Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Gut-derived acetate promotes B10 cells with antiinflammatory effects

Autoimmune diseases are characterized by a breakdown of immune tolerance partly due to environmental factors. The short-chain fatty acid acetate, derived mostly from gut microbial fermentation of dietary fiber, promotes antiinflammatory Tregs and protects mice from type 1 diabetes, colitis, and allergies. Here, we show that the effects of acetate extend to another important immune subset involved in tolerance, the IL-10-producing regulatory B cells (B10 cells). Acetate directly promoted B10 cell differentiation from mouse B1a cells both in vivo and in vitro. These effects were linked to metabolic changes through the increased production of acetyl-coenzyme A, which fueled the TCA cycle and promoted posttranslational lysine acetylation. Acetate also promoted B10 cells from human blood cells through similar mechanisms. Finally, we identified that dietary fiber supplementation in healthy individuals was associated with increased blood-derived B10 cells. Direct delivery of acetate or indirect delivery via diets or bacteria that produce acetate might be a promising approach to restore B10 cells in noncommunicable diseases.

A cost-utility analysis of atezolizumab in the second-line treatment of patients with metastatic bladder cancer

Background

Despite initial promising results, the IMvigor211 clinical trial failed to demonstrate an overall survival (os) benefit for atezolizumab compared with chemotherapy as second-line treatment for metastatic bladder cancer (mbc). However, given lessened adverse events (aes) and preserved quality of life (qol) with atezolizumab, there might still be investment value. To evaluate that potential value, we conducted a cost-utility analysis (cua) of atezolizumab compared with chemotherapy from the perspective of the Canadian health care payer.

Methods

A partitioned survival model was used to evaluate atezolizumab compared with chemotherapy over a lifetime horizon (5 years). The base-case analysis was conducted for the intention-to-treat (itt) population, with additional scenario analyses for subgroups by IMvigor-defined PD-L1 status. Health outcomes were evaluated through life-year gains and quality-adjusted life-years (qalys). Cost estimates in 2018 Canadian dollars for systemic treatment, aes, and end-of-life care were incorporated. The incremental cost-effectiveness ratio (icer) was used to compare treatment strategies. Parameter and model uncertainty were assessed through sensitivity and scenario analyses. Per Canadian guidelines, cost and effectiveness were discounted at 1.5%.

Results

For the itt population, the expected qalys for atezolizumab and chemotherapy were 0.75 and 0.56, with expected costs of $90,290 and $8,466 respectively. The resultant icer for atezolizumab compared with chemotherapy was $430,652 per qaly. Scenario analysis of patients with PD-L1 expression levels of 5% or greater led to a lower icer ($334,387 per qaly). Scenario analysis of observed compared with expected benefits demonstrated a higher icer, with a shorter time horizon ($928,950 per qaly).

Conclusions

Despite lessened aes and preserved qol, atezolizumab is not considered cost-effective for the second-line treatment of mbc.

Feeding practices of pre-school children and associated factors in Kathmandu, Nepal

BACKGROUND

In developing countries such as Nepal, many children aged below 3 years do not grow at a sufficiently high rate and are vulnerable to micronutrient deficiencies (e.g. vitamin A). Challenges to child nutrition can result from poverty, unhealthy traditional practices, inadequate caring and feeding practices. The present study aimed to assess the feeding practices of pre-school children and their associated factors.

METHODS

A cross-sectional study was carried out in pre-schools located in Kathmandu district between February and March 2018. Three levels in terms of price range (lower, medium and higher level) of pre-schools were selected to reach the mothers of children aged ≤3 years. A structured questionnaire was administered to 145 mothers. Descriptive analyses were conducted to observe the characteristics of the population. Multinomial logistic regression analyses were performed to identify the association for the factors of mothers' perception of their current feeding practices.

RESULTS

We found that dal-bhat/jaulo was a common complementary food irrespective of socio-economic background. Interestingly, mothers who had received a higher education were significantly less likely to change their feeding practices (odds ratio = 0.118, confidence interval = 0.01-0.94). The mothers that fed a higher quantity porridge to their children showed a high willingness to change the feeding practices.

CONCLUSIONS

Poor feeding practices are still an important public health problem in Nepal and were observed to be associated with low socio-economic status, unawareness and a lack of knowledge towards dietary diversity combined with strong beliefs related to social forces and cultures.

Metastatic colorectal cancer: therapeutic options for treating refractory disease

Therapeutic options for chemorefractory metastatic colorectal cancer (mcrc) have significantly expanded since 2009. The oral targeted therapies regorafenib and trifluridine/tipiracil have been established to be efficacious and safe in patients with mcrc who have progressed beyond 2 or more lines of chemotherapy. Evidence for the use of immunotherapy in a subgroup of this patient population is also encouraging, particularly in patients with mcrc that exhibits high microsatellite instability or deficient mismatch repair. Those significant advances have led to Health Canada approval of 3 novel therapeutic options for the treatment of patients with chemorefractory mcrc. However, the limited clinical efficacy of those treatments underscores the need for ongoing development of systemic therapy options for this unique cohort of patients. Here, we review the current and emerging treatment landscape for chemorefractory mcrc.

Substance use among treatment seeking Indian adolescent girls: Are they unique?

INTRODUCTION

Substance use among adolescents is on the rise across the globe along with a diminution of gender gap observed earlier posing a huge public health burden. Unfortunately, there is a paucity of literature on adolescent substance use. The literature is even sparse about substance use among adolescent girls. The current study aims to provide a glimpse of the profile and pattern of substance use among Indian adolescent girls seeking treatment for substance use problems in a specialty addiction treatment centre in India.

MATERIALS AND METHODS

This study is retrospective in design. Information regarding socio-demographics and substance use were extracted from the medical records of adolescent girls (≤ 19 years) who sought treatment for substance use problems during 2004-2018, at the adolescent clinic of a tertiary addiction treatment centre located in north India was retrieved carried out. The data was statistically analysed using SPSS.

RESULTS

A total of 28 girls sought treatment during this period. The mean age of the girls was 15.89 ± 2.72 years. Most of the girls were students (6/28) or had never started working (12/28). Majority of them were coming from an urban background (89.3%) and were educated up to 10^th class (85.5%). A total of 17 (60.7%) girls sought treatment for opioids use of which 11 were using illicit opioids like heroin and five (29.9%) of them reported taking opioids by injecting route primarily. History of past abstinence attempts, and treatment attempt were present in very few of them (10.7% and 14.3%).

CONCLUSION

Our study suggests a distinct substance use profile of adolescent girls. There is a need for further systematic studies to assess their clinical needs.

Glycemic Status at the Time of Presentation in Acute Organophosphorous Poisoning and its Correlation with Severity and Clinical Outcome

BACKGROUND

Organophosphorus insecticides (OPI) are one of the most extensively used classes of insecticides. Huge scientific body of evidence suggests that OPI exposure is a major toxicological threat that may affect human and animal health because of their various toxicities such as neurotoxicity, endocrine toxicity, immunotoxicity, reproductive toxicity, genotoxicity and ability to induce organ damage, alterations in cellular oxidative balance and disrupt glucose homeostasis. Mortality among organophosphorous (OP) poisoning patients despite advancements in its management is of concern.Of the various contributing factors,extremes and fluctuation in the glycemic status is a well documented parameter affecting the outcomes in critical illness although studies with respect to OP poisoning are deficient. All varieties of glycemic changes from hypoglycemia to hyperglycemia and ketoacidosis in OP poisoning along with other toxicological effects are reported,studies corroborating these findings are only few. The present endeavor was undertaken to study various glycemic changes in acute OP poisoning and it's bearing on clinical severity and clinical outcome.

AIMS AND OBJECTIVES

1. To assess the glycemic status by estimating random blood glucose level at the time of admission in cases of acute organophosphorous poisoning 2. To assess severity of the poisoning with various poisoning scales(PSS and POP) and level of serum pseudocholinesterase. 3. To correlate the documented blood glucose level with the severity and clinical outcome.

METHOD

A prospective analytical study of 100 patients with diagnosed acute poisoning, above the age of 18 years, non diabetic, with no history of mixed poisoning or condition affecting blood glucose levels and fulfilling the inclusion and exclusion criterias was done over a period of one year. The glycemic status at the time of presentation was documented and the patients were grouped into hypoglycemics, euglycemics and hyperglycemics and the same was correlated with the severity and clinical outcome using descriptive statistics, association and test of significance using MedCalc.

RESULTS

A prospective analytical study of 100 patients of acute organophosphate poisoning was done and on the basis of blood glucose levels at the time of presentation were further categorised into hypoglycemics (37%), euglycemics (52%) hyperglycaemic (11%). The outcome in terms of mortality was 59.45%,9.6% and 63.63% in the respective groups. The ventilator requirements among the three groups were 94.59%,53.84% and 100% respectively. Chisquare test to study the association between the presentation Random Blood Glucose (RBG) and the established Peradeniya Organophosphorous Poisoning Scale (POP) (Table 1) and Poisoning Severity Scale (PSS) (Table 2) revealed the study to be statistically significant (p value= 0.001)indicating both the extremes of glycemic status are associated with higher clinical severity and poorer outcomes.

CONCLUSION

We conclude that the glycemic status at the time of presentation in acute organophosphate poisoning patients is a simple, cheap, reliable marker in guiding the clinical severity and outcome when considered with clinical severity scores and S.ChE in a resource limited country like India.

Anti-basal Ganglia Antibodies (ABGA) and Excitatory Neurotransmitters in Obsessive-compulsive Disorder (OCD)

Introduction

OCD is a complex disorder with multiple aetiological theories. Recent research points to role of autoimmunity as well as hyperactivity of glutaminergic pathways in aetiopathogenesis of the disorder. It is possible that autoimmune mechanisms may modulate excitatory neurotransmission resulting in OCD.

Aims/objectives

This study aimed to study the association between serum anti-basal ganglia autoantibodies (ABGA) and Glx (glutamate + glutamine) levels in caudate nucleus and anterior cingulate cortex as demonstrated by 1H-MRS (proton magnetic resonance spectroscopy).

Methods

Thirty psychotropic-naive OCD patients and an equal number of age, gender matched healthy controls were studied using 1H-MRS and levels of Glx were obtained. ABGA was measured using ELISA (enzyme linked immunosorbent assay) technique and categorised as present or absent in the serum.

Results

ABGA was present in significantly higher proportion of patients as compared to controls (P < 0.05). Glx level was significantly higher (as measured by 1H-MRS) in patients with ABGA as compared to those without ABGA (P = 0.02). The study results did not differ based on age, gender, disease severity and illness duration.

Conclusions

The study demonstrates presence of ABGA in at least a subset of OCD population. The significant correlation between brain Glx levels and presence of ABGA provides a putative neurobiological framework for OCD. The strengths of the study include psychotropic-naive patients, blinded investigators and use of standardized instruments. The limitations include small sample size, use of Glx as proxy measure of glutamate and lack of other disorder controls. Similar studies on a larger sample are warranted for a better understanding.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

A randomised controlled trial assessing the efficacy of co-phenylcaine nasal spray in flexible transnasal pharyngolaryngoscopy

INTRODUCTION The aim of this study was to assess whether using co-phenylcaine nasal spray before flexible transnasal pharyngolaryngoscopy results in reduced pain and discomfort during the procedure. METHODS This was a randomised controlled trial. Eighty-four patients were randomised to receive either co-phenylcaine nasal spray or placebo nasal spray before performing transnasal flexible pharyngolaryngoscopy. Patient reported outcome measures included pain, discomfort, unpleasantness and willingness to repeat the procedure while clinician reported outcome measures comprised ease of examination and quality of view obtained during the procedure. RESULTS There was no statistically significant difference in scores for pain, discomfort, unpleasantness and willingness to repeat the procedure between the co-phenylcaine and placebo groups. On the other hand, ease of examination scores were significantly better for the co-phenylcaine group than for the placebo group. CONCLUSIONS The majority of patients do not find flexible pharyngolaryngoscopy unpleasant or painful with or without topical nasal anaesthesia. However, the spray does appear to help the examiner in completing a satisfactory assessment.

Inflammatory cytokines and glutaminergic excitotoxicity in patients with obsessive-compulsive disorder (OCD)

Introduction

In vitro studies have demonstrated possible neuroprotective effects of the following pro-inflammatory cytokines: IL-6, IL-1β and TNF-α against glutaminergic excitotoxicity in brain through different pathways.

Objectives

In the current study, we aim to correlate level of the above pro-inflammatory cytokines in serum with glutamate levels in head of caudate nucleus measured using Proton Magnetic Resonance Spectroscopy (1H-MRS) in patients with obsessive-compulsive disorder (OCD), a neuropsychiatric illness with possible multifactorial aetiology including immunological and excitotoxic factors.

Method

Thirty psychotropic-naïve patients with OCD and an equal number of gender and age-matched normal controls were recruited in the study. A detailed psychiatric assessment was carried out including sociodemographic and clinical variables. A 3T MR imaging and spectroscopy session was carried out in head of caudate nucleus. Further, absolute quantification of glutamate level was obtained using LC model. Simultaneously, 5 mL of blood sample was collected and assayed for the above pro-inflammatory cytokines (Siemens, Immulite™). The level of glutamate was correlated with the cytokine levels in patients with OCD.

Results

The level of Glx was significantly higher in patients with OCD as compared to controls (P < 0.05). The Glx level negatively correlated with two of the three pro-inflammatory cytokines: IL-6 and TNF-α (r = −0.807; r = −0.838; P < 0.05) while no significant correlation was demonstrated with IL-1β.

Conclusions

The findings provide preliminary evidence regarding possible neuroprotective effects of pro-inflammatory cytokines against glutaminergic excitotoxicity in patients with OCD. Further studies including patients with other psychiatric illnesses as controls are required for confirmation of the above findings.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

The diagnostic value of fine needle aspiration in parotid lumps

INTRODUCTION

Fine needle aspiration (FNA) is a safe and quick method of diagnosing superficial lumps, which aids preoperative planning. However, FNA of the parotid gland has not gained the widespread acceptance noted in other head and neck lumps. The aim of this study was to determine the ability of FNA of the parotid gland to differentiate benign and malignant disease, and to determine the impact on surgical outcome.

METHODS

A retrospective analysis of 201 consecutive parotid operations with preoperative FNA in a large district hospital in the UK was performed. The diagnostic characteristics were calculated for benign and malignant disease, and the impact on surgical procedure was determined.

RESULTS

In identifying benign disease, FNA has a sensitivity of 85% and a specificity of 76%. In detecting malignant disease, FNA has a sensitivity and specificity of 52% and 92% respectively. A false positive on FNA was associated with a higher incidence of neck dissection.

CONCLUSIONS

FNA is a useful diagnostic test. However, owing to low sensitivity, it is necessary to interpret it in the context of all other clinical information.

Interaction between the ionic liquids 1-alkyl-3-methylimidazolium tetrafluoroborate and Pluronic® P103 in aqueous solution: a DLS, SANS and NMR study

The effect of three ionic liquids (ILs) 1-alkyl 3-methyl imidazlolium tetraflouroborates (C(n)mim BF(4)n=4, 6, 8) on micellar solutions of an ethylene oxide-propylene oxide block copolymer (PEO-PPO-PEO), Pluronic® P103 was examined from scattering and NMR techniques. The ILs alter the cloud point and micelle size dependant on their alkyl chain length and the results are discussed in terms of their behavior as cosolvent/cosurfactant. Cloud point data support the hydrogen bonding between the imidazolium cation and P103 while dynamic light scattering (DLS) and small angle neutron scattering (SANS) reveal that presence of ionic liquid is not conducive to the micelle formation of P103. The selective nuclear Overhauser effect (NOESY) indicates that the PPO block of the P103 interacts with the alkyl group of the C(n)mim(+) cation by hydrophobic interaction. Through this kind of interactions, C(n)mim BF(4) and P103 can form mixed micelles. This result indicates that the presence of ILs hinders the micelle formation of P103 in solution and promotes P103 to orient at air/water interface.

Safe and adequate placement of nasogastric tubes in the presence of a cuffed tracheostomy tube

This case report and review of the literature aims to highlight the importance of the use of a chest radiograph to check the placement of nasogastric tubes after insertion in an awake patient with an inflated cuffed tracheostomy tube regardless of an acidic pH test.

Efficacy of isavuconazole, voriconazole and fluconazole in temporarily neutropenic murine models of disseminated Candida tropicalis and Candida krusei

OBJECTIVES

The aim of this study was to assess the dose-response of isavuconazole, voriconazole and fluconazole in disseminated Candida tropicalis and Candida krusei infections.

METHODS

Mice were immunosuppressed using either one dose [temporarily neutropenic (TN)] or two doses [persistently neutropenic (PN)] of cyclophosphamide. Treatment was started 5 h after infection with oral isavuconazole (6, 15, 30, 60, 90, 120 or 150 mg/kg equivalent active compound), intravenous voriconazole (5, 20 or 40 mg/kg plus grapefruit gavage twice daily) or oral fluconazole (15, 50 or 150 mg/kg) all administered twice daily. Kidney burden was assessed for C. tropicalis, and kidney and brain burden for C. krusei.

RESULTS

Vehicle controls developed a non-lethal infection with high burdens in both models. In the TN models, isavuconazole, voriconazole and fluconazole (>50 mg/kg) reduced kidney burden compared with controls; >60 mg/kg isavuconazole and 50 mg/kg fluconazole were superior to alternative treatments (other than voriconazole 40 mg/kg). Isavuconazole (all doses) reduced brain burden (P<0.05) in the C. krusei model; fluconazole (all doses) and voriconazole (5 and 20 mg/kg) did not. In the C. krusei kidney burden model, isavuconazole 120 and 150 mg/kg and voriconazole 40 mg/kg were superior to controls and fluconazole. In the C. tropicalis model, PN isavuconazole (all doses), voriconazole (>5 mg/kg) and fluconazole (all doses) reduced kidney burden (P<0.05). Only isavuconazole (all doses) and 40 mg/kg voriconazole were effective against C. krusei in the brain, isavuconazole and voriconazole reduced tissue burden (P<0.05). Fluconazole had no significant effect on brain burden even at 150 mg/kg.

CONCLUSIONS

Isavuconazole significantly reduced kidney burden in mice infected with C. tropicalis and both kidney and brain burdens in mice infected with C. krusei. Isavuconazole was as effective as voriconazole and much more effective than fluconazole at reducing brain burden.

Evidence for a long-range component in the pion emission source in Au+Au collisions at sqrt sNN=200 GeV

Emission source functions are extracted from correlation functions constructed from charged pions produced at midrapidity in Au+Au collisions at sqrt[s(NN)]=200 GeV. The source parameters extracted from these functions at low k(T) give first indications of a long tail for the pion emission source. The source extension cannot be explained solely by simple kinematic considerations. The possible role of a halo of secondary pions from resonance emissions is explored.

Dense-medium modifications to jet-induced hadron pair distributions in Au+Au collisions at sqrt s NN=200 GeV

Azimuthal correlations of jet-induced high-p(T) charged hadron pairs are studied at midrapidity in Au+Au collisions at sqrt[s(NN)]=200 GeV. The distribution of jet-associated partner hadrons (1.0<p(T)<2.5 GeV/c) per trigger hadron (2.5<p(T)<4.0 GeV/c) is found to vary with collision centrality, in both shape and yield, indicating a significant effect of the nuclear collision medium on the jet fragmentation process.

Common suppression pattern of eta and pi0 mesons at high transverse momentum in Au + Au collisions at square root S(NN) = 200 GeV

Inclusive transverse momentum spectra of eta mesons have been measured within p(T) = 2-10 GeV/c at midrapidity by the PHENIX experiment in Au + Au collisions at square root S(NN) = 200 GeV. In central Au+Au the eta yields are significantly suppressed compared to peripheral Au + Au, d + Au, and p + p yields scaled by the corresponding number of nucleon-nucleon collisions. The magnitude, centrality, and p(T) dependence of the suppression is common, within errors, for eta and pi0. The ratio of eta to pi0 spectra at high p(T) amounts to 0.40 < R(eta/pi)0 < 0.48 for the three systems, in agreement with the world average measured in hadronic and nuclear reactions and, at large scaled momentum, in e+e- collisions.

Single electrons from heavy-flavor decays in collisions at

The invariant differential cross section for inclusive electron production in p+p collisions at [FORMULA: SEE TEXT] has been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider over the transverse momentum range 0.4<or=pT<OR=5.0 GeV/c in the central rapidity region ([FORMULA: SEE TEXT]). The contribution to the inclusive electron spectrum from semileptonic decays of hadrons carrying heavy flavor, i.e., charm quarks or, at high , bottom quarks, is determined via three independent methods. The resulting electron spectrum from heavy-flavor decays is compared to recent leading and next-to-leading order perturbative QCD calculations. The total cross section of charm quark-antiquark pair production is determined to be [FORMULA: SEE TEXT].

Measurement of identified and inclusive photon second-harmonic parameter and implications for direct photon production in [FORMULA: SEE TEXT] Au+Au

The azimuthal distribution of identified pi0 and inclusive photons has been measured in [FORMULA: SEE TEXT] Au+Au collisions with the PHENIX experiment at the Relativistic Heavy-Ion Collider (RHIC). The second-harmonic parameter (nu2) was measured to describe the observed anisotropy of the azimuthal distribution. The measured inclusive photon is consistent with the value expected for the photons from hadron decay and is also consistent with the lack of direct photon signal over the measured pT range 1-6 GeV/c. An attempt is made to extract nu2 of direct photons.

Nuclear modification of electron spectra and implications for heavy quark energy loss in Au+Au collisions at [FORMULA: SEE TEXT]

The PHENIX experiment has measured midrapidity ([FORMULA: SEE TEXT]) transverse momentum spectra ([FORMULA: SEE TEXT]) of electrons as a function of centrality in Au+Au collisions at [FORMULA: SEE TEXT]. Contributions from photon conversions and from light hadron decays, mainly Dalitz decays of pi0 and eta mesons, were removed. The resulting nonphotonic electron spectra are primarily due to the semileptonic decays of hadrons carrying heavy quarks. Nuclear modification factors were determined by comparison to nonphotonic electrons in p+p collisions. A significant suppression of electrons at high pT is observed in central Au+Au collisions, indicating substantial energy loss of heavy quarks.

Measurement of transverse single-spin asymmetries for midrapidity production of neutral pions and charged hadrons in polarized p + p collisions at square root(s) = 200 GeV

Transverse single-spin asymmetries to probe the transverse-spin structure of the proton have been measured for neutral pions and nonidentified charged hadrons from polarized proton-proton collisions at midrapidity and square root(s) = 200 GeV. The data cover a transverse momentum (pT) range 1.0-5.0 GeV/c for neutral pions and 0.5-5.0 GeV/c for charged hadrons, at a Feynman-x value of approximately zero. The asymmetries seen in this previously unexplored kinematic region are consistent with zero within errors of a few percent. In addition, the inclusive charged hadron cross section at midrapidity from 0.5 < pT < 7.0 GeV/c is presented and compared to next-to-leading order perturbative QCD (pQCD) calculations. Successful description of the unpolarized cross section above approximately 2 GeV/c suggests that pQCD is applicable in the interpretation of the asymmetry results in the relevant kinematic range.

Saturation of azimuthal anisotropy in Au + Au collisions at (square root)s(NN) = 62-200 GeV

New measurements are presented for charged hadron azimuthal correlations at midrapidity in Au+Au collisions at (square root)s(NN) = 62.4 and 200 GeV. They are compared to earlier measurements obtained at (square root)s(NN) = 130 GeV and in Pb + Pb collisions at (square root)s(NN) = 17.2 GeV. Sizeable anisotropies are observed with centrality and transverse momentum (pT) dependence characteristic of elliptic flow (upsilon2). For a broad range of centralities, the observed magnitudes and trends of the differential anisotropy, upsilon2(pT), change very little over the collision energy range (square root)s(NN) = 62-200 GeV, indicating saturation of the excitation function for upsilon2 at these energies. Such a saturation may be indicative of the dominance of a very soft equation of state for (square root)s(NN) approximately 60-200 GeV.

Centrality dependence of direct photon production in (square root)S(NN) = 200 GeV Au + Au collisions

The first measurement of direct photons in Au + Au collisions at (square root)S(NN) = 200 GeV is presented. The direct photon signal is extracted as a function of the Au + Au collision centrality and compared to next-to-leading order perturbative quantum chromodynamics calculations. The direct photon yield is shown to scale with the number of nucleon-nucleon collisions for all centralities.

Deuteron and antideuteron production in Au+Au collisions at square root of s(NN)=200 GeV

The production of deuterons and antideuterons in the transverse momentum range 1.1<p(T)<4.3 GeV/c at midrapidity in Au+Au collisions at square root of s(NN)=200 GeV has been studied by the PHENIX experiment at RHIC. A coalescence analysis, comparing the deuteron and antideuteron spectra with that of proton and antiproton, has been performed. The coalescence probability is equal for both deuterons and antideuterons and it increases as a function of p(T), which is consistent with an expanding collision zone. Comparing (anti)proton yields, p /p=0.73+/-0.01, with (anti)deuteron yields, d /d=0.47+/-0.03, we estimate that n /n=0.64+/-0.04. The nucleon phase space density is estimated from the coalescence measurement.

Centrality dependence of charm production from a measurement of single electrons in Au+Au collisions at sqrt[s(NN)]=200 GeV

The PHENIX experiment has measured midrapidity transverse momentum spectra (0.4<p(T)<4.0 GeV/c) of single electrons as a function of centrality in Au+Au collisions at sqrt[s(NN)]=200 GeV. Contributions from photon conversions and Dalitz decays of light neutral mesons are measured by introducing a thin (1.7% X0) converter into the PHENIX acceptance and are statistically removed. The subtracted nonphotonic electron spectra are primarily due to the semileptonic decays of hadrons containing heavy quarks, mainly charm at lower p(T). For all centralities, the charm production cross section is found to scale with the nuclear overlap function, T(AA). For minimum-bias collisions the charm cross section per binary collision is N(cc )/T(AA)=622+/-57(stat)+/-160(syst) microb.

Bose-Einstein correlations of charged pion pairs in Au + Au collisions at square root sNN = 200 GeV

Bose-Einstein correlations of identically charged pion pairs were measured by the PHENIX experiment at midrapidity in Au + Au collisions at square root s(NN)=200 GeV. The Bertsch-Pratt radius parameters were determined as a function of the transverse momentum of the pair and as a function of the centrality of the collision. Using the standard core-halo partial Coulomb fits, and a new parametrization which constrains the Coulomb fraction as determined from the unlike-sign pion correlation, the ratio R(out)/R(side) is within 0.8-1.1 for 0.25< <k(T)> <1.2 GeV/c. The centrality dependence of all radii is well described by a linear scaling in N(1/3)(part), and R(out)/R(side) for <k(T)> approximately 0.45 GeV/c is approximately constant at unity as a function of centrality.

Measurement of nonrandom event-by-event fluctuations of average transverse momentum in square root of (sNN)=200 GeV Au+Au and p+p collisions

Event-by-event fluctuations of the average transverse momentum of produced particles near midrapidity have been measured by the PHENIX Collaboration in square root of (sNN)=200 GeV Au+Au, and p+p collisions at the Relativistic Heavy Ion Collider. The fluctuations are observed to be in excess of the expectation for statistically independent particle emission for all centralities. The excess fluctuations exhibit a dependence on both the centrality of the collision and on the pT range over which the average is calculated. Both the centrality and pT dependence can be well reproduced by a simulation of random particle production with the addition of contributions from hard-scattering processes.

Compact sources as the origin of the soft γ-ray emission of the Milky Way

The Milky Way is known to be an abundant source of gamma-ray photons, now determined to be mainly diffuse in nature and resulting from interstellar processes. In the soft gamma-ray domain, point sources are expected to dominate, but the lack of sensitive high-resolution observations did not allow for a clear estimate of the contribution from such sources. Even the best imaging experiment revealed only a few point sources, accounting for about 50% of the total Galactic flux. Theoretical studies were unable to explain the remaining intense diffuse emission. Investigating the origin of the soft gamma-rays is therefore necessary to determine the dominant particle acceleration processes and to gain insights into the physical and chemical equilibrium of the interstellar medium. Here we report observations in the soft gamma-ray domain that reveal numerous compact sources. We show that these sources account for the entirety of the Milky Way's emission in soft gamma-rays, leaving at most a minor role for diffuse processes.

J/psi production from proton-proton collisions at square root of s=200 GeV

J/psi production has been measured in proton-proton collisions at square root of s=200 GeV over a wide rapidity and transverse momentum range by the PHENIX experiment at the Relativistic Heavy Ion Collider. Distributions of the rapidity and transverse momentum, along with measurements of the mean transverse momentum and total production cross section are presented and compared to available theoretical calculations. The total J/psi cross section is 4.0+/-0.6(stat)+/-0.6(syst)+/-0.4(abs) mu b. The mean transverse momentum is 1.80+/-0.23(stat)+/-0.16(syst) GeV/c.