Shuttling Active Elements in and out of Ultrathin Nanowires: Toward Rational Design of Multicomponent Catalysts

One-dimensional nanostructures, with a high ratio of surface-bulk atoms, find applications as active catalysts. Here, we report tunability in ultrathin single-crystalline AuPdPt nanowires by modifying synthesis conditions and postsynthetic treatment in a controlled ambient atmosphere. The surface microstructure modification of these nanostructures has been analyzed by integrating the results of three crucial techniques including Z-contrast HAADF-STEM imaging, X-ray photoelectron spectroscopy, and electrochemically active surface area from cyclic voltammograms.

Effectiveness of Comprehensive Intervention Programme on Quality of life, fatigue, self-efficacy, and psychosocial distress among head and neck cancer patients receiving radiotherapy

PURPOSE

The study aimed at evaluating the Effectiveness of Comprehensive Intervention Programme (CIP) on Quality of life (QOL), fatigue, self-efficacy, and psychosocial distress among Head and Neck Cancer (HNC) patients receiving radiotherapy treatment.

METHODS

Single-centre non-RCT time series study was conducted among 134 HNC patients (67 observed, followed by 67 subjected to CIP). FACT- H&N, FACT-F, Cancer Behavior Inventory and psychosocial distress scales were used to assess QOL, fatigue, self-efficacy, and psychosocial distress respectively. CIP was provided to the intervention arm twice a week during the course of radiation therapy along with the standard care; the control arm received only standard care. Data were collected before commencing radiotherapy, and post-test assessments were carried out at the end of radiotherapy treatment, and at 3 and 6 months after completion of radiotherapy.

RESULTS

Repeated measures ANOVA revealed a statistically significant improvement with CIP in QOL (F (1.917) = 454.103, p = 0.001), fatigue (F (2.106) = 183.775, p = 0.001), self-efficacy (F (2.429) = 190.861, p = 0.001), and psychosocial distress (F (2.288) = 290.105, p = 0.001) in the intervention arm.

CONCLUSION

The CIP implemented to address multitude of issues in HNC patients receiving radiotherapy, proved to be effective in reducing the impact of treatment on QOL, fatigue, self-efficacy and psychosocial distress in HNC patients receiving radiotherapy.

Pulmonary Function and Diffusing Capacity of Carbon Monoxide in Hypersensitivity Pneumonitis: An Observational Study of 152 Patients

OBJECTIVE

Hypersensitivity pneumonitis (HP) is an inflammatory and/or fibrotic lung disease. The restrictive lung function with low diffusing capacity of carbon monoxide (DLCO) is common in interstitial lung diseases (ILD). There are limited data on pulmonary function test (PFT) in HP and its role for diagnosis is questionable. We analyzed the data of 152 HP patients for type of defect, lung volume, and DLCO.

MATERIAL AND METHODS

The present study is a retrospective analysis of 152 patients at one of the tertiary chest institutes in India. All diagnosed cases with at least spirometry were included. PFT findings were classified and graded as obstructive, restrictive, and mixed patterns. The correlation of PFT was calculated with disease duration and 6MWT distance.

RESULTS

The majority were female [106 (70%)], with a mean age of 47.8 ± 12.3 years. Spirometry with lung volume data were available for 97% patients. PFT was abnormal in 118 (80%) cases. Among the patterns of abnormality, the most common type was restrictive (74%) followed by mixed (15%) and obstructive (11%) with the majority in the severe to very severe grade. The mean total lung capacity (TLC) and residual volume (RV) were reduced, with the grade more severe when the pattern of abnormality was restrictive while the RV/ TLC was higher suggestive of air tapping. DLCO data were available for 132 (87%) cases, with levels decreased in 67%. The severity of DLCO was highest when the pattern of abnormality was restrictive. One of the PFT parameters was abnormal in 137 (90%) cases, with isolated decreased DLCO levels seen in 16 (10%) cases. Forced vital capacity (FVC), TLC, and DLCO showed positive correlation with 6MWT distance (FVC r = .22, P = .02; TLC r = .28, P = .003; DLCO r = .30, P = .002).

CONCLUSION

The PFT abnormality is seen in >80% of HP patients. All types of abnormality were seen, with the restrictive pattern being the most common. Isolated decreased DLCO levels were seen in 10% of cases. We advised to do full PFT for diagnosis and followup of HP.

Epitaxial Heterostructures of CsPbBr3 Perovskite Nanocrystals with Post-transition Metal Bismuth

The facet chemistry of halide perovskite nanocrystals plays a key role in designing nanoscale epitaxial heterostructures. However, despite significant successes achieved in designing these nanocrystals, their heterostructures with several leading transition metals could not be established yet. Herein, the possible heterostructures of metals beyond transition metals are explored and the epitaxial combinations of soft CsPbBr3 nanocrystals with the post-transition metal Bi(0) are reported. These heterostructures are built with interfacing facets having hexagonal atomic configurations of both the rhombicuboctahedron CsPbBr3 and octahedral Bi(0). A high reaction temperature and the presence of alkylamine kept Bi(III) in reduced form and helped in sustaining these CsPbBr3-Bi(0) heteronanocrystals. Since understanding of and synthesis optimization of metal-halide perovskite heterostructures are limited, this finding adds a new fundamental insight in designing ionic and nonionic materials heterojunctions. Furthermore, oxidation and sulfidation of Bi(0) are studied, and the possible oxide/sulfide heterostructures with CsPbBr3 are discussed.

Thirty years of emotional intelligence: A scoping review of emotional intelligence training programme among nurses

The stressful environment of any healthcare setting can be detrimental to nurses' mental and emotional health. In recent years, emotional intelligence (EI) has emerged as a vital psychological resource that positively impacts mental and emotional health and improves organizational functioning and success. This scoping review aimed to collate, synthesize and outline the research conducted on EI training programmes among nurses to assess their effectiveness in improving staff nurses' EI. Electronic databases of MEDLINE via PubMed, CINAHL, Scopus, Cochrane, ProQuest, Embase and Web of Science were comprehensively searched for related studies published between 1990 and 2021 (updated in May 2022). Two investigators independently screened the abstracts of the retrieved studies against the inclusion and exclusion criteria. Out of 728 initially retrieved studies, only 7 were included in the final synthesis. The PRISMA-ScR (2018) checklist was used to report the study findings. All the studies included in the review reported a significant improvement in nurses' EI after a training programme. The results also indicate that EI interventions are an effective way to improve nurses' psychological resources (improve resilience and coping skills; reduce anxiety and stress), leadership qualities, job performance and patient experience of nursing care. As nurses are exposed to a wide range of emotions, human pain and suffering, the results of this review suggest that improving the EI skills of nurses through short training programmes is an effective way to maintain their emotional and mental well-being. This scoping review is preregistered in Prospero (CRD42020161084).

Hybrid Aeromaterials for Enhanced and Rapid Volumetric Photothermal Response

Conversion of light into heat is essential for a broad range of technologies such as solar thermal heating, catalysis and desalination. Three-dimensional (3D) carbon nanomaterial-based aerogels have been shown to hold great promise as photothermal transducer materials. However, until now, their light-to-heat conversion is limited by near-surface absorption, resulting in a strong heat localization only at the illuminated surface region, while most of the aerogel volume remains unused. We present a fabrication concept for highly porous (>99.9%) photothermal hybrid aeromaterials, which enable an ultrarapid and volumetric photothermal response with an enhancement by a factor of around 2.5 compared to the pristine variant. The hybrid aeromaterial is based on strongly light-scattering framework structures composed of interconnected hollow silicon dioxide (SiO2) microtubes, which are functionalized with extremely low amounts (in order of a few μg cm-3) of reduced graphene oxide (rGO) nanosheets, acting as photothermal agents. Tailoring the density of rGO within the framework structure enables us to control both light scattering and light absorption and thus the volumetric photothermal response. We further show that by rapid and repeatable gas activation, these transducer materials expand the field of photothermal applications, like untethered light-powered and light-controlled microfluidic pumps and soft pneumatic actuators.

Effectiveness of Integrated Emotional-Self Enhancement (IESE) program among staff nurses: protocol for a quasi-experimental study

Background: Staff nurses face frequent emotional situations in their work environment. The constant contact with suffering patients, and the busy work environment, pose tremendous stress on nurses' physical and emotional health. The Emotional Intelligence skills of empathy, self-awareness, motivation, self-control, and keeping relationships, can help handle difficult emotions and allow nurses to work in an organized, calm, and professional way. This study aims to implement and assess the effectiveness of a training program developed by the investigator, tailored to the mental and emotional needs of staff nurses who are working in an organization. The study also aims to observe any significant change, correlation, and association in the staff nurses' level of emotional intelligence, intrinsic motivation, self-compassion, emotional labor, and nurse-in-charges' and patients' perception of nursing care after the program. Methods: A quasi-experimental (one-group) study design was used in this study. The study will involve 80 staff nurses working in a selected hospital in India. The staff nurses will be selected from the hospital's general wards using convenience sampling. For the current study, a quasi-experimental design will be used. The investigator will deliver a training program, divided into four sessions of two hours each. Data will be collected from the participants at baseline and 3-months pre-intervention; and post-test data will be collected immediately after the intervention, at 3-month, and 6-month follow-up, to observe any significant change in the study variables before and after the intervention. Results: The current study primarily focuses on the vital aspect of developing emotional needs, for promoting a better work-life balance. Research findings from the study will significantly contribute to the evidence based Emotional Intelligence programs for staff nurses, and if proven effective, could be delivered extensively in the hospitals. Trial registration: The study is registered in June 2019 under the Central Trial Registry of India ( CTRI/2019/08/020592).

Effectiveness of health literacy and relaxing music on quality of sleep and risk for antenatal depression

Background

Pregnant women experience increased sleep disturbances during the third trimester of their pregnancy, which may result in the development of psychological issues in the perinatal period. There is a dearth of interventional studies that combine health literacy and the provision of music for the benefit of pregnant women in South Asia.

Aim

To determine the effectiveness of a combination of Comprehensive Health literacy And Relaxing Music (CHARM) interventions on quality of sleep and risk for antenatal depression among women visiting antenatal outpatient departments of a tertiary hospital in South India.

Methods

A four-arm parallel-group randomized controlled trial was adopted; 128 low-risk primigravid women were recruited and randomly assigned to the four groups using block randomization. The interventions included relaxing music interventions, comprehensive health-literacy interventions, combinations of both as CHARM interventions, and standard antenatal care. All the interventions were provided for four weeks. The quality of sleep among pregnant women was assessed using the Pittsburgh Sleep Quality Index Scale at baseline and after four weeks of intervention. Women at risk of developing antenatal depression were screened using the Edinburgh Postnatal Depression Scale-Antenatal Version.

Results

Pregnant women who received CHARM interventions had significant improvement in quality of sleep when compared with other interventions (F(3,124) =15.0, P < .001, effect size η p2= 0.27). Also, 38 (29.6%) of the included pregnant women were at risk of developing antenatal depression, which was reduced to 21 (16.4%) following the intervention.

Conclusion

CHARM intervention could promote quality sleep and reduce the risk of developing antenatal depression, thereby improving perinatal mental health.

Effect of Lifestyle Modification Intervention Programme on Bone Mineral Density among Postmenopausal Women with Osteoporosis

Objectives

Osteoporosis is one of the major public health problems worldwide among postmenopausal osteoporotic women. Lifestyle modification interventions along with pharmacotherapy help to revert bone loss and prevent complications.

Methods

A randomised controlled trial was conducted at Kasturba Hospital, Manipal from January 2019 to December 2021 among postmenopausal women with osteoporosis. The postmenopausal women who attended the osteoporosis clinic and were within the age group of 45-65 years, could speak and understand English or Kannada and whose bone mineral density (BMD) score was between -1 and -3 were included in the study. The total sample size of the study was 120 with 60 in each of the experimental and control groups. After obtaining informed consent, a stratified block randomisation method was used to allocate the participants to intervention and control groups. The BMD was monitored by the portable ultrasound densitometer by a technician at the outpatient departments. The baseline information was collected by a structured demographic questionnaire. Intervention group participants received a lifestyle modification intervention program (LMIP) whereas the control group received standard regular care from the physician. Follow-up was done at three and six months.

Results

The results revealed that the increase in the BMD median score among the experimental group was from -2.2 (-2.5- -1.8) to -1.5 (-1.8- -0.65) whereas in the control group, it was from -2.3 (-2.6- -1.9) to -2.0 (-2.4- -1.5). The results of the Mann Whitey U test showed a statistical significance between the intervention and control groups in the post-test after six months (U = 505.5; P <0.05). Wilcoxon signed rank test showed a significant change in both the intervention and control groups from pre-test to post-test I (3 months) and post-test II (6 months; P <0.001).

Conclusion

The lifestyle modification intervention was found to be effective in improving the bone health status of postmenopausal women. Hence it is very important to integrate it into regular therapy.

Ultrafast time-resolved carrier dynamics in tellurium nanowires using optical pump terahertz probe spectroscopy

We report carrier relaxation dynamics in semiconducting tellurium nanowires (average diameter ∼ 10 nm) using ultrafast time-resolved terahertz spectroscopy. After photoexcitation using an 800 nm pump pulse, we observed an initial increase in the THz conductivity due to the absorption of THz radiation by photoexcited carriers. The time evolution of the differential conductivity (Δσ(τ_pp) = σ_{pump on}(τ_pp) - σ_{pump off}) shows a bi-exponential relaxation with the initial fast decay time scale of τ₁ ∼ 25 ps followed by a longer relaxation time constant of τ₂ ∼ 100 ps. Interestingly, the two time scales depend on the amount of the capping agent present on the surface of TeNWs, showing a faster relaxation of the photoexcited carriers as the percentage of capping decreases. This is physically interpreted as the surface state mediated relaxation mechanism of the photo-pumped carriers depending on the density of available surface states. A quantitative understanding is obtained using a coupled rate equation model taking into account the decay mechanisms determined from the surface mediated relaxation rate (D_S) and direct recombination rate (D_R) of the electron-hole pairs. Furthermore, the measured lattice temperature (T_L) dependent dynamics, showing a faster relaxation at lower temperature, is understood using the same rate equation model, giving a power law dependence of the electron-hole recombination rate (D_R) on T_L as D_R ∝ T_L^-1/2. This is explained by estimating D_R using the van Roosbroeck-Shockley theory taking into account the density of states () of one-dimensional nanowires. Furthermore, to understand the measured frequency-dependent THz photoconductivity, we model Δσ(ω) using the Boltzmann transport equation taking into account the energy-dependent scattering rates showing the dominant role of short range (Γ_sr) and Coulomb scattering (Γ_C) rates in the relaxation process, which further provides a measure of the charged and neutral impurity concentrations.

Role of sleep questionnaires in predicting obstructive sleep apnea amongst interstitial lung diseases patients

Introduction

The co-existence of obstructive sleep apnea (OSA) and interstitial lung diseases (ILD) results in significant morbidity and mortality. So screening for OSA is important for its early diagnosis among ILD patients. The commonly used questionnaires for screening of OSA are Epworth sleep score (ESS) and STOP-BANG. However, the validity of these questionnaires among ILD patients is not well studied. The aim of this study was to assess the utility of these sleep questionnaires in detection of OSA among ILD patients.

Methods

It was a prospective observational study of one year in a tertiary chest centre in India. We enrolled 41 stable cases of ILD who were subjected to self-reported questionnaires (ESS, STOP-BANG, and Berlin questionnaire). The diagnosis of OSA was done by Level 1 polysomnography. The correlation analysis was done between the sleep questionnaires and AHI. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for all the questionnaires. The cutoff values of STOPBANG and ESS questionnaire were calculated from the ROC analyses. P value of <0.05 was considered to be significant.

Results

OSA was diagnosed in 32 (78%) patients with mean AHI of 21.8 ± 17.6.The mean age was 54.8 ± 8.9 years with majority being female (78%) and mean body mass index (BMI) was 29.7 ± 6.4 kg/m2. The mean ESS and STOPBANG score were 9.2 ± 5.4 and 4.3 ± 1.8, respectively, and 41% patients showed high risk for OSA with Berlin questionnaire. The sensitivity for detection of OSA was highest (96.1%) with ESS and lowest with Berlin questionnaire (40.6%). The receiver operating characteristics (ROC) area under curve for ESS was 0.929 with optimum cutoff point of 4, sensitivity of 96.9%, and specificity of 55.6%, while ROC area under curve for STOPBANG was 0.918 with optimum cutoff point of 3, sensitivity of 81.2% and specificity of 88.9%.The combination of two questionnaires showed sensitivity of >90%. The sensitivity also increased with the increasing severity of OSA. AHI showed positive correlation with ESS (r = 0.618, P < 0.001) and STOPBANG (r = 0.770, P < 0.001).

Conclusion

The ESS and STOPBANG showed high sensitivity with positive correlation for prediction of OSA in ILD patients. These questionnaires can be used to prioritize the patients for polysomnography (PSG) among ILD patients with suspicion of OSA.

A Qualitative Study of Decision-making (DM) in Surgery and Cancer Care: an Indian Perspective

Cancer psychology is a vitally important part of cancer management. Qualitative research is a gateway to exploring this. Weighing the treatment options in terms of quality of life and survival is important. Given the globalization of healthcare seen in the last decade, the exploration of the decision-making process in a developing nation was deemed highly appropriate. The aim is to explore the thoughts of surgical colleagues and care providing clinicians about patient decision-making in cancer care in developing countries, with special reference to India. The secondary objective was to identify factors that may have a role to play in decision-making in India. A prospective qualitative study. The exercise was carried out at Kiran Mazumdhar Shah Cancer Center. The hospital is a tertiary referral center for cancer services in the city of Bangalore, India. A qualitative study by methodology, a focus group discussion was undertaken with the members of the head and neck tumor board. The results showed, in India, decision-making is predominantly led by the clinicians and the patient's family members. A number of factors play an important role in the decision-making process. These include as follows: health outcome measures (quality of life, health-related quality of life), clinician factors (knowledge, skill, expertise, judgment), patient factors (socio-economic, education, cultural), nursing factors, translational research, and resource infrastructure. Important themes and outcomes emerged from the qualitative study. As modern healthcare moves towards a patient-centered care approach, evidence-based patient choice and patient decision-making clearly have a greater role to play, and the cultural and practical issues demonstrated in this article must be considered.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13193-022-01521-x.

Effect of task-based bilateral arm training on upper limb recovery after stroke: A systematic review and meta-analysis

OBJECTIVE

Upper limb recovery is a crucial component of stroke rehabilitation aimed to maximize functional activities and reduce disability. Using both arms post stroke is essential to carry out many functional activities but the evidence on bilateral arm training (BAT) is understudied. To investigate the evidence for efficacy of task-based BAT on upper limb recovery, function, and participation post stroke.

METHODS

We included 13 randomized controlled trials, and methodological quality was assessed using Cochrane risk of bias tool and the PEDro scale. The outcome measures such as Fugl-Meyer Assessment-Upper Extremity (FMA-UE), Action Research Arm Test (ARAT), Wolf Motor Function Test (WMFT), Motor Activity Log (MAL), Box and Block Test (BBT), Modified Barthel Index (MBI), Functional Independence Measure (FIM), and Stroke Impact Scale (SIS) were synthesized and analysed based on ICF.

RESULTS

When comparing BAT with control group, BAT showed improvement in the pooled standard mean difference (SMD) of FMA-UE (SMD= 0.62, 95% confidence interval (CI), 0.12 to 1.12, p = 0.01; I²=83%). The control group showed significant improvement in MAL-QOM (SMD= -0.10, 95%CI, -0.77 to 0.58, p = 0.78; I²=89%). Compared to conventional group, BAT showed a significant improvement in BBT (SMD= 0.52, 95%CI, 0.04 to 1.00, p = 0.03; I²=0%). When compared with BAT, unimanual training yielded a significant improvement (SMD= -0.60, 95%CI, -0.98 to -0.22, p = 0.002; I²=0%) in MAL-QOM. In real-life participation, the control group showed improvement in SIS (SMD= -0.17, 95% (CI), -0.70 to 0.37, p = 0.54; I²=48%) over BAT.

CONCLUSIONS

Task-based BAT appears to improve upper limb motor function post stroke. The benefits of task-based BAT on activity performance and participation in real life are not statistically significant.

Identification of the Bravais lattice and cell parameters through quantitative model-based transmission electron microscopy and Niggli cell reduction theory: the case of intermetallic Ni5Pb2Te3

This article demonstrates a simple and effective way to accurately determine the Bravais lattice type and cell parameters of an unknown phase by combining quantitative model-based high-resolution (scanning) transmission electron microscopy and Niggli cell reduction theory. This method was applied to the Ni5Pb2Te3 phase in the Ni–Pb–Te ternary system, which exists at high temperatures and forms from the interaction of Ni contacts with PbTe thermoelectric materials. The structure was identified to be triclinic with the space group P1 and cell parameters a = 5.43 ± 0.09 Å, b = 3.93 ± 0.03 Å, c = 3.75 ± 0.01 Å, α = 115.4 ± 0.2°, β = 93.4 ± 0.6° and γ = 91.1 ± 0.1°. The methodology is particularly beneficial for the class of problems where the phase under study coexists in a multiphase environment.

Physical activity interventions for glycaemic control in African adults - A systematic review and meta-analysis

BACKGROUND AND AIM

Growing evidence indicates that increasing physical activity may aid in regulating altered glycaemic control, thereby mitigating the risk of diabetes. However, the evidence summarising the efficacy of physical activity on glycaemic control among African adults remains unconsolidated. Our objective was to provide an amalgamated summary of the empirical evidence that explored the effectiveness of physical activity interventions on glycaemic control among African adults.

METHODS

A systematic search of six journal databases for the studies exploring the efficacy of physical activity on glycaemic control among African adults until March 21, 2022, was administered. Two independent reviewers screened the citations based on a priori set eligibility criteria. Data were analysed using inverse variance method and a summary of findings was synthesised using the Grading of Recommendations, Assessment, Development and Evaluations approach.

RESULTS

Of the 14,624 citations retrieved, 26 articles with 1474 participants were included for final analysis. Most of the included trials had a high risk of bias (N = 20; 76.92%). Our review found a significant reduction in fasting blood glucose (FBG, -2.18 [ 95% CI -3.18, -1.18] mmol/L), insulin (-0.99 [-2.71, 0.74] μU/L), Glycosylated haemoglobin (HbA1C) (-0.53% [-0.88, -0.19]), Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) (-0.74% [-1.10, -0.38]) and insulin sensitivity (-0.90 μU/l/min [-1.75, -0.06]) following physical activity interventions. The review reports low certainty of evidence across all outcome measures.

DISCUSSION AND CONCLUSION

Physical activity interventions were found to improve glycaemic control among African adults. However, the optimal physical activity dose for demonstrating meaningful benefits on glucose tolerance still remains unclear due to the limited number of primary studies available.

Tuning Catalytic Activity in Ultrathin Bimetallic Nanowires via Surface Segregation: Some Insights

The efficiency of heterogeneous catalysts critically depends on the nature of the surface. We present results on controlling the composition in ultrathin bimetallic AuPd. AuPd wires were grown using Au nanowire templates; the surface composition could be tuned by increasing the amount of Pd. Further, segregation of Pd to the surface could be induced in alloyed nanowires by annealing under a controlled CO atmosphere. Electrocatalytic activity of these bimetallic systems is assessed for the methanol oxidation reaction (MOR). While the MOR potential shows a monotonic increase with Pd content, the specific activity displays a typical volcano-type behavior. The CO-annealed nanowires show a lowering of potential owing to a higher Pd content on the surface while still maintaining the specific activity. These findings provide clear strategies to independently control the reaction potential and the activities of nanocatalysts. The experimental findings are well supported by the theoretical investigations using density functional theory (DFT) calculations.

Dirac surface plasmons in photoexcited bismuth telluride nanowires: optical pump-terahertz probe spectroscopy

Collective excitation of Dirac plasmons in graphene and topological insulators has opened new possibilities of tunable plasmonic materials ranging from THz to mid-infrared regions. Using time resolved Optical Pump-Terahertz Probe (OPTP) spectroscopy, we demonstrate the presence of plasmonic oscillations in bismuth telluride nanowires (Bi₂Te₃ NWs) after photoexcitation using an 800 nm pump pulse. In the frequency domain, the differential conductivity (Δσ = σ_{pump on}-σ_{pump off}) spectrum shows a Lorentzian response where the resonance frequency (ω_p), attributed to surface plasmon oscillations, shifts with photogenerated carrier density (n) as . This dependence establishes the absorption of THz radiation by the Dirac surface plasmon oscillations of the charge carriers in the Topological Surface States (TSS) of Bi₂Te₃ NWs. Moreover, we obtain a modulation depth, tunable by pump fluence, of ∼40% over the spectral range of 0.5 to 2.5 THz. In addition, the time evolution of Δσ(t) represents a long relaxation channel lasting for more than 50 ps. We model the decay dynamics of Δσ(t) using coupled second order rate equations, highlighting the contributions from surface recombination as well as from trap mediated relaxation channels of the photoinjected carriers.

Comparison of two self-sampling methods for human papillomavirus (HPV) DNA testing among women with high prevalence rates

One major advantage of molecular assays for human papillomavirus (HPV) DNA detection is that these assays can be performed on self-collected samples unlike cytology or visual inspection with acetic acid (VIA). This cross-sectional study was carried out between March 2017 and April 2019 to compare the diagnostic performance in self-collected urine and vaginal samples for HPV DNA detection. Viral DNA was extracted from processed samples using a Qiagen viral DNA extraction Kit (QIAamp DNA Mini Kit). To detect four common high-risk HPV types (16, 18, 31, 45), multiplex real-time polymerase chain reaction (PCR) targeting the LCR/E6/E7 region of the HPV genome was performed in ABI 7500 cycler (Applied Biosystems). The negative samples were screened by conventional PCR targeting the L1 capsid region to exclude other HPV types. The overall agreement between the two self-collecting sampling methods was 64.04% with a κ value of 0.29 pointing towards a fair agreement (P < .01). The sensitivity of HPV DNA detection in urine samples was 57.95% (47.52%, 67.72), and specificity was 84.6% (66.47%, 93.85%) when compared with vaginal samples. The study concludes that self-collected vaginal HPV DNA testing is more sensitive than unpreserved-urine samples for HPV DNA detection in a hospital-based setting.

A mixed-methods systematic review on barriers to exclusive breastfeeding

INTRODUCTION

The World Health Organization recommends exclusive breastfeeding for every newborn during the first 6 months of life, yet women come across various challenges to continuing it.

AIM

This systematic review was intended to identify barriers to exclusive breastfeeding among mothers.

METHODS

MEDLINE, Cumulative Index to Nursing and Allied health literature, ProQuest, Web of Science and Scopus databases were searched from January 1990 to October 2017. The systematic review included quantitative, qualitative and mixed-methods studies to identify barriers to exclusive breastfeeding among mothers of reproductive age with an infant aged between 0 and 12 months. All studies were screened based on titles, abstracts and full text by two reviewers independently. The methodological quality of included studies was assessed using appropriate tools. Of the 9737 eligible records, 44 studies were included for analysis. Classification of barriers to exclusive breastfeeding was adopted from the conceptual framework of factors affecting breastfeeding practices given by Hector and colleagues.

RESULTS

In total 32 barriers were grouped under individual, group and society level factors. Meta-analysis indicated that mothers who smoked had 2.49 times more odds of not exclusively breastfeeding than non-smoking mothers and mothers who had undergone caesarean section had 1.69 times more risk of cessation of exclusive breastfeeding than mothers who have had a vaginal childbirth.

CONCLUSION

The systematic review revealed a complex interplay of various barriers related to exclusive breastfeeding. It is recommended that context-specific strategies should be designed in accordance with barriers existing in a region or country.

Thermal History-Dependent Current Relaxation in hBN/MoS2 van der Waals Dimers

Combining atomically thin layers of van der Waals (vdW) materials in a chosen vertical sequence is an emerging route to create devices with desired functionalities. While this method aims to exploit the individual properties of partnering layers, strong interlayer coupling can significantly alter their electronic and optical properties. Here we explored the impact of the vdW epitaxy on electrical transport in atomically thin molybdenum disulfide (MoS₂) when it forms a vdW dimer with crystalline films of hexagonal boron nitride (hBN). We observe a thermal history-dependent long-term (over ∼40 h) current relaxation in the overlap region of MoS₂/hBN heterostructures, which is absent in bare MoS₂ layers (or homoepitaxial MoS₂/MoS₂ dimers) on the same substrate. Concurrent relaxation in the low-frequency Raman modes in MoS₂ in the heterostructure region suggests a slow structural relaxation between trigonal and octahedral polymorphs of MoS₂ as a likely driving mechanism that also results in inhomogeneous charge distribution in the MoS₂ layer. Our experiment yields an aspect of vdW heteroepitaxy that can be generic to electrical devices with atomically thin transition-metal dichalcogenides.

Modulation of the bacterial population in commercial cucumber fermentations by brining salt type

AIMS

Differences in the bacterial population of cucumber fermentations brined with no salt, 100 mmol l^-1 (1·1%) calcium chloride (CaCl₂ ) or 1·03 mol l^-1 (6%) sodium chloride (NaCl) were studied.

METHODS AND RESULTS

Changes in the microbiology and chemistry of commercial and laboratory scale cucumber fermentations occurring as a function of time were monitored using colony counts and metagenetic analysis, and a pH probe and high-performance liquid chromatography analysis respectively. Dissolved oxygen and carbon dioxide content were monitored in commercial fermentations. Fermentations brined with calcium chloride (CaCl₂ ) or no salt sustained faster microbial growth and reduction in pH than those brined with 1·03 mol l^-1 NaCl. Leuconostoc, Lactococcus and Weissella dominated in fermentations brined with no salt or 100 mmol l^-1 CaCl₂ on day 1 as compared to Weissella and enterobacteria in fermentations containing 1·03 mol l^-1 NaCl. Lactobacilli dominated all fermentations by the third day, regardless of salt type, and was followed, in relative abundance by Pediococcus, Leuconostoc, Lactococcus and Weissella. From 84 to 96% of the population was composed of Lactobacillus by day 7 of the fermentations, except in the no salt fermentations in which a mixed population of LAB remained. The population of LAB found in commercial cucumber fermentations brined with 100 mmol l^-1 CaCl₂ (n = 18) or 1·03 mol l^-1 NaCl (n = 9) mimicked that of laboratory fermentations. A declining population of aerobes was detected in commercial fermentations brined with CaCl₂ on day 1.

CONCLUSION

A reduced NaCl content in cucumber fermentation enhances microbial diversity.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study fills a knowledge gap and aids in the design of improved reduced NaCl cucumber fermentations.

Ultra-sensitive graphene-bismuth telluride nano-wire hybrids for infrared detection

The myriad technological applications of infrared radiation sensors make the search for ultra-sensitive detectors extremely crucial. Materials such as bismuth telluride (Bi2Te3), having a small bulk band gap of 0.17 eV, are ideal infrared detectors. However, due to the high recombination rate of photo-generated charge carriers in the bulk, the electrical response under optical illumination is typically very weak in these materials. We have circumnavigated this by sensitizing graphene with Bi2Te3 nano-wires. These hybrid devices show an ultra-high sensitivity of ∼106 A W-1, under incident electromagnetic radiation from 940 nm to 1720 nm. The theoretical limit of the noise equivalent power and specific detectivity in these devices are ∼10-18 W Hz-1/2 and ∼1011 Jones respectively, which are comparable to those of some of the best known detectors.

Ultrathin Au-Alloy Nanowires at the Liquid-Liquid Interface

Ultrathin bimetallic nanowires are of importance and interest for applications in electronic devices such as sensors and heterogeneous catalysts. In this work, we have designed a new, highly reproducible and generalized wet chemical method to synthesize uniform and monodispersed Au-based alloy (AuCu, AuPd, and AuPt) nanowires with tunable composition using microwave-assisted reduction at the liquid-liquid interface. These ultrathin alloy nanowires are below 4 nm in diameter and about 2 μm long. Detailed microstructural characterization shows that the wires have an face centred cubic (FCC) crystal structure, and they have low-energy twin-boundary and stacking-fault defects along the growth direction. The wires exhibit remarkable thermal and mechanical stability that is critical for important applications. The alloy wires exhibit excellent electrocatalytic activity for methanol oxidation in an alkaline medium.

Designing Diameter-Modulated Heterostructure Nanowires of PbTe/Te by Controlled Dewetting

Heterostructures consisting of semiconductors with controlled morphology and interfaces find applications in many fields. A range of axial, radial, and diameter-modulated nanostructures have been synthesized primarily using vapor phase methods. Here, we present a simple wet chemical routine to synthesize heterostructures of PbTe/Te using Te nanowires as templates. A morphology evolution study for the formation of these heterostructures has been performed. On the basis of these control experiments, a pathway for the formation of these nanostructures is proposed. Reduction of a Pb precursor to Pb on Te nanowire templates followed by interdiffusion of Pb/Te leads to the formation of a thin shell of PbTe on the Te wires. Controlled dewetting of the thin shell leads to the formation of cube-shaped PbTe that is periodically arranged on the Te wires. Using control experiments, we show that different reactions parameters like rate of addition of the reducing agent, concentration of Pb precursor and thickness of initial Te nanowire play a critical role in controlling the spacing between the PbTe cubes on the Te wires. Using simple surface energy arguments, we propose a mechanism for the formation of the hybrid. The principles presented are general and can be exploited for the synthesis of other nanoscale heterostructures.

Ultra-high sensitivity infra-red detection and temperature effects in a graphene-tellurium nanowire binary hybrid

The optoelectronic performance of hybrid devices from graphene and optically sensitive semiconductors exceeds conventional photodetectors due to a large in-built optical gain. Tellurium nanowire (TeNW), being a narrow direct band gap semiconductor (∼0.65 eV), is as an excellent potential candidate for near infra-red (NIR) detection. Here we demonstrate a new graphene-TeNW binary hybrid that exhibits a maximum photoresponsivity of ∼10⁶ A W^-1 at 175 K in the NIR regime (920 nm-1720 nm), which exceeds the photoresponsivity of the most common NIR photodetectors. The resulting noise-equivalent power (NEP) is as low as 2 × 10^-18 W Hz^-1/2, and the specific detectivity (D*) exceeds 5 × 10¹³ cm Hz^1/2 W^-1 (Jones). The temperature range of optimal operation, which extends up to ≈220 K and ≈260 K for 1720 nm and 920 nm excitation, respectively, is primarily limited by the electrical conductivity of the TeNW layer, and can further be improved by lowering of the defect density as well as inter-wire electronic coupling.

Crumpled sheets of reduced graphene oxide as a highly sensitive, robust and versatile strain/pressure sensor

Sensing of mechanical stimuli forms an important communication pathway between humans/environment and machines. The progress in such sensing technology has possible impacts on the functioning of automated systems, human machine interfacing, health-care monitoring, prosthetics and safety systems. The challenges in this field range from attaining high sensitivity to extreme robustness. In this article, sensing of complex mechanical stimuli with a patch of taped crumpled reduced graphene oxide (rGO) has been reported which can typically be assembled under household conditions. The ability of this sensor to detect a wide variety of pressures and strains in conventional day-to-day applications has been demonstrated. An extremely high gauge factor (∼10³) at ultralow strains (∼10^-4) with fast response times (<20.4 ms) could be achieved with such sensors. Pressure resulting from a gentle touch to over human body weight could be sensed successfully. The capability of the sensor to respond in a variety of environments could be exploited in the detection of water and air pressures both below and above atmospheric, with a single device.

Manipulation of Optoelectronic Properties and Band Structure Engineering of Ultrathin Te Nanowires by Chemical Adsorption

Band structure engineering is a powerful technique both for the design of new semiconductor materials and for imparting new functionalities to existing ones. In this article, we present a novel and versatile technique to achieve this by surface adsorption on low dimensional systems. As a specific example, we demonstrate, through detailed experiments and ab initio simulations, the controlled modification of band structure in ultrathin Te nanowires due to NO₂ adsorption. Measurements of the temperature dependence of resistivity of single ultrathin Te nanowire field-effect transistor (FET) devices exposed to increasing amounts of NO₂ reveal a gradual transition from a semiconducting to a metallic state. Gradual quenching of vibrational Raman modes of Te with increasing concentration of NO₂ supports the appearance of a metallic state in NO₂ adsorbed Te. Ab initio simulations attribute these observations to the appearance of midgap states in NO₂ adsorbed Te nanowires. Our results provide fundamental insights into the effects of ambient on the electronic structures of low-dimensional materials and can be exploited for designing novel chemical sensors.

Graphene-oxide-supported ultrathin Au nanowires: efficient electrocatalysts for borohydride oxidation

We report stable ultrathin Au nanowires supported on reduced graphene oxide with outstanding electrocatalytic activity for borohydride oxidation.

We report stable ultrathin Au nanowires supported on reduced graphene oxide with outstanding electrocatalytic activity for borohydride oxidation. Electrochemical impedance spectroscopy measurements showed abnormal inductive behavior, indicative of surface reactivation. DFT calculations indicate that the origin of the high activity stems from the position of the Au d-band center.

Rapid synthesis of hybrids and hollow PdO nanostructures by controlled in situ dissolution of a ZnO nanorod template: insights into the formation mechanism and thermal stability

Hollow nanomaterials have attracted a lot of interest by virtue of their wide range of applications that arise primarily due to their unique architecture. A common strategy to synthesize hollow nanomaterials is by nucleation of the shell material over a preformed core and subsequent dissolution of the core in the second step. Herein an ultrafast, microwave route has been demonstrated, to synthesize PdO nanotubes in a single step using ZnO as a sacrificial template. The mechanism of the nanotube formation has been investigated in detail using control experiments. By tuning the starting ratio of PdCl2 : ZnO, hollow to hybrid PdO nanostructures could be obtained using the same method. Conversion of the PdO to Pd nanotubes has been shown by simple NaBH4 treatment. The thermal stability of the PdO nanotubes has been studied. The insights presented here are general and applicable for the synthesis of hybrids/hollow structures in other systems as well.

Synthesis of Hollow Nanotubes of Zn2SiO4 or SiO2: Mechanistic Understanding and Uranium Adsorption Behavior

We report a facile synthesis of Zn2SiO4 nanotubes using a two-step process consisting of a wet-chemical synthesis of core-shell ZnO@SiO2 nanorods followed by thermal annealing. While annealing in air leads to the formation of hollow Zn2SiO4, annealing under reducing atmosphere leads to the formation of SiO2 nanotubes. We rationalize the formation of the silicate phase at temperatures much lower than the temperatures reported in the literature based on the porous nature of the silica shell on the ZnO nanorods. We present results from in situ transmission electron microscopy experiments to clearly show void nucleation at the interface between ZnO and the silica shell and the growth of the silicate phase by the Kirkendall effect. The porous nature of the silica shell is also responsible for the etching of the ZnO leading to the formation of silica nanotubes under reducing conditions. Both the hollow silica and silicate nanotubes exhibit good uranium sorption at different ranges of pH making them possible candidates for nuclear waste management.

Directed Assembly of Ultrathin Gold Nanowires over Large Area by Dielectrophoresis

Ultrathin Au nanowires (∼2 nm diameter) are interesting from a fundamental point of view to study structure and electronic transport and also hold promise in the field of nanoelectronics, particularly for sensing applications. Device fabrication by direct growth on various substrates has been useful in demonstrating some of the potential applications. However, the realization of practical devices requires device fabrication strategies that are fast, inexpensive, and efficient. Herein, we demonstrate directed assembly of ultrathin Au nanowires over large areas across electrodes using ac dielectrophoresis with a mechanistic understanding of the process. On the basis of the voltage and frequency, the wires either align in between or across the contact pads. We exploit this assembly to produce an array of contacting wires for statistical estimation of electrical transport with important implications for future nanoelectronic/sensor applications.

Hemophilus influenzae meningitis and septicaemia in a 14-month-old child after primary immunisation

We report a 14-month-male child, who developed Hemophilus influenzae meningitis after three primary doses of the vaccine. The child presented with fever and seizures. H. influenzae was isolated from both cerebrospinal fluid (CSF) and blood. The child also had features of septicaemia. Procalcitonin (104 ng/ml) and C-reactive protein (CRP--42.6 mg/dl) were high. Appropriate antibiotics were given. The child made an uneventful recovery. This case highlights vaccine failure, especially after primary immunisation alone.

Respiratory paralysis in a child: The severe axonal variant of childhood Guillain-Barré syndrome

Guillain-Barre syndrome (GBS) is a common cause of acute flaccid paralysis in children. Axonal variants of this disease are rare, and frequently life-threatening or debilitating. The course and outcome of a 17-month-old child with acute flaccid paralysis including severe respiratory involvement are presented. GBS was suspected. Nerve conduction studies demonstrated acute motor-sensory axonal neuropathy including both phrenic nerves. The difficulties with the diagnosis and management of this severe and life-threatening condition are discussed. Significant morbidity is also highlighted. Axonal variants of GBS although rare cause significant morbidity in children. Diagnosis relies solely on accurate neurophysiologic testing and is important because the available treatment options for GBS are frequently ineffective in these variants.

Room temperature growth of ultrathin Au nanowires with high areal density over large areas by in situ functionalization of substrate

Although ultrathin Au nanowires (∼2 nm diameter) are expected to demonstrate several interesting properties, their extreme fragility has hampered their use in potential applications. One way to improve the stability is to grow them on substrates; however, there is no general method to grow these wires over large areas. The existing methods suffer from poor coverage and associated formation of larger nanoparticles on the substrate. Herein, we demonstrate a room temperature method for growth of these nanowires with high coverage over large areas by in situ functionalization of the substrate. Using control experiments, we demonstrate that an in situ functionalization of the substrate is the key step in controlling the areal density of the wires on the substrate. We show that this strategy works for a variety of substrates ranging like graphene, borosil glass, Kapton, and oxide supports. We present initial results on catalysis using the wires grown on alumina and silica beads and also extend the method to lithography-free device fabrication. This method is general and may be extended to grow ultrathin Au nanowires on a variety of substrates for other applications.

Au2S(x)/CdS nanorods by cation exchange: mechanistic insights into the competition between cation-exchange and metal ion reduction

It is well known that metals with higher electron affinity like Au tend to undergo reduction rather than cation-exchange. It is experimentally shown that under certain conditions cation-exchange is dominant over reduction. Thermodynamic calculation further consolidates the understanding and paves the way for better predictability of cation-exchange/reduction reactions for other systems.

New insights into electronic and geometric effects in the enhanced photoelectrooxidation of ethanol Using ZnO nanorod/ultrathin Au nanowire hybrids

Oxidation of small organic molecules in a fuel cell is a viable method for energy production. However, the key issue is the development of suitable catalysts that exhibit high efficiencies and remain stable during operation. Here, we demonstrate that amine-modified ZnO nanorods on which ultrathin Au nanowires are grown act as an excellent catalyst for the oxidation of ethanol. We show that the modification of the ZnO nanorods with oleylamine not only modifies the electronic structure favorably but also serves to anchor the Au nanowires on the nanorods. The adsorption of OH(-) species on the Au nanowires that is essential for ethanol oxidation is facilitated at much lower potentials as compared to bare Au nanowires leading to high activity. While ZnO shows negligible electrocatalytic activity under normal conditions, there is significant enhancement in the activity under light irradiation. We demonstrate a synergistic enhancement in the photoelectrocatalytic activity of the ZnO/Au nanowire hybrid and provide mechanistic explanation for this enhancement based on both electronic as well as geometric effects. The principles developed are applicable for tuning the properties of other metal/semiconductor hybrids with potentially interesting applications beyond the fuel cell application demonstrated here.

Wrinkling of atomic planes in ultrathin Au nanowires

A detailed understanding of structure and stability of nanowires is critical for applications. Atomic resolution imaging of ultrathin single crystalline Au nanowires using aberration-corrected microscopy reveals an intriguing relaxation whereby the atoms in the close-packed atomic planes normal to the growth direction are displaced in the axial direction leading to wrinkling of the (111) atomic plane normal to the wire axis. First-principles calculations of the structure of such nanowires confirm this wrinkling phenomenon, whereby the close-packed planes relax to form saddle-like surfaces. Molecular dynamics studies of wires with varying diameters and different bounding surfaces point to the key role of surface stress on the relaxation process. Using continuum mechanics arguments, we show that the wrinkling arises due to anisotropy in the surface stresses and in the elastic response, along with the divergence of surface-induced bulk stress near the edges of a faceted structure. The observations provide new understanding on the equilibrium structure of nanoscale systems and could have important implications for applications in sensing and actuation.

Atomic structure of quantum gold nanowires: quantification of the lattice strain

Theoretical studies exist to compute the atomic arrangement in gold nanowires and the influence on their electronic behavior with decreasing diameter. Experimental studies, e.g., by transmission electron microscopy, on chemically synthesized ultrafine wires are however lacking owing to the unavailability of suitable protocols for sample preparation and the stability of the wires under electron beam irradiation. In this work, we present an atomic scale structural investigation on quantum single crystalline gold nanowires of 2 nm diameter, chemically prepared on a carbon film grid. Using low dose aberration-corrected high resolution (S)TEM, we observe an inhomogeneous strain distribution in the crystal, largely concentrated at the twin boundaries and the surface along with the presence of facets and surface steps leading to a noncircular cross section of the wires. These structural aspects are critical inputs needed to determine their unique electronic character and their potential as a suitable catalyst material. Furthermore, electron-beam-induced structural changes at the atomic scale, having implications on their mechanical behavior and their suitability as interconnects, are discussed.