41 research outputs found
Inflammation-induced Id2 promotes plasticity in regulatory T cells
No full textTH17 cells originating from regulatory T (Treg) cells upon loss of the Treg-specific transcription factor Foxp3 accumulate in sites of inflammation and aggravate autoimmune diseases. Whether an active mechanism drives the generation of these pathogenic ��ex-Foxp3 TH17�� cells, remains unclear. Here we show that pro-inflammatory cytokines enhance the expression of transcription regulator Id2, which mediates cellular plasticity of Treg into ex-Foxp3 TH17 cells. Expression of Id2 in in vitro differentiated iTreg cells reduces the expression of Foxp3 by sequestration of the transcription activator E2A, leading to the induction of TH17-related cytokines. Treg-specific ectopic expression of Id2 in mice significantly reduces the Treg compartment and causes immune dysregulation. Cellular fate-mapping experiments reveal enhanced Treg plasticity compared to wild-type, resulting in exacerbated experimental autoimmune encephalomyelitis pathogenesis or enhanced anti-tumor immunity. Our findings suggest that controlling Id2 expression may provide a novel approach for effective Treg cell immunotherapies for both autoimmunity and cancer. (C) 2018, The Author(s
Comparison of the Oral Hygiene and Dental Caries status of patients suffering from Schizophrenia between outpatients of Government Hospitals and Institutionalized individuals in Chennai city: A cross sectional study
No full textINTRODUCTION:
Schizophrenia is a serious psychological disorder that affects not only the mental health but also the general as well as oral health. Schizophrenic patients are often found to be less conscious about their Dental problems which leads to complicated outcomes and increased prevalence of Dental diseases among them. The aim of the study is to compare the Oral hygiene and Dental caries status among patients with schizophrenia between outpatients in Government Hospitals and institutionalized individuals in Chennai city.
MATERIALS AND METHODS:
A total of 174 patients with schizophrenia were taken among which 42 outpatients were from a Government Hospital and 132 institutionalized individuals were from two different institutions for schizophrenic patients. At first, their demographic data were obtained and they were classified modifying the WHO’s seven group criteria into four age groups: 15-30 years, 31-45 years, 46-60 years and above 60 years. Their Oral hygiene and Dental caries status was screened by the trained investigator and evaluated with the help of Debris Index – Simplified (DI-S), Calculus Index – Simplified (CI-S), Oral Hygiene Index – Simplified (OHI-S) and Decayed – Missing – Filled Tooth Index (DMFT). The data regarding their Oral hygiene and Dental caries status were compared between two genders, between the four age groups and between the three institutions.
RESULT:
Institutionalised individuals from the two different institutions showed better Oral hygiene status (mean OHI-S score 2.1±1.09 and 2.0±1.04) and Dental caries status (mean DMFT score 4.9±6.75 and 3.7±5.34) than that of the outpatients of the Government Hospital (mean OHI-S score 2.9±1.30 and mean DMFT score 6.4±4.37). Kruskal Wallis test and Bonferroni adjusted Mann Whitney U test showed that the significant difference in the Oral hygiene and Dental
caries status exists between male and female patients, between the patients from the predefined four age groups and between the patients from different institutions. Pearson Chi Square value confirmed that the differences in the ‘Good’, ‘Fair’ and ‘Poor’ status of Oral hygiene among the patients from different institutions are statistically significant.
CONCLUSIONS:
As the outpatients were found to have poorer Oral hygiene and Dental caries status than the institutionalised individuals, the family members of the outpatients should be educated about the harmful effects of poor Oral health and motivated to help their patients to practice good Oral hygiene on a routine basis. They should also be advised for frequent Dental check up to prevent any further complication
Future sea-level projections with a coupled atmosphere-ocean-ice-sheet model
No full textClimate-forced, offline ice-sheet model simulations have been used extensively in assessing how much ice-sheets can contribute to future global sea-level rise. Typically, these model projections do not account for the two-way interactions between ice-sheets and climate. To quantify the impact of ice-ocean-atmosphere feedbacks, here we conduct greenhouse warming simulations with a coupled global climate-ice-sheet model of intermediate complexity. Following the Shared Socioeconomic Pathway (SSP) 1-1.9, 2-4.5, 5-8.5 emission scenarios, the model simulations ice-sheet contributions to global sea-level rise by 2150 of 0.2 ± 0.01, 0.5 ± 0.01 and 1.4 ± 0.1 m, respectively. Antarctic ocean-ice-sheet-ice-shelf interactions enhance future subsurface basal melting, while freshwater-induced atmospheric cooling reduces surface melting and iceberg calving. The combined effect is likely to decelerate global sea-level rise contributions from Antarctica relative to the uncoupled climate-forced ice-sheet model configuration. Our results demonstrate that estimates of future sea-level rise fundamentally depend on the complex interactions between ice-sheets, icebergs, ocean and the atmosphere. © 2023, The Author(s).11Ysciescopu
An explicitly spin-free compact open-shell coupled cluster theory using a multireference combinatoric exponential ansatz: formal development and pilot applications
No full textIn this paper, we present a comprehensive account of an explicitly spin-free compact state-universal multireference coupled cluster (CC) formalism for computing the state energies of simple open-shell systems, e.g., doublets and biradicals, where the target open-shell states can be described by a few configuration state functions spanning a model space. The cluster operators in this formalism are defined in terms of the spin-free unitary generators with respect to the common closed-shell component of all model functions (core) as vacuum. The spin-free cluster operators are either closed-shell-like n hole-n particle excitations (denoted by Tμ) or involve excitations from the doubly occupied (nonvalence) orbitals to the singly occupied (valence) orbitals (denoted by Seμ). In addition, there are cluster operators with exchange spectator scatterings involving the valence orbitals (denoted by Sreμ). We propose a new multireference cluster expansion ansatz for the wave operator with the above generally noncommuting cluster operators which essentially has the same physical content as the Jeziorski-Monkhorst ansatz with the commuting cluster operators defined in the spin-orbital basis. The Tμ operators in our ansatz are taken to commute with all other operators, while the Seμ and Sreμ operators are allowed to contract among themselves through the spectator valence orbitals. An important innovation of this ansatz is the choice of an appropriate automorphic factor accompanying each contracted composite of cluster operators in order to ensure that each distinct excitation generated by this composite appears only once in the wave operator. The resulting CC equations consist of two types of terms: a "direct" term and a "normalization" term containing the effective Hamiltonian operator. It is emphasized that the direct term is almost quartic in the cluster amplitudes, barring only a handful of terms and termination of the normalization term depends on the valence rank of the effective Hamiltonian operator and the excitation rank of the cluster operators at which the theory is truncated. Illustrative applications are presented by computing the state energies of neutral doublet radicals and doublet molecular cations and ionization energies of neutral molecules and comparing our results with the other open-shell CC theories, benchmark full CI results (when available) in the same basis, and the experimental results. Highly encouraging results show the efficacy of the method
Analytic first derivatives for a spin-adapted open-shell coupled cluster theory: Evaluation of first-order electrical properties
No full text
Bcl11b prevents catastrophic autoimmunity by controlling multiple aspects of a regulatory T cell gene expression program
No full textFoxp3 and its protein partners establish a regulatory T (Treg) cell transcription profile and promote immunological tolerance. However, molecular features contributing to a Treg-specific gene expression program are still incompletely understood. We find that the transcription factor Bcl11b is a prominent Foxp3 cofactor with multifaceted functions in Treg biology. Optimal genomic recruitment of Foxp3 and Bcl11b is critically interdependent. Genome-wide occupancy studies coupled with gene expression profiling reveal that Bcl11b, in association with Foxp3, is primarily responsible in establishing a Treg-specific gene activation program. Furthermore, Bcl11b restricts misdirected recruitment of Foxp3 to sites, which would otherwise result in an altered Treg transcriptome profile. Consequently, Treg-specific ablation of Bcl11b results in marked breakdown of immune tolerance, leading to aggressive systemic autoimmunity. Our study provides previously underappreciated mechanistic insights into molecular events contributing to basic aspects of Treg function. Furthermore, it establishes a therapeutic target with potential implications in autoimmunity and cancer. Copyright © 2019 The Author
The spin-free analogue of Mukherjee's state-specific multireference coupled cluster theory
No full textIII-nitride nanowire light-emitting diodes: design and characterization
No full textIII-nitride semiconductors have been intensively studied for optoelectronic devices, due to the superb advantages offered by this materials system. The direct energy bandgap III-nitride semiconductors can absorb or emit light efficiently over a broad spectrum, ranging from 0.65 eV (InN) to 6.4 eV (AlN), which encompasses from deep ultraviolet to near infrared spectrum. However, due to the lack of native substrates, conventional III-nitride planar heterostructures generally exhibit very high dislocation densities that severely limit the device performance and reliability. On the other hand, nanowire heterostructures can be grown on lattice mismatched substrates with drastically reduced dislocation densities, due to highly effective lateral stress relaxation. Nanowire light-emitting diodes (LEDs) with emission in the ultraviolet to visible wavelength range have recently been studied for applications in solid-state lighting, flat-panel displays, and solar-blind detectors. In this thesis, investigation of the systematic process flow of design and epitaxial growth of group III-nitride nanoscale heterostructures was done. Moreover, demonstration of phosphor-free nanowire white LEDs using InGaN/AlGaN nanowire heterostructures grown directly on Si(111) substrates by molecular beam epitaxy was made. Full-color emission across nearly the entire visible wavelength range was realized by controlling the In composition in the InGaN active region. Strong white-light emission was recorded for the unpackaged nanowire LEDs with an unprecedentedly high color rendering index of 98. Moreover, LEDs with the operating wavelengths in the ultraviolet (UV) spectra, with emission wavelength in the range of 280-320 nm (UV-B) or shorter wavelength hold tremendous promise for applications in phototherapy, skin treatments, high speed dissociation and high density optical recording. Current planar AlGaN based UV-B LEDs have relatively low quantum efficiency due to their high dislocation density resulted from the large lattice mismatch between the AlGaN and suitable substrates. In this study, associated with the achievement of visible LEDs, the development of high brightness AlGaN/GaN nanowire UV-LEDs via careful design and device fabrication was shown. Strong photoluminescence spectra were recorded from these UV-B LEDs. The emission peak can be tunable from 290 nm to 320 nm by varying the Al content in AlGaN active region which can be done by optimizing the growth condition including Al/Ga flux ratio and also the growth temperature. Such visible to UV-B nanowire LEDs are ideally suited for future smart lighting, full-color display, phototherapy and skin treatments applications
