814 research outputs found
Implications of JWST galaxies for galaxy formation at high redshift
Using a semi-analytic galaxy-formation model, we study analogues of 8
recently discovered JWST galaxies at . We select analogues from a
cosmological simulation with a volume and an effective
particle number of enabling resolution of every atomic-cooling galaxy
at . We vary model parameters to reproduce the observed UV luminosity
function of , aiming for a statistically representative
high-redshift galaxy mock catalogue. Using the forward-modelled JWST
photometry, we identify analogues from this catalogue and study their
properties as well as possible evolutionary paths and local environments. We
find faint JWST galaxies () remain consistent with
standard galaxy-formation model and that our fiducial catalogue includes large
samples of their analogues. The properties of these analogues broadly agree
with conventional SED fitting results, except for having systematically lower
redshifts due to the evolving UV luminosity function, and for having higher
specific star formation rates as a result of burstier histories in our model.
On the other hand, only a handful of bright galaxy analogues can be identified
for observed galaxies. Moreover, in order to reproduce
JWST galaxy candidates, boosted star-forming efficiencies and reduced feedback
regulation are necessary relative to models of lower-redshift populations. This
suggests star formation in the first galaxies could differ significantly from
their lower-redshift counterparts. We also find that these candidates are
subject to low-redshift contamination, which is present in our fiducial results
as both the dusty or quiescent galaxies at .Comment: 10 pages, 11 figures, submitted to MNRAS, comments welcome
Effect of Process Parameters and Metallographic Studies of ASS-304 Stainless Steel at Various Temperatures under Warm Deep Drawing
AbstractWarm forming of high strength sheet metal alloys are in great demand and its application has importance in defense and nuclear industries. In the present investigation the austenitic stainless steel (ASS)-304 blanks are deep drawn under warm conditions using 20Ton hydraulic press and observed that at lower punch speed when the cup is drawn at elevated temperatures the formability is improved. Numbers of deep draw experiments are conducted under warm conditions to study the microstructure at elevated temperatures for punch corner region cups at variable speeds. In this investigation, changes in the microstructure are observed for deep drawn cups at ambient and elevated temperatures
REVERSAL OF CLONIDINE-INDUCED HYPOTHERMIA BY DECAFFEINATED TEA/COFFEE EXTRACT, AND THEIR FRACTIONS IN MICE
Objective: To study the effect of decaffeinated tea extract (DTE) and decaffeinated coffee extract (DCE) and their respective fractions viz: chloroform fractions (DTCf and DCCf), ethyl acetate fractions (DTEa and DCEa), diethyl ether fractions (DTDe and DCDe) and acetone-water fractions (DTAw and DCAw) against clonidine-induced hypothermia in mice.
Methods: Clonidine (0.1 mg/kg, i. p.) administered to a group of mice pretreated 30 min before with the dose of DTE or DCE or their respective fractions. Rectal temperature was measured at the time of clonidine administration and thereafter at every 30 min up to 2 h test period.
Results: DTE 200 DTE 300 has significantly inhibited clonidine-induced hypothermia. Among the fractions tested, DTE fraction-DTEa 100 and 200 and DCE fractions DCDe 200 and DCAw 200 significantly (p<0.0001) reversed clonidine-induced hypothermia; the effect of DTEa was found to be more sustained.
Conclusion: Both, the decaffeinated tea and coffee contain ingredients that reverse clonidine-induced hypothermia, but they are required to do so in very large doses which are not achievable with normally administered doses of decaffeinated tea or coffee
AutoCharge: Autonomous Charging for Perpetual Quadrotor Missions
Battery endurance represents a key challenge for long-term autonomy and
long-range operations, especially in the case of aerial robots. In this paper,
we propose AutoCharge, an autonomous charging solution for quadrotors that
combines a portable ground station with a flexible, lightweight charging tether
and is capable of universal, highly efficient, and robust charging. We design
and manufacture a pair of circular magnetic connectors to ensure a precise
orientation-agnostic electrical connection between the ground station and the
charging tether. Moreover, we supply the ground station with an electromagnet
that largely increases the tolerance to localization and control errors during
the docking maneuver, while still guaranteeing smooth un-docking once the
charging process is completed. We demonstrate AutoCharge on a perpetual 10
hours quadrotor flight experiment and show that the docking and un-docking
performance is solidly repeatable, enabling perpetual quadrotor flight
missions
A Genetic Screen for Attenuated Growth Identifies Genes Crucial for Intraerythrocytic Development of Plasmodium falciparum
A majority of the Plasmodium falciparum genome codes for genes with unknown functions, which presents a major challenge to understanding the parasite's biology. Large-scale functional analysis of the parasite genome is essential to pave the way for novel therapeutic intervention strategies against the disease and yet difficulties in genetic manipulation of this deadly human malaria parasite have been a major hindrance for functional analysis of its genome. Here, we used a forward functional genomic approach to study P. falciparum and identify genes important for optimal parasite development in the disease-causing, intraerythrocytic stages. We analyzed 123 piggyBac insertion mutants of P. falciparum for proliferation efficiency in the intraerythrocytic stages, in vitro. Almost 50% of the analyzed mutants showed significant reduction in proliferation efficiency, with 20% displaying severe defects. Functional categorization of genes in the severely attenuated mutants revealed significant enrichment for RNA binding proteins, suggesting the significance of post-transcriptional gene regulation in parasite development and emphasizing its importance as an antimalarial target. This study demonstrates the feasibility of much needed forward genetics approaches for P. falciparum to better characterize its genome and accelerate drug and vaccine development
Life cycle and host range of Phycitasp. rejected for biological control of prickly acacia in Australia
Prickly acacia (Vachellia nilotica subsp. indica), a native of the Indian subcontinent, is a serious weed of the grazing areas of northern Australia and is a target for classical biological control. Native range surveys in India identified a leaf webber, Phycita sp. (Lepidoptera: Pyralidae) as a prospective biological control agent for prickly acacia. In this study, we report the life cycle and host-specificity test results Phycita sp. and highlight the contradictory results between the no-choice tests in India and Australia and the field host range in India. In no-choice tests in India and Australia, Phycita sp. completed development on two of 11 and 16 of 27 non-target test plant species, respectively. Although Phycita sp. fed and completed development on two non-target test plant species (Vachellia planifrons and V. leucophloea) in no-choice tests in India, there was no evidence of the insect on the two non-target test plant species in the field. Our contention is that oviposition behaviour could be the key mechanism in host selection of Phycita sp., resulting in its incidence only on prickly acacia in India. This is supported by paired oviposition choice tests involving three test plant species (Acacia baileyana, A. mearnsii and A. deanei) in quarantine in Australia, where eggs were laid only on prickly acacia. However, in paired oviposition choice trials, only few eggs were laid, making the results unreliable. Although oviposition choice tests suggest that prickly acacia is the most preferred and natural host, difficulties in conducting choice oviposition tests with fully grown trees under quarantine conditions in Australia and the logistic difficulties of conducting open-field tests with fully grown native Australian plants in India have led to rejection of Phycita sp. as a potential biological control agent for prickly acacia in Australia
Native-like aggregates of Factor VIII (FVIII) are immunogenic von Willebrand Factor deficient and hemophilia A mice
The administration of recombinant Factor VIII (FVIII) is the first line therapy for Hemophilia A (HA), but 25–35% of patients develop an inhibitory antibody response. In general, the presence of aggregates contributes to unwanted immunogenic responses against therapeutic proteins. FVIII has been shown to form both native-like and non-native aggregates. Previously, we showed that non-native aggregates of FVIII are less immunogenic compared to the native protein. Here we investigated the effect of native-like aggregates of FVIII on immunogenicity in HA and von Willebrand Factor knockout (vWF−/−) mice. Mice immunized with native-like aggregates showed significantly higher inhibitory antibody titers compared to animals that received native FVIII. Following re-stimulation in vitro with native FVIII, the activation of CD4+ T cells isolated from mice immunized with native-like aggregates is ~4 fold higher than mice immunized with the native protein. Furthermore, this is associated with increases in the secretion of pro-inflammatory cytokines IL-6 and IL-17 in the native-like aggregate treatment group. The results indicate that the native-like aggregates of FVIII are more immunogenic than native FVIII for both the B cell and T cell responses
Electron spin resonance studies of the ligand exchange in cupric complexes with diethyldithiocarbamate and diethyldithiophosphate as ligands
The kinetics of ligand substitutions in the cupric complexes where a diethyldithiocarbamate (dtc) is replaced by a diethyldithiophosphate (dtp) has been studied with chloroform as solvent. The relative concentrations of the paramagnetic species produced in the reactions have been determined using electron spin resonance. The reaction studies suggest the presence of the short time equilibria: Cu (dtc) + dtpH ⇋ Cu (dtc) (dtp) + dtcH Cu (dtc) (dtp) + dtpH⇋Cu (dtp) + dtcH where the equilibrium constants have the value, 0.0625 and 0.00143 respectively. The equilibria are disturbed by the reaction: dtcH + dtpH → (C H)2 NH + dtp+ CS with a rate constantk = 0.07 1. mole sec. at 26°C. Analysis of the thermodynamic parameters determined from the study of the kinetics of the reactions at various temperatures shows that dtp group favours more solvent and excess ligand coordination than dtc. This is consistent with the study of "Long time equilibrium" which indicates that Cu (dtp) exists with further two weakly bonded dtpH groups in the axial positions in chloroform solutions
An MFS Transporter-Like ORF from MDR Acinetobacter baumannii AIIMS 7 Is Associated with Adherence and Biofilm Formation on Biotic/Abiotic Surface
A major facilitator superfamily (MFS) transporter-like open reading frame (ORF) of 453 bp was identified in a pathogenic strain Acinetobacter baumannii AIIMS 7, and its association with adherence and biofilm formation was investigated. Reverse transcription PCR (RT-PCR) showed differential expression in surface-attached biofilm cells than nonadherent cells. In vitro translation showed synthesis of a ~17 kDa protein, further confirmed by cloning and heterologous expression in E. coli DH5α. Up to 2.1-, 3.1-, and 4.1- fold biofilm augmentation was observed on abiotic (polystyrene) and biotic (S. cerevisiae/HeLa) surface, respectively. Scanning electron microscopy (SEM) and gfp-tagged fluorescence microscopy revealed increased adherence to abiotic (glass) and biotic (S. cerevisiae) surface. Extracellular DNA(eDNA) was found significantly during active growth; due to probable involvement of the protein in DNA export, strong sequence homology with MFS transporter proteins, and presence of transmembrane helices. In summary, our findings show that the putative MFS transporter-like ORF (pmt) is associated with adherence, biofilm formation, and probable eDNA release in A. baumannii AIIMS 7
Astrocytic‐neuronal crosstalk gets jammed: Alternative perspectives on the onset of neuropsychiatric disorders
Investigating interactions of glia cells and synapses during development and in adulthood is the focus of several research programmes which aim at understanding the neurobiology of brain physiological and pathological processes. Both glia-specific released and membrane-bound proteins play essential roles in the development, maintenance and functionality of synaptic connections. Alterations in synaptic contacts in specific brain areas are hallmarks of several brain diseases, such as major depressive disorder, autism spectrum disorder and schizophrenia. Thus, a deeper knowledge about putative astrocyte dysfunctions which might affect the synaptic compartment is warranted to improve treatment options. Here, we present the latest advances about the role of glia cells in orchestrating the arrangement of synapses and neuronal networks in physiological and pathological states. We specifically focus on the role of astrocytes in the phagocytosis of neuronal synapses as a novel mechanism which drives the refinement of neuronal circuits and might be affected in pathological conditions. Finally, we propose this astrocyte-dependent mechanism as a putative alternative target of pharmacological interventions for the treatment of brain disorders
- …