On the absence of collective motion in a bulk suspension of spontaneously rotating dielectric particles.

A suspension of dielectric particles rotating spontaneously when subjected to a DC electric field in two dimensions next to a no-slip electrode has proven to be an ideal model for active matter [Bricard et al., Nature, 2013, 503, 95-98]. In this system, an electrohydrodynamic (EHD) instability called Quincke rotation was exploited to create self-propelling particles which aligned with each other due to EHD interactions, giving rise to collective motion on large length scales. It is natural to question whether a suspension of such particles in three dimensions will also display collective motion and spontaneously flow like bacterial suspensions do. Using molecular dynamics type simulations, we show that dielectrophoretic forces responsible for chaining in the direction of the applied electric field in conventional electrorheological fluids and the counter-rotation of neighboring particles in these chains prevent collective motion in suspensions undergoing spontaneous particle rotations. Our simulations discover that the fundamental microstructural unit of a suspension under Quincke rotation is a pair of counter-rotating spheres aligned in the direction of the electric field. We perform a linear stability analysis that explains this observation.

Ni6Se5, an unexplored transition metal chalcogenide of formula M(n+1)Xn(2 ≤n≤ 8), for high-performance hybrid supercapacitor and Li-ion battery application.

This work reports anin situ, one-step hydrothermal preparation procedure of a binder-free electrode growth of Ni6Se5on nickel foam (Ni6Se5/NF) with a rod-like structure. Ni6Se5is an enveloped transition metal chalcogenides of formula M(n+1)Xn(where 2 ≤n≤ 8, M is a transition metal and X is chalcogen) of the nickel selenide family. The Ni6Se5/NF electrode described here demonstrates an exceptional lifetime of 81% capacitance retention over 20000 cycles and a high specific capacitance of 473.5 Fg-1at a current density of 4 Ag-1. The Ni6Se5/NF/activated carbon asymmetric supercapacitor (SC) exhibits a remarkable 97.3 Whkg-1energy density and a 2325 Wkg-1power density. Ni6Se5served as an active electrode material in SC applications and offered exceptional power density and long cycle life. Ni6Se5/NF, used as an anode for Li-ion batteries, has a lithium storage capacity of 939.7 mAhg-1at 100 mAg-1current density. Ni6Se5's (active electrode material) excellent energy storage capability, which was previously unreported, is particularly beneficial for electrochemical energy storage device applications.

Recent advances in methanol production from methanotrophs.

Methanol, the simplest aliphatic molecule of the alcohol family, finds diverse range of applications as an industrial solvent, a precursor for producing other chemicals (e.g., dimethyl ether, acetic acid and formaldehyde), and a potential fuel. There are conventional chemical routes for methanol production such as, steam reforming of natural gas to form syngas, followed by catalytic conversion into methanol; direct catalytic oxidation of methane, or hydrogenation of carbon dioxide. However, these chemical routes are limited by the requirement for expensive catalysts and extreme process conditions, and plausible environmental implications. Alternatively, methanotrophic microorganisms are being explored as biological alternative for methanol production, under milder process conditions, bypassing the requirement for chemical catalysts, and without imposing any adverse environmental impact. Methanotrophs possess inherent metabolic pathways for methanol production via biological methane oxidation or carbon dioxide reduction, thus offering a surplus advantage pertaining to the sequestration of two major greenhouse gases. This review sheds light on the recent advances in methanotrophic methanol production including metabolic pathways, feedstocks, metabolic engineering, and bioprocess engineering approaches. Furthermore, various reactor configurations are discussed in view of the challenges associated with solubility and mass transfer limitations in methanotrophic gas fermentation systems.

Treatment and Outcome of Autoimmune Hepatitis (AIH): Audit of 28 UK centres.

BACKGROUND: With few data regarding treatment and outcome of patients with AIH outside of large centres we present such a study of patients with AIH in 28 UK hospitals of varying size and facilities. METHODS: Patients with AIH were identified in 14 University and 14 District General hospitals; incident cases during 2007-2015 and prevalent cases, presenting 2000-2015. Treatment and outcomes were analysed. RESULTS: In 1267 patients with AIH, followed-up for 3.8(0-15) years, 5- and 10-year death/transplant rates were 7.1+0.8% and 10.1+1.3% (all-cause) and 4.0+0.6% and 5.9+1% (liver-related) respectively. Baseline parameters independently associated with death/transplantation for all-causes were: older age, vascular/respiratory co-morbidity, cirrhosis, decompensation, platelet count, attending transplant centre and for liver-related: the last four of these and peak bilirubin All-cause and liver-related death/transplantation was independently associated with: non-treatment with corticosteroids, non-treatment with a steroid-sparing agent (SSA), non-treatment of asymptomatic or non-cirrhotic patients and initial dose of Prednisolone >35mg/0.5mg/kg/day (all-cause only), but not with type of steroid (Prednisolone versus Budesonide) or steroid duration beyond 12-months. Subsequent all-cause and liver-death/transplant rates showed independent associations with smaller percentage fall in serum ALT after 1 and 3-months, but not with failure to normalise levels over 12-months. CONCLUSIONS: We observed higher death/transplant rates in patients with AIH who were untreated with steroids (including asymptomatic or non-cirrhotic sub-groups), those receiving higher Prednisolone doses and those who did not receive an SSA. Similar death/transplant rates were seen in those receiving Prednisolone or Budesonide, those continuing steroids after 12-months and patients attaining normal ALT within 12-months versus not.

Process engineering strategy for large scale outdoor cultivation of Tetradesmus obliquus CT02 coupled with pH guided CO2 feeding.

A novel CO2 tolerant microalga Tetradesmus obliquus CT02, was previously evaluated to be a suitable bio refinery platform for synthesis of bioactive molecules, biodiesel, and biofertilizer. In the present study, a process engineering strategy was developed targeting improved growth performance of the strain at large scale under fluctuating outdoor environmental conditions. The strategy relies on maintaining pH of the culture at its optimal value via cascade control with CO2 feeding. The strategy was developed at laboratory scale bubble column photobioreactor under diurnal variation of simulated sunlight intensity and was further validated through growth performance of the strain under outdoor conditions in a 100 L airlift bioreactor. Under laboratory condition, 53.3% and 85.16% improvement in biomass concentration (1.87 g L-1) and productivity (114.8 mg L-1 day-1) was achieved as compared to the uncontrolled pH, respectively. The strategy demonstrated a significant improvement in biomass concentration and productivity by 225.7% and 121.6% respectively, compared to the pH uncontrolled batch, even under outdoor fluctuating environmental condition.

Two-stage integrated process for bio-methanol production coupled with methane and carbon dioxide sequestration: Kinetic modelling and experimental validation.

The study demonstrates a two-stage integrated process for bio-methanol production using Methylosinus trichosporium NCIMB 11131, coupled with sequestration of methane and carbon dioxide. The first stage involved generation of methanotrophic biomass via sequestration of methane; which was used as biocatalyst to reduce carbon dioxide into methanol in the second stage. Maximum biomass titer of 3.39 g L-1 and productivity of 0.60 g L-1 d-1 were achieved in semi-batch stirred tank reactor with methane concentration in the inlet gas mixture of 2.5% v/v and gas flow rate of 0.5 vvm. Methane fixation rate was estimated to be 0.32 g L-1 d-1. Maximum methanol titer of 0.58 g L-1 was achieved at headspace carbon dioxide concentration of 50% v/v and liquid to headspace volume ratio 10:90. Subsequently, a kinetic model was developed to predict and understand the system behaviour in terms of dynamic profile of growth, methanol formation, concentration of dissolved methane or carbon dioxide in the aqueous phase and headspace carbon dioxide concentration, in response to varying process parameters. The model can serve as a tool for estimation of process parameters and aid in overall production optimization.

Mortality comparision in patients receiving either Remdesivir or Remdesivir plus Baricitinib combination in case of moderate to severe COVID-19 Pneumonia: A retrospective study.

Remdesivir and Baricitinib have recently been approved by FDA for the treatment of moderate to severe COVID-19 pneumonia. However, there is limited research work available to assess their beneficial effects. MATERIAL: We conducted retrospective study comparing remdesivir and baricitinib-remdesivir combination therapy in hospitalized adults with moderate to severe Covid-19. All the patients received remdesivir for 5 days and one subgroup had received baricitinib (≤14 days) along with remdesivir. The decision to administer remdesivir only or remdesivir along with baricitinib was the treating clinician's discretion. The primary outcome was to assess the 28-day mortality. OBSERVATION: A total of 50 patients with moderate or severe COVID-19 pneumonia had received either remdesivir alone or both remdesivir and baricinitib during the duration of 1st April 2021 to 30th June 2021in our hospital. The 28-day mortality was 9.091% in the combination group and 14.29% in the remdesivir only group (risk difference= -5.195%, risk ratio for death=0.3634; 95% CI, 0.1281, 3.161; p=0. 0.3086). Patients who had a FiO2 requirement of 100% at any point of time had 100% mortality, irrespective of the drug received. CONCLUSION: Baricitinib and remdesivir combination was superior to remdesivir alone in reducing 28-day mortality among patients with moderate to severe Covid-19, although this difference was statistically insignificant.

Management of a complicated 'pacemaker pocket' site infection.

Pocket site infection after implantation of a pacemaker is a dreaded complication which requires removing the device and reimplanting it at a contralateral site. Difficulties arise when the patient is dependent on pacing and when there are issues with venous access at the contralateral site. We report a patient with pacemaker pocket site infection with congenital complete heart block managed with explantation of the device, semi-permanent pacing during antibiotic treatment, reimplantation of the device at the contralateral site and management of subtotal subclavian vein stenosis noted during reimplantation.

Is there any demand for improved cooking stoves? Evidence from Bangladesh.

Despite the multifarious benefits of improved cooking stoves (ICSs) over traditional biomass stoves, the ICSs adoption rate in rural Bangladesh remains nominal. This paper provides evidence that there is a growing demand for this environmentally friendly and less-hazardous stove. Using a discrete choice experiment (DCE) technique, we surveyed 259 sample households in the south-western region of Bangladesh. The results from the mixed logit model suggest that households are willing to pay (WTP) about $7 on average for a 'realistic' (i.e., one unit or 25 %) reduction in fuel consumption and smoke emission. Moreover, we found that a one-unit (33 %) reduction of cooking time and maintenance frequency increases households' WTP by about $3 and $5 respectively. Finally, this study underscores that extensive promotion, lower installation costs and higher social awareness about health risks and environmental degradation are likely to promote ICSs adoption.

Tricuspid annular PVCS: Radiofrequency ablation by subtricuspid retrograde catheter approach.

Tricuspid annular PVCs constitute 8% of idiopathic PVCs and 5% of RV PVCs. Although a rare entity to encounter in routine clinical practice, it can be a prime culprit behind major arrhythmic burden in few individuals. Electroanatomic approach with sub tricuspid retrograde catheter technique can target those annular PVCs and decrease the arrhythmia burden to normal or near normal range. Although procedural approach for parahisian PVCs requires a close look to avoid injury to native conduction system, TA PVCs are a real challenge due to inherent catheter instability and contact issue in sub tricuspid retrograde approach.

Cilia density and flow velocity affect alignment of motile cilia from brain cells.

In many organs, thousands of microscopic 'motile cilia' beat in a coordinated fashion generating fluid flow. Physiologically, these flows are important in both development and homeostasis of ciliated tissues. Combining experiments and simulations, we studied how cilia from brain tissue align their beating direction. We subjected cilia to a broad range of shear stresses, similar to the fluid flow that cilia themselves generate, in a microfluidic setup. In contrast to previous studies, we found that cilia from mouse ependyma respond and align to these physiological shear stress at all maturation stages. Cilia align more easily earlier in maturation, and we correlated this property with the increase in multiciliated cell density during maturation. Our numerical simulations show that cilia in densely packed clusters are hydrodynamically screened from the external flow, in agreement with our experimental observation. Cilia carpets create a hydrodynamic screening that reduces the susceptibility of individual cilia to external flows.

Adaptive laboratory evolution induced novel mutations in Zymomonas mobilis ATCC ZW658: a potential platform for co-utilization of glucose and xylose.

A systematic adaptive laboratory evolution strategy was employed to develop a potential Zymomonas mobilis strain with the ability to co-utilize glucose and xylose. Z. mobilis ATCC ZW658, a recombinant xylose fermenting strain, was subjected to adaptive laboratory evolution over a period of 200 days under strict selection pressure of increasing concentration of xylose. The evolved strain exhibited 1.65 times increase in the overall specific xylose utilization rate when compared with the parent strain. Furthermore, the strain displayed significantly improved performance in terms of co-fermentation of xylose in the presence of glucose with specific glucose and xylose utilization rate of 1.24 g g-1 h-1 and 1.34 g g-1 h-1, respectively. Altered phenotypic response of the evolved strain, in terms of improved xylose utilization, co-utilization of mixed sugars, enhanced growth, ethanol production, and reduced xylitol production has been explained by novel mutations, identified using next-generation sequencing, in xylose assimilating, metabolizing, and crucial regulatory pathway genes and key enzyme activity assays.

Interesting response to ventricular overdrive pacing during regular narrow QRS tachycardia. What is the mechanism?

33 year old gentleman has undergone an electrophysiology study for recurrent paroxysmal palpitation. During one of the episodes of palpitation a regular narrow QRS tachycardia was documented which has terminated with intravenous adenosine. Baseline electrocardiogram did not show any pre-excitation. Atrial-His (AH) and His-Ventricular (HV) intervals were normal at baseline. There was no evidence of dual atrioventricular (AV) nodal physiology. Earliest atrial electrogram during ventricular pacing was recorded at coronary sinus (CS) 9,10 dipoles placed at CS OS region. Narrow QRS tachycardia with cycle length (TCL) of 400 ms and earliest retrograde atrial activation at CS 9,10 dipoles was induced with programmed ventricular stimulation. Ventricular overdrive (VOD) pacing was performed at 30 ms shorter than TCL during the tachycardia (Fig: 1). What is the mechanism of tachycardia?

Active Particles Powered by Quincke Rotation in a Bulk Fluid.

Dielectric particles suspended in a weakly conducting fluid are known to spontaneously start rotating under the action of a sufficiently strong uniform dc electric field due to the Quincke rotation instability. This rotation can be converted into translation when the particles are placed near a surface providing useful model systems for active matter. Using a combination of numerical simulations and theoretical modeling, we demonstrate that it is possible to convert this spontaneous Quincke rotation into spontaneous translation in a plane perpendicular to the electric field in the absence of surfaces by relying on geometrical asymmetry instead.

An antipyrine based fluorescence "turn-on" dual sensor for Zn2+ and Al3+ and its selective fluorescence "turn-off" sensing towards 2,4,6-trinitrophenol (TNP) in the aggregated state.

A 2,6-diformyl-p-cresol (DFC)-4-amino antipyrine (AP) based dual signaling fluorescent Schiff base ligand (DFCAP) is found to exhibit colorimetric and fluorescence turn on selective sensing towards metal ions, Zn2+ and Al3+. It also exhibits a significant aggregation induced emission (AIE) phenomenon by controlling the water-THF solvent ratio which provides robust green emissive fluorogenic aggregates with well-defined morphologies. Turn-on fluorescence enhancements as high as 195 fold and 168 fold in methanol for Al3+ and Zn2+ at 480 nm and 508 nm, respectively, were noticed. The binding constants and stoichiometry determined from the fluorescence titration data are K = 7.63 × 104 M-1 and 3.42 × 104 M-1 and 1 : 1 complexation for both Al3+ and Zn2+ respectively, supported by Job's method. DFCAP shows high sensitivity towards the detection of Zn2+ and Al3+ ions with very low detection limit values of ca. ∼21 nM and 30 nM respectively. Besides by applying its attractive AIE feature, the green emissive hydrosol functions as a good chemosensor with high sensitivity for a selected explosive TNP through ground state complexation with a LOD value of ca. ∼1.74 µM and especially a high Stern-Volmer quenching constant of ca. ∼4.14 × 105 M-1. For instant 'naked eye' response for the trace detection of TNP in the solution state, we fabricated a simple paper strip that could detect TNP on-site in a fast, inexpensive and simple way.

Interesting case of narrow QRS tachycardia. What is the mechanism?

A 67-year-old female presented with history of recurrent palpitations. During one of the episodes of palpitation, a narrow QRS tachycardia was recorded and it was reported to be terminated with intravenous adenosine. The 12-lead electrocardiogram (ECG) showed no manifest ventricular preexcitation. ECG was within normal limits. The patient underwent an electrophysiology study after informed consent. She was taking calcium channel blockers and that was stopped five half-lives prior to the procedure. As catheters were being placed, a narrow QRS tachycardia got induced. During the study, there was development of right bundle branch block during the tachycardia. What is the mechanism of the tachycardia?

Computing the motor torque of Escherichia coli.

The rotary motor of bacteria is a natural nano-technological marvel that enables cell locomotion by powering the rotation of semi-rigid helical flagellar filaments in fluid environments. It is well known that the motor operates essentially at constant torque in counter-clockwise direction but past work have reported a large range of values of this torque. Focusing on Escherichia coli cells that are swimming and cells that are stuck on a glass surface for which all geometrical and environmental parameters are known (N. C. Darnton et al., J. Bacteriol., 2007, 189, 1756-1764), we use two validated numerical methods to compute the value of the motor torque consistent with experiments. Specifically, we use (and compare) a numerical method based on the boundary integral representation of Stokes flow and also develop a hybrid method combining boundary element and slender body theory to model the cell body and flagellar filament, respectively. Using measured rotation speed of the motor, our computations predict a value of the motor torque in the range 440 pN nm to 829 pN nm, depending critically on the distance between the flagellar filaments and the nearby surface.

Proton triggered emission and selective sensing of picric acid by the fluorescent aggregates of 6,7-dimethyl-2,3-bis-(2-pyridyl)-quinoxaline.

A heteroatom containing organic fluorophore 6,7-dimethyl-2,3-bis-(2-pyridyl)-quinoxaline (BPQ) is weakly emissive in solution but its emission properties are highly enhanced in the aggregated state due to the restriction of intramolecular rotation (RIR) and large amplitude vibrational modes, demonstrating the phenomenon, aggregation induced emission enhancement (AIEE). It has strong proton capture capability, allowing reversible fluorescence switching in basic and acidic medium and the emission color changes from blue to green in the aggregated state through protonation. It has been explained as a competition between intramolecular charge transfers (ICTs) and the AIEE phenomena at a lower pH range (pH ∼1-4). Such behavior enables it as a fluorescent pH sensor for detection in acidic and basic medium. Morphologies of the particles are characterized using optical and field emission scanning electron microscopic (FESEM) studies. The turn off fluorescence properties of aggregated BPQ have been utilized for the selective detection of picric acid and the fluorescence quenching is explained due to ground state complexation with a strong quenching constant, 7.81 × 10(4) M(-1).

Aggregation induced emission enhancement of 4,4'-bis(diethylamino)benzophenone with an exceptionally large blue shift and its potential use as glucose sensor.

Optical emission from a luminogen in solid state is generally red shifted with respect to its solution phase emission. However, in our present study, we report exceptionally large blue shifted enhanced emission from aggregated hydrosol of 4,4'-bis(diethylamino)benzophenone (BZP) compared to its solution phase emission in any good solvent. This exceptional blue emission from aggregated structure of BZP arises from its locally excited states with the concomitant suppression of twisted intramolecular charge transfer (TICT) motion. This is known as aggregation induced locally excited (AILE) state emission. A broad red shifted emission is also observed in case of larger aggregated structure of BZP and it originates from the excited intramolecular charge transfer (ICT) state of planar BZP. Morphology of the aggregated BZP is also studied by scanning electron microscopy and optical microscopy. This AILE emission of the luminogen is used for sensing glucose in aqueous solution at very low concentration. The quenching of AILE in presence of glucose has been explained due to hydrogen bonded complexation between glucose and BZP molecule present at the surface of the aggregated structure and is responsible for crystal softening, i.e. loosening of crystal packing.