A carbonyl-decorated two-dimensional polymer as a charge-trapping layer for non-volatile memory storage devices with a high endurance and wide memory window

The charge-trapping mechanism in conjugated polymers is a performance obstacle in many optoelectronic devices harnessed for non-volatile memory applications. Herein, a carbonyl-decorated organic 2D-polymer (TpDb)-based charge-trapping memory device has been developed with a wide memory window (3.2 V) with low programming and erasing voltages of +3/-2 and -3/+2. The TpDb was synthesized by a potentially scalable solid-state aldol condensation reaction. The inherent structural defects and the semi-conjugated nature of the enone network in TpDb offer effective charge-trapping through the localization of charges in specific functional groups (CO). The interlayer hydrogen bonding enhances the packing density of the 2D-polymer layers thereby improving the memory storage properties of the material. Furthermore, the TpDb exhibits excellent features for non-volatile memory applications including over 10 000 cycles of write/read endurance and a prolonged retention performance of 104 seconds at high temperatures (100 °C).

Endowing networks with desired symmetries and modular behavior

Symmetries in a network regulate its organization into functional clustered states. Given a generic ensemble of nodes and a desirable cluster (or group of clusters), we exploit the direct connection between the elements of the eigenvector centrality and the graph symmetries to generate a network equipped with the desired cluster(s), with such a synthetical structure being furthermore perfectly reflected in the modular organization of the network's functioning. Our results solve a relevant problem of designing a desired set of clusters and are of generic application in all cases where a desired parallel functioning needs to be blueprinted.

Antimicrobial resistance in bacteria isolated from the poultry production system in Nepal

SETTING

Twenty poultry farms in five provinces of Nepal were selected for studying bacterial pathogens and their antimicrobial resistance (AMR) patterns.

OBJECTIVE

To document the proportion of cloacal swabs collected from 3,230 broiler and 3,230 layer chickens from September to December 2021 that grew isolates of Escherichia coli, Enterococcus spp. and Salmonella spp. along with their AMR patterns.

DESIGN

This was a cross-sectional descriptive study.

RESULTS

In broiler birds, Enterococcus spp., Salmonella spp. and E. coli were identified in respectively 36%, 39% and 63% of swabs. In layer birds, Enterococcus spp., Salmonella spp. and E. coli were identified in respectively 31%, 48% and 60% of swabs. For both bird types, there was variation in bacterial prevalence between the regions. For all three bacterial isolates, the lowest antimicrobial resistance was found with amikacin. For the other nine antibiotics tested, >50% of bacterial isolates showed resistance; between 60% and 90% of isolates showed resistance to ciprofloxacin and trimethoprim-sulfamethoxazole. Multidrug resistance ranged from 45% to 46% for Salmonella spp., 37-44% for E. coli and 13-17% for Enterococcus spp.

CONCLUSION

This study shows that a large proportion of poultry in Nepal are infected with potentially pathogenic bacteria, and these are frequently resistant to commonly used antibiotics. Nepal urgently needs to implement corrective measures.

A membrane-based green and low-cost system for ensuring safe drinking water in a selenium-affected region

Towards an efficient, low-cost solution to the problem of contamination of groundwater by selenium leached out from earth's mineral crust, a new system is developed using a novel graphene-based nanocomposite membrane. The system not only purified selenium-contaminated groundwater with high degree but also ensured safe disposal of the rejected selenium through algorithmic chemical stabilization in a mineral matrix. All experiments were conducted with live contaminated water from selenium affected area rather than using synthetic solution in a semi-pilot unit involving a largely fouling-free flat sheet cross-flow membrane module. Pure water flux of up to 190 Lm^-2h^-1(LMH) with 96-97% selenium rejection at an optimum operating pressure of only 14 bar could be achieved. Rejected selenium was stabilized in mineral matrix through chemical coagulation-precipitation using suitable coagulants following prior optimization of the critical operating parameters by Model-based calibration toolbox (MATLAB R2020a). A high degree of stabilization efficiency (99.8%) could be achieved as reflected in an error-index of only 1.13%. For selenium-affected region, the membrane-integrated hybrid treatment system proved to be a potential candidate technology offering safe drinking water at an approximate cost of only 1.77 $/m³ which was found to be affordable to the consumers in subsequent willingness to pay survey.

Enhanced etching characteristics of Si{100} in NaOH-based two-component solution

Silicon wet bulk micromachining is the most widely used technique for the fabrication of diverse microstructures such as cantilevers, cavities, etc. in laboratory as well as in industry for micro-electromechanical system (MEMS) application. Although, increasing the throughput remains inevitable, and can be done by increasing the etching rate. Furthermore, freestanding structure release time can be reduced by the improved undercutting rate at convex corners. In this work, we have investigated the etching characteristics of a non-conventional etchant in the form of hydroxylamine (NH2OH) added sodium hydroxide (NaOH) solution. This research is focused on Si{100} wafer as this orientation is largely used in the fabrication of planer devices (e.g., complementary metal-oxide semiconductors) and microelectromechanical systems (e.g., inertial sensors). We have performed a systematic and parametric analysis without and with 12% NH2OH in 10 M NaOH for improved etching characteristics such as etch rate, undercutting at convex corners, and etched surface morphology. 3D scanning laser microscope is used to measure average surface roughness (Ra), etch depth (d), and undercutting length (l). Morphology of the etched Si{100} surface is examined using optical and scanning electron microscopes. The addition of NH2OH in NaOH solution remarkably exhibited a two-fold increment in the etching rate of a Si{100} surface. Furthermore, the addition of NH2OH significantly improves the etched surface morphology and undercutting at convex corners. Undercutting at convex corners is highly prudent for the quick release of microstructures from the substrate. In addition, we have studied the effect of etchant age on etching characteristics. Results presented in this article are of large significance for engineering applications in both academic and industrial laboratories.

A rare case of abdominal cocoon caused by brucellosis

Brucella is the most common zoonosis in the world and is also included among the neglected endemic zoonoses by the World Health Organization. Its clinical presentation is often vague and it is not frequently suspected. A thorough history of social-economic status and animal exposure is often missed. We present a case of abdominal cocoon in a young patient residing at a dairy farm who tested positive for Brucella serology. Timely diagnosis and management prevented the progression of this debilitating condition to intestinal obstruction.

Enhanced magnetic and room temperature intrinsic magnetodielectric effect in Mn modified Ba2Mg2Fe12O22 Y-type hexaferrite

We have reported a systematic investigation on structural, magnetic, magnetodielectric and magnetoimpedance characteristics of Y-type Ba₂Mg₂(Fe_1-x Mn _x )₁₂O₂₂ (0  ⩽  x  ⩽  0.12) hexaferrite synthesized by solid-state reaction route. Rietveld refinement of x-ray diffraction pattern confirms the phase purity of all the samples with rhombohedral crystal structure. The Mn dopant modulates not only superexchange angle near to the boundary of magnetic blocks but also magnetic transition temperature. Temperature-dependent magnetization data suggests that due to Mn doping at Fe sites, ferrimagnetic to proper screw transition temperature (T _II) increases from 190 K to 208 K, while there is a decrease in proper screw to longitudinal conical spin transition temperature (T _I) from 35 K to 25 K. We observe remarkable decrease in the magnetic field from 20 kOe to 12 kOe to produce intermediate spin ordering from ferrimagnetic ordering which can be understood because of modification of superexchange angle due to Mn doping. The value of loss tangent decreases with increasing doping concentration at 300K, i.e. ~60% and 180% in BMFM4 (x  =  0.04) and BMFM8 (x  =  0.08) respectively as compared to BMF, suggesting the evolution of intrinsic feature in the doped samples. Magnetodielectric (MD) effect shows that in the low-frequency regime, the robust MD effect is because of Maxwell-Wagner interfacial polarization, whereas in the high-frequency regime intrinsic effect dominates. Further, magnetoimpedance measurement confirms the presence of substantial intrinsic MD% (~6%) at 1.3 T applied field at 300 K for 4% Mn-doped sample. Finally, the nature and strength of magnetoelectric coupling in BMFM4 and BMFM8 samples at 300 K is found to be biquadratic (P ² M ²) and maximum strength of coupling is 3.09  ×  10^-4 emu² g^-2 and 2.34  ×  10^-4 emu² g^-2, respectively.

Study of the Prevalence of Dyspepsia in the Adult Population in a Rural Community of Bangladesh

Dyspepsia is a symptom complex that includes epigastric pain, post-prandial fullness, bloating, early satiety, belching, nausea, vomiting, heartburn, acid regurgitations and anorexia. The most widely applied definition of dyspepsia is the Rome working team formulation namely chronic or recurrent pain or discomfort centered in the upper abdomen. Till date the prevalence of dyspepsia in Bangladesh has not been studied much. The last study was done in 1987 in a rural community and the prevalence of dyspepsia was found to be 41.4%. However, associated risk factors were not assessed and definition of dyspepsia was much narrower as well as the dysmotility type dyspepsia was not included in that study. Hence it is now high time to carry out another study to see the prevalence of dyspepsia in Bangladesh and the risk factors associated with it. To determine the prevalence of dyspepsia and the demographic risk factors associated with dyspepsia in the adult population in the rural community of Bangladesh. This cross sectional population based study carried out in Ghior Union of Manikgonj district of Bangladesh from January 2007 to April 2008. All persons 18 years or above living in Ghior Union were considered as the study populations with using a pre-designed questionnaire. This study showed that the prevalence of dyspepsia to be 61.9%. Reflux- like dyspepsia was the commonest sub-type of dyspepsia without reflux symptoms comprising 43.9% of the total population and 70.9% of the dyspeptics. Dysmotility like dyspepsia comprised more than half of the dyspeptics. Nausea (40.7%) was the most predominant dysmotility like dyspeptic symptoms followed by early satiety (38.4%); 13.9% of the population had history of recurrent upper abdominal pain and 11.9% of the population had gastro-esophageal reflux disease (GERD). There was considerable overlapping (16.7%) of IBS with dyspepsia. Female sex, younger age (<40 years), low family income (<5000 Taka per month), lower educational level (up to primary level), smoking and use of NSAIDs were significantly associated with dyspepsia. The prevalence of dyspepsia in adult population of Bangladesh is 61.9% which is very high compared to other countries and also much higher than the prevalence found in our country thirty years back. A great change in the socio-economic status and lifestyle of the people along with environmental pollution and food adulteration may be responsible for this increase in prevalence. This study was conducted in only one union of this country, so it was not representative of the whole population of the country. Therefore further study with large population size including rural and urban peoples from different parts of Bangladesh is needed to estimate the accurate prevalence of dyspepsia in our country.

Highly efficient & stable Bi & Sb anodes using lithium borohydride as solid electrolyte in Li-ion batteries

All solid-state Li-ion batteries using commercial Bi and Sb as negative electrodes with a high coulombic efficiency (90–99%) and high capacity retention of 82 and 95%, respectively.

Risk factors for diagnostic delay in Crohn's disease and their impact on long-term complications: how do they differ in a tuberculosis endemic region?

BACKGROUND

The diagnosis of Crohn's disease (CD) can be delayed in clinical practice. In tuberculosis endemic areas, empirical anti-tubercular therapy further delays treatment.

AIM(S)

To assess risk factors for diagnostic delay and its impact on the long-term complications of Crohn's disease in India where tuberculosis is endemic.

METHODS

Data from a large prospectively established inflammatory bowel disease registry were analysed retrospectively. The time from onset of symptoms to diagnosis (diagnostic delay) was calculated and categorised into two groups based on median diagnostic delay. The risk factors for delay including anti-tubercular therapy were analysed. Logistic regression analysis was done to assess impact of diagnostic delay on development of stenotic and fistular complications including need for surgery.

RESULTS

Seven hundred and twenty Crohn's disease patients (60.3% male, median: 28 years) were included. Main outcome measures were stenosis, fistula and need for surgery. Subjects with diagnostic delay >18 months (median) developed significantly higher stenotic complications and surgery (OR 4.12; 95% CI: 2.74-6.33, P < 0.001 and OR 2.41, 95% CI: 1.68-3.42, P < 0.001), respectively, compared to those ≤18 months. There was no difference in the development of fistulous complications. 193/720 (27%) received anti-tubercular therapy which significantly contributed to diagnostic delay (OR: 2.47; 95% CI: 1.76-3.47, P < 0.001) with 47% showing initial clinical response (Crohn's disease activity index- CDAI decrease >100). Moreover, the incidence of stenotic complications was significantly higher in patients who had received prior anti-tubercular therapy (55/193 (28.49%) vs 78/527 (14.8%), P < 0.001, OR: 2.60, 95% CI: 1.64-4.12).

CONCLUSIONS

Diagnostic delay in Crohn's disease is associated with significantly higher stenotic complications and need for surgery. Empirical anti-tubercular therapy is the single largest contributor to diagnostic delay in tuberculosis endemic areas. Despite initial clinical response to anti-tubercular therapy, long-term stenotic complications are higher.

Evaluation of Pharmacokinetic and Pharmacodynamic Drug-Drug Interaction of Sacubitril/Valsartan (LCZ696) and Sildenafil in Patients With Mild-to-Moderate Hypertension

Sacubitril/valsartan (LCZ696) is indicated for the treatment of patients with heart failure and reduced ejection fraction (HFrEF). Since patients with HFrEF may receive sacubitril/valsartan and sildenafil, both increasing cyclic guanosine monophosphate, the present study evaluated the pharmacokinetic and pharmacodynamic drug interaction potential between sacubitril/valsartan and sildenafil. In this open‐label, three‐period, single sequence study, patients with mild‐to‐moderate hypertension (153.8 ± 8.2 mmHg mean systolic blood pressure (SBP)) received a single dose of sildenafil 50 mg, sacubitril/valsartan 400 mg once daily for 5 days, and sacubitril/valsartan and sildenafil coadministration. When coadministered with sildenafil, the AUC and C_max of valsartan decreased by 29% and 39%, respectively. Coadministration of sacubitril/valsartan and sildenafil resulted in a greater decrease in BP (–5/–4/–4 mmHg mean ambulatory SBP/DBP/MAP (mean arterial pressure)) than with sacubitril/valsartan alone. Both treatments were generally safe and well tolerated in this study; however, the additional BP reduction suggests that sildenafil should be administered cautiously in patients receiving sacubitril/valsartan. Unique identifier: NCT01601470.

Mitotic Activity in Glioblastoma Correlates with Estimated Extravascular Extracellular Space Derived from Dynamic Contrast-Enhanced MR Imaging

BACKGROUND AND PURPOSE

A number of parameters derived from dynamic contrast-enhanced MR imaging and separate histologic features have been identified as potential prognosticators in high-grade glioma. This study evaluated the relationships between dynamic contrast-enhanced MRI-derived parameters and histologic features in glioblastoma multiforme.

MATERIALS AND METHODS

Twenty-eight patients with newly presenting glioblastoma multiforme underwent preoperative imaging (conventional imaging and T1 dynamic contrast-enhanced MRI). Parametric maps of the initial area under the contrast agent concentration curve, contrast transfer coefficient, estimate of volume of the extravascular extracellular space, and estimate of blood plasma volume were generated, and the enhancing fraction was calculated. Surgical specimens were used to assess subtype and were graded (World Health Organization classification system) and were assessed for necrosis, cell density, cellular atypia, mitotic activity, and overall vascularity scores. Quantitative assessment of endothelial surface area, vascular surface area, and a vascular profile count were made by using CD34 immunostaining. The relationships between MR imaging parameters and histopathologic features were examined.

RESULTS

High values of contrast transfer coefficient were associated with the presence of frank necrosis (P = .005). High values of the estimate of volume of the extravascular extracellular space were associated with a fibrillary histologic pattern (P < .01) and with increased mitotic activity (P < .05). No relationship was found between mitotic activity and histologic pattern, suggesting that the correlation between the estimate of volume of the extravascular extracellular space and mitotic activity was independent of the histologic pattern.

CONCLUSIONS

A correlation between the estimate of volume of the extravascular extracellular space and mitotic activity is reported. Further work is warranted to establish how dynamic contrast-enhanced MRI parameters relate to more quantitative histologic measurements, including markers of proliferation and measures of vascular endothelial growth factor expression.

Energetic assessment of fixation of CO2 and subsequent biofuel production using B. cereus SM1 isolated from sewage treatment plant

The ongoing work on global warming resulting from green house gases (GHGs) has led to explore the possibility of bacterial strains which can fix carbon dioxide (CO2) and can generate value-added products. The present work is an effort in this direction and has carried out an exhaustive batch experiments for the fixation of CO2 using B. Cereus SM1 isolated from sewage treatment plant (STP). The work has incorporated 5-day batch run for gaseous phase inlet CO2 concentration of 13 ± 1 % (%v/v). 84.6 (±5.76) % of CO2 removal was obtained in the gaseous phase at mentioned CO2 concentration (%v/v). Energetic requirement for CO2 fixation was assessed by varying Fe[II] ion concentration (0-200 ppm) on the per-day basis. The cell lysate obtained from CO2 fixation studies (Fe[II] ion = 100 ppm) was analyzed using Fourier transformation infrared spectroscopy (FTIR) and gas chromatography-mass spectroscopy (GC-MS). This analysis confirmed the presence of fatty acids and hydrocarbon as valuable products. The hydrocarbons were found in the range of C11-C22 which is equivalent to light oil. The obtained fatty acids were found in the range of C11-C19. The possibility of fatty acid conversion to biodiesel was explored by carrying out the transesterification reaction. The yield of biodiesel was obtained as 86.5 (±0.048) % under the transesterification reaction conditions. Results of this research work can provide the valuable information in the implementation of biomitigation of CO2 at real scenario.

Dynamics and relaxation of charge carriers in poly(methylmethacrylate)-based polymer electrolytes embedded with ionic liquid

In the present paper, we have studied dynamics and relaxation of the charge carriers in polymethylmethacrylate-lithium bis(trifluoromethane sulfonyl)imide polymer electrolytes embedded with 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid. We have analyzed the frequency dependent conductivity spectra using the random free-energy barrier model coupled with the contribution of electrode polarization in the low frequency region. The temperature dependence of ionic conductivity, and relaxation time obtained from the analysis of the spectra exhibits Vogel-Tammann-Fulcher type behavior. The Barton-Nakajima-Namikawa relation is consistent with the results obtained from the random free-energy barrier model. The scaling of ac conductivity spectra has been performed to understand the effect of temperature as well as the composition on the relaxation mechanism. The analysis of the ac conductivity also clearly indicates the existence of a nearly constant loss phenomenon at low temperatures or at high frequencies.

Therapeutic plasma exchange in paediatric SLE: a case series from India

Therapeutic plasma exchange (TPE) has been reported to be a useful adjunct in severe systemic lupus erythematosus (SLE) but paediatric literature continues to be scanty. We hereby present three cases of refractory paediatric SLE (pSLE) with thrombotic thrombocytopenic purpura (TTP), diffuse alveolar haemorrhage (DAH) and crescentic glomerulonephritis which were treated with TPE as an adjunctive therapy. TPE was carried out in haemodialysis units using the membrane filtration technique. Demonstrable benefit of TPE was seen in all three cases. In refractory pSLE, TPE may be a useful tool and should be considered. The report additionally highlights the feasibility of undertaking TPE in haemodialysis units, which is important as haemodialysis units are more readily available than dedicated apheresis units in developing countries.

A nanofiltration-coagulation integrated system for separation and stabilization of arsenic from groundwater

A membrane-integrated hybrid treatment system has been developed for continuous removal of arsenic from contaminated groundwater with simultaneous stabilization of arsenic rejects for safe disposal. Both trivalent and pentavalent arsenic could be removed by cross flow nanofiltration following a chemical pre-oxidation step for conversion of trivalent arsenic into pentavalent form. The very choice of the membrane module and its judicious integration with upstream oxidation and downstream stabilization resulted in continuous removal of more than 98% arsenic from water that contained around 190 mg L(-1) of total suspended solid, 205 mg L(-1) of total dissolved solid, 0.18 mg L(-1) of arsenic and 4.8 mg L(-1) of iron at a pH of 7.2. The used flat sheet cross flow membrane module yielded a high flux of 144-145 L m(-2) h(-1) at a transmembrane pressure of only 16 kgf·cm(-2) without the need for frequent replacement of the membranes. Transmembrane pressure, cross flow rate through the membrane module and oxidant dose were found to have pronounced effects on arsenic rejection and pure water flux. For the first time, an effective scheme for protection of the total environment has been ensured in this context where arsenic separated with high degree of efficiency has been stabilized in a solid matrix of iron and calcium under response surface optimized conditions. The study culminated in a total and sustainable solution to the problem of arsenic contamination of groundwater by offering arsenic-free water at a reasonably low price of only 1.41$·m(-3).

Arsenic removal from contaminated groundwater by membrane-integrated hybrid plant: optimization and control using Visual Basic platform

A simulation software (ARRPA) has been developed in Microsoft Visual Basic platform for optimization and control of a novel membrane-integrated arsenic separation plant in the backdrop of absence of such software. The user-friendly, menu-driven software is based on a dynamic linearized mathematical model, developed for the hybrid treatment scheme. The model captures the chemical kinetics in the pre-treating chemical reactor and the separation and transport phenomena involved in nanofiltration. The software has been validated through extensive experimental investigations. The agreement between the outputs from computer simulation program and the experimental findings are excellent and consistent under varying operating conditions reflecting high degree of accuracy and reliability of the software. High values of the overall correlation coefficient (R (2) = 0.989) and Willmott d-index (0.989) are indicators of the capability of the software in analyzing performance of the plant. The software permits pre-analysis, manipulation of input data, helps in optimization and exhibits performance of an integrated plant visually on a graphical platform. Performance analysis of the whole system as well as the individual units is possible using the tool. The software first of its kind in its domain and in the well-known Microsoft Excel environment is likely to be very useful in successful design, optimization and operation of an advanced hybrid treatment plant for removal of arsenic from contaminated groundwater.

A Visual Basic simulation software tool for performance analysis of a membrane-based advanced water treatment plant

A Visual Basic simulation software (WATTPPA) has been developed to analyse the performance of an advanced wastewater treatment plant. This user-friendly and menu-driven software is based on the dynamic mathematical model for an industrial wastewater treatment scheme that integrates chemical, biological and membrane-based unit operations. The software-predicted results corroborate very well with the experimental findings as indicated in the overall correlation coefficient of the order of 0.99. The software permits pre-analysis and manipulation of input data, helps in optimization and exhibits performance of an integrated plant visually on a graphical platform. It allows quick performance analysis of the whole system as well as the individual units. The software first of its kind in its domain and in the well-known Microsoft Excel environment is likely to be very useful in successful design, optimization and operation of an advanced hybrid treatment plant for hazardous wastewater.