Leptogenesis as the origin of matter

We explore in some detail the hypothesis that the generation of a primordial lepton-antilepton asymmetry (Leptogenesis) early on in the history of the Universe is the root cause for the origin of matter. After explaining the theoretical conditions for producing a matter-antimatter asymmetry in the Universe we detail how, through sphaleron processes, it is possible to transmute a lepton asymmetry -- or, more precisely, a (B-L)-asymmetry -- into a baryon asymmetry. Because Leptogenesis depends in detail on properties of the neutrino spectrum, we review briefly existing experimental information on neutrinos as well as the seesaw mechanism, which offers a theoretical understanding of why neutrinos are so light. The bulk of the review is devoted to a discussion of thermal Leptogenesis and we show that for the neutrino spectrum suggested by oscillation experiments one obtains the observed value for the baryon to photon density ratio in the Universe, independently of any initial boundary conditions. In the latter part of the review we consider how well Leptogenesis fits with particle physics models of dark matter. Although axionic dark matter and Leptogenesis can be very naturally linked, there is a potential clash between Leptogenesis and models of supersymmetric dark matter because the high temperature needed for Leptogenesis leads to an overproduction of gravitinos, which alter the standard predictions of Big Bang Nucleosynthesis. This problem can be resolved, but it constrains the supersymmetric spectrum at low energies and the nature of the lightest supersymmetric particle (LSP). Finally, as an illustration of possible other options for the origin of matter, we discuss the possibility that Leptogenesis may occur as a result of non-thermal processes.Comment: 53 pages, minor corrections, one figure and references added, matches published versio

Strong interface-induced spin-orbit coupling in graphene on WS2

Interfacial interactions allow the electronic properties of graphene to be modified, as recently demonstrated by the appearance of satellite Dirac cones in the band structure of graphene on hexagonal boron nitride (hBN) substrates. Ongoing research strives to explore interfacial interactions in a broader class of materials in order to engineer targeted electronic properties. Here we show that at an interface with a tungsten disulfide (WS2) substrate, the strength of the spin-orbit interaction (SOI) in graphene is very strongly enhanced. The induced SOI leads to a pronounced low-temperature weak anti-localization (WAL) effect, from which we determine the spin-relaxation time. We find that spin-relaxation time in graphene is two-to-three orders of magnitude smaller on WS2 than on SiO2 or hBN, and that it is comparable to the intervalley scattering time. To interpret our findings we have performed first-principle electronic structure calculations, which both confirm that carriers in graphene-on-WS2 experience a strong SOI and allow us to extract a spin-dependent low-energy effective Hamiltonian. Our analysis further shows that the use of WS2 substrates opens a possible new route to access topological states of matter in graphene-based systems.Comment: Originally submitted version in compliance with editorial guidelines. Final version with expanded discussion of the relation between theory and experiments to be published in Nature Communication

The Spin Structure of the Nucleon

We present an overview of recent experimental and theoretical advances in our understanding of the spin structure of protons and neutrons.Comment: 84 pages, 29 figure

Frequency of resistance to methicillin and other antimicrobial agents among Staphylococcus aureus strains isolated from pigs and their human handlers in Trinidad

Background: Methicillin-resistant Staphylococcus aureus (MRSA) has emerged recently worldwide in production animals, particularly pigs and veal calves, which act as reservoirs for MRSA strains for human infection. The study determined the prevalence of MRSA and other resistant strains of S. aureus isolated from the anterior nares of pigs and human handlers on pig farms in Trinidad. Methods: Isolation of S. aureus was done by concurrently inoculating Baird-Parker agar (BPA) and Chromagar MRSA (CHROM) with swab samples and isolates were identified using standard methods. Suspect MRSA isolates from Chromagar and BPA were subjected to confirmatory test using Oxoid PBP2 latex agglutination test. The disc diffusion method was used to determine resistance to antimicrobial agents. Results: The frequency of isolation of MRSA was 2.1% (15 of 723) for pigs but 0.0% (0 of 72) for humans. Generally, for isolates of S. aureus from humans there was a high frequency of resistance compared with those from pigs, which had moderate resistance to the following antimicrobials: penicillin G (54.5%, 51.5%), ampicillin (59.1%, 49.5%), and streptomycin (59.1%, 37.1%), respectively. There was moderate resistance to tetracycline (36.4%, 41.2%) and gentamycin (27.2%, 23.7%) for human and pig S. aureus isolates, respectively, and low resistance to sulfamethoxazole-trimethoprim (4.5%, 6.2%) and norfloxacin (9.1%, 12.4%), respectively. The frequency of resistance to oxacillin by the disc method was 36.4 and 34.0% from S. aureus isolates from humans and pigs, respectively. Out of a total of 78 isolates of S. aureus from both human and pig sources that were resistant to oxacillin by the disc diffusion method, only 15 (19.2%) were confirmed as MRSA by the PBP'2 latex test kit. Conclusions: The detection of MRSA strains in pigs, albeit at a low frequency, coupled with a high frequency of resistance to commonly used antimicrobial agents in pig and humans could have zoonotic and therapeutic implications. Finally, the diagnostic limitation of using CHROMagar and testing for oxacillin resistance by the disc diffusion method alone to determine MRSA strains without performing confirmatory tests cannot be overemphasized because the possibility of overdiagnosis of MRSA infections cannot be ignored

Cost-Effectiveness Analysis of Stereotactic Ablative Body Radiation Therapy Compared With Surgery and Radiofrequency Ablation in Two Patient Cohorts: Metastatic Liver Cancer and Hepatocellular Carcinoma

Aims: To compare the cost-effectiveness of stereotactic ablative body radiation therapy (SABR) with radiofrequency ablation and surgery in adult patients with metastatic liver cancer and hepatocellular carcinoma (HCC). / Materials and methods: Two patient cohorts were assessed: liver oligometastases and HCC. For each patient cohort, a decision analytic model was constructed to assess the cost-effectiveness of interventions over a 5-year horizon. A Markov process was embedded in the decision model to simulate the possible prognosis of cancer. Data on transition probabilities, survival, side-effects, quality of life and costs were obtained from published sources and the SABR Commissioning through Evaluation (CtE) scheme. The primary outcome was the incremental cost-effectiveness ratio with respect to quality-adjusted life-years. The robustness of the results was examined in a sensitivity analysis. Analyses were conducted from a National Health Service and Personal Social Services perspective. / Results: In the base case analysis, which assumed that all three interventions were associated with the same cancer progression rates and mortality rates, SABR was the most cost-effective intervention for both patient cohorts. This conclusion was sensitive to the cancer progression rate, mortality rate and cost of interventions. Assuming a willingness-to-pay threshold of £20 000 per quality-adjusted life-year, the probability that SABR is cost-effective was 57% and 50% in liver oligometastases and HCC, respectively. / Conclusions: Our results indicate a potential for SABR to be cost-effective for patients with liver oligometastases and HCC. This finding supports further investigation in clinical trials directly comparing SABR with surgery and radiofrequency ablation

Characteristics of men responding to an invitation to undergo testing for prostate cancer as part of a randomised trial

Background: Sociodemographic characteristics are associated with participating in cancer screening and trials. We compared the characteristics of those responding with those not responding to a single invitation for prostate-specific antigen (PSA) testing for prostate cancer as part of the Cluster randomised triAl of PSA testing for Prostate cancer (CAP). / Methods: Age, rurality and deprivation among 197,763 men from 271 cluster-randomised primary care centres in the UK were compared between those responding (n = 90,300) and those not responding (n = 100,953) to a prostate cancer testing invitation. / Results: There was little difference in age between responders and nonresponders. Responders were slightly more likely to come from urban rather than rural areas and were slightly less deprived than those who did not respond. / Conclusion: These data indicate similarities in age and only minor differences in deprivation and urban location between responders and nonresponders. These differences were smaller, but in the same direction as those observed in other screening trials. / Trial registration: ISRCTN92187251. Registered on 29 November 2004

Using linked routinely collected health data to describe prostate cancer treatment in New South Wales, Australia: a validation study

<p>Abstract</p> <p>Background</p> <p>Population-based patterns of care studies are important for monitoring cancer care but conducting them is expensive and resource-intensive. Linkage of routinely collected administrative health data may provide an efficient alternative. Our aim was to determine the accuracy of linked routinely collected administrative data for monitoring prostate cancer care in New South Wales (NSW), Australia.</p> <p>Methods</p> <p>The NSW Prostate Cancer Care and Outcomes Study (PCOS), a population-based survey of patterns of care for men aged less than 70 years diagnosed with prostate cancer in NSW, was linked to the NSW Cancer Registry, electronic hospital discharge records and Medicare and Pharmaceutical claims data from Medicare Australia. The main outcome measures were treatment with radical prostatectomy, any radiotherapy, external beam radiotherapy, brachytherapy or androgen deprivation therapy, and cancer staging. PCOS data were considered to represent the true treatment status. The sensitivity and specificity of the administrative data were estimated and relevant patient characteristics were compared using chi-squared tests.</p> <p>Results</p> <p>The validation data set comprised 1857 PCOS patients with treatment information linked to Cancer Registry records. Hospital and Medicare claims data combined described treatment more accurately than either one alone. The combined data accurately recorded radical prostatectomy (96% sensitivity) and brachytherapy (93% sensitivity), but not androgen deprivation therapy (76% sensitivity). External beam radiotherapy was rarely captured (5% sensitivity), but this was improved by including Medicare claims for radiation field setting or dosimetry (86% sensitivity). False positive rates were near 0%. Disease stage comparisons were limited by one-third of cases having unknown stage in the Cancer Registry. Administrative data recorded treatment more accurately for cases in urban areas.</p> <p>Conclusions</p> <p>Cancer Registry and hospital inpatient data accurately captured radical prostatectomy and brachytherapy treatment, but not external beam radiotherapy or disease stage. Medicare claims data substantially improved the accuracy with which all major treatments were recorded. These administrative data combined are valid for population-based studies of some aspects of prostate cancer care.</p

The NMR restraints grid at BMRB for 5,266 protein and nucleic acid PDB entries

Several pilot experiments have indicated that improvements in older NMR structures can be expected by applying modern software and new protocols (Nabuurs et al. in Proteins 55:483–186, 2004; Nederveen et al. in Proteins 59:662–672, 2005; Saccenti and Rosato in J Biomol NMR 40:251–261, 2008). A recent large scale X-ray study also has shown that modern software can significantly improve the quality of X-ray structures that were deposited more than a few years ago (Joosten et al. in J. Appl Crystallogr 42:376–384, 2009; Sanderson in Nature 459:1038–1039, 2009). Recalculation of three-dimensional coordinates requires that the original experimental data are available and complete, and are semantically and syntactically correct, or are at least correct enough to be reconstructed. For multiple reasons, including a lack of standards, the heterogeneity of the experimental data and the many NMR experiment types, it has not been practical to parse a large proportion of the originally deposited NMR experimental data files related to protein NMR structures. This has made impractical the automatic recalculation, and thus improvement, of the three dimensional coordinates of these structures. We here describe a large-scale international collaborative effort to make all deposited experimental NMR data semantically and syntactically homogeneous, and thus useful for further research. A total of 4,014 out of 5,266 entries were ‘cleaned’ in this process. For 1,387 entries, human intervention was needed. Continuous efforts in automating the parsing of both old, and newly deposited files is steadily decreasing this fraction. The cleaned data files are available from the NMR restraints grid at http://restraintsgrid.bmrb.wisc.edu

Alteration of renal respiratory Complex-III during experimental type-1 diabetes

<p>Abstract</p> <p>Background</p> <p>Diabetes has become the single most common cause for end-stage renal disease in the United States. It has been established that mitochondrial damage occurs during diabetes; however, little is known about what initiates mitochondrial injury and oxidant production during the early stages of diabetes. Inactivation of mitochondrial respiratory complexes or alteration of their critical subunits can lead to generation of mitochondrial oxidants, mitochondrial damage, and organ injury. Thus, one goal of this study was to determine the status of mitochondrial respiratory complexes in the rat kidney during the early stages of diabetes (5-weeks post streptozotocin injection).</p> <p>Methods</p> <p>Mitochondrial complex activity assays, blue native gel electrophoresis (BN-PAGE), Complex III immunoprecipitation, and an ATP assay were performed to examine the effects of diabetes on the status of respiratory complexes and energy levels in renal mitochondria. Creatinine clearance and urine albumin excretion were measured to assess the status of renal function in our model.</p> <p>Results</p> <p>Interestingly, of all four respiratory complexes only cytochrome c reductase (Complex-III) activity was significantly decreased, whereas two Complex III subunits, Core 2 protein and Rieske protein, were up regulated in the diabetic renal mitochondria. The BN-PAGE data suggested that Complex III failed to assemble correctly, which could also explain the compensatory upregulation of specific Complex III subunits. In addition, the renal F₀F₁-ATPase activity and ATP levels were increased during diabetes.</p> <p>Conclusion</p> <p>In summary, these findings show for the first time that early (and selective) inactivation of Complex-III may contribute to the mitochondrial oxidant production which occurs in the early stages of diabetes.</p

Chronic kidney disease and use of dental services in a united states public healthcare system: a retrospective cohort study

<p>Abstract</p> <p>Background</p> <p>As several studies have shown an association between periodontal disease and chronic kidney disease (CKD), regular dental care may be an important strategy for reducing the burden of CKD. Access to dental care may be limited in the US public health system.</p> <p>Methods</p> <p>In this retrospective cohort study of 6,498 adult patients with (n = 2,235) and without (n = 4,263) CKD and at least 12 months of follow-up within the San Francisco Department of Public Health Community Health Network clinical databases, we examined the likelihood of having a dental visit within the observation period (2005-2010) using Cox proportional hazards models. To determine whether dental visits reflected a uniform approach to preventive service use in this setting, we similarly examined the likelihood of having an eye visit among those with diabetes, for whom regular retinopathy screening is recommended. We defined CKD status by average estimated glomerular filtration rate based on two or more creatinine measurements ≥ 3 months apart (no CKD, ≥ 60 ml/min/1.73 m²; CKD, < 60 ml/min/1.73 m²).</p> <p>Results</p> <p>Only 11.0% and 17.4% of patients with and without CKD, respectively, had at least one dental visit. Those with CKD had a 25% lower likelihood of having a dental visit [HR = 0.75, 95% CI (0.64-0.88)] than those without CKD after adjustment for confounders. Among the subgroup of patients with diabetes, 11.8% vs. 17.2% of those with and without CKD had a dental visit, while 58.8% vs. 57.8% had an eye visit.</p> <p>Conclusions</p> <p>Dental visits, but not eye visits, in a US public healthcare setting are extremely low, particularly among patients with CKD. Given the emerging association between oral health and CKD, addressing factors that impede dental access may be important for reducing the disparate burden of CKD in this population.</p