Reducing the time-step errors in diffusion Monte Carlo.

We modify the reweighting factor of the projector used in diffusion Monte Carlo to reduce the time-step error of the total energy. Furthermore, we present a reweighting scheme that has the desirable feature that it is exactly size-consistent, i.e., the energy of a system containing widely separated fragments is the same as the sum of the energies of the individual fragments. The practical utility of the latter improvement is that it reduces the time-step error of the binding energies of some weakly interacting systems.

Nonlocal pseudopotentials and time-step errors in diffusion Monte Carlo.

We present a version of the T-moves approach for treating nonlocal pseudopotentials in diffusion Monte Carlo, which has much smaller time-step errors than the existing T-moves approaches, while at the same time preserving desirable features such as the upper-bound property for the energy. In addition, we modify the reweighting factor of the projector used in diffusion Monte Carlo to reduce the time-step error. The latter is applicable not only to pseudopotential calculations but also to all-electron calculations.

Accurate energies of transition metal atoms, ions, and monoxides using selected configuration interaction and density-based basis-set corrections.

The semistochastic heat-bath configuration interaction method is a selected configuration interaction plus perturbation theory method that has provided near-full configuration interaction (FCI) levels of accuracy for many systems with both single- and multi-reference character. However, obtaining accurate energies in the complete basis-set limit is hindered by the slow convergence of the FCI energy with respect to basis size. Here, we show that the recently developed basis-set correction method based on range-separated density functional theory can be used to significantly speed up basis-set convergence in SHCI calculations. In particular, we study two such schemes that differ in the functional used and apply them to transition metal atoms and monoxides to obtain total, ionization, and dissociation energies well converged to the complete-basis-set limit within chemical accuracy.

Accounting for spectroscopic effects in laser-based open-path eddy covariance flux measurements.

A significant portion of the production and consumption of trace gases (e.g. CO2 , CH4 , N2 O, NH3 , etc.) by world ecosystems occurs in areas without sufficient infrastructure or easily available grid power to run traditional closed-path flux stations. Open-path analyzer design allows such measurements with power consumption 10-150 times below present closed-path technologies, helping to considerably expand the global coverage and improve the estimates of gas emissions and budgets, informing the remote sensing and modeling communities and policy decisions, all the way to IPCC reports. Broad-band nondispersive infrared devices have been used for open-path CO2 and H2 O measurements since the late 1970s, but since recently, a growing number of new narrow-band laser-based instruments are being rapidly developed. The new design comes with its own challenges, specifically: (a) mirror contamination, and (b) uncontrolled air temperature, pressure and humidity, affecting both the gas density and the laser spectroscopy of the measurements. While the contamination can be addressed via automated cleaning, and density effects can be addressed via the Webb-Pearman-Leuning approach, the spectroscopic effects of the in situ temperature, pressure and humidity fluctuations on laser-measured densities remain a standing methodological question. Here we propose a concept accounting for such effects in the same manner as Webb et al. proposed to account for respective density effects. Derivations are provided for a general case of flux of any gas, examined using a specific example of CH4 fluxes from a commercially available analyzer, and then tested using "zero-flux" experiment. The proposed approach helps reduce errors in open-path, enclosed, and temperature- or pressure-uncontrolled closed-path laser-based flux measurements due to the spectroscopic effects from few percents to multiple folds, leading to methodological advancement and geographical expansion of the use of such systems providing reliable and consistent results for process-level studies, remote sensing and Earth modeling applications, and GHG policy decision-making.

Fellowship-Trained Orthopaedic Trauma Surgeons Achieve Better Postoperative Radiographic Parameters After Intramedullary Nailing of Intertrochanteric Femur Fractures when Compared With Non-trauma-Trained Surgeons.

INTRODUCTION: Intertrochanteric femoral fractures are common orthopaedic injuries accounting for nearly 30% of all fracture-related hospitalizations. Because many factors predictive of failure are related to technical aspects of the surgery, the purpose of this study was to compare radiographic parameters after fixation, comparing fellowship-trained orthopaedic trauma surgeons with surgeons who did not complete an orthopaedic trauma fellowship. METHODS: We initiated a search for CPT code 27245 across our hospital network to identify 100 consecutive patients treated by five fellowship-trained orthopaedic traumatologists and 100 consecutive patients treated by community surgeons. Patients were then stratified based on their surgeon's subspecialty training (trauma vs community). Primary outcome variables were neck-shaft angle (NSA), a comparison of the repaired NSA with the uninjured side, tip-apex distance, and reduction quality. RESULTS: One hundred patients were included in each group. The mean age in the community group was 77 years compared with 79 years in the trauma group. The mean tip-apex distance for the trauma group was 10 mm compared with 21 mm for the community group ( P < 0.001). The mean postoperative NSA for the trauma group was 133° compared with 127° for the community group ( P < 0.001). The mean difference of the NSA of the repaired side compared with the uninjured side was 2.5° of valgus in the trauma group compared with 5° of varus for the community group ( P < 0.001). There were 93 good reductions in the trauma group compared with 19 in the community group ( P < 0.001). There were 0 poor reductions in the trauma group and 49 in the community group ( P < 0.001). DISCUSSION: Overall, we have shown that fellowship-trained orthopaedic trauma surgeons achieve better reductions when treating intertrochanteric femur fractures with intramedullary nails. Orthopaedic residency training should emphasize teaching proper techniques and acceptable parameters for reduction and implant placement when treating geriatric intertrochanteric femur fractures.

Catalytic inhibitor of Protein Phosphatase 5 activates the extrinsic apoptotic pathway by disrupting complex II in kidney cancer.

Serine/threonine protein phosphatase-5 (PP5) is involved in tumor progression and survival, making it an attractive therapeutic target. Specific inhibition of protein phosphatases has remained challenging because of their conserved catalytic sites. PP5 contains its regulatory domains within a single polypeptide chain, making it a more desirable target. Here we used an in silico approach to screen and develop a selective inhibitor of PP5. Compound P053 is a competitive inhibitor of PP5 that binds to its catalytic domain and causes apoptosis in renal cancer. We further demonstrated that PP5 interacts with FADD, RIPK1, and caspase 8, components of the extrinsic apoptotic pathway complex II. Specifically, PP5 dephosphorylates and inactivates the death effector protein FADD, preserving complex II integrity and regulating extrinsic apoptosis. Our data suggests that PP5 promotes renal cancer survival by suppressing the extrinsic apoptotic pathway. Pharmacologic inhibition of PP5 activates this pathway, presenting a viable therapeutic strategy for renal cancer.

A Case of Cyanosis With Saturation Gap: Dapsone-Induced Methemoglobinemia.

Dapsone is an antibiotic used in the management of dermatologic infections and opportunistic infection prophylaxis in developed countries. Methemoglobinemia (MetHb) is a known complication of dapsone use that can result in cyanosis. MetHb is an aberrant form of hemoglobin produced physiologically by auto-oxidation. An impairment in the process of auto-oxidation due to genetic defects or the use of drugs/toxins causes its levels to rise. Management involves timely recognition and the use of methylene blue (MB) or ascorbic acid. We describe the diagnosis and management of a patient with acquired MetHb as a result of dapsone use.

Altered toxicological endpoints in humans from common quaternary ammonium compound disinfectant exposure.

Humans are frequently exposed to Quaternary Ammonium Compounds (QACs). QACs are ubiquitously used in medical settings, restaurants, and homes as cleaners and disinfectants. Despite their prevalence, nothing is known about the health effects associated with chronic low-level exposure. Chronic QAC toxicity, only recently identified in mice, resulted in developmental, reproductive, and immune dysfunction. Cell based studies indicate increased inflammation, decreased mitochondrial function, and disruption of cholesterol synthesis. If these findings translate to human toxicity, multiple physiological processes could be affected. This study tested whether QAC concentrations could be detected in the blood of 43 human volunteers, and whether QAC concentrations influenced markers of inflammation, mitochondrial function, and cholesterol synthesis. QAC concentrations were detected in 80 % of study participants. Blood QACs were associated with increase in inflammatory cytokines, decreased mitochondrial function, and disruption of cholesterol homeostasis in a dose dependent manner. This is the first study to measure QACs in human blood, and also the first to demonstrate statistically significant relationships between blood QAC and meaningful health related biomarkers. Additionally, the results are timely in light of the increased QAC disinfectant exposure occurring due to the SARS-CoV-2 pandemic. MAIN FINDINGS: This study found that 80 % of study participants contained QACs in their blood; and that markers of inflammation, mitochondrial function, and sterol homeostasis varied with blood QAC concentration.

Intracranial neurenteric cyst: A case report and differential diagnosis of intracranial cystic lesions.

Neurenteric cysts are uncommon, benign lesions that are rarely located intracranially. These cysts are likely due to aberrant embryologic development of the notochord. Clinically, neurenteric cysts may present with symptoms of mass effect, or they can be asymptomatic and incidentally discovered. Imaging features of neurenteric cysts have significant overlap with other intracranial cystic lesions, which can make diagnosis difficult. We present a case of a 35-year-old female with a histopathologically confirmed neurenteric cyst in the premedullary and left cerebellomedullary cistern, with associated symptoms of headache, dizziness, tinnitus, and dysphagia. The patient underwent surgical resection, with improvement in symptoms. We present a review of literature, and a discussion of typical features of multiple intracranial cystic lesions. We hope to promote accurate preoperative diagnosis, to allow for appropriate surgical technique to reduce the risk of recurrence.

The Ground State Electronic Energy of Benzene.

We report on the findings of a blind challenge devoted to determining the frozen-core, full configuration interaction (FCI) ground-state energy of the benzene molecule in a standard correlation-consistent basis set of double-ζ quality. As a broad international endeavor, our suite of wave function-based correlation methods collectively represents a diverse view of the high-accuracy repertoire offered by modern electronic structure theory. In our assessment, the evaluated high-level methods are all found to qualitatively agree on a final correlation energy, with most methods yielding an estimate of the FCI value around -863 mEH. However, we find the root-mean-square deviation of the energies from the studied methods to be considerable (1.3 mEH), which in light of the acclaimed performance of each of the methods for smaller molecular systems clearly displays the challenges faced in extending reliable, near-exact correlation methods to larger systems. While the discrepancies exposed by our study thus emphasize the fact that the current state-of-the-art approaches leave room for improvement, we still expect the present assessment to provide a valuable community resource for benchmark and calibration purposes going forward.

Prevalence of substance use among moroccan adolescents and association with academic achievement.

AIM: To investigate rates of drug and alcohol use and their association with academic performance in Moroccan youth. METHODS: An adapted version of the European School Project on Alcohol and Other Drugs survey was administered to 2139 10(th)-12(th) graders in 36 Moroccan public high schools. Two multiple logistic regressions were completed, one for male and one for female subjects. Grade average was used as a two-part outcome variable, and drug use was used as a four-level categorical independent variable. Parents' education levels and socioeconomic status were included as covariates. RESULTS: Of the subjects, 181 girls (16%) and 390 boys (40%) reported ever having used alcohol, hashish, or psychotropic drugs. Girls who had used any of those substances in the past 30 d demonstrated an adjusted odds ratio (AOR) of 2.62 (95%CI: 1.31-5.22) of having average or below-average grades, and those with any lifetime use showed an AOR of 1.72 (95%CI: 1.07-2.77). Among the boys, use in the past 30 d was associated with an AOR of 2.08 (95%CI: 1.33-3.24) of average or below average grades, and use in the last 12 mo with an AOR of 1.74 (95%CI: 1.00-3.05). Any lifetime use among male and previous 12 mo use among female subjects were not significantly associated with academic achievement. CONCLUSION: Among Moroccan adolescents, drug use is substantially different between boys and girls. In both genders, lower academic achievement was associated with alcohol, hashish, or psychotropic drug use in the last 30 d.

CE: Champions for central line care.

OVERVIEW: In 2012, acute care hospitals in the United States reported 30,100 central line-associated bloodstream infections (CLABSIs) to the National Healthcare Safety Network of the Centers for Disease Control and Prevention. Known to substantially increase morbidity, length of stay, and cost of care, CLABSIs are associated with a mortality rate of 12% to 25% and an additional cost of $22,885 to $29,330 per incident. Following five months with a sustained CLABSI rate of zero per 1,000 catheter days, the acuity adaptable critical care unit at Geisinger Medical Center in Danville, Pennsylvania, saw the CLABSI rate spike to 3.97 per 1,000 catheter days in March 2011, prompting a quality improvement project and, ultimately, the implementation within the unit of a champion team program to guide central line care.

An assessment of H1N1 influenza-associated acute respiratory distress syndrome severity after adjustment for treatment characteristics.

Pandemic influenza caused significant increases in healthcare utilization across several continents including the use of high-intensity rescue therapies like extracorporeal membrane oxygenation (ECMO) or high-frequency oscillatory ventilation (HFOV). The severity of illness observed with pandemic influenza in 2009 strained healthcare resources. Because lung injury in ARDS can be influenced by daily management and multiple organ failure, we performed a retrospective cohort study to understand the severity of H1N1 associated ARDS after adjustment for treatment. Sixty subjects were identified in our hospital with ARDS from "direct injury" within 24 hours of ICU admission over a three month period. Twenty-three subjects (38.3%) were positive for H1N1 within 72 hours of hospitalization. These cases of H1N1-associated ARDS were compared to non-H1N1 associated ARDS patients. Subjects with H1N1-associated ARDS were younger and more likely to have a higher body mass index (BMI), present more rapidly and have worse oxygenation. Severity of illness (SOFA score) was directly related to worse oxygenation. Management was similar between the two groups on the day of admission and subsequent five days with respect to tidal volumes used, fluid balance and transfusion practices. There was, however, more frequent use of "rescue" therapy like prone ventilation, HFOV or ECMO in H1N1 patients. First morning set tidal volumes and BMI were significantly associated with increased severity of lung injury (Lung injury score, LIS) at presentation and over time while prior prescription of statins was protective. After assessment of the effect of these co-interventions LIS was significantly higher in H1N1 patients. Patients with pandemic influenza-associated ARDS had higher LIS both at presentation and over the course of the first six days of treatment when compared to non-H1N1 associated ARDS controls. The difference in LIS persisted over the duration of observation in patients with H1N1 possibly explaining the increased duration of mechanical ventilation.