Measurement of the isolated prompt photon production cross section in pp collisions at √s=7 TeV

The differential cross section for the inclusive production of isolated prompt photons has been measured as a function of the photon transverse energy E(T)(γ) in pp collisions at √s=7  TeV using data recorded by the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 2.9  pb(-1). Photons are required to have a pseudorapidity |η(γ)|<1.45 and E(T)(γ)>21  GeV, covering the kinematic region 0.006<x(T)<0.086. The measured cross section is found to be in agreement with next-to-leading-order perturbative QCD calculations.

Efficient Nanoporous Silicon Membranes for Integrated Microfluidic Separation and Sensing Systems

Nanoporous devices constitute emerging platforms for selective molecule separation and sensing, with great potential for high throughput and economy in manufacturing and operation. Acting as mass transfer diodes similar to a solid-state device based on electron conduction, conical pores are shown to have superior performance characteristics compared to traditional cylindrical pores. Such phenomena, however, remain to be exploited for molecular separation. Here we present performance results from silicon membranes created by a new synthesis technique based on interferometric lithography. This method creates millimeter sized planar arrays of uniformly tapered nanopores in silicon with pore diameter 100 nm or smaller, ideally-suited for integration into a multi-scale microfluidic processing system. Molecular transport properties of these devices are compared against state-of-the-art polycarbonate track etched (PCTE) membranes. Mass transfer rates of up to fifteen-fold greater than commercial sieve technology are obtained. Complementary results from molecular dynamics simulations on molecular transport are reported.

Search for stopped Gluinos in pp collisions at square root s=7 TeV

The results of the first search for long-lived gluinos produced in 7 TeV pp collisions at the CERN Large Hadron Collider are presented. The search looks for evidence of long-lived particles that stop in the CMS detector and decay in the quiescent periods between beam crossings. In a dataset with a peak instantaneous luminosity of 1×10(32) cm-2 s-1, an integrated luminosity of 10 pb-1, and a search interval corresponding to 62 hours of LHC operation, no significant excess above background was observed. Limits at the 95% confidence level on gluino pair production over 13 orders of magnitude of gluino lifetime are set. For a mass difference mg - mχ1(0) >100 GeV/c2, and assuming BR(g→gχ1(0))=100%, mg < 370 GeV/c2 are excluded for lifetimes from 10 μs to 1000 s.

Search for quark compositeness with the dijet centrality ratio in pp collisions at √s=7 TeV

A search for quark compositeness in the form of quark contact interactions, based on hadronic jet pairs (dijets) produced in proton-proton collisions at √s=7 TeV, is described. The data sample of the study corresponds to an integrated luminosity of 2.9 pb(-1) collected with the CMS detector at the LHC. The dijet centrality ratio, which quantifies the angular distribution of the dijets, is measured as a function of the invariant mass of the dijet system and is found to agree with the predictions of the standard model. A statistical analysis of the data provides a lower limit on the energy scale of quark contact interactions. The sensitivity of the analysis is such that the expected limit is 2.9 TeV; because the observed value of the centrality ratio at high invariant mass is below the expectation, the observed limit is 4.0 TeV at the 95% confidence level.

Search for dijet resonances in 7 TeV pp collisions at CMS

A search for narrow resonances in the dijet mass spectrum is performed using data corresponding to an integrated luminosity of 2.9 pb⁻¹ collected by the CMS experiment at the Large Hadron Collider. Upper limits at the 95% confidence level are presented on the product of the resonance cross section, branching fraction into dijets, and acceptance, separately for decays into quark-quark, quark-gluon, or gluon-gluon pairs. The data exclude new particles predicted in the following models at the 95% confidence level: string resonances, with mass less than 2.50 TeV, excited quarks, with mass less than 1.58 TeV, and axigluons, colorons, and E6 diquarks, in specific mass intervals. This extends previously published limits on these models.

Chronic humoral rejection of human kidney allografts is associated with MMP-2 accumulation in podocytes and its release in the urine

Chronic humoral rejection (CHR) is an important cause of late graft failures following kidney transplantation. Overall, the pathophysiology of CHR is poorly understood. Matrix metalloproteinase-2 (MMP-2), a type IV collagenase, has been implicated in chronic kidney disease and allograft rejection in previous studies. We examined the presence of MMP-2 in allograft biopsies and in the urine of kidney transplant recipients with CHR. MMP-2 staining was detected by immunohistochemistry in podocytes for all CHR patients but less frequently in patients with other renal complications. Urinary MMP-2 levels were also significantly higher in CHR patients (median 4942 pg/mL, N = 27) compared to non-CHR patients (median 598 pg/mL, N = 65; p < 0.001). Elevated urinary MMP-2 correlated with higher levels of proteinuria in both CHR and non-CHR patients. Longitudinal analysis indicated that increase in urine MMP-2 coincided with initial diagnosis of CHR as documented by the biopsies. Using an enzymatic assay, we demonstrated that MMP-2 was present in its active form in the urine of patients with CHR. Overall, our findings associate MMP-2 with glomerular injury as well as interstitial fibrosis and tubular atrophy observed in patients with CHR.

Rigorous surface enhanced Raman spectral characterization of large-area high-uniformity silver-coated tapered silica nanopillar arrays

Surface enhanced Raman spectroscopy (SERS) has been increasingly utilized as an analytical technique with significant chemical and biological applications (Qian et al 2008 Nat. Biotechnol. 26 83; Fujita et al 2009 J. Biomed. Opt. 14 024038; Chou et al 2008 Nano Lett.8 1729; Culha et al 2003 Anal. Chem. 75 6196; Willets K A 2009 Anal. Bioanal. Chem. 394 85; Han et al 2009 Anal. Bioanal. Chem. 394 1719; Sha et al 2008 J. Am. Chem. Soc. 130 17214). However, production of a robust, homogeneous and large-area SERS substrate with the same ultrahigh sensitivity and reproducibility still remains an important issue. Here, we describe a large-area ultrahigh-uniformity tapered silver nanopillar array made by laser interference lithography on the entire surface of a 6 inch wafer. Also presented is the rigorous optical characterization method of the tapered nanopillar substrate to accurately quantify the Raman enhancement factor, uniformity and repeatability. An average homogeneous enhancement factor of close to 10(8) was obtained for benzenethiol adsorbed on a silver-coated nanopillar substrate.

Response to pegylated interferon and ribavirin in Asian American patients with chronic hepatitis C genotypes 1 vs 2/3 vs 6

Chronic hepatitis C is generally underappreciated in Asian Americans, and most pivotal studies were conducted in western countries and only included a small numbers of Asian patients. Our goal was to examine and compare treatment outcomes in these patients with genotypes 1 vs 2/3 vs 6. We performed a retrospective cohort study of 167 consecutive treatment-naïve Asian American patients treated with pegylated interferon (PEG IFN) plus ribavirin (RBV) at two community clinics in Northern California from 12/00 to 1/08. Primary outcome was sustained virological response rate by intention-to-treat analysis. The overall completion rate was 76%, and treatment adherence (completion of ≥ 75-80% PEG IFN + RBV dose for ≥ 75-80% of intended duration) was 74%. Significant depression was noted in only 4% of patients. Sustained virologic response in patients with genotype 6 treated for 48 weeks was similar to that seen in those with genotype 2/3 (74%vs 75%, P = 0.89) and significantly higher than those with genotype 1 (74%vs 49%, P = 0.016). On multivariate analysis inclusive of sex, age, body mass index (≤ 25 vs > 25) and viral load, only treatment adherence and genotype (2/3 and 6 treated for 48 weeks) were found to be significant predictors of sustained virologic response. We conclude that significant depression is rare in Asian American patients (4%). Patients with genotype 6 treated for 48 weeks appear to have a similar treatment response rate as patients with genotype 2/3 and a significantly higher response rate than those with genotype 1.

First measurement of Bose-Einstein correlations in proton-proton collisions at √s=0.9 and 2.36 TeV at the LHC

Bose-Einstein correlations have been measured using samples of proton-proton collisions at 0.9 and 2.36 TeV center-of-mass energies, recorded by the CMS experiment at the CERN Large Hadron Collider. The signal is observed in the form of an enhancement of pairs of same-sign charged particles with small relative four-momentum. The size of the correlated particle emission region is seen to increase significantly with the particle multiplicity of the event.

Transverse-momentum and pseudorapidity distributions of charged hadrons in pp collisions at square root of s = 7 TeV

Charged-hadron transverse-momentum and pseudorapidity distributions in proton-proton collisions at square root of s = 7  TeV are measured with the inner tracking system of the CMS detector at the LHC. The charged-hadron yield is obtained by counting the number of reconstructed hits, hit pairs, and fully reconstructed charged-particle tracks. The combination of the three methods gives a charged-particle multiplicity per unit of pseudorapidity dN(ch)/dη|(|η|<0.5) = 5.78 ± 0.01(stat) ± 0.23(syst) for non-single-diffractive events, higher than predicted by commonly used models. The relative increase in charged-particle multiplicity from square root of s = 0.9 to 7 TeV is [66.1 ± 1.0(stat) ± 4.2(syst)]%. The mean transverse momentum is measured to be 0.545 ± 0.005(stat) ± 0.015(syst)  GeV/c. The results are compared with similar measurements at lower energies.

Safety of pramlintide added to mealtime insulin in patients with type 1 or type 2 diabetes: a large observational study

The objective of this Phase 4, open-label, multicentre, observational study was to fulfil food and drug administration (FDA) postapproval requirement to evaluate in healthcare practices the risk of insulin-induced severe hypoglycaemia following initiation of pramlintide therapy in N = 1297 patients with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) with inadequate glycaemic control. The duration of the study was approximately 6 months. During the adjustment period (0-3 months), the incidence and event rate of patient-ascertained severe hypoglycaemia (PASH) were 4.8% and 0.33 events/patient-year in patients with T1DM and 2.8% and 0.19 events/patient-year in patients with T2DM. During the maintenance period (>3-6 months), the incidence and event rate of PASH declined in patients with T1DM or T2DM. This study confirms that in healthcare practices, the risk of insulin-induced severe hypoglycaemia following the initiation of pramlintide is low in patients with T1DM or T2DM.

Patient safety and systematic reviews: finding papers indexed in MEDLINE, EMBASE and CINAHL

OBJECTIVE

To develop search strategies for identifying papers on patient safety in MEDLINE, EMBASE and CINAHL.

METHODS

Six journals were electronically searched for papers on patient safety published between 2000 and 2006. Identified papers were divided into two gold standards: one to build and the other to validate the search strategies. Candidate terms for strategy construction were identified using a word frequency analysis of titles, abstracts and keywords used to index the papers in the databases. Searches were run for each one of the selected terms independently in every database. Sensitivity, precision and specificity were calculated for each candidate term. Terms with sensitivity greater than 10% were combined to form the final strategies. The search strategies developed were run against the validation gold standard to assess their performance. A final step in the validation process was to compare the performance of each strategy to those of other strategies found in the literature.

RESULTS

We developed strategies for all three databases that were highly sensitive (range 95%-100%), precise (range 40%-60%) and balanced (the product of sensitivity and precision being in the range of 30%-40%). The strategies were very specific and outperformed those found in the literature.

CONCLUSION

The strategies we developed can meet the needs of users aiming to maximise either sensitivity or precision, or seeking a reasonable compromise between sensitivity and precision, when searching for papers on patient safety in MEDLINE, EMBASE or CINAHL.

Potassium accumulation as dynamic modulator of neurohypophysial excitability

Activity-dependent modulation of excitable responses from neurohypophysial axons and their secretory swellings has long been recognized as an important regulator of arginine vasopressin and oxytocin release during patterned stimulation. Various activity-dependent mechanisms, including action potential broadening, potassium accumulation, and autocrine or paracrine feedback, have been proposed as underlying mechanisms. However, the relevance of any specific mechanism on net excitability in the intact preparation, during different levels of overall activation, and during realistic stimulation with trains of action potentials has remained largely undetermined. Using high-speed optical recordings and potentiometric dyes, we have quantified the dynamics of global excitability under physiologically more realistic conditions, that is in the intact neurohypophysis during trains of stimuli at varying frequencies and levels of overall activity. Net excitability facilitated during stimulation at low frequencies or at low activity. During persistent high-intensity or high-frequency stimulation, net excitability became severely depressed. Depression of excitable responses was strongly affected by manipulations of extracellular potassium levels, including changes to resting [K(+)](out), increases of interstitial spaces with hypertonic solutions and inhibition of Na(+)/K(+) ATPase activity. Application of the GABA(A) receptor blocker bicuculline or manipulations of Ca(2+) influx showed little effect. Numerical simulation of K(+) accumulation on action potentials of individual axons reproduced optically recorded population responses, including the overall depression of action potential (AP) amplitudes, modest AP broadening and the prominent loss of hyperpolarizing undershoots. Hence, extracellular potassium accumulation dominates activity-dependent depression of neurohypophysial excitability under elevated stimulation conditions. The intricate dependence on the short-term stimulation history and its resulting feedback on neurohypophysial excitability renders [K(+)](out) accumulation a surprisingly complex mechanism for regulating axonal excitability and subsequent neuroendocrine release.