Precision Determination of the Neutral Weak Form Factor of ^{48}Ca

We report a precise measurement of the parity-violating (PV) asymmetry A_{PV} in the elastic scattering of longitudinally polarized electrons from ^{48}Ca. We measure A_{PV}=2668±106(stat)±40(syst) parts per billion, leading to an extraction of the neutral weak form factor F_{W}(q=0.8733  fm^{-1})=0.1304±0.0052(stat)±0.0020(syst) and the charge minus the weak form factor F_{ch}-F_{W}=0.0277±0.0055. The resulting neutron skin thickness R_{n}-R_{p}=0.121±0.026(exp)±0.024(model)  fm is relatively thin yet consistent with many model calculations. The combined CREX and PREX results will have implications for future energy density functional calculations and on the density dependence of the symmetry energy of nuclear matter.

Deeply Virtual Compton Scattering Cross Section at High Bjorken x_{B}

We report high-precision measurements of the deeply virtual Compton scattering (DVCS) cross section at high values of the Bjorken variable x_{B}. DVCS is sensitive to the generalized parton distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton form factors (CFFs) of the nucleon as a function of x_{B}, while systematically including helicity flip amplitudes. In particular, the high accuracy of the present data demonstrates sensitivity to some very poorly known CFFs.

New Measurements of the Beam-Normal Single Spin Asymmetry in Elastic Electron Scattering over a Range of Spin-0 Nuclei

We report precision determinations of the beam-normal single spin asymmetries (A_{n}) in the elastic scattering of 0.95 and 2.18 GeV electrons off ^{12}C, ^{40}Ca, ^{48}Ca, and ^{208}Pb at very forward angles where the most detailed theoretical calculations have been performed. The first measurements of A_{n} for ^{40}Ca and ^{48}Ca are found to be similar to that of ^{12}C, consistent with expectations and thus demonstrating the validity of theoretical calculations for nuclei with Z≤20. We also report A_{n} for ^{208}Pb at two new momentum transfers (Q^{2}) extending the previous measurement. Our new data confirm the surprising result previously reported, with all three data points showing significant disagreement with the results from the Z≤20 nuclei. These data confirm our basic understanding of the underlying dynamics that govern A_{n} for nuclei containing ≲50 nucleons, but point to the need for further investigation to understand the unusual A_{n} behavior discovered for scattering off ^{208}Pb.

Measurement of the Nucleon F_{2}^{n}/F_{2}^{p} Structure Function Ratio by the Jefferson Lab MARATHON Tritium/Helium-3 Deep Inelastic Scattering Experiment

The ratio of the nucleon F_{2} structure functions, F_{2}^{n}/F_{2}^{p}, is determined by the MARATHON experiment from measurements of deep inelastic scattering of electrons from ^{3}H and ^{3}He nuclei. The experiment was performed in the Hall A Facility of Jefferson Lab using two high-resolution spectrometers for electron detection, and a cryogenic target system which included a low-activity tritium cell. The data analysis used a novel technique exploiting the mirror symmetry of the two nuclei, which essentially eliminates many theoretical uncertainties in the extraction of the ratio. The results, which cover the Bjorken scaling variable range 0.19<x<0.83, represent a significant improvement compared to previous SLAC and Jefferson Lab measurements for the ratio. They are compared to recent theoretical calculations and empirical determinations of the F_{2}^{n}/F_{2}^{p} ratio.

Form Factors and Two-Photon Exchange in High-Energy Elastic Electron-Proton Scattering

We present new precision measurements of the elastic electron-proton scattering cross section for momentum transfer (Q^{2}) up to 15.75  (GeV/c)^{2}. Combined with existing data, these provide an improved extraction of the proton magnetic form factor at high Q^{2} and double the range over which a longitudinal or transverse separation of the cross section can be performed. The difference between our results and polarization data agrees with that observed at lower Q^{2} and attributed to hard two-photon exchange (TPE) effects, extending to 8  (GeV/c)^{2} the range of Q^{2} for which a discrepancy is established at >95% confidence. We use the discrepancy to quantify the size of TPE contributions needed to explain the cross section at high Q^{2}.

High accuracy spectroscopy of 3- and 4-body Λ hypernuclei at Jefferson Lab

JLab E12-19-002 Experiment is planned to measure the Λ-binding energies of 3ΛH [Jπ = 1/2+ or 3/2+(T = 0)] and 4ΛH (1+) at JLab Hall C. The expected accuracy for the binding-energy measurement is |ΔBtotal Λ | ≃ 70 keV. The accurate spectroscopy for these light hypernuclei would shed light on the puzzle of the small binding energy and short lifetime of 3ΛH, and the chargesymmetry breaking in the ΛN interaction. We aim to perform the experiment in 2025.

Study of Λn FSI with Λ quasi-free productions on the 3H(e, e′K+)X reaction at JLab

Abstract. An nnΛ is a neutral baryon system with no charge. The study of the pure Λ-neutron system such as nnΛ gives us information on the Λn interaction. The nnΛ search experiment (E12-17-003) was performed at JLab Hall A in 2018. In this article, the Λn FSI was investigated by a shape analysis of the 3H(e, e′K+)X missing mass spectrum, and a preliminary result for the Λn FSI study is given.

Cross-section measurement of virtual photoproduction of iso-triplet three-body hypernucleus, Λnn

Missing-mass spectroscopy with the 3H(e, e′K+) reaction was carried out at Jefferson Lab’s (JLab) Hall A in Oct–Nov, 2018. The differential cross section for the 3H(γ∗, K+)Λnn was deduced at ω = Ee − Ee′ = 2.102 GeV and at the forward K+-scattering angle (0° ≤ θγ∗K ≤ 5°) in the laboratory frame. Given typical predicted energies and decay widths, which are (BΛ, Γ) = (−0.25, 0.8) and (−0.55, 4.7) MeV, the cross sections were found to be 11.2 ± 4.8(stat.)+4.1−2.1(sys.) and 18.1 ± 6.8(stat.)+4.2−2.9(sys.) nb/sr, respectively. The obtained result would impose a constraint for interaction models particularly between Λ and neutron by comparing to theoretical calculations.

Study of the Λ/Σ0 electroproduction in the low-Q2 region at JLab

We performed an experiment using tritium and hydrogen cryogenic gas targets at Thomas Jefferson National Accelerator Facility (JLab) in 2018 (E12-17-003)[1, 2]. In this article, we discuss the Λ/Σ0 hyperon electroproduction from hydrogen target. Elementary Λ/Σ0 hyperon production processes are important not only for an absolute mass scale calibration in our experiment, but also for the study of the electroproduction mechanisms themselves. In this article, we reported the results of the differential cross section for the p(e, e’K+)Λ/Σ0 reaction at Q2 ∼ 0.5 (GeV/c)2.

Deep Exclusive Electroproduction of π^{0} at High Q^{2} in the Quark Valence Regime

We report measurements of the exclusive neutral pion electroproduction cross section off protons at large values of x_{B} (0.36, 0.48, and 0.60) and Q^{2} (3.1 to 8.4  GeV^{2}) obtained from Jefferson Lab Hall A experiment E12-06-014. The corresponding structure functions dσ_{T}/dt+εdσ_{L}/dt, dσ_{TT}/dt, dσ_{LT}/dt, and dσ_{LT^{'}}/dt are extracted as a function of the proton momentum transfer t-t_{min}. The results suggest the amplitude for transversely polarized virtual photons continues to dominate the cross section throughout this kinematic range. The data are well described by calculations based on transversity generalized parton distributions coupled to a helicity flip distribution amplitude of the pion, thus providing a unique way to probe the structure of the nucleon.

Accurate Determination of the Neutron Skin Thickness of ^{208}Pb through Parity-Violation in Electron Scattering

We report a precision measurement of the parity-violating asymmetry A_{PV} in the elastic scattering of longitudinally polarized electrons from ^{208}Pb. We measure A_{PV}=550±16(stat)±8(syst) parts per billion, leading to an extraction of the neutral weak form factor F_{W}(Q^{2}=0.00616  GeV^{2})=0.368±0.013. Combined with our previous measurement, the extracted neutron skin thickness is R_{n}-R_{p}=0.283±0.071  fm. The result also yields the first significant direct measurement of the interior weak density of ^{208}Pb: ρ_{W}^{0}=-0.0796±0.0036(exp)±0.0013(theo)  fm^{-3} leading to the interior baryon density ρ_{b}^{0}=0.1480±0.0036(exp)±0.0013(theo)  fm^{-3}. The measurement accurately constrains the density dependence of the symmetry energy of nuclear matter near saturation density, with implications for the size and composition of neutron stars.

Ruling out Color Transparency in Quasielastic ^{12}C(e,e^{'}p) up to Q^{2} of 14.2 (GeV/c)^{2}

Quasielastic ^{12}C(e,e^{'}p) scattering was measured at spacelike 4-momentum transfer squared Q^{2}=8, 9.4, 11.4, and 14.2  (GeV/c)^{2}, the highest ever achieved to date. Nuclear transparency for this reaction was extracted by comparing the measured yield to that expected from a plane-wave impulse approximation calculation without any final state interactions. The measured transparency was consistent with no Q^{2} dependence, up to proton momenta of 8.5  GeV/c, ruling out the quantum chromodynamics effect of color transparency at the measured Q^{2} scales in exclusive (e,e^{'}p) reactions. These results impose strict constraints on models of color transparency for protons.

TRAF6-IRF5 kinetics, TRIF, and biophysical factors drive synergistic innate responses to particle-mediated MPLA-CpG co-presentation

Innate immune responses to pathogens are driven by co-presentation of multiple pathogen-associated molecular patterns (PAMPs). Combinations of PAMPs can trigger synergistic immune responses, but the underlying molecular mechanisms of synergy are poorly understood. Here, we used synthetic particulate carriers co-loaded with monophosphoryl lipid A (MPLA) and CpG as pathogen-like particles (PLPs) to dissect the signaling pathways responsible for dual adjuvant immune responses. PLP-based co-delivery of MPLA and CpG to GM-CSF-driven mouse bone marrow-derived antigen-presenting cells (BM-APCs) elicited synergistic interferon-β (IFN-β) and interleukin-12p70 (IL-12p70) responses, which were strongly influenced by the biophysical properties of PLPs. Mechanistically, we found that MyD88 and interferon regulatory factor 5 (IRF5) were necessary for IFN-β and IL-12p70 production, while TRIF signaling was required for the synergistic response. Both the kinetics and magnitude of downstream TRAF6 and IRF5 signaling drove the synergy. These results identify the key mechanisms of synergistic Toll-like receptor 4 (TLR4)-TLR9 co-signaling in mouse BM-APCs and underscore the critical role of signaling kinetics and biophysical properties on the integrated response to combination adjuvants.

Probing the Deuteron at Very Large Internal Momenta

We measure ^{2}H(e,e^{'}p)n cross sections at 4-momentum transfers of Q^{2}=4.5±0.5  (GeV/c)^{2} over a range of neutron recoil momenta p_{r}, reaching up to ∼1.0  GeV/c. We obtain data at fixed neutron recoil angles θ_{nq}=35°, 45°, and 75° with respect to the 3-momentum transfer q[over →]. The new data agree well with previous data, which reached p_{r}∼500  MeV/c. At θ_{nq}=35° and 45°, final state interactions, meson exchange currents, and isobar currents are suppressed and the plane wave impulse approximation provides the dominant cross section contribution. We compare the new data to recent theoretical calculations, where we observe a significant discrepancy for recoil momenta p_{r}>700  MeV/c.

Probing Few-Body Nuclear Dynamics via ^{3}H and ^{3}He (e,e^{'}p)pn Cross-Section Measurements

We report the first measurement of the (e,e^{'}p) three-body breakup reaction cross sections in helium-3 (^{3}He) and tritium (^{3}H) at large momentum transfer [⟨Q^{2}⟩≈1.9  (GeV/c)^{2}] and x_{B}>1 kinematics, where the cross section should be sensitive to quasielastic (QE) scattering from single nucleons. The data cover missing momenta 40≤p_{miss}≤500  MeV/c that, in the QE limit with no rescattering, equals the initial momentum of the probed nucleon. The measured cross sections are compared with state-of-the-art ab initio calculations. Overall good agreement, within ±20%, is observed between data and calculations for the full p_{miss} range for ^{3}H and for 100≤p_{miss}≤350  MeV/c for ^{3}He. Including the effects of rescattering of the outgoing nucleon improves agreement with the data at p_{miss}>250  MeV/c and suggests contributions from charge-exchange (SCX) rescattering. The isoscalar sum of ^{3}He plus ^{3}H, which is largely insensitive to SCX, is described by calculations to within the accuracy of the data over the entire p_{miss} range. This validates current models of the ground state of the three-nucleon system up to very high initial nucleon momenta of 500  MeV/c.

Detection and analysis of mycovirus-related RNA viruses from grape powdery mildew fungus Erysiphe necator

The fungus, Erysiphe necator Schw., is an important plant pathogen causing powdery mildew disease in grapevines worldwide. In this study, high-throughput sequencing of double-stranded RNA extracted from the fungal tissue combined with bioinformatics was used to examine mycovirus-related sequences associated with E. necator. The results showed the presence of eight mycovirus-related sequences. Five of these sequences representing three new mycoviruses showed alignment with sequences of viruses classified in the genus Alphapartitivirus in the family Partitiviridae. Another three sequences representing three new mycoviruses showed similarity to classifiable members of the genus Mitovirus in the family Narnaviridae. These mycovirus isolates were named Erysiphe necator partitivirus 1, 2, and 3 (EnPV 1-3) and Erysiphe necator mitovirus 1, 2, and 3 (EnMV 1-3) reflecting their E. necator origin and their phylogenetic affiliation with other mycoviruses.

Zika Virus: Yet Another Emerging Threat to Nepal

Zika virus (ZIKV) is a flavivirus with single stranded RNA related to yellow fever, dengue, West Nile, and Japanese encephalitis viruses and is transmitted by Aedes mosquitoes primarily by Aedes aegipti which is widely distributed in Nepal. ZIKV was first identified incidentally in Rhesus monkey in Uganda in 1947 and human infection in 1952; and by now outbreaks of ZIKV disease have been recorded in Africa, the Americas, Asia and the Pacific. The World Health Organization (WHO) has recently declared the ZIKV an international public health emergency. The aim of this paper is to briefly summarize origin, signs, symptoms, transmission, diagnosis, preventions and management of ZIKV and possible threat to Nepal in light of endemicity of other arbovirus infections and common mosquito vector species in Nepal. Keyword: Aedes aegypti; aedes albopictus; zika virus; microcephaly; birth defect; Nepal.

Identification of new aquaporin genes and single nucleotide polymorphism in bread wheat

Major facilitators of water movement through plant cell membranes include aquaporin proteins. Wheat is among the largest and most important cereal crops worldwide; however, unlike other model plants such as rice, maize and Arabidopsis, little has been reported on wheat major intrinsic proteins (MIPs). This study presents a comprehensive computational identification of 349 new wheat expressed sequence tags (ESTs), encoding 13 wheat aquaporin genes. Identified aquaporins consist of 6 plasma membrane intrinsic proteins (PIP) and 1 TIP showing high sequence similarity with rice aquaporins. We also identified 4 NOD26-like intrinsic proteins (NIP) and 2 SIP members that showed more divergence. Further, expression analysis of the aquaporin genes using the available EST information in UniGene revealed their transcripts were differentially regulated in various stress- and tissue-specific libraries. Allele specific Polymerase chain reaction (PCR) primers based on single nucleotide polymorphism (SNP) were designed using PIP as the target gene and validated on a core set of Indian wheat genotypes. A 3D theoretical model of the wheat aquaporin protein was built by homology modeling and could prove to be useful in the further functional characterization of this protein. Collectively with expression and bioinformatics analysis, our results support the idea that the genes identified in this study signify an important genetic resource providing potential targets to modify the water use properties of wheat.

Paraoxonase 1 (PON1) C/T-108 association with longitudinal mean arterial blood pressure

BACKGROUND

Blood pressure is a complex quantitative trait with a strong genetic component. In this study, we leveraged the Veterans Affairs electronic medical record system to explore the relationship between Paraoxonase 1 (PON1)-108 C/T (rs705379) and mean arterial blood pressure (MAP).

METHODS

Outpatient blood pressure data over an approximate 8-year period was collected from the Veterans Affairs Hypertensive Cohort (N = 1,302). Association between genotype and longitudinal MAP was further explored using a random effects model controlling for age, ancestry, renal function, and other determinants of blood pressure. To control for population stratification, principal component groupings based on ancestry informative markers in this dataset were included as covariates (in addition to self-identified ancestry). Data from the African American Study of Kidney Disease and Hypertension (AASK, N = 857) was used to confirm significant findings in an independent cohort.

RESULTS

There was a significant interaction between PON1-108 C/T genotype and follow-up age group. At a younger age (<50 years), there was an estimated 2.53 mm Hg (95% confidence interval: 1.06, 4.00) increase in MAP with each additional C-allele. At the older age groups, there were no significant associations between PON1-108 C/T genotype and MAP. Using data from the AASK trial, the C-allele at PON1-108 C/T was significantly associated with a higher MAP (P = 0.005) but only among younger participants (<54 years).

CONCLUSIONS

The PON1-108 polymorphism may be associated with MAP in an age-dependent manner.

Synthesis of nano-dimensional ZnO and Ga doped ZnO thin films by vapor phase transport and study as transparent conducting oxide

We report synthesis of polycrystalline ZnO and Ga doped ZnO (ZnO:Ga) thin films (approximately 80 nm) on Si and quartz substrates in a non-vacuum muffle furnace, a simple and cost-effective route, without any catalyst/reactive carrier gases, at relatively low processing temperature of 550 degrees C. The crystalline phases of the films are identified by grazing angle X-ray diffraction (GAXRD). The growth of ZnO films is examined with scanning electron microscope (SEM) as a function of deposition time. An optical transmission of approximately 90% is observed for pure ZnO film having a resistivity of approximately 2.1 Omega-cm as measured by van der Pauw technique. Doping with Ga results in single phase ZnO:Ga films, retaining an optical transmission of about 80% and three orders of magnitude decrease in resistivity as compared to pure ZnO film.

Mortality due to dapsone hypersensitivity syndrome complicating multi-drug therapy for leprosy in Nepal

Dapsone is a component of multi-drug therapy (MDT) for the treatment of all types of leprosy. It is known that dapsone hypersensitivity syndrome (DHS) complicates the treatment in a proportion of patients. We performed a retrospective study of patients commenced on MDT between 1990 and 2006; 2% developed DHS and 0.25% died due to DHS.

Growth and Structure of Carbon Nanotube Y-Junctions

The effect of a catalyst on the growth and structure of carbon nanotube Y-junctions (CNTYs) using chemical vapor deposition has been investigated. Cobalt-, magnesium-, and calcium-nitrates are utilized as precursors of catalysts Co, Mg, Ca, Co/Mg, Co/Ca, and Mg/Ca for CNTY synthesis. Experimental result shows that Co/Mg or Co/Ca can grow CNTYs with straight branches while Co, Mg, Ca, and Mg/Ca will not grow any CNTYs, indicating that only combinations of Co with Mg or Ca will facilitate the formation of CNTYs. In addition, the effect of the carbon source on the formation of CNTYs has also been studied. It is found that thiophene (C4H4S) can promote the formation of CNTYs, while other sources such as methane (CH4) and acetylene (C2H2) cannot. The result shows that both the catalyst and the carbon source substantially affect the formation of CNTYs.

Results of autogenous trephine biopsy needle bone grafting in fractures of radius and ulna

Cortico-Cancellous bone graft harvested from the anterior iliac crest by the conventional open method is associated with more morbidity and is more time consuming as compared to the percutaneous method using trephine biopsy needle. The aim of the study was to determine whether cancellous bone graft harvested from anterior iliac crest using trephine biopsy needle consistently achieved bone union in comminuted fractures and fractures of more than 3 weeks duration of radius and ulna and also to determine the morbidity at the donor site. Autogenous cancellous bone graft was harvested percutaneously from 28 iliac crests in 16 patients and applied at fracture sites of 30 forearm bones using a 4mm trephine biopsy needle after the fractures had been fixed with plate and screws. The patients were followed up regularly upto 6 to 9 months post - operatively in the OPD to determine the union status of the fractured bones and the morbidity at the donor site. 29 of the 30 fractures of the forearm bones united without any problems. The shaft of a trephine got bent during the harvesting procedure at the beginning of the study due to improper technique. Cancellous bone graft harvested from the anterior iliac crest results in predictable good union results in comminuted fractures of forearm bones and also fractures presenting after 3 weeks of injury. It is also an easier and quicker way of harvesting bone graft and is associated with lesser morbidity and earlier recovery as compared to conventional open method.

Serodiagnosis of Japanese encephalitis among Nepalese patients by the particle agglutination assay

Japanese encephalitis (JE) is a serious health problem in the southwestern region of Nepal. Serological diagnostic kits for routine diagnostic use in this region have not been available. This study was performed to examine if the particle agglutination (PA) assay for Japanese encephalitis virus (JEV) IgM could be applicable to the samples collected in Nepal and also to evaluate the accuracy of clinical diagnosis of JE. One hundred and ninety-three blood samples were collected from the patients clinically diagnosed with JE or other infectious diseases in the JE-endemic, southwestern region of Nepal, in 2000. The PA assay was performed on these 193 serum samples and the results were compared with those by IgM-capture ELISA. Eighty-six samples were IgM-positive by the PA assay, and 71 of 86 were also positive by IgM-capture ELISA (sensitivity, 99%; specificity, 88%; positive predictive value, 0.82; negative predictive value, 0.99). These results suggest that the PA assay is a simple, reliable and useful diagnostic test to support clinical diagnosis in rural hospitals of Asia including Nepal.

Synthesis of a bacteriophage MB78 late protein by novel ribosomal frameshifting

MB78 is a virulent phage of Salmonella typhimurium that possesses a number of interesting features, making it a suitable organism to study the regulation of gene expression. A detailed physical map of this phage genome has been constructed and is being extensively studied at the molecular level. Here, we demonstrate the expression of two late proteins of bacteriophage MB78 derived from the same gene as a result of possible ribosomal frameshifting. In vitro transcription-translation yields a major protein that migrates as 28kDa, whereas in vivo expression using pET expression vectors yields two equally expressed proteins of molecular sizes 28 and 26kDa. A putative slippery sequence TTTAAAG and a pseudoknot structure, two essential cis elements required for the classical ribosomal frameshifting, are identified in the reading frame. Mutations created at the slippery sequence resulted in a single 28kDa protein and completely abolished the expression of 26kDa protein. Thus, we have produced the first evidence that ribosomal frameshifting occurs in bacteriophage MB78 of Salmonella typhimurium.

Electron microscopic examination of Aedes albopictus clone C6/36 cells infected with dengue virus 2 at elevated incubation temperature

Morphological changes such as loss of cytoplasm, membrane destruction and vacuolar swelling in Aedes albopictus clone C6/36 cells infected with dengue virus 2 (DV-2) New Guinea B strain and incubated at 28 degrees C and 37 degrees C, were observed under electron microscope. Both infected and uninfected cells showed significant damage at 37 degrees C in contrast to normal appearance at 28 degrees C. A higher number of virus particles were observed in the cytoplasm at 37 degrees C than at 28 degrees C.

Identification of a strong promoter of bacteriophage MB78 that lacks consensus sequence around minus 35 region and interacts with phage specific factor

A strong promoter of bacteriophage MB78 does not have minus 35 consensus sequence although it has a TGn motif immediately upstream of minus 10 sequence as well as the AT rich UP element. It is efficiently recognised by the sigma 70 RNA polymerase, however, a phage-specific factor competes with sigma 70 RNA polymerase for binding to this region, the binding of the factor being stronger than that of the polymerase. Contrary to the reports in the literature the polymerase appears not to bind to the UP element whereas the phage-specific factor does. The latter seems to be involved in the regulation of the promoter activity.

Clonal propagation of Picrorhiza kurroa royle ex benth. by shoot tip culture

A procedure has been developed for the clonal propagation of Picrorhiza kurroa Royle ex Benth. through shoot tip culture. Murashige and Skoog's medium (1962) supplemented with kinetin (3.0 to 5.0 mg/l) supported rapid proliferation of multiple shoots from the explants. Addition of indole-3-acetic acid (1.0 mg/l) to the kinetin containing medium showed marked improvement in the growth of regenerated shoots. However, presence of IAA in the medium did not alter the frequency of shoot multiplication. Rooting was readily achieved upon transferring shoots onto MS medium containing ∝-naphthaleneacetic acid (1.0 mg/l). Plantlets were successfully transferred to soil.