110 research outputs found
Continuous Spin Representations of the Poincar\'e and Super-Poincar\'e Groups
We construct Wigner's continuous spin representations of the Poincar\'e
algebra for massless particles in higher dimensions. The states are labeled
both by the length of a space-like translation vector and the Dynkin indices of
the {\it short little group} , where is the space-time dimension.
Continuous spin representations are in one-to-one correspondence with
representations of the short little group. We also demonstrate how combinations
of the bosonic and fermionic representations form supermultiplets of the
super-Poincar\'e algebra. If the light-cone translations are nilpotent, these
representations become finite dimensional, but contain zero or negative norm
states, and their supersymmetry algebra contains a central charge in four
dimensions.Comment: 19 page
A Note on the Non-Commutative Wess-Zumino Model
We show that the noncommutative Wess-Zumino (NCWZ) Lagrangian with
permutation terms in the interaction parts is renormalizable at one-loop level
by only a wave function renormalization. When the non-commutativity vanishes,
the logarithmic divergence of the wave function renormalization of the NCWZ
theory is the same as that of the commutative one. Next the algebras of
noncommutative field theories (NCFT's) are studied. From Neother currents, the
field representation for the generators of NCFT's is extracted. Then based on
this representation, the commutation relations between the generators are
calculated for NCFT's. The symmetry properties of NCFT's inferred from these
commutation relations are discussed and compared with those of the commutative
ones.Comment: 10 pages with no figure
Gammaherpesvirus-Driven Plasma Cell Differentiation Regulates Virus Reactivation from Latently Infected B Lymphocytes
Gammaherpesviruses chronically infect their host and are tightly associated with the development of lymphoproliferative diseases and lymphomas, as well as several other types of cancer. Mechanisms involved in maintaining chronic gammaherpesvirus infections are poorly understood and, in particular, little is known about the mechanisms involved in controlling gammaherpesvirus reactivation from latently infected B cells in vivo. Recent evidence has linked plasma cell differentiation with reactivation of the human gammaherpesviruses EBV and KSHV through induction of the immediate-early viral transcriptional activators by the plasma cell-specific transcription factor XBP-1s. We now extend those findings to document a role for a gammaherpesvirus gene product in regulating plasma cell differentiation and thus virus reactivation. We have previously shown that the murine gammaherpesvirus 68 (MHV68) gene product M2 is dispensable for virus replication in permissive cells, but plays a critical role in virus reactivation from latently infected B cells. Here we show that in mice infected with wild type MHV68, virus infected plasma cells (ca. 8% of virus infected splenocytes at the peak of viral latency) account for the majority of reactivation observed upon explant of splenocytes. In contrast, there is an absence of virus infected plasma cells at the peak of latency in mice infected with a M2 null MHV68. Furthermore, we show that the M2 protein can drive plasma cell differentiation in a B lymphoma cell line in the absence of any other MHV68 gene products. Thus, the role of M2 in MHV68 reactivation can be attributed to its ability to manipulate plasma cell differentiation, providing a novel viral strategy to regulate gammaherpesvirus reactivation from latently infected B cells. We postulate that M2 represents a new class of herpesvirus gene products (reactivation conditioners) that do not directly participate in virus replication, but rather facilitate virus reactivation by manipulating the cellular milieu to provide a reactivation competent environment
l-Tetrahydropalmatine, an Active Component of Corydalis yanhusuo W.T. Wang, Protects against Myocardial Ischaemia-Reperfusion Injury in Rats
l-Tetrahydropalmatine (l-THP) is an active ingredients of Corydalis yanhusuo W.T. Wang, which protects against acute global cerebral ischaemia-reperfusion injury. In this study, we show that l-THP is cardioprotective in myocardial ischaemia-reperfusion injury and examined the mechanism. Rats were treated with l-THP (0, 10, 20, 40 mg/kg b.w.) for 20 min before occlusion of the left anterior descending coronary artery and subjected to myocardial ischaemia-reperfusion (30 min/6 h). Compared with vehicle-treated animals, the infarct area/risk area (IA/RA) of l-THP (20, 40 mg/kg b.w.) treated rats was reduced, whilst l-THP (10 mg/kg b.w.) had no significant effect. Cardiac function was improved in l-THP-treated rats whilst plasma creatine kinase activity declined. Following treatment with l-THP (20 mg/kg b.w.), subunit of phosphatidylinositol 3-kinase p85, serine473 phosphorylation of Akt and serine1177 phosphorylation of endothelial NO synthase (eNOS) increased in myocardium, whilst expression of inducible NO synthase (iNOS) decreased. However, the expression of HIF-1Ξ± and VEGF were increased in I30 minR6 h, but decreased to normal level in I30 minR24 h, while treatment with l-THP (20 mg/kg b.w.) enhanced the levels of these two genes in I30 minR24 h. Production of NO in myocardium and plasma, activity of myeloperoxidase (MPO) in plasma and the expression of tumour necrosis factor-Ξ± (TNF-Ξ±) in myocardium were decreased by l-THP. TUNEL assay revealed that l-THP (20 mg/kg b.w.) reduced apoptosis in myocardium. Thus, we show that l-THP activates the PI3K/Akt/eNOS/NO pathway and increases expression of HIF-1Ξ± and VEGF, whilst depressing iNOS-derived NO production in myocardium. This effect may decrease the accumulation of inflammatory factors, including TNF-Ξ± and MPO, and lessen the extent of apoptosis, therefore contributing to the cardioprotective effects of l-THP in myocardial ischaemia-reperfusion injury
Effect of scheduled monitoring of liver function during anti-Tuberculosis treatment in a retrospective cohort in China
Investigation of the Chemical Compositions in Tobacco of Different Origins and Maturities at Harvest by GCβMS and HPLCβPDA-QTOF-MS
Meta-Analysis of the Distribution of Pharmaceuticals and Personal Care Products in Natural Streams of United States and Its Correlations with Anthropogenic Factors
Pharmaceuticals and personal care products (PPCPs) are
ubiquitous
in natural environments. Due to their inherent relationships with
human activities, we hypothesized that factors relating to anthropogenic
activities could be useful in predicting the extent of PPCP pollution
in natural waterways. A meta-analysis was performed on reported PPCP
concentrations in streams across the United States from 2000 to 2022.
Existing US census and land cover data were then collected and analyzed
for their potential correlations with the PPCP distribution. Studies
of 163 sampling sites reported a total of 109 unique PPCPs, with individual
concentrations ranging from 0.0019 to 79.5 ΞΌg/L. A total of
37 PPCPs were detected in all three land use types (developed, forested,
and agricultural). These common PPCPs had varying correlations with
anthropogenic factors, i.e., population size, demographic distribution,
or income. Cholesterol and coprostanol varied significantly in concentration
between different types of land use, despite a lack of correlation
with population size. However, caffeine and 1,7-dimethylxanthine interacted
with both the population size and land use. Our results allow a greater
insight into the prevalence of PPCPs in the environment and the need
to account for many variables to predict the environmental concentrations
of these pollutants
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