447 research outputs found
Improved spatial separation of neutral molecules
We have developed and experimentally demonstrated an improved electrostatic
deflector for the spatial separation of molecules according to their
dipole-moment-to-mass ratio. The device features a very open structure that
allows for significantly stronger electric fields as well as for stronger
deflection without molecules crashing into the device itself. We have
demonstrated its performance using the prototypical OCS molecule and we discuss
opportunities regarding improved quantum-state-selectivity for complex
molecules and the deflection of unpolar molecules.Comment: 6 figure
The association between indoor temperature and body mass index in children:the PIAMA birth cohort study
Background: Several experimental studies showed consistent evidence for decreased energy expenditure at higher ambient temperatures. Based on this, an association between thermal exposure and body weight may be expected. However, the effect of thermal exposure on body weight has hardly been studied. Therefore, this study investigated the association between indoor temperature and body mass index (BMI) in children in real life. Methods: This longitudinal observational study included 3 963 children from the Dutch Prevention and Incidence of Asthma and Mite Allergy (PIAMA) birth cohort that started in 1996. These children were followed from birth until the age of 11 years. Winter indoor temperature (living room and bedroom) was reported at baseline and BMI z-scores were available at 10 consecutive ages. Missing data were multiply imputed. Associations between indoor temperature and BMI were analyzed using generalized estimating equations (GEE), adjusted for confounders and stratified by gender. In a subgroup of 104 children, bedroom temperature was also measured with data loggers. Results: Mean reported living room and bedroom temperature were 20.3 degrees C and 17.4 degrees C, respectively. Reported and measured bedroom temperatures were positively correlated (r = 0.42, p = 0.001). Neither reported living room temperature (-0.03 = 0.04) and bedroom temperature (-0.01 = 0.02) nor measured bedroom temperature (-0.04 = 0.05) were associated with BMI z-score between the age of 3 months and 11 years. Conclusions: This study in children did not support the hypothesized association between indoor temperature and BMI in a real life setting
Evaluation of lung function changes before and after surfactant application during artificial ventilation in newborn rats with congenital diaphragmatic hernia
Patients with congenital diaphragmatic hernia (CDH) have unilateral or bilateral hypoplasia of the lungs including delayed maturation of the terminal air sacs. Because these lungs are highly susceptible to barotrauma and oxygen toxicity, even in full-term newborns, continued research into optimal ventilatory regimen is essential to improve survival rate and to prevent ongoing lung damage. Against this background, the effect of exogenous surfactant application is evaluated. In newborn rats, CDH was induced after a single dose of 2,4 dichloro-4'-nitrophenyl (Nitrofen) (400 mg/kg) on day 10 of gestation. The newborn rats were intubated immediately after hysterotomy, transferred to a heated multichambered body plethysmograph, and artificially ventilated. Inspiratory peak pressures were initially set at 17 cm H2O, with positive end-expiratory pressure at 0 cm H2O and FIO2at 1.0. The pressure was raised in steps of 5 cm H2O, from 5 to 30 cm H2O, to obtain pressure- volume diagrams at 0, 1, and 6 hours of artificial ventilation. These measurements were obtained in controls and in CDH rats with and without endotracheal installation of bovine surfactant (n = 4 to 10 in each group). Significant differences in lung volume between CDH and control rats were observed at all time-points. Surfactant application had a positive effect on lung volume, especially in control rats at t = 1 hour. No significant differences were observed between the CDH groups at t = 1 or t = 6 hours. In this animal model, the effect of artificial ventilation as well as the beneficial short-term effect of exogenous surfactant application have been evaluated. A continued positive effect on lung volume in CDH lungs could not be determined. Routine administration of exogenous surfactant in human CDH patients is not supported by these experimental results
Characterization of two relacidines belonging to a novel class of circular lipopeptides that act against Gram-negative bacterial pathogens
The development of sustainable agriculture and the increasing antibiotic resistance of human pathogens call for novel antimicrobial compounds. Here, we describe the extraction and characterization of a class of cationic circular lipopeptides, for which we propose the name relacidines, from the soil bacterium Brevibacillus laterosporus MG64. Relacidines are composed of a fatty acid side chain (4-methylhexanoic acid) and 13 amino acid residues. A lactone ring is formed by the last five amino acid residues and three positively charged ornithines are located in the linear fragment. Relacidines selectively combat Gram-negative pathogens, including phytopathogens and human pathogens. Further investigation of the mode of action revealed that relacidine B binds to the lipopolysaccharides but does not form pores in the cell membrane. We also provide proof to show that relacidine B does not affect the biosynthesis of the cell wall and RNA. Instead, it affects the oxidative phosphorylation process of cells and diminishes the biosynthesis of ATP. Transcription of relacidines is induced by plant pathogens, which strengthens the potential of B. laterosporus MG64 to be used as a biocontrol agent. Thus, we identified a new group of potent antibiotic compounds for combating Gram-negative pathogens of plants or animals
Therapy reduction in patients with Down syndrome and myeloid leukemia: the international ML-DS 2006 trial
Children with myeloid leukemia associated with Down syndrome (ML-DS) have superior outcome compared with non-DS patients, but suffer from higher constitutional cytotoxic drug susceptibility. We analyzed the outcome of 170 pediatric patients with ML-DS enrolled in the prospective, multicenter, open-label, nonrandomized ML-DS 2006 trial by Nordic Society for Pediatric Hematology and Oncology (NOPHO), Dutch Childhood Oncology Group (DCOG), and Acute Myeloid Leukemia–Berlin-Frankfurt-Münster (AML-BFM) study group. Compared with the historical control arm (reduced-intensity protocol for ML-DS patients from the AML-BFM 98 trial), treatment intensity was reduced by lowering the cumulative dose of etoposide (950 to 450 mg/m2) and intrathecal central nervous system prophylaxis while omitting maintenance therapy. Still, 5-year overall survival (89% 6 3% vs 90% 6 4%; Plog-rank 5 .64), event-free survival (EFS; 87% 6 3% vs 89% 6 4%; Plog-rank 5 .71), and cumulative incidence of relapse/ nonresponse (CIR/NR; 6% 6 3% vs 6% 6 2%; PGray 5 .03) did not significantly differ between the ML-DS 2006 trial and the historical control arm. Poor early treatment response (5-year EFS, 58% 6 16% vs 88% 6 3%; Plog rank 5 .0008) and gain of chromosome 8 (CIR/NR, 16% 6 7% vs 3% 6 2%, PGray 5 .02; 5-year EFS, 73% 6 8% vs 91% 6 4%, Plog rank 5 .018) were identified as independent prognostic factors predicting a worse EFS. Five of 7 relapsed patients (71%) with cytogenetic data had trisomy 8. Our study reveals prognostic markers for children with ML-DS and illustrates that reducing therapy did not impair excellent outcome. The trial was registered at EudraCT as #2007-006219-2. (Blood. 2017;129(25): 3314-3321
Interaction and Modulation of Two Antagonistic Cell Wall Enzymes of Mycobacteria
Bacterial cell growth and division require coordinated cell wall hydrolysis and synthesis, allowing for the removal and expansion of cell wall material. Without proper coordination, unchecked hydrolysis can result in cell lysis. How these opposing activities are simultaneously regulated is poorly understood. In Mycobacterium tuberculosis, the resuscitation-promoting factor B (RpfB), a lytic transglycosylase, interacts and synergizes with Rpf-interacting protein A (RipA), an endopeptidase, to hydrolyze peptidoglycan. However, it remains unclear what governs this synergy and how it is coordinated with cell wall synthesis. Here we identify the bifunctional peptidoglycan-synthesizing enzyme, penicillin binding protein 1 (PBP1), as a RipA-interacting protein. PBP1, like RipA, localizes both at the poles and septa of dividing cells. Depletion of the ponA1 gene, encoding PBP1 in M. smegmatis, results in a severe growth defect and abnormally shaped cells, indicating that PBP1 is necessary for viability and cell wall stability. Finally, PBP1 inhibits the synergistic hydrolysis of peptidoglycan by the RipA-RpfB complex in vitro. These data reveal a post-translational mechanism for regulating cell wall hydrolysis and synthesis through protein–protein interactions between enzymes with antagonistic functions
Stress imaging in patients with a Fontan circulation: A systematic review
INTRODUCTION: The aims of this study were to provide an overview of the cardiac stress response in Fontan patients and of the use, safety and clinical value of stress imaging in Fontan patients. METHODS: Studies evaluating cardiac function using stress imaging in Fontan patients published up until 12 December 2021 were included in this review. RESULTS: From 1603 potential studies, 32 studies met the inclusion criteria. In total, stress imaging tests of 728 Fontan patients were included. Cardiac function was most often measured using physical stress (61%), all other studies used dobutamine-induced stress. Stroke volume (SV) increased in most studies (71%), mean SV at rest ranged from 27 mL/m 2 to 60 mL/m 2 versus 27 mL/m 2 to 101 mL/m 2 during stress, and increased with an average of 4%. Ejection fraction increased in almost all studies, whereas both end-systolic volume and end-diastolic volume decreased during stress. Higher heart rates were obtained with physical stress (82-180) compared to dobutamine induced stress (73-128). Compared to controls, increases in heartrate and SV were lower and end-diastolic volume decreased abnormally in 75% of reporting studies. No major adverse events were reported. Poorer cardiac stress response was related to decreased exercise capacity and higher risk for long-term (adverse) outcomes in Fontan patients. DISCUSSION: Cardiac stress response in Fontan patients differs from healthy subjects, reflected by lower increases in heart rate, diminished preload and decreased cardiac output, especially during higher levels of exercise. Stress imaging is safe, however the added clinical value needs to be investigated in more detail
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