Imposing Motion Variability for Ergonomic Human-Robot Collaboration

OCCUPATIONAL APPLICATIONS"Overassistive" robots can adversely impact long-term human-robot collaboration in the workplace, leading to risks of worker complacency, reduced workforce skill sets, and diminished situational awareness. Ergonomics practitioners should thus be cautious about solely targeting widely adopted metrics for improving human-robot collaboration, such as user trust and comfort. By contrast, introducing variability and adaptation into a collaborative robot's behavior could prove vital in preventing the negative consequences of overreliance and overtrust in an autonomous partner. This work reported here explored how instilling variability into physical human-robot collaboration can have a measurably positive effect on ergonomics in a repetitive task. A review of principles related to this notion of "stimulating" robot behavior is also provided to further inform ergonomics practitioners of existing human-robot collaboration frameworks.

Graphene-Based Analog of Single-Slit Electron Diffraction

This work reports the experimental demonstration of single-slit diffraction exhibited by electrons propagating in encapsulated graphene with an effective de Broglie wavelength corresponding to their attributes as massless Dirac fermions. Nanometer-scale device designs were implemented to fabricate a single-slit followed by five detector paths. Predictive calculations were also utilized to readily understand the observations reported. These calculations required the modeling of wave propagation in ideal case scenarios of the reported device designs to more accurately describe the observed single-slit phenomenon. This experiment was performed at room temperature and 190 K, where data from the latter highlighted the exaggerated asymmetry between electrons and holes, recently ascribed to slightly different Fermi velocities near the K point. This observation and device concept may be used for building diffraction switches with versatile applicability.

Comparison of Serum Zinc in Children of Wilson Disease and Non-Wilsonian Volunteers in Bangladesh

Wilson disease (WD) is an autosomal recessive disorder of copper metabolism with diverse clinical manifestations. Zinc (Zn) has been used for treatment of WD. Recent studies showed low serum zinc level in patients suffering from WD than the normal. This cross-sectional analytical study has been designed to compare the serum zinc level between paediatric patients suffering from WD but yet not started treatment and children who have normal ALT level. This study was carried out at the Department of Pediatric Gastroenterology and Nutrition, BSMMU, Dhaka, Bangladesh from July 2018 to June 2019. Total 51 children were included in this study. Among them 27 were diagnosed case of WD aged between three to eighteen years and 24 children of same ages who were suffering from other than liver disease having normal ALT were included as volunteers. The patients of WD were divided into four groups according to their presentation as acute hepatitis, chronic liver disease (CLD), acute liver failure & neuropsychiatric manifestation. Informed written consent was obtained from all patients and volunteers for participation in this study. Along with other physical findings and laboratory investigations 3 ml of venous blood were collected for estimation of serum zinc level. After estimation of serum zinc level results were analyzed statistically. The difference in serum zinc levels were compared between the groups. Serum zinc level was significantly lower in Wilson disease patients (43.8±19.7μg/dl; range: 13-83) compared to volunteers group (67.8±11.8μg/dl; range: 47-97) p<0.001. Among the diseased group, serum zinc level were significantly lower in 18 CLD (38.4±17.4μg/dl) and in 4 acute liver failure (33.1±3.7μg/dl) compared to 4 acute hepatitis (71.8±4.3μg/dl) (p=0.001) and (p<0.001) respectively. Mean serum zinc level was low in 4 Wilsonian acute liver failure (33.1±3.7μg/dl), which was significant compared to those (23) who presented as Wilson disease non acute liver failure (45.7±20.8μg/dl) (p=0.013). Serum zinc level was significantly lower in Wilson disease children compared to the volunteers. Zinc level was also found significantly low in Wilson disease presented as CLD and acute liver failure in comparison to Wilson disease presented as acute hepatitis.

COPD and glycopyrronium responsiveness assessment: An appraisal

Clinical Trial Registration

ECR/159/Inst/WB/2013/RR-20.

Background

Glycopyrronium bromide (a long-acting antimuscarinic agent: LAMA) appears pharmacokinetically suitable for testing bronchodilator responsiveness as salbutamol (short-acting β2-agonist: SABA). Exploring the feasibility, acceptability, degree of reversibility with glycopyrronium, and its comparison with that of salbutamol may be intriguing.

Methods

New, consecutive, and willing outpatient attendees in the same season of the two consecutive years with chronic obstructive pulmonary disease (FEV1/FVC <0.07; FEV1 <80% of predicted) were subjected to serial responsiveness with inhalation of salbutamol first followed by 50 μg dry powder glycopyrronium [Salbutamol- Glycopyrronium] (phase-1) in the first year and glycopyrronium followed by salbutamol [Glycopyrronium- Salbutamol] (phase-2) in the following year. We looked for the acceptability, adverse reactions, and degree of changes in FEV1, FVC, FEV1/FVC, and FEF25-75 with comparison between the two groups.

Results

The [Salbutamol- Glycopyrronium] group (n = 86) were similar in age, body mass index, and FEV1 to the [Glycopyrronium- Salbutamol] group (n = 88). Both the agents could make a significant (P <.0001) improvement in the parameters independently or as add-on when used serially in alternate orders. The intergroup difference at no stage was significant. The sensitive patients to salbutamol (n = 48), glycopyrronium (n = 44), and both (n = 12) have improvement of 165, 189, and 297 mL while a both-insensitive group (n = 70) had barely 44 mL of improvement. The protocol was universally accepted without any adverse events.

Conclusion

Serial testing of salbutamol and glycopyrronium responsiveness in alternate orders provides an insight regarding the independent and the add-on effects of these two agents. About 40% of our chronic obstructive pulmonary disease patients had no clinically appreciable difference in FEV1 with the salbutamol + glycopyrronium combination inhalation.

Evaluation of Fecal Pancreatic Elastase-1 as a Measure of Pancreatic Exocrine Function in Children with Pancreatitis

Pancreatic exocrine insufficiency occurs as a clinical consequence of chronic pancreatitis leading to fat maldigestion, malabsorption and malnutrition. Fecal elastase-1 is a laboratory-based test used for the diagnosis or exclusion of pancreatic exocrine insufficiency. The aim of the study was to observe the value of fecal elastase-1 in children with pancreatitis as an indicator of pancreatic exocrine insufficiency. This was a cross-sectional descriptive study conducted from January 2017 through June 2018. Thirty children with pain abdomen as control and 36 patients with pancreatitis as cases were included. An ELISA technique which recognizes human pancreatic elastase-1 from spot stool sample was employed for the test. Fecal elastase-1 activity in spot stool samples in acute pancreatitis (AP) ranged from 198.2-500μg/g with a mean of 342.1±136.4μg/g, acute recurrent pancreatitis (ARP) ranged from 15-500μg/g with a mean of 332.8±194.5μg/g and chronic pancreatitis (CP) ranged from 15-492.8μg/g with a mean of 222.2±197.1μg/g was obtained. In controls, fecal elastase-1 ranged from 28.4-500μg/g with a mean of 398.8±114.9μg/g. Disease severity was classified as mild to moderate pancreatic insufficiency (fecal elastase-1 100 to 200μg/g stool) was found in AP (14.3%) and CP (6.7%) cases. The severe pancreatic insufficiency (fecal elastase-1<100μg/g stool) was observed in ARP (28.6%) and CP (46.7%) cases. Malnutrition was observed in severe pancreatic insufficiency cases. This study result showed that fecal elastase-1 can be used as a measure of pancreatic exocrine function in children with pancreatitis.

The impact of lockdown on symptoms and health status of patients with chronic airway diseases: An appraisal of patient perceived impressions

Background

The pandemic-specific lockdown may influence the health status of patients with chronic airflow obstruction (CAO) as COPD, COPD-PH, and chronic asthma.

Objectives

To find the impact of the lockdown on symptoms, and the degree of perceived change in physical activity and emotional health with possible reasons including the indicators of ambient air pollution.

Methods

A cohort of CAO patients was telephonically enquired regarding their perceived well-being in symptom status, physical activity, and emotional health with the perceived contribution from plausible reasons (regular medication, simple food, no pollution, and family attention) for the change; all being expressed in percentages. The change in symptom scores as 0-39, 40-79, and 80-100 were regarded as 'low', 'medium', and 'high' respectively. The impact of the individual contributing factor was calculated statistically. The assessment of the CAT (COPD assessment test) score and the ambient air pollution (PM2.5 and PM10) was also done for their association with well-being.

Results

There was a universal improvement (p < 0.5) in COPD (n = 113), COPD-PH, (n = 40), and chronic asthma, (n = 19) as regards symptoms, physical activity, and emotional health that tallies to overall and individual change in CAT score. There were concomitant reductions in PM10 and PM2.5 levels during the lockdown compared to the same period of the previous year. All the four listed factors contributed with the 'no/low pollution' and 'simple food being the most important; on acting together, they reduced the moderate and severe symptoms impressively.

Conclusion

Reduced air pollution and simple food appear most important for the improvement of CAO patients during the lockdown period.

Prevalence and health status of COPD in rural West Bengal

Background

Understanding the spirometry-based prevalence with concomitant assessment of the health status is important to appreciate the chronic obstructive pulmonary disease (COPD)-scenario in a geographic area. There is hardly any such rural data available from the developing world.

Methods

We screened the adult population (>40 but <75 years) of seven villages in two different blocks of Birbhum district, West Bengal, for the presence respiratory symptoms (active or historical within 1 year). Those screened positive were tested with spirometry to diagnose COPD on having post bronchodilator FEV1/FVC <0.7. The COPD subjects were then applied with COPD assessment test (CAT).

Results

Out of 6255 subjects residing in the villages, 1984 subjects belonged to the target age group and 51.56% (1013 of 1984) of them qualified for spirometry which was possible in 953 (88.81%) of them. COPD was identified in 166 (16.36%) of symptomatic individuals. The calculated prevalence of COPD was 2.65% in overall population and 8.367% in population above 40 years. The COPD patients (mean age 59.77 ± 9.47 years) had a male preponderance (120 [72.29%] of 166). They were mostly malnourished (body mass index = 17.15 ± 2.97), with poorhealth status (CAT = 15) and moderate degree (GOLD category-II) of airflow limitation showing FEV1/FVC as 0.60 ± 0.07 and the mean post bronchodilator FEV1 as 52% of predicted (1.26 ± 0.42 L). Most of the sufferers (74.09%) were either active (n = 88) or ex-smokers (n = 35) (>10 pack-years). The nonsmokers constituted 25, 90% (n = 43).

Conclusion

The rural COPD prevalence in Bengal is far higher than the estimated national average with the health status of the sufferers been poor.

Studies on the behaviour of a passive containment cooling system for the Indian Advanced Heavy Water Reactor

A passive containment cooling system has been proposed for the advanced heavy water reactor being designed in India. This is to provide long term cooling for the reactor containment following a loss of coolant accident. The system removes energy released into the containment through immersed condensers kept in a pool of water. An important aspect of immersed condenser’s working is the potential degradation of immersed condenser’s performance due to the presence of noncondensable gases. An experimental programme to investigate the passive containment cooling system behaviour and performance has been undertaken in a phased manner. In the first phase, system response tests were conducted on a small scale model to under­stand the phenomena involved. Tests were conducted with constant energy input rate and with varying energy input rate simulating decay heat. With constant energy input rate, pressures in volume V1 and V2 reached almost steady value. With varying energy input rate V1 pressure dropped below the pressure in V2. The system could efficiently purge air from V1 to V2. The paper deals with the details of the tests conducted and the results obtained.

Analytical study of flow instability behaviour in a boiling two-phase natural circulation loop under low quality conditions

Analytical investigations have been carried out to study the flow instability behaviour in a boiling two-phase natural circulation loop under low quality conditions. For this purpose, the computer code TINFLO-S has been developed. The code solves the conservation equations of mass, momentum and energy and equation of state for homogeneous equilibrium two-phase flow using linear analytical technique. The results of the code have been validated with the experimental data of the loop for both the steady state and stability. The study reveals that the stability behaviour of low quality flow oscillations is different from that of the high quality flow oscillations. The instability reduces with increase in power and throttling at the inlet of the heater. The instability first increases and then reduces with increase in pressure at any subcooling. The effects of diameter of riser pipe, heater and the height of the riser on this instability are also investigated.

Experimental studies on condensation of steam mixed with noncondensable gas inside the vertical tube in a pool filled with subcooled water

A passive containment cooling system with immersed condensers has been proposed as one of the alternatives for the Advanced Heavy Water Reactor (AHWR) being designed in India. The system removes residual/decay heat released into the containment through the immersed condensers kept in a pool of water following loss of coolant accident. An important aspect of the immersed condensers is the potential degradation of its performance due to the presence of noncondensable gases. Experiments are performed to obtain reliable data on condensation phenomena in presence of air. These experiments are conducted on full-scale tubes of condensers immersed in a pool of water maintaining similar conditions as in the prototype of AHWR. A method has been proposed for the determination of the local heat transfer rate using correlations given in literature. The parametric effects of air mass fraction, pressure, steam flow, etc. on condensation heat transfer in presence of noncondensable gas have been studied. The experimental results are compared with the correlations given in literature.

The increasing trend and the seasonal variation in attendance of diffuse parenchymal lung disease patients presenting to a pulmonary clinic in Eastern India

Background:

Diffuse parenchymal lung disease (DPLD) is not an uncommon problem in clinical practice. Although the exact prevalence of DPLD in India is not known, the relative etiological distribution in DPLD in India has been reported. There has been no information as regards the seasonality of the disease.

Patients and Methods:

The archive of the Institute of Pulmocare and Research, Kolkata, was searched for the number of new patients registered at the outpatient department to a single consultant (practicing in the same style on appointment only) over years from 2009 to 2019. The attendance (absolute and relative) was arranged year wise and then month wise to look for the annual and seasonal trends, if any.

Results:

A total of 2226 patients were registered from 2009 to 2019. There has been a steady increase in both the absolute number (104 in 2009 to 204 in 2019) and the relative percentage of attendance (4.36% in 2009 to 6.9% in 2019) of new registration of DPLD patients over the years. Regarding seasonal variation, two consistent peaks in attendance have been observed as December–January and April–May over the years with dips in February and September; the first being more consistent then the latter.

Conclusions:

The increase in relative attendance in the DPLD patients over the years needs further investigation to establish a rising trends in incidence and prevalence of DPLD. The unequivocal trend in seasonal variation needs attention and further research.

Impact of long-term doxycycline on lung function & exacerbations: A real-world open, prospective pilot observation on chronic obstructive pulmonary disease

Background & objectives:

Upregulation of matrix metalloproteinases (MMPs) is related to the pathogenesis of chronic obstructive pulmonary disease (COPD). We aimed at assessing the tolerability and impact of long-term use of MMP inhibitor doxycycline in COPD.

Methods:

A cohort of COPD patients was randomized to continue a uniform COPD treatment with or without add-on long-term oral doxycycline. The lung exacerbations (spirometry), adverse events and health status (COPD Assessment Test score) were noted at 3, 6, 9 and 12 months of therapy. Measurement of the serum MMP-2, and 9 and high-sensitive C-reactive protein (hs-CRP) levels was done at the start of the study and at three months, whenever possible.

Results:

There were 27, 19, 13 and 10 patients with add-on doxycycline group and 22, 19, 11 and 7 patients with COPD treatment alone at 3, 6, 9 and 12 months of treatment respectively. The improvement was obviousaconsistent and serial improvement of health st nd mostly (at 6 and 12 months) significant (P>0.05) for lung function parameters [forced expiratory volume in one second (FEV₁), FEV₁/forced vital capacity (FVC) and forced expiratory flow at 25-75% of FVC (FEF_25-75)] and universal for health status at all measurements, with an overall 26.69 per cent reduction in exacerbations. The analysis with the lung function changes in the available population with protocol violation also supported the same trend. The concomitant reduction in serum MMP-9 (P=0.01), MMP-2 (P=0.01) and hs-CRP (P=0.0001) levels (n=21) at three months was also significant. The adverse reactions with add-on doxycycline appeared acceptable.

Interpretation & conclusions:

Long-term doxycycline appears well tolerated and seems to improve lung function, health status and exacerbations in COPD. The claim needs further scientific validations.

Population genetic structure and association mapping for iron toxicity tolerance in rice

Iron (Fe) toxicity is a major abiotic stress which severely reduces rice yield in many countries of the world. Genetic variation for this stress tolerance exists in rice germplasms. Mapping of gene(s)/QTL controlling the stress tolerance and transfer of the traits into high yielding rice varieties are essential for improvement against the stress. A panel population of 119 genotypes from 352 germplasm lines was constituted for detecting the candidate gene(s)/QTL through association mapping. STRUCTURE, GenAlEx and Darwin softwares were used to classify the population. The marker-trait association was detected by considering both the Generalized Linear Model (GLM) and Mixed Linear Model (MLM) analyses. Wide genetic variation was observed among the genotypes present in the panel population for the stress tolerance. Linkage disequilibrium was detected in the population for iron toxicity tolerance. The population was categorized into three genetic structure groups. Marker-trait association study considering both the Generalized Linear Model (GLM) and Mixed Linear Model (MLM) showed significant association of leaf browning index (LBI) with markers RM471, RM3, RM590 and RM243. Three novel QTL controlling Fe-toxicity tolerance were detected and designated as qFeTox4.3, qFeTox6.1 and qFeTox10.1. A QTL reported earlier in the marker interval of C955-C885 on chromosome 1 is validated using this panel population. The present study showed that QTL controlling Fe-toxicity tolerance to be co-localized with the QTL for Fe-biofortification of rice grain indicating involvement of common pathway for Fe toxicity tolerance and Fe content in rice grain. Fe-toxicity tolerance QTL qFeTox6.1 was co-localized with grain Fe-biofortification QTLs qFe6.1 and qFe6.2 on chromosome 6, whereas qFeTox10.1 was co-localized with qFe10.1 on chromosome 10. The Fe-toxicity tolerance QTL detected from this mapping study will be useful in marker-assisted breeding programs.

Graphene quantum Hall effect parallel resistance arrays

As first recognized in 2010, epitaxial graphene on SiC(0001) provides a platform for quantized Hall resistance (QHR) metrology unmatched by other two-dimensional structures and materials. Here we report graphene parallel QHR arrays, with metrologically precise quantization near 1000 Ω. These arrays have tunable carrier densities, due to uniform epitaxial growth and chemical functionalization, allowing quantization at the robust ν = 2 filling factor in array devices at relative precision better than 10^-8. Broad tunability of the carrier density also enables investigation of the ν = 6 plateau. Optimized networks of QHR devices described in this work suppress Ohmic contact resistance error using branched contacts and avoid crossover leakage with interconnections that are superconducting for quantizing magnetic fields up to 13.5 T. Our work enables more direct scaling of resistance for quantized values in arrays of arbitrary network geometry.

Onsager-Casimir frustration from resistance anisotropy in graphene quantum Hall devices

We report on nonreciprocity observations in several configurations of graphene-based quantum Hall devices. Two distinct measurement configurations were adopted to verify the universality of the observations (i.e., two-terminal arrays and four-terminal devices). Our findings determine the extent to which epitaxial graphene anisotropies contribute to the observed asymmetric Hall responses. The presence of backscattering induces a device-dependent asymmetry rendering the Onsager-Casimir relations limited in their capacity to describe the behavior of such devices, except in the low-field classical regime and the fully quantized Hall state. The improved understanding of this quantum electrical process broadly limits the applicability of the reciprocity principle in the presence of quantum phase transitions and for anisotropic two-dimensional materials.

Two chair test: a substitute of 6 min walk test appear cardiopulmonary reserve specific

Background

A simple and efficient exercise test possible in a small space is welcome to supplement 6 min walk test (6MWT) that demands a 100 feet corridor to perform.

Methods

The proposed two chair test (2CT) makes a person to sit and move five times between two chairs placed face to face at 5 feet apart and note the changes in pulse-rate (PR) and arterial oxygen saturation (SpO₂) at every 10 s for 2 min after that. Comparison of the post-exercise measurements (PR and SpO₂) with a repeat performance in same patients was done for reproducibility and doing the same after 6MWT and 2CT in another set of patients was meant for for acceptability. The statistical analysis was made on moment to moment change, mean maximal difference and mean cumulative difference for the measurements using p value, z-score, r value and principal component analysis (PCA).

Findings

A total of 40 and 60 volunteers were included for testing reproducibility and acceptability. On both the sets, the difference in most of comparisons between the measured variable (PR and SpO₂) showed the p values remaining insignificant (>0.05), and z-score being <1 SD of the corresponding other and the correlation coefficients (r) remaining excellent (>0.9). Furthermore, the PCA shows complete overlapping. The post-exercise changes did not corelate the walking distance in 6MWT.

Interpretation

The proposed 2CT demands small space and appears reproducible and comparable with 6MWT in terms of its post-exercise impact on PR and SpO₂. This novel test also appears more of cardiopulmonary reserve specific.

Enhancing Thermal Interface Conductance to Graphene Using Ni-Pd Alloy Contacts

To identify superior thermal contacts to graphene, we implement a high-throughput methodology that systematically explores the Ni-Pd alloy composition spectrum and the effect of Cr adhesion layer thickness on thermal interface conductance with monolayer graphene. Frequency domain thermoreflectance measurements of two independently prepared Ni-Pd/Cr/graphene/SiO₂ samples identify a maximum metal/graphene/SiO₂ junction thermal interface conductance of 114 ± (39, 25) MW/m² K and 113 ± (33, 22) MW/m² K at ∼10 at. % Pd in Ni-nearly double the highest reported value for pure metals and 3 times that of pure Ni or Pd. The presence of Cr, at any thickness, suppresses this maximum. Although the origin of the peak is unresolved, we find that it correlates with a region of the Ni-Pd phase diagram that exhibits a miscibility gap. Cross-sectional imaging by high-resolution transmission electron microscopy identifies striations in the alloy at this particular composition, consistent with separation into multiple phases. Through this work, we draw attention to alloys in the search for better contacts to two-dimensional materials for next-generation devices.

Stochastic point process models for multi-compartment dendritic-tree input-output transformations in spiking neurons

We extend stochastic point-process generalized linear models (PPGLMs) to the estimation of input-output transformations in dendritic trees and their contribution to the generation of soma action potentials in multi-compartmental models of single neurons. We used simulations of a model enthorinal cortex pyramidal neuron, with known dentritic tree and soma spatial organization, including active compartments defined in terms of standard cable and standard Hodgkin-Huxley equations. Each dendritic compartment (391 total) was endowed with either excitatory (E) or inhibitory (I) synaptic inputs whose strength was randomly specified. We examined the cases of both homogeneous and inhomogeneous spatial distributions for E and I synaptic inputs. The times for synaptic inputs followed a Poisson process with different mean rate regimes varying from 50 to 600 inputs/s. The soma membrane potential received also a background noise in the form of an Ornstein-Uhlenbeck process. Our main findings are: (1) Power spectra of soma membrane potentials revealed subthreshold resonances at ~40 Hz and ~80 Hz; (2) The contribution of different dendritic compartments, under the examined input ranges and spatial distributions, depended not only of the dendrite-soma path distance, but also on the number of compartments in the dendritic segment. (3) Estimated conditional intensity functions (CIFs) with PPGLMs successfully predicted spiking activity based on given E-I input times; area under ROC curves computed on test data varied from 0.8 - 0.95. (4) The CIF models identified compartments and regions receiving E-I synaptic inputs; Estimated temporal filters were consistent with dendrite-soma path distances and input weights. We expect this type of PPGLMs to contribute to data-driven identification of input-output transformations in dentritic trees based on single-neuron Ca²⁺ and voltage indicator imaging data.

Ferroelectric Domain Walls in PbTiO3 Are Effective Regulators of Heat Flow at Room Temperature

Achieving efficient spatial modulation of phonon transmission is an essential step on the path to phononic circuits using "phonon currents". With their intrinsic and reconfigurable interfaces, domain walls (DWs), ferroelectrics are alluring candidates to be harnessed as dynamic heat modulators. This paper reports the thermal conductivity of single-crystal PbTiO₃ thin films over a wide variety of epitaxial-strain-engineered ferroelectric domain configurations. The phonon transport is proved to be strongly affected by the density and type of DWs, achieving a 61% reduction of the room-temperature thermal conductivity compared to the single-domain scenario. The thermal resistance across the ferroelectric DWs is obtained, revealing a very high value (≈5.0 × 10^-9 K m² W^-1), comparable to grain boundaries in oxides, explaining the strong modulation of the thermal conductivity in PbTiO₃. This low thermal conductance of the DWs is ascribed to the structural mismatch and polarization gradient found between the different types of domains in the PbTiO₃ films, resulting in a structural inhomogeneity that extends several unit cells around the DWs. These findings demonstrate the potential of ferroelectric DWs as efficient regulators of heat flow in one single material, overcoming the complexity of multilayers systems and the uncontrolled distribution of grain boundaries, paving the way for applications in phononics.

Effect of doxycyline in chronic obstructive pulmonary disease - An exploratory study

PURPOSE

Various mechanisms, including oxidative stress, inflammation, and protease-antiprotease imbalance are proposed for the progressive decline in lung function in chronic obstructive pulmonary disease (COPD). Doxycycline, a broad spectrum tetracycline antibiotic, is reported to have non-antimicrobial matrix metalloproteinases (MMP) inhibitory action in various inflammatory conditions. The effect of doxycycline in COPD is hereby assessed in the present randomized prospective study.

PATIENTS AND METHODS

The first group of COPD patients (n = 30; mild (n = 3), moderate (n = 6), severe (n = 7), very severe (n = 14) as per GOLD II & III criteria was prescribed the standard therapy, a combination of (i) short acting anti-muscarinic agent (SAMA) + short acting β2 agonist (SABA) inhaled and (ii) corticosteroid inhaled (ICS) + long acting β2 agonist (LABA) (iii) ICS + LABA + LAMA. Whereas doxycycline (100 mg), was used daily once or twice as per Body Mass Index (BMI), as an add-on to existing standard therapy for the second group of patients (n = 30; mild (n = 2), moderate (n = 7), severe (n = 8), very severe (n = 13). All recruited patients were followed-up after 3 months of treatment. Lung function index FEV1(%) predicted, FEV1/FVC (%), quality of life status including COPD Assessment Test (CAT), St. George's Respiratory Questionnaire (SGRQ) were assessed. Routine blood cell count also was performed.

RESULTS

Biochemical analysis included estimation of oxidative stress markers, inflammatory cytokines and proteases in plasma of both the groups. Reduction in oxidative stress is evidenced by a significant decrease in Lipid hydro peroxides (LPO), total oxidative stress (TOS) and increase in glutathione peroxidase (GSH-PX), reduced glutathione (GSH) and total anti-oxidant capacity (TAO) nitrite and nitrate (NOx) along with peroxynitrate following 3 months of add-on doxycycline treatment. Reduced levels of cytokines such as interleukin IL-6, TNF-α, IL-8 were also observed. Multivariate analysis identified TNF-α major effective discriminant among pre and post doxycycline treated COPD patients. The expression of TNF-α was inversely correlated with FEV1/FVC (%) changes. The levels of MMP-2 and MMP-9/tissue inhibitors of metalloproteinases (TIMP)-1 ratio (MMP-9/ TIMP-1), also decreased significantly and the decline could be associated with TOS. A significant increase in bilirubin and reduced glutathione (GSH) level was noticed in standard therapy group.

CONCLUSION

These data suggest that the improvement in lung function and quality of life in COPD patients may probably be attributed to the antioxidant, anti-inflammatory and anti-MMP activity of doxycycline. The potential therapeutic role of long-term doxycycline, in addition to its traditional antibiotic effect, definitely warrants further attention.

Metabolomic signatures of asthma-COPD overlap (ACO) are different from asthma and COPD

INTRODUCTION

Asthma-chronic obstructive pulmonary disease (COPD) overlap, termed as ACO, is a complex heterogeneous disease without any clear diagnostic or therapeutic guidelines. The pathophysiology of the disease, its characteristic features, and existence as a unique disease entity remains unclear. Individuals with ACO have a faster lung function decline, more frequent exacerbations, and worse quality of life than those with COPD or asthma alone.

OBJECTIVES

The present study aims to determine whether ACO has a distinct metabolic profile in comparison to asthma and COPD.

METHODS

Two different groups of patients were recruited as discovery (D) and validation (V) cohorts. Serum samples obtained from moderate and severe asthma patients diagnosed as per GINA guidelines [n = 34(D); n = 32(V)], moderate and severe COPD cases identified by GOLD guidelines [n = 30(D); 32(V)], ACO patients diagnosed by joint GOLD and GINA guidelines [n = 35(D); 40(V)] and healthy controls [n = 33(D)] were characterized using nuclear magnetic resonance (NMR) spectrometry.

RESULTS

Multivariate and univariate analysis indicated that 12 metabolites [lipid, isoleucine, N-acetylglycoproteins (NAG), valine, glutamate, citric acid, glucose, L-leucine, lysine, asparagine, phenylalanine and histidine] were dysregulated in ACO patients when compared with both asthma and COPD. These metabolites were further validated in a fresh cohort of patients, which again exhibited a similar expression pattern.

CONCLUSIONS

Our findings suggest that ACO has an enhanced energy and metabolic burden associated with it as compared to asthma and COPD. It is anticipated that our results will stimulate researchers to further explore ACO and unravel the pathophysiological complexities associated with the disease.

Determination of size dependent carrier capture in InGaN/GaN quantum nanowires by femto-second transient absorption spectroscopy: effect of optical phonon, electron-electron scattering and diffusion

Understanding the ultrafast processes corresponding to carrier capture, thermalization and relaxation is essential to design high speed optoelectronic devices. Here, we have investigated a size dependent carrier capture process in InGaN/GaN 20, 50 nm nanowires and quantum well systems. Femto-second transient absorption spectroscopy reveals that the carrier capture is a two-step process. The carriers are captured in the barrier by polar optical phonon (POP) scattering. They further scatter into the active region by electron-electron and POP scatterings. The capture is found to slow down for quantum confined structures. A significant number of carriers are found to disappear from the barrier during the diffusion process. All the experimental observations are explained in a simulation framework depicting various scattering mechanisms.

Enhanced luminescence from InGaN/GaN nano-disk in a wire array caused by surface potential modulation during wet treatment

Here we have demonstrated the profound impact of surface potential on the luminescence of an array of InGaN/GaN nano-disk in a wire heterostructure. The change in surface potential is brought about by a combination of dry and successive wet-processing treatments. The photoluminescence (PL) properties are determined as a function of size and height of this array of nano-disks. The observed characteristics are coherently explained by considering a change in quantum confinement induced by the change in surface potential, quantum-confined Stark effect, exciton binding energy and strain relaxation for varying surface potential. The change in hole bound state energy due to parabolic potential well near the side-wall is found to be the dominating factor. The PL peak position, full width at half-maximum, strain relaxation and integrated PL intensity are studied as a function of incident power and temperature. The devices demonstrate higher integrated PL intensity and slope efficiency.

The impact on health status in short- and long-terms of a novel and non-orthodox real-world COPD rehabilitation effort in rural India: an appraisal

Background

Rehabilitation has been an integral part of management of COPD. Since the implementation of the standard rehabilitation protocol is hardly possible in the rural developing world, aiming to make a feasible alternate effort may be worthwhile.

Methods

COPD patients diagnosed through spirometry were first stabilized with 6 weeks of uniform pharmacotherapy. Subsequently, they were subjected to a curriculum-based intensive single-session intervention with education, bronchial hygiene, and exercise training. The latter involved whole body exercise, pursed lip breathing, and diaphragmatic exercise. The participants continued to practice the exercises under real-world encouragement and supervision from trained volunteers. The impact was appraised in terms of change in health status through COPD assessment test (CAT) score measurements at stabilization, and after 6 weeks and 1 year of the intensive training and education.

Results

At stabilization, 70 out of 96 selected COPD subjects (73%) turned up (with mean age 62±9 years and mean FEV₁ as 1.16±0.39 L) showing improvement as per CAT score (p=0.0001) from pharmacotherapy. After practicing the imparted education and training for 6 weeks, all these 70 participants had further significant improvement in the health status (n=70, p=0.00001). This improvement, been reinforced and supervised, continued to last even at 1 year (n=54, p=0.0001).

Conclusion

The self-managed practice of a single-session education and training under real-world supervision can bring forth significant long-term improvement in the health status of COPD sufferers. Such simple and feasible intervention may substitute formal COPD rehabilitation programs in resource constraint situations.

Geochemical signatures and isotopic systematics constraining dynamics of fluoride contamination in groundwater across Jamui district, Indo-Gangetic alluvial plains, India

A data set of 76 water samples are obtained from surface and sub-surface water bodies to investigate chemical parameters and stable isotopic signatures in order to drive factors leading to fluoride (F^-) contamination in groundwater of parts of Jamui district, India. Hydrochemical facies reveals that F^- concentration is lower in Ca²⁺-HCO₃^- facies representative of recharge area, while discharge area has a tendency towards Na⁺-HCO₃^- facies with elevated F^- concentration. The ionic ratios Na⁺/Ca²⁺>1, Na⁺/Cl^->1, (Ca²⁺+Mg²⁺)/HCO₃^-<1, Na⁺+K⁺ = 0.5TZ⁺ and Ca²⁺+Mg²⁺ = TZ⁺ witness silicate weathering by water-rock interaction coupled with ion exchange and prolonged residence time, are the principle factors for fluoride contamination (3.6 mg/L to 5.8 mg/L) in 67% of deeper bore wells. Geochemical modelling testifies excess of alkalinity due to the dominance of bicarbonate ion leading to calcite precipitation and dissolution of fluoride in solution contributing to fluoride contamination. The chemometric analysis reveals that the water chemistry of the study area is controlled by both anthropogenic and natural sources, and enrichment of fluoride in groundwater is possibly from geogenic source (fractured granite gneiss). The stable isotope plot shows that most of the samples fall along local meteoric water line indicating that the groundwater is originated from local precipitation with a possibility of evaporative enrichment. Groundwater enriched in δ¹⁸O is positively correlated with F^- suggesting evaporation and longer residence time of water. Spatially elevated F^- prevails in the eastern bank of Kiul River and along the groundwater flow direction, which is attributed to control of dynamics of hydrogeological conditions.

High-resolution computerized tomography changes in diffuse parenchymal lung disease from chronic hypersensitivity pneumonitis related to bird antigen

Background:

Chronic hypersensitivity pneumonitis (HP) is the most common cause of diffuse parenchymal lung disease (DPLD) in India. There is no data regarding the avian antigen exposure-associated DPLD from the country.

Methods:

Chronic HP from exposure to avian antigen was diagnosed when the high resolution computerized tomography (HRCT) showed features for HP and was supported by the history of exposure to pigeons, the presence of precipitin antibodies (IgG) to avian antigen in high titre with negative rheumatoid factor, antinuclear antibody, and no clinical clue for a collagen vascular disease. The HRCT changes were noted on Likert scale (0–5) in terms of affection of peripheral and/or axial involvement, reticulation, honeycombing, haze, mosaic, traction bronchiectasis, pleural reactions, features of pulmonary hypertension, and air cysts. Cardiomegaly and independent cardiac chamber enlargement were also recorded.

Results:

The lower lobes were predominantly (65.6%) affected with similar frequency (78.1) of peripheral and axial parenchymal affection. The parenchymal changes in HRCT were haze or ground-glass opacity (100%), mosaic appearance (93.75%), reticulations (68.75%), traction bronchiectasis (34.3%), air cysts (21.8%), and honeycombing (9.37%). Pleural reactions, though not described so far, were found in 50% of cases. Features of pulmonary hypertension (87.5%), cardiomegaly (50%), left and right atrial enlargement (81.2% and 78.1%), and right ventricular enlargement (31.2%) were the common echocardiography findings.

Conclusion:

Chronic HP from avian exposure shows predominantly lower lobe involvement with haze, reticulation, features of pulmonary hypertension, and pleural reactions as common HRCT findings. The likelihood of pulmonary hypertension appears high and although honeycombing is often present, the classical UIP pattern has not been found.

Analysis and Characterization of Alumina Particles Reinforced Ultra High Molecular Weight Polyethylene Composite for Acetabular Cup

Composites of ultra high molecular weight polyethylene (UHMWPE) reinforced with 5, 10 and 15 percent of alumina were prepared by a technique of uniform mixing and moulding. Acetabular cups were produced by compression moulding methods. A new walk simulator was also developed in-house for testing the tribological performances of these cups. The results from walk simulator tests are encouraging. Using a human walk simulator machine we did in vitro wear testing. Characterizations were performed to analyse the microstructure, composition, phase purity and crystalline by using XRD, DSC/TGA. Biocompatibility test was done by cytotoxicity, hemocompatibility and MTT assay methods. Biocompatibility tests gave hemolysis counts with these polymer composites well within the acceptable range and the results indicate a significant improvement in biocompatibility of the polymer composites over the in parent polymers.

Strong Size Dependency on the Carrier and Photon Dynamics in InGaN/GaN Single Nanowalls Determined Using Photoluminescence and Ultrafast Transient Absorption Spectroscopy

Here, we have demonstrated strong size dependency of quasi-equilibrium and nonequilibrium carrier and photon dynamics in InGaN/GaN single nanowalls using photoluminescence and transient absorption spectroscopy. We demonstrate that two-dimensional carrier confinement, strain relaxation, and modified density of states lead to a reduced Stokes shift, smaller full width at half-maxima, increased exciton binding energy, and reduced nonradiative recombination. The ultrafast transient spectroscopy shows that carrier capture is a two-step process dominated by optical phonons and carrier-carrier scattering in succession. The carrier capture is a strongly size-dependent process and becomes slower due to modulation of the density of available states for progressively decreasing nanowall sizes. The slowest process is the electron-hole recombination, which is also extremely size-dependent and the rate increases by almost an order of magnitude in comparison to that of quantum-well structures. Electron-hole wave function overlap and modified density of states are among the key aspects in determining all the properties of these structures.

Pancreatic stellate cells in pancreatic cancer: In focus

Pancreatic stellate cells are stromal cells that have multiple physiological functions such as the production of extracellular matrix, stimulation of amylase secretion, phagocytosis and immunity. In pancreatic cancer, stellate cells exhibit a different myofibroblastic-like morphology with the expression of alpha-smooth muscle actin, the activated form is engaged in several mechanisms that support tumorigenesis and cancer invasion and progression. In contrast to the aforementioned observations, eliminating the stromal cells that are positive for alpha-smooth muscle actin resulted in immune-evasion of the cancer cells and resulted in worse prognosis in animal models. Understanding the cancer-stromal signaling in pancreatic adenocarcinoma will provide novel strategies for therapy. Here we provide an updated review of studies that handle the topic "pancreatic stellate cells in cancer" and recent experimental approaches that can be the base for future directions in therapy.

Tuberculosis associated pulmonary hypertension: The revelation of a clinical observation

Background:

Pulmonary tuberculosis is not listed as a cause of pulmonary hypertension (PH). Scanty information is available in the literature regarding this issue.

Methods:

A group of patients with a history of pulmonary tuberculosis were diagnosed to have PH on the basis of a novel clinico-radio-echocardiographic criteria. Subdivided into two groups on the basis of the history of smoking, we looked for their demographic, spirometric, radiological characteristics along with the quality of life assessment.

Results:

A total of 40 patients (21 smokers and 19 nonsmokers) were found to have PH with history of pulmonary tuberculosis. The two groups were similar radiologically including the extent of fibrosis. The nonsmoker group had lower age range (52.16 ± 14.81 vs. 63.1 ± 10.05, P = 0.01), worse chronic obstructive pulmonary disease (COPD) assessment test score (16.11 ± 6.24 vs. 13.9 ± 5.6, P = 0.25) and higher pulmonary artery (PA) pressure (46.39 ± 7.44 vs. 44.55 ± 8.04, P = 0.46) compared to the smokers. Overall and for the smoker group, in particular, the spirometric pictures were favoring obstruction without reversibility as in COPD (forced expiratory volume in 1 second [FEV₁] % as 64.26 ± 18.38 and 58.85 ± 14.61 with % of predicted FEV₁ being 43.74 ± 17.26 and 42.38 ± 16.64 respectively). However, those with no history of smoking had restrictive changes as in diffuse parenchymal lung disease (DPLD) in their spirometry (FEV₁/forced vital capacity [FVC] of 79.33 ± 19.93 and FVC as 49.67 ± 11.54% of predicted). The smoker group had far more obvious involvement of the small airways in terms of change in FEF_25-75 compared to nonsmokers (FEF_25-75 = 22.85 ± 19.68 vs. 63.83 ± 48.61).

Conclusion:

PH appears associated with the history of pulmonary tuberculosis. With or without a history of smoking, they pose two distinct phenotypes in spirometry as COPD and DPLD. The DPLD phenotype had worse quality of life.

Expression of microRNA-155 correlates positively with the expression of Toll-like receptor 7 and modulates hepatitis B virus via C/EBP-β in hepatocytes

Effective recognition of viral infection and successive activation of antiviral innate immune responses are vital for host antiviral defence, which largely depends on multiple regulators, including Toll-like receptors (TLRs) and microRNAs. Several early reports suggest that specific TLR-mediated immune responses can control hepatitis B virus (HBV) replication and express differentially with disease outcome. Considering the versatile function of miR-155 in the TLR-mediated innate immune response, we aimed to study the association between miR-155 and TLRs and their subsequent impact on HBV replication using both a HBV-replicating stable cell line (HepG2.2.15) and HBV-infected liver biopsy and serum samples. Our results showed that miR-155 was suppressed during HBV infection and a subsequent positive correlation of miR-155 with TLR7 activation was noted. Further, ectopic expression of miR-155 in vitro reduced HBV load as evidenced from reduced viral DNA, mRNA and subsequently reduced level of secreted viral antigens (HBsAg and HBeAg). Our results further suggested that CCAAT/enhancer-binding protein-β (C/EBP-β), a positive regulator of HBV transcription, was inhibited by miR-155. Taken together, our study established a correlation between miR-155 and TLR7 during HBV infection and also demonstrated in vitro that increased miR-155 level could help to reduce HBV viral load by targeting C/EBP-β.

Novel algorithm to identify and differentiate specific digital signature of breath sound in patients with diffuse parenchymal lung disease

BACKGROUND AND OBJECTIVE

Auscultation is an important part of the clinical examination of different lung diseases. Objective analysis of lung sounds based on underlying characteristics and its subsequent automatic interpretations may help a clinical practice.

METHODS

We collected the breath sounds from 8 normal subjects and 20 diffuse parenchymal lung disease (DPLD) patients using a newly developed instrument and then filtered off the heart sounds using a novel technology. The collected sounds were thereafter analysed digitally on several characteristics as dynamical complexity, texture information and regularity index to find and define their unique digital signatures for differentiating normality and abnormality. For convenience of testing, these characteristic signatures of normal and DPLD lung sounds were transformed into coloured visual representations. The predictive power of these images has been validated by six independent observers that include three physicians.

RESULTS

The proposed method gives a classification accuracy of 100% for composite features for both the normal as well as lung sound signals from DPLD patients. When tested by independent observers on the visually transformed images, the positive predictive value to diagnose the normality and DPLD remained 100%.

CONCLUSIONS

The lung sounds from the normal and DPLD subjects could be differentiated and expressed according to their digital signatures. On visual transformation to coloured images, they retain 100% predictive power. This technique may assist physicians to diagnose DPLD from visual images bearing the digital signature of the condition.

Association of hypoglycemia, hypocalcemia and hypomagnesemia in neonates with perinatal asphyxia

The clinical evidence of neurological menifestations associated with asphyxia is described as hypoxic ischaemic encephalopathy (HIE). A variety of metabolic problems are present in asphyxiated newborns including hypoglycemia, hypocalcemia, hypomagnesemia and others metabolic abnormalities. Some of these biochemical disturbances may trigger seizure or potentiate further brain damage. This cross sectional case-control study was done in Mymensingh Medical College Hospital, to identify the association of hypoglycemia, hypocalcemia, hypomagnesemia in neonates with perinatal asphyxia. Study period was six months. Sample size was 60. Among total sample 30 term asphyxiated newborns of <24 hours age were case and equal number term healthy newborns <24 hours age were control. The main clinical presentations were delayed cry after birth along with respiratory distress, convulsion and absence of cry in asphyxiated newborns. Major physical findings were cyanosis, convulsion and tachypnoea in asphyxiated group. The mean value of serum calcium level was significantly lower in asphyxiated newborns (7.37 ± 0.10mg/dl) than control value (8.04±0.09mg/dl). Hypocalcemia was found among 23.33% babies in case group. On the contrary, hypocalcemia was found in single baby among control group. The mean value of serum magnesium was significantly lower in asphyxiated newborns (1.83 ± 0.04mg/dl) than control value (1.96 ± 0.05mg/dl). Hypomagnesemia was found among 3(10%) newborns but none was found among control group. Hypoglycemia was found in 7(23.33%) cases though the mean value of blood glucose was higher in case group (5.72 ± 0.62mmol/l) than control group (4.87 ± 0.15mmol/l) difference was not statistically significant. Combined hypoglycemia, hypocalcemia and hypomagnesemia were found in 1(3.33%) case; combined hypoglycemia and hypocalcemia were found in 2(6.67%) cases; and combined hypocalcemia and hypomagnesemia were found in 1(3.33%) case. During the study period, 3(10.0%) cases were expired but no death occurred among control group. This study shows isolated or combined hypoglycemia, hypocalcemia, hypomagnesemia are frequently found in newborns with perinatal asphyxia. So, it is necessary to monitor blood glucose, serum calcium and also serum magnesium among asphyxiated newborns for proper management.