2D-semiconductors with strong light-matter interaction are attractive materials for integrated and tunable optical devices. Here, we demonstrate room-temperature wavelength multiplexing of the two-primary bright excitonic channels (A-, B-) in monolayer transition metal dichalcogenides (TMDs) arising from a dark exciton mediated transition. We present how tuning dark excitons an out-of-plane electric field cedes the system equilibrium from one excitonic channel to the other, encoding the field polarization into wavelength information.
View Article and Find Full Text PDFHeterostructures combining a thin layer of quantum emitters and planar nanostructures enable custom-tailored photoluminescence in an integrated fashion. Here, we demonstrate a photonic Rashba effect from valley excitons in a WSe monolayer, which is incorporated into a photonic crystal slab with geometric phase defects, that is, into a Berry-phase defective photonic crystal. This phenomenon of spin-split dispersion in momentum space arises from a coherent geometric phase pickup assisted by the Berry-phase defect mode.
View Article and Find Full Text PDFPsychopharmacology (Berl)
December 2020
Rationale: It is critical to identify potential risk factors, such as a history of early life stress (ELS), that may confer specific vulnerabilities to increased drug intake.
Objective: In this study, we examined whether male and female rhesus monkeys with a history of ELS (infant maltreatment; MALT) demonstrated significantly greater cocaine intake compared with controls.
Methods: Monkeys were trained to self-administer cocaine during 4-h sessions at a peak dose (0.
Am J Transplant
September 2012
We report the results of a large series of chain transplantations that were facilitated by a multicenter US database in which 57 centers pooled incompatible donor/recipient pairs. Chains, initiated by nondirected donors, were identified using a computer algorithm incorporating virtual cross-matches and potential to extend chains. The first 54 chains facilitated 272 kidney transplants (mean chain length = 5.
View Article and Find Full Text PDFAm J Transplant
February 2011
Optimizing the possibilities for kidney-paired donation (KPD) requires the participation of donor-recipient pairs from wide geographic regions. Initially it was envisaged that donors would travel to the recipient center; however, to minimize barriers to participation and simplify logistics, recent trends have involved transporting the kidneys rather than the donors. The goal of this study was to review outcomes of this practice.
View Article and Find Full Text PDFBackground: Hyperparathyroidism often remains or develops after kidney transplantation. Vitamin D sterol used as treatment for an elevated parathyroid hormone (PTH) level and associated bone disease may be contraindicated due to hypercalcemia. The calcimimetic cinacalcet HCl (cinacalcet), which lowers PTH and calcium (Ca) in chronic kidney disease patients, may represent an alternate therapeutic modality.
View Article and Find Full Text PDFThe organ donor shortage has been the most important hindrance in getting listed patients transplanted. Living kidney donors who are incompatible with their intended recipients are an untapped resource for expanding the donor pool through participation in transplant exchanges. Chain transplantation takes this concept further, with the potential to benefit even more recipients.
View Article and Find Full Text PDFDonor advocacy is a critical feature of live donor transplantation. Donor Advocates and Donor Advocate Teams (DAT) are now routine to the practice of live donor evaluation in the USA. Multidisciplinary in nature, DATs gather both medical and psychosocial information about potential live organ donors and then render a decision as to whether or not these individuals are suitable to participate.
View Article and Find Full Text PDFProviding transplantation opportunities for patients with incompatible live donors through kidney paired donation (KPD) is seen as one of the important strategies for easing the crisis in organ availability. It has been estimated that an additional 1000-2000 transplants per year could be accomplished if a national KPD program were implemented in the United States. While most of these transplants could be arranged within the participants' local or regional area, patients with hard-to-match blood types or broad HLA sensitization would benefit from matching across larger geographic areas.
View Article and Find Full Text PDFBackground: RAD is a potent immunosuppressive agent that has been shown to be effective in preventing acute and chronic allograft rejection in animal models. The HMGCoA reductase inhibitors have been found to reduce the incidence of graft vascular disease (GVD) in heart transplant patients and in animal models. This study was designed to investigate the effects of fluvastatin or pravastatin in a rodent model of GVD produced using low doses of RAD to prevent acute rejection.
View Article and Find Full Text PDFBackground: There are presently no established pre-transplant tests that consistently identify patients who may be at increased risk for acute rejection episodes after renal transplantation. We studied whether pretransplant serum levels of C-reactive protein (CRP), a marker for the presence of systemic inflammation, would predict the occurrence of acute rejection episodes after renal transplantation.
Methods: Pretransplant serum was tested for CRP level in 97 consecutive renal transplant recipients.
Background: Although chronic rejection is the most important cause of late allograft loss, none of the currently available immunosuppressive agents successfully target this problem. Clinical and laboratory studies suggest that 3-hydroxy-3-methyl-glutaryl co-enzyme A (HMG-CoA) reductase inhibitors (HRIs) may decrease the incidence of and pathophysiologic factors leading to chronic rejection.
Methods: A number of clinical and laboratory investigations have been designed to evaluate the effect of HRIs on chronic rejection.
Flow cytometry assays, which measure CD69 activation and intracellular cytokine production, have been used to measure peripheral blood lymphocyte (PBL) responses to in vitro antigen exposure. In the present study, we show that, in healthy individuals and immunosuppressed kidney transplant recipients, CD69 expression and intracellular cytokine production by peripheral blood T cells compare favorably to thymidine uptake as a measure of PBL response to alloantigen in mixed leukocyte culture (MLC). Heparinized whole blood from 23 healthy individuals was incubated for 24-48 h with 3rd party allogeneic monocytes; blood from twelve kidney transplant recipients was incubated with monocytes from their kidney donor and with monocytes from unrelated individuals.
View Article and Find Full Text PDFBackground: Kupffer cells, after exposure to alloantigen via the portal vein, mediate an immunosuppressive effect involving enhanced production of PGE2. We hypothesize that up-regulation of Kupffer cell CoA-independent transacylase (CoA-IT) by portal venous transfusion (PVT) is a possible mechanism of increased PGE2 production. Additionally, enhanced lymphocyte apoptosis, a process known to be macrophage dependent and facilitated by PGE2, is postulated as a possible mechanism of PVT-induced, Kupffer cell-mediated immunosuppression.
View Article and Find Full Text PDFThe immunosuppressive effect of portal venous blood transfusions in organ transplantation has been well established and may be mediated by increased Kupffer cell production of the immunosuppressive arachidonic acid metabolite prostaglandin E2 (PGE2). In this study, butyrate, a short-chain fatty acid known to enhance gene transcription, is hypothesized to enhance Kupffer cell PGE2 production by altering cyclooxygenase or phospholipase A2 (PLA2) activity, thus augmenting the immunosuppressive effect of portal venous transfusion. Lewis rats were given a portal venous transfusion of Wistar-Firth blood or saline 1 h prior to Kupffer cell harvest.
View Article and Find Full Text PDFBackground: Enhanced Kupffer cell production of the immunosuppressive arachidonic acid metabolite prostaglandin E2 (PGE2) has been shown to be a mechanism of the immunosuppressive effect of portal venous transfusions (PVT). Butyrate, a four-carbon short-chain fatty acid, has received increased attention because of its ability to enhance gene transcription. This study tested the hypothesis that the intrahepatic delivery of butyrate enhances Kupffer cell PGE2 production and thus augments the immunosuppressive effect of PVT.
View Article and Find Full Text PDFBackground: We have reported that heart transplant recipients treated with pravastatin demonstrate decreases in the incidence of clinically severe acute rejection episodes, the incidence and progression of transplant coronary vasculopathy, and natural killer cytotoxicity. These patients also exhibited a significant improvement in 1-year allograft survival. Because of these clinical findings suggesting an immunosuppressive effect of pravastatin unique to transplant recipients and the unclear role of natural killer cells in allograft rejection, we postulated that pravastatin may exert its immunomodulatory effect by acting with cyclosporine to alter T lymphocyte function.
View Article and Find Full Text PDFBackground: Little has been written about allograft survival in non-African-American minority groups. We examine the success of kidney transplantation in 1900 Asian recipients.
Methods: Data from 42,252 cadaveric and 16,115 live donor kidney transplant recipients were monitored from the United Network for Organ Sharing Scientific Renal Transplant Registry from 1991 through 1996.