Femtosecond photoelectron diffraction: A new approach to image molecular structure during photochemical reactions.

Continuing technical advances in the creation of (sub-) femtosecond VUV and X-ray pulses with Free-Electron Lasers and laser-based high-harmonic-generation sources have created new opportunities for studying ultrafast dynamics during chemical reactions. Here, we present an approach to image the geometric structure of gas-phase molecules with fewfemtosecond temporal and sub-Ångström spatial resolution using femtosecond photoelectron diffraction. This technique allows imaging the molecules “from within” by analyzing the diffraction of inner-shell photoelectrons that are created by femtosecond VUV and X-ray pulses. Using pump-probe schemes, ultrafast structural changes during photochemical reactions can thus be directly visualized with a temporal resolution that is only limited by the pulse durations of the pump and the probe pulse and the synchronization of the two light pulses. Here, we illustrate the principle of photoelectron diffraction using a simple, geometric scattering model and present results from photoelectron diffraction experiments on laser-aligned molecules using X-ray pulses from a Free-Electron Laser

Combustion synthesis and upconversion luminescence properties of Er3+, Yb3+ doped gadolinium oxide nanophosphor

Gd2O3: Er3+, Yb3+ Nanophosphor prepared by combustion synthesis method.  Optical and Upconversion luminescence properties of rare earth doped nanophosphors were studied. The nanophosphors were characterized using Scanning electron microscopy, X-ray diffraction and ultraviolet–visible absorption spectroscopy. The results of XRD show cubic phase can be obtained, the average crystalline size could be calculated as 38 and 49nm respectively, which coincided with the results from SEM images. The UV- Vis optical spectra were also studied. Upconversion luminescence spectra of samples under the range of 980 nm, excitation were investigated. The strong red and weak green emission was observed. The possible upconversion luminescence mechanisms for Er3+, Yb3+ doped gadolinium nanophosphor were also discussed

Amenability of low- grade uranium towards column bioleaching by acidithiobacillus ferrooxidans

ABSTRACT : R & D studies were carried out at NML using Acidithiobacillus ferrooxidans (Ac.TJ in column for the bio-recovery of uranium from the low-grade uranium ore containing 0.024% U308 of Turamdih Mines, Singhbhum. A recovery of 55 .48% uranium was obtained in bio-leaching as against -- 44.0% in sterile control in 30 days at 1.7pH in a column containing 2 . 5kg ore of particle size mainly in the ra,., 5-1mm . In the large scale column , leaching with 80kg ore of particle size -0.5cm, uranium biorecovery was found to be 69.8% in comparison to a recovery of 55% in control set at 1.7 pH in 50 days. The uranium recoveries followed indirect leaching mechanism

Bioleaching - an alternate uranium ore processing technology for India

Meeting the feed supply of uranium fuel in the present and planned nuclear reactors calls for huge demand of uranium, which at the current rate of production, shows a mismatch. The processing methods at UCIL (DAE) needs to be modified/ changed or re-looked into because of its very suitability in near future for low-index raw materials which are either unmined or stacked around if mined. There is practically no way to process tailings with still some values. Efforts were made to utilize such resources (low-index ore of Turamdih mines, containing 0.03% U3O8) by NML in association with UCIL as a national endeavor. In this area, the R&D work showed the successful development of a bioleaching process from bench scale to lab scale columns and then finally to the India’s first ever large scale column, from the view point of harnessing such a processing technology as an alternative for the uranium industry and nuclear sector in the country. The efforts culminated into the successful operation of large scale trials at the 2ton level column uranium bioleaching that was carried out at the site of UCIL, Jaduguda yielding a maximum recovery of 69% in 60 days. This achievement is expected to pave the way for scaling up the activity to a 100T or even more heap bioleaching trials for realization of this technology, which needs to be carried out with the support of the nuclear sector in the country keeping in mind the national interest

Decreased Level of Vitamin D is Associated with Rheumatoid Arthritis Patients from Western Region of Nepal

Background: Rheumatoid Arthritis (RA) is a progressive, chronic type of autoimmune disease and the role of vitamin D in the pathogenesis of RA is under investigation. Objective: The objective of this study was to determine the vitamin D deficiency in patients with RA as compared to healthy controls and to assess the relationship between serum vitamin D and anti-cyclic citrullinated peptide (anti-CCP) antibody levels in patients with newly diagnosed rheumatoid arthritis. Methods: The study was conducted between January 2017 to February 2018 at Fishtail Hospital and Research centre. A total of 63 patients with early RA diagnosed and a control group of 56 healthy participants, not on vitamin D supplements were recruited from Department of Internal Medicine. Five ml of blood samples were drawn from cubital veins. Blood glucose, creatinine, uric acid, calcium, RA factor, 25-hydroxy vitamin D, anti-CCP antibody, and erythrocyte sedimentation rates were measured in a centralized laboratory of Fishtail Hospital and Research centre. Results: The level of serum 25-hydroxy vitamin D were significantly lower in RA group (20.03 ±9.97 ng/mL) in comparison to the control group (24.46 ±8.45 ng/mL) (p<0.003). Our result indicates the prevalence of vitamin D deficiency was more in RA group compared with control group (47.61% vs. 33.16%, p <0.002). The level of Anti-CCP is significantly high in RA group than control group. In RA patients serum 25-hydroxy vitamin D levels were negatively correlated to anti-CCP antibody levels (rs = 0.72, p <0.001), and erythrocyte sedimentation rate (rs = 3.95, p <0.005). Conclusion: In RA patient vitamin D deficiency is quite common and serum 25-hydroxy vitamin D level was negatively correlated to anti-CCP antibody level. Our results suggest that vitamin D level is a motivation factor rather than a consequence of RA activity

Effect of firing temperature on the particles size of Gd2O3: Eu doped nanophosphors

The paper reports that synthesis and characterization of Eu2+ doped Gd2O3 nanophosphors prepared by combustion synthesis. It has been reported that the effect of synthesis temperature on particle size dependence phenomenon of rare earth doped nanophosphors. The sample was characterized by XRD pattern and FTIR study. Synthesized sample shows cubic structure verified by the XRD results.&nbsp; Size of the particle was caculated by scherer equation the avarage size obtained 15, 23 and 55 at 4000C, 5000C and 6000C respectively. In this synthesis urea used as a fuel for created reducing atmosphere during sample preparation.&nbsp

Thermoluminescence and Mechanoluminescence studies of (Cd0.95 Zn0.05)S: Ag doped phosphor

Through the execution of experimental investigation, mechanoluminescence of (Cd,Zn)S: Ag phosphor was studied which is synthesized by solid state reaction. In the observation, the peak value of ML depends on different concentration. It is seen that ML intensity increases with Ag ion concentration in (Cd, Zn)S phosphor. The peak value of TL depends on the different UV-irradiation time. It is seen that as UV-irradiation exposure increases the TL intensity also increases

Healthcare Utilization Patterns for Acute Febrile Illness in Bangladesh, Nepal, and Pakistan: Results from the Surveillance for Enteric Fever in Asia Project

Background: Characterizing healthcare-seeking patterns for acute febrile illness is critical for generating population-based enteric fever incidence estimates from facility-based surveillance data. Methods: We used a hybrid model in the Surveillance for Enteric Fever in Asia Project (SEAP) to assess incidence of enteric fever at 6 study hospitals in 3 countries. We recruited individuals presenting to the hospitals and obtained blood cultures to evaluate for enteric fever. For this analysis, we undertook cluster random household surveys in Dhaka, Bangladesh (2 sites); Karachi, Pakistan; Kathmandu, Nepal; and Kavrepalanchok, Nepal between January 2017 and February 2019, to ascertain care-seeking behavior for individuals with 1) fever for ≥3 consecutive days within the past 8 weeks; or 2) fever resulting in hospitalization within the past year. We also collected data about disease severity and household demographics and assets. We used mixed-effect multivariable logistic regression models to identify determinants of healthcare seeking at study hospitals and determinants of culture-confirmed enteric fever. Results: We enrolled 31 841 households (53926 children) in Bangladesh, 25510 households (84196 children and adults) in Nepal, and 21310 households (108031 children and adults) in Pakistan. Children <5 years were most likely to be taken to the study hospitals for febrile illness at all sites. Household wealth was positively correlated with healthcare seeking in 4 of 5 study sites, and at least one marker of disease severity was positively associated with healthcare seeking in 3 of 5 catchment areas. Wealth and disease severity were variably predictive of blood culture-confirmed enteric fever. Conclusions: Age, household wealth, and disease severity are important determinants of healthcare seeking for acute febrile illness and enteric fever risk in these communities, and should be incorporated into estimation models for enteric fever incidence

A Cluster-based, Spatial-sampling Method for Assessing Household Healthcare Utilization Patterns in Resource-limited Settings

Background: Implementation of population-based surveys is resource intensive and logistically demanding, especially in areas with rapidly changing demographics and incomplete or no enumeration of the underlying population and their residences. To remove the need for pre-enumeration and to simplify field logistics for the population healthcare utilization survey used for the Surveillance for Enteric Fever in Asia Project in Nepal, we incorporated a geographic information system-based geosurvey and field mapping system into a single-stage cluster sampling approach. Methods: A survey was administered to ascertain healthcare-seeking behavior in individuals with recent suspected enteric fever. Catchment areas were based on residential addresses of enteric fever patients using study facilities; clusters were randomly selected from digitally created grids using available satellite images and all households within clusters were offered enrollment. A tablet-compatible geosurvey and mapping system that allowed for data-syncing and use in areas without cellular data was created using the ArcGIS suite of software. Results: Between January 2017 and November 2018, we surveyed 25 521 households in Nepal (16 769 in urban Kathmandu and 8752 in periurban Kavrepalanchok), representing 84 202 individuals. Overall, the survey participation rate was 90.9%, with geographic heterogeneity in participation rates within each catchment area. Areas with higher average household wealth had lower participation rates. Conclusion: A geographic information system-based geosurvey and field mapping system allowed creation of a virtual household map at the same time as survey administration, enabling a single-stage cluster sampling method to assess healthcare utilization in Nepal for the Surveillance for Enteric Fever in Asia Project. This system removed the need for pre-enumeration of households in sampling areas, simplified logistics and could be replicated in future community surveys

Estimating the Seroincidence of Scrub Typhus using Antibody Dynamics after Infection

Scrub typhus, a vector-borne bacterial infection, is an important but neglected disease globally. Accurately characterizing the burden is challenging because of nonspecific symptoms and limited diagnostics. Prior seroepidemiology studies have struggled to find consensus cutoffs that permit comparisons of estimates across contexts and time. In this study, we present a novel approach that does not require a cutoff and instead uses information about antibody kinetics after infection to estimate seroincidence. We use data from three cohorts of scrub typhus patients in Chiang Rai, Thailand, and Vellore, India, to characterize antibody kinetics after infection and two population serosurveys in the Kathmandu Valley, Nepal, and Tamil Nadu, India, to estimate seroincidence. The samples were tested for IgM and IgG responses to Orientia tsutsugamushi-derived recombinant 56-kDa antigen using commercial enzyme-linked immunosorbent assay kits. We used Bayesian hierarchical models to characterize antibody responses after scrub typhus infection and used the joint distributions of the peak antibody titers and decay rates to estimate population-level incidence rates in the cross-sectional serosurveys. Median responses persisted above an optical density (OD) of 1.8 for 23.6 months for IgG and an OD of 1 for 4.5 months for IgM. Among 18- to 29-year-olds, the seroincidence was 10 per 1,000 person-years (95% CI, 5-19) in Tamil Nadu, India, and 14 per 1,000 person-years (95% CI: 10-20) in the Kathmandu Valley, Nepal. When seroincidence was calculated with antibody decay ignored, the disease burden was underestimated by more than 50%. The approach can be deployed prospectively, coupled with existing serosurveys, or leverage banked samples to efficiently generate scrub typhus seroincidence estimates