On homogeneous CR manifolds and their CR algebras

In this paper we show some results on homogeneous CR manifolds, proved by introducing their associated CR algebras. In particular, we give different notions of nondegeneracy (generalizing the usual notion for the Levi form) which correspond to geometrical properties for the corresponding manifolds. We also give distinguished equivariant CR fibrations for homogeneous CR manifolds. In the second part of the paper we apply these results to minimal orbits for the action of a real form of a semisimple Lie group \^G on a flag manifold \^G/Q.Comment: 14 pages. AMS-LaTeX v2: minor revisio

Microchips and their significance in isolation of circulating tumor cells and monitoring of cancers

In micro-fluid systems, fluids are injected into extremely narrow polymer channels in small amounts such as micro-, nano-, or pico-liter scales. These channels themselves are embedded on tiny chips. Various specialized structures in the chips including pumps, valves, and channels allow the chips to accept different types of fluids to be entered the channel and along with flowing through the channels, exert their effects in the framework of different reactions. The chips are generally crystal, silicon, or elastomer in texture. These highly organized structures are equipped with discharging channels through which products as well as wastes of the reactions are secreted out. A particular advantage regarding the use of fluids in micro-scales over macro-scales lies in the fact that these fluids are much better processed in the chips when they applied as micro-scales. When the laboratory is miniaturized as a microchip and solutions are injected on a micro-scale, this combination makes a specialized construction referred to as "lab-on-chip". Taken together, micro-fluids are among the novel technologies which further than declining the costs; enhancing the test repeatability, sensitivity, accuracy, and speed; are emerged as widespread technology in laboratory diagnosis. They can be utilized for monitoring a wide spectrum of biological disorders including different types of cancers. When these microchips are used for cancer monitoring, circulatory tumor cells play a fundamental role

Granulomatous gastritis: a diagnostic dilemma?

Granulomatous inflammation of the gastrointestinal tract is an uncommon entity, an aetiopathogenic diagnosis can be reached only by combining the morphological examination with clinical and laboratory investigations. We report two cases of granulomatous gastritis: a 27-year-old woman presenting with weight loss and a 55-year-old woman presenting with epigastric pain and vomiting. Upper oesophagastroduodenoscopy in these cases showed antral hyperaemia and histopathology showed non-caseating gastric granulomatous inflammation. Both the cases were extensively worked-up for possible tuberculosis (TB) as the Patients lived in an endemic area, before starting steroids for the possibility of Crohn\u27s disease (CD). The first Patient improved but the second Patient had a flare of underlying undiagnosed TB. Granulomatous gastritis present a diagnostic challenge for treating physicians because of similar clinical, laboratory and endoscopical features between CD and intestinal TB

Time-resolved terahertz dynamics in thin films of the topological insulator Bi2_{2}Se3_3

We use optical pump--THz probe spectroscopy at low temperatures to study the hot carrier response in thin Bi$_2$Se$_3$ films of several thicknesses, allowing us to separate the bulk from the surface transient response. We find that for thinner films the photoexcitation changes the transport scattering rate and reduces the THz conductivity, which relaxes within 10 picoseconds (ps). For thicker films, the conductivity increases upon photoexcitation and scales with increasing both the film thickness and the optical fluence, with a decay time of approximately 5 ps as well as a much higher scattering rate. These different dynamics are attributed to the surface and bulk electrons, respectively, and demonstrate that long-lived mobile surface photo-carriers can be accessed independently below certain film thicknesses for possible optoelectronic applications.Comment: 4+ pages, 3 figures. Submitte

Complexities of X chromosome inactivation status in female human induced pluripotent stem cells—a brief review and scientific update for autism research

Induced pluripotent stem cells (iPSCs) allow researchers to make customized patient-derived cell lines by reprogramming noninvasively retrieved somatic cells. These cell lines have the potential to faithfully represent an individual’s genetic background; therefore, in the absence of available human brain tissue from a living patient, these models have a significant advantage relative to other models of neurodevelopmental disease. When using human induced pluripotent stem cells (hiPSCs) to model X-linked developmental disorders or inherited conditions that undergo sex-specific modulation of penetrance (e.g., autism spectrum disorders), there are significant complexities in the course and status of X chromosome inactivation (XCI) that are crucial to consider in establishing the validity of cellular models. There are major gaps and inconsistencies in the existing literature regarding XCI status during the derivation and maintenance of hiPSCs and their differentiation into neurons. Here, we briefly describe the importance of the problem, review the findings and inconsistencies of the existing literature, delineate options for specifying XCI status in clonal populations, and develop recommendations for future studies

Experimental maps of DNA structure at nucleotide resolution distinguish intrinsic from protein-induced DNA deformations

Recognition of DNA by proteins depends on DNA sequence and structure. Often unanswered is whether the structure of naked DNA persists in a protein–DNA complex, or whether protein binding changes DNA shape. While X-ray structures of protein–DNA complexes are numerous, the structure of naked cognate DNA is seldom available experimentally. We present here an experimental and computational analysis pipeline that uses hydroxyl radical cleavage to map, at single-nucleotide resolution, DNA minor groove width, a recognition feature widely exploited by proteins. For 11 protein–DNA complexes, we compared experimental maps of naked DNA minor groove width with minor groove width measured from X-ray co-crystal structures. Seven sites had similar minor groove widths as naked DNA and when bound to protein. For four sites, part of the DNA in the complex had the same structure as naked DNA, and part changed structure upon protein binding. We compared the experimental map with minor groove patterns of DNA predicted by two computational approaches, DNAshape and ORChID2, and found good but not perfect concordance with both. This experimental approach will be useful in mapping structures of DNA sequences for which high-resolution structural data are unavailable. This approach allows probing of protein family-dependent readout mechanisms.National Institutes of Health [R01GM106056 to R.R., T.D.T.; U54CA121852 in part to T.D.T.]; Boston University Undergraduate Research Opportunities Program [Faculty Matching Grants to D.O. and Y.J.]; USC Graduate School [Research Enhancement Fellowship and Manning Endowed Fellowship to T.P.C.]. R.R. is an Alfred P. Sloan Research Fellow. Funding for open access charge: Boston University. (R01GM106056 - National Institutes of Health; U54CA121852 - National Institutes of Health; Boston University Undergraduate Research Opportunities Program; USC Graduate School; Boston University)https://academic.oup.com/nar/article/46/5/2636/4829691?searchresult=1https://academic.oup.com/nar/article/46/5/2636/4829691?searchresult=1Published versio

The Frequency of IgA Nephropathy at a Single Center in Pakistan

Objectives: To detect the prevalence of IgA nephropathy in Pakistani patients, as no significant published data from this part of the developing world is available in the international literature for reference. Method: The study was conducted in a university hospital on 105 consecutive renal biopsy specimens. Direct immunofluorescence microscopy was performed using antibodies specific for the heavy chains of IgG, IgA, IgM, C3 and fibrinogen. Results: Seventy-nine (79) cases were classified as glomerulopathies, out of which 10 cases (12.65%) were diagnosed as IgA nephropathy, among which one case was that of Henoch- Schonlein purpura. The age range was 6 to 65 years with median age of 25 years and male to female ratio was 1.5: 1. Nephrotic range proteinuria was seen in 40% of cases and 50% cases showed impaired renal function. The light microscopic examination revealed diffuse proliferative pattern in 3 cases out of which one case showed crescent formations. Focal-segmental glomerulosclerosis, minimum histologic lesion and advanced chronic glomerulonephritic patterns were observed in 2 cases each and in one case focal proliferative morphology was appreciated. Conclusion: The frequency of IgA nephropathy among glomerular diseases was 12.65% in our study, which is somewhat higher when comparing the studies from North America, United Kingdom and Northwest Europe. However, it was significantly lower when comparing the studies from other parts of Asi

Short view of leukemia diagnosis and treatment in Iran

Background: Early diagnosis and treatment of leukemia patients remains a fundamental aim in clinical oncology, especially in developing country. Present study highlights the basic requirements of these patients in Iran. Better understanding of these issues may lead to improve the healthcare standards toward leukemia diagnosis and treatment. Methods: This descriptive study included 101 specialists in hematology-oncology and pathology serving in oncology centers. The participants were then asked to fill out a standard questionnaire on the issues around diagnosis and treatment of blood malignancies. Results: According to specialists, unfair distribution of facilities across the country, delayed diagnosis of disease, absence of psychological support for patients, and insufficient financial support were the main reasons of inappropriate diagnosis and treatment in leukemia patients. Conclusions: Our results show that making an amendment to health policies by preparing well-equipped medical centers in all provinces, improving the morale of patients through consultation during the process of treatment, and above all, subsiding leukemia patients' financial problems will promote the health standard regarding the leukemia diagnosis and treatment in Iran. © 2015, Tehran University of Medical Sciences (TUMS). All rights reserved