2:Nd3+/n-Ag materials lattice parameter a was at the same level and in accordance with the standard value a0 = 5.411 Å (ICDD - 43-1002). The SEM and AFM observations depicted the grainy structure of all obtained CeO2-powder samples. The estimated grain size ranged from 50 to 500 nm. The diverse grain shapes and packing was remarked in the samples. According to our knowledge, the relationship between the structural, spectroscopic and morphological characteristics of CeO2 samples was presented in this work for the first time.

Selective attentional bias to food-related stimuli in healthy individuals with characteristics towards orthorexia nervosa.

PURPOSE: It has been argued that orthorexia nervosa (ON) is a unique type of disordered eating of food considered by the individual to be healthy. Given that in other eating disorder populations attentional preference for food-related cues influences eating behaviours, is it also likely that these biases may be a characteristic of ON tendency. METHODS: Eighty healthy individuals completed the ORTO-15 questionnaire (ON tendency), a modified Stroop task containing words related to healthy and unhealthy foods and perceived hunger levels pre- and post-testing. The ORTO-15 was used to identify participants within this sample who demonstrated more or less of the characteristics of ON. RESULTS: Results suggest that the presence of attentional bias to healthy, but not for unhealthy food-related stimuli independently predict increased ON tendency. Increased attentional bias towards healthy food-related stimuli is associated with increased scores on the ORTO-15. CONCLUSION: Attentional bias, as a deficit in information processing, towards healthy food-related stimuli accounts for variability in ON characteristics. LEVEL OF EVIDENCE: Level I, experimental study.

Understanding drinking among midlife men in the United Kingdom: A systematic review of qualitative studies.

OBJECTIVES: This study reviews qualitative research into the sociocultural meanings and subjective experiences that midlife men in the United Kingdom (UK) associate with their drinking. In the UK, average weekly alcohol consumption is highest among midlife men, and they are disproportionately affected by alcohol harm. There is increasing recognition that public health messages to support behaviour change must be based on an in-depth understanding of drinking motivations and experiences. STUDY DESIGN AND METHODS: Systematic literature review of studies exploring motivations for and experiences of drinking among UK men aged 45-60 using qualitative methodology. Medline, PsycINFO and the Social Science Citation Index were used, along with manual searches of key journals, Google searches and a call for evidence. The Critical Appraisal Skills Programme tool was used to quality-assess papers. Thematic synthesis was used to combine and analyse the data. RESULTS: From 5172 titles and abstracts (1995-2018), 11 publications were included, representing 6 unique studies. Five themes were identified: 'Drinking Motivations'; 'Drinking Justifications'; 'Drinking Strategies and Control'; 'Social Norms and Identity' and 'Harm'. Motivations for drinking among midlife men were associated with relaxation, socialising and maintenance of male friendships. They justified drinking as a choice and emphasised their ability to meet responsibilities, which they contrasted with 'problem drinkers'. Social norms governed drinking behaviours as an expression of masculinity. CONCLUSION: This review highlights the significance of the meanings and social importance of alcohol consumption among midlife men. Interventions using information and guidance should consider these when aiming to effectively influence the way this group drinks.

A focus on homocysteine in autism.

Homocysteine is an amino acid, which plays several important roles in human physiology. A wide range of disorders, including neuropsychiatric disorders and autism, are associated with increased homocysteine levels in biological fluids. Various B vitamins: B6 (pyridoxine), B12 (cobalamin), and B9 (folic acid) are required as co-factors by the enzymes involved in homocysteine metabolism. Therefore, monitoring of homocysteine levels in body fluids of autistic children can provide information on genetic and physiological diseases, improper lifestyle (including dietary habits), as well as a variety of pathological conditions. This review presents information on homocysteine metabolism, determination of homocysteine in biological fluids, and shows abnormalities in the levels of homocysteine in the body fluids of autistic children.

Bone mineral density, its predictors, and outcomes in peritoneal dialysis patients.

The objective of the present work was to assess bone mineral density (BMD) and its predictors in peritoneal dialysis (PD) patients, to check the history of those patients 4 years after the assessment, and to relate thoses outcome to BMD. We used dual-energy X-ray absorptiometry to measure BMD in 26 patients at the femoral neck (FN), and we related those measurements to demographic, nutrition, and laboratory data. Four years after the assessments, the outcomes of those patients were checked and related to BMD. In the study patients, the mean FN BMD was 0.842 +/- 0.137 g/cm2. Serum albumin, lean body mass, alkaline phosphatase (ALP), and treatment with acetylsalicylic acid were significant predictors for BMD in the first multivariate model. A second model included blood pH, serum phosphorus, serum creatinine, and age as significant BMD predictors. Hemoglobin or hematocrit could have replaced phosphorus as a BMD predictor The prevalences of abnormal values for BMD predictors in the study patients were phosphorus > 4.5 mg/dL, 69.2%; pH < 7.36, 53.8%; albumin < 3.5 g/dL, 46.1%; ALP > 104 IU/L, 23.1%; and hemoglobin < 11.0 g/ dL, 23.1%. In 8 patients, a successful renal transplantation occurred at 8.5 +/- 9.3 months; 9 patients died at 25.9 +/- 12.5 months; and 9 patients continued dialysis for a further 50.4 +/- 1.7 months. The highest BMD was found in the patients who underwent renal transplantation (0.962 +/- 0.110 g/cm2); the lowest BMD was found in the patients who died (0.737 +/- 0.100 g/ cm2, p = 0.001). In PD patients, low BMD indicates worse outcome. High prevalences of predictors for low BMD (age, poor nutrition status, metabolic acidosis, high phosphorus, anemia) also contribute to worse outcome in PD patients.

Vitamin supplementation reduces the level of homocysteine in the urine of autistic children.

Significant differences in homocysteine levels in the urine of autistic children are observed. We hypothesized that vitamin supplementation might reduce the level of urinary homocysteine. To rationalize such a hypothesis, analyses were performed using the gas chromatography/mass spectrometry method. The homocysteine level in the urine of autistic children was measured twice: (1) before vitamin supplementation (group C, 30 autistic children) and (2) after supplementation, with either folic acid and vitamins B(6) and B(12) (group A1, 24 autistic children) or vitamins B(6) and B(12) alone (group A2, 6 autistic children). The homocysteine level in the urine of autistic children before vitamin supplementation was 2.41 ± 1.10 mmol/mol creatinine (mean ± SD difference). After treatment, the homocysteine level was reduced to 1.13 ± 0.44 and 1.33 ± 0.39 mmol/mol creatinine for A1 and A2 groups, respectively. The intake of vitamins B(6) and B(12), together with folic acid, was found to be more effective in lowering the levels of urinary homocysteine than the intake of vitamins B(6) and B(12) alone. Our findings may lead to the recommendation of including vitamins B(6) and B(12) together with folic acid supplementation in the diets of children with autism.

Homocysteine level in urine of autistic and healthy children.

Homocysteine is an amino acid which plays several important roles in human physiology and is an important biomarker for possible deficiencies of various vitamins (vitamin B6 and B12, folic acid). In this work GC-MS method was used to determine the levels of homocysteine in the urine of autistic and healthy children. The levels of homocysteine in urine samples from 34 autistic and 21 healthy children were 2.36 ± 1.24 and 0.76 ± 0.31 (mmol∙mol⁻¹ creatinine), respectively. The higher level of homocysteine in autistic children may indicate deficiencies of folic acid and vitamins B6 and B12 in nutrition of these children. The results of this work were taken into consideration in the nutrition of autistic children treated in the Navicula Centre of Diagnosis and Therapy of Autism in Lódz (Poland).

Seroconversion rate to positivity for antibodies against core antigen of hepatitis B virus and duration of renal replacement therapy.

BACKGROUND: Prevalence of total antibodies against core antigen (anti-HBc) of hepatitis B virus (HBV) is greater in longer dialysed patients, but there are no data indicating a relationship between the higher seroconversion rate to anti-HBc positivity and longer renal replacement therapy (RRT) vintage prior to seroconversion. Our aim was to evaluate the association between RRT duration and seroconversion to anti-HBc positivity. METHODS: An incidence of anti-HBc was evaluated in 425 anti-HBc-negative intermittent haemodialysis (IHD) patients: Group I included patients who underwent first anti-HBc testing 31 days from first IHD session, and Group II or III included patients with RRT duration < 3 or ≥ 3 years, respectively. Anti-HBc testing was repeated every 6-12 months. Sex, age, RRT duration, anti-HCV, HCV RNA, ALT, ASP, GGT, full vaccination series against HBV with developed anti-HBs titre > 10 IU/L, hepatitis history and underlying kidney diseases were used as independent variables predicting seroconversion to anti-HBc positivity. RESULTS: Seroconversion rate to anti-HBc positivity was 2.59, 2.12 and 2.44 episodes/100 patient-years in Group I (n = 174), II (n = 170) and III (n = 80), respectively. In the entire group, there were 15 seroconversions to anti-HBc and one seroconversion to HBsAg positivity. The only variable predicting seroconversion in all HBsAg-negative patients (n = 424) was the lack of full vaccination series against HBV with developed anti-HBs titre > 10 IU/L maintained during the study (ß - 0.112, P = 0.04). CONCLUSIONS: Seroconversion rate to anti-HBc positivity is not related to duration of RRT treatment but to ineffective vaccination against HBV.

Determination of tryptophan in urine of autistic and healthy children by gas chromatography/mass spectrometry.

BACKGROUND: Tryptophan is an amino acid, which is responsible for the production of serotonin in the body. Lower levels of tryptophan may play a role in pediatric disorders. In this work the urinary level of tryptophan in autistic and healthy children was compared. MATERIAL/METHODS: The samples of urine were taken from 33 autistic children (10 on a restricted diet of gluten and casein free and 23 no diet) and 21 healthy children. The level of tryptophan was determined by gas chromatography/mass spectrometry (GC/MS). In this method tryptophan was derivatized and extracted simultaneously. The method was validated. RESULTS: Significantly lower relative urinary levels of tryptophan were obtained for both autistic children with a restricted diet 1.98±1.17 µg/mL (mean ±SD) and autistic children without a diet 7.44±1.33 µg/mL (mean ±SD) compared to healthy children 14.24±2.01 µg/mL (mean ±SD). The method has a limit of quantification (LOQ) of 0.15 µg/mL and a lower limit of detection (LOD) of 0.04 µg/mL for tryptophan in urine. CONCLUSIONS: This method is precise and sensitive for the detection of low concentrations of tryptophan and can be applicable to monitoring its level in human urine. Children with autism have a higher deficiency of tryptophan than the control group of healthy children. Lower levels of tryptophan may lead to the worsening of autistic symptoms such as mild depression and increased irritability.

Predictors of bone mineral density in dialyzed and non-dialyzed patients with chronic kidney disease.

In this study, we assessed predictors of bone mineral density (BMD) in chronic kidney disease (CKD) patients with declining renal function. Among the 106 patients enrolled, 26 were treated with peritoneal dialysis [PD: 15 women; age; 55.7 +/- 17.7 years; dialysis vintage: 16.6 months (range: 6.3 - 45.5 months)]; 60, with hemodialysis [HD: 26 women; age: 54.8 +/- 15.3 years; dialysis vintage: 36.9 months (range: 6.0 - 279.6 months)]; and 20 were in CKD stage 2 or 3 (11 women; age: 49.4 +/- 15.8 years). We measured BMD in the femoral neck. Anthropometric measurements assessing nutrition status and routine laboratory parameters were obtained. The femoral neck BMD was 0.842 +/- 0.137 g/ cm2 (PD patients), 0.813 +/- 0.204 g/cm2 (HD patients), and 0.988 +/- 0.197 g/cm2 (CKD patients). In a stepwise backward regression analysis with all patients included, sex, age, body mass index, serum albumin, creatinine, parathyroid hormone, blood pH, and dialysis treatment were significant predictors of BMD (corrected R2 for the model: 0.977), with blood pH being the most powerful predictor (beta = 0.872, p = 0.000). We expect better preservation of BMD in CKD patients more rigorously treated for acid-base imbalance.

Visfatin and endogenous secretory receptor for advanced glycation end-products in diabetic type 2 and non-diabetic patients undergoing intermittent hemodialysis.

BACKGROUND/AIMS: To examine plasma levels of visfatin and endogenous secretory receptor for advanced glycation end-products (esRAGE) in diabetic and non-diabetic patients treated with intermittent hemodialysis (IHD), and to explore the possible associations between them, insulin resistance evaluated by homeostasis model assessment for insulin resistance (HOMA-IR), as well as selected biochemical and anthropometric parameters. METHODS: The study was carried out in 65 IHD patients. Type 2 diabetic patients (n = 28) were included into group I, non-diabetics (n = 37)-into group II. The reference group included 25 healthy volunteers. RESULTS: There were no significant differences between group I and II in plasma level of visfatin and esRAGE. HOMA-IR was higher in group I than in group II. In both groups these parameters were higher than in healthy subjects. In group I, visfatin correlated with insulin concentration (r = 0.428, P = 0.023), HOMA-IR with esRAGE (r = -0.374, P = 0.049). In group II, esRAGE correlated with waist-to-hip ratio (r = -0.343, P = 0.037), HOMA-IR with body mass index (r = 0.499, P = 0.001) and LDL cholesterol (r = -0.384, P = 0.018). CONCLUSIONS: Serum concentrations of visfatin and esRAGE are increased in IHD patients. There is no difference in visfatin and esRAGE levels between diabetic and non-diabetic IHD patients. In diabetic IHD patients receiving insulin, lower esRAGE levels are associated with higher insulin resistance, whereas plasma visfatin level is positively related to plasma insulin concentration. Waist-to-height ratio is a significant determinant of plasma visfatin level and HOMA-IR. Insulin resistance seems to be a link between esRAGE and visfatin in IHD diabetics.

Total body mass is better than body mass index as a prognostic parameter for bone mineral density in dialyzed patients.

Assuming that nutrition status also influences bone mineral density (BMD) in dialyzed patients, we compared BMD in two groups of dialyzed patients: those with a body mass index (BMI) above 25 kg/m2 [group I: n = 20; 11 women; 19 on peritoneal dialysis (PD), 1 on hemodialysis (HD); age: 60.9 +/- 13.6 years; time on dialysis: 19.3 months (range: 6.5 - 45.7 months)], and those with a BMI below 25 kg/m2 [group II: n = 10; 7 women; 7 on PD, 3 on HD; age: 46.6 +/- 21.8 years; time on dialysis: 21.3 months (range: 6.3 - 59.6 months)]. Anthropometric indices of nutrition status and body composition by bioimpedance analysis were checked in all patients. We measured BMD in the femoral neck (FN) and lumbar spine by dual-energy X-ray absorptiometry. Laboratory parameters of nutrition, inflammatory status, and Ca-P balance were simultaneously measured. Influence of age and sex on BMD was taken into consideration. The patients in group I were significantly older than the patients in group II (p = 0.035), but they had significantly higher BMD parameters. After regression analysis, which included age, sex, hip and waist circumferences, total body mass, lean and fat body mass, and BMI in all dialyzed patients, age (beta = -0.558, deltaR2 = 0.131, p = 0.003) and total body mass (beta = 0.408, deltaR2 = 0.131, p = 0.024) were the only independent variables that predicted FN BMD, age being the stronger predictor. In dialysis patients, BMI is associated with BMD, but the only important parameter of body composition for predicting FN BMD in this group is total body mass.

Does ingestion of regular coffee influence serum lipid profile in dialysis patients?

We checked whether dialysis patients who drink coffee might have a serum lipid profile different from that of nondrinkers of coffee. The study was performed in 30 patients (26 on peritoneal dialysis, 4 on hemodialysis). Group I included patients who drank 1 - 3 cups of coffee daily (140 - 420 mg caffeine) for at least 2 years before the study [n = 11; dialysis vintage: 29.1 months (range: 8.7 - 59.6 months); age: 56.0 +/- 14.6 years]. Group II consisted of patients who said that they were nondrinkers of caffeinated coffee [n = 19; dialysis vintage: 15.2 months (range: 6.3 - 45.4 months); age: 56.3 +/- 19.8 years). Serum lipid profile, anthropometric and bioimpedance measurements, and laboratory indices of nutrition and inflammation status were examined. Compared with group II, group I showed higher serum high-density lipoprotein (HDL) cholesterol (45.1 +/- 12.8 mg/dL vs. 37.7 +/- 6.6 mg/dL, p = 0.045) and lower low-density lipoprotein (LDL) cholesterol (104.7 +/- 15.7 mg/dL vs. 139.0 +/- 41.8 mg/dL, p = 0.007). Other examined parameters did not differ significantly between the groups, with the exception of serum albumin [4.0 g/dL (range: 3.1 - 4.3 g/dL) in group I vs. 3.3 g/dL (range: 2.9 - 4.4 g/dL) in group II, p = 0.020]. Adjustment for age and sex additionally showed differences in bioimpedance and anthropometric measurements. Compared with group II, group I showed lower waist and hip circumferences, a lower waist/height ratio, a lower fat body mass, and a higher lean body mass as a percentage of total body mass. When adjustments were made for age, sex, and fat body mass, differences in lipid profile were nonsignificant. In the overall group, a correlation was seen between lean body mass and total cholesterol (r = -0.487, p = 0.006). Lower LDL and higher HDL serum cholesterol may occur in dialyzed patients who drink coffee not only because of the direct influence of coffee ingredients on serum lipid profile, but mainly because of a more favorable body composition and better protein nutrition in coffee drinkers.