Preliminary characterization of anelastic effects in the flexure mechanism for a new Kibble balance at NIST

A new Kibble balance is being built at the National Institute of Standards and Technology (NIST). For the first time in one of the highly accurate versions of this type of balance, a single flexure mechanism is used for both modes of operation: the weighing mode and the velocity mode. The mechanism is at the core of the new balance design as it represents a paradigm shift for NIST away from using knife edge-based balance mechanisms, which exhibit hysteresis in the measurement procedure of the weighing mode. Mechanical hysteresis may be a limiting factor in the performance of highly accurate Kibble balances approaching single digit nanonewton repeatability on a nominal 100 g mass, as targeted in this work. Flexure-based mechanisms are known to have very good static hysteresis when used as a null detector. However, for larger and especially longer lasting deformations, flexures are known to exhibit anelastic drift. We seek to characterize, and ideally compensate for, this anelastic behavior after deflections during the velocity mode to enable a 10 accurate Kibble balancemeasurement on a nominal 100 g mass artifact with a single flexure-based balance mechanism

Free-range grazing by large herbivores in degraded large-scale dry sandy grassland-heathland ecosystems

Free-range grazing by large herbivores combined with one-time mowing of over-aged heathlands offers an excellent management tool to maintain and enhance biodiversity in degraded large scale, low productive, semi-open dry sandy grassland-heathland ecosystems. Grazing improves habitat quality, supports typical species communities and represses invasive species

Measurement of compartment pressure of the rectus sheath during intra-abdominal hypertension in rats

Objective: To investigate whether the compartment pressure of the rectus sheath (CPRS) reflects the intra-abdominal pressure (IAP) under various conditions of intra-abdominal hypertension (IAH). Design and setting: Prospective experimental study with in vivo pressure measurements at the Institute for Clinical and Experimental Surgery, University of Saarland. Animals: Sprague-Dawley rats. Interventions: Stepwise increase and decrease in IAP with continuous measurement of the correspondent CPRS. Measurements and results: Physiological IAP (2 mmHg) and CPRS (6 mmHg) showed astatistically significant difference. Stepwise elevation in IAP was associated with asimultaneous increase in CPRS. Accordingly, stepwise decompression of IAP resulted in astepwise decrease in CPRS. Under both conditions Bland-Altman analysis comparing IAP to correspondent CPRS showed avery good agreement for IAP at or above 12 mmHg. In addition, closure of the overlaying subcutaneous tissue and skin did not affect CPRS or its correlation with IAP. Conclusions: CPRS accurately reflects IAP for IAP of 12 mmHg or higher. Thus CPRS measurements may represent anovel approach for diagnosis and monitoring of IA

Absolute proteomic quantification reveals design principles of sperm flagellar chemosensation

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Troetschel, C., Hamzeh, H., Alvarez, L., Pascal, R., Lavryk, F., Boenigk, W., Koerschen, H. G., Mueller, A., Poetsch, A., Rennhack, A., Gui, L., Nicastro, D., Struenker, T., Seifert, R., & Kaupp, U. B. Absolute proteomic quantification reveals design principles of sperm flagellar chemosensation. Embo Journal, 39(4), (2020): e102723, doi:10.15252/embj.2019102723.Cilia serve as cellular antennae that translate sensory information into physiological responses. In the sperm flagellum, a single chemoattractant molecule can trigger a Ca2+ rise that controls motility. The mechanisms underlying such ultra‐sensitivity are ill‐defined. Here, we determine by mass spectrometry the copy number of nineteen chemosensory signaling proteins in sperm flagella from the sea urchin Arbacia punctulata. Proteins are up to 1,000‐fold more abundant than the free cellular messengers cAMP, cGMP, H+, and Ca2+. Opto‐chemical techniques show that high protein concentrations kinetically compartmentalize the flagellum: Within milliseconds, cGMP is relayed from the receptor guanylate cyclase to a cGMP‐gated channel that serves as a perfect chemo‐electrical transducer. cGMP is rapidly hydrolyzed, possibly via “substrate channeling” from the channel to the phosphodiesterase PDE5. The channel/PDE5 tandem encodes cGMP turnover rates rather than concentrations. The rate‐detection mechanism allows continuous stimulus sampling over a wide dynamic range. The textbook notion of signal amplification—few enzyme molecules process many messenger molecules—does not hold for sperm flagella. Instead, high protein concentrations ascertain messenger detection. Similar mechanisms may occur in other small compartments like primary cilia or dendritic spines.We thank Heike Krause for preparing the manuscript. Financial support by the Deutsche Forschungsgemeinschaft (DFG) via the priority program SPP 1726 “Microswimmers” and the Cluster of Excellence 1023 “ImmunoSensation” is gratefully acknowledged. We thank D. Stoddard for management of the UTSW cryo‐electron microscope facility, which is funded in part by a Cancer Prevention and Research Institute of Texas (CPRIT) Core Facility Award (RP170644). This study was supported by HHS|National Institutes of Health (NIH) grant R01 GM083122 and by CPRIT grant RR140082 to D. Nicastro

Modified Blalock Taussig shunt: a not-so-simple palliative procedure

OBJECTIVES Thirty-two consecutive isolated modified Blalock Taussig (BT) shunts performed in infancy since 2004 were reviewed and analysed to identify the risk factors for shunt intervention and mortality. METHODS Sternotomy was the only approach used. Median age and weight were 10.5 (range 1-74) days and 2.9 (1.9-4.4) kg, respectively. Shunt palliation was performed for biventricular hearts (Tetralogy of Fallot/double outlet right ventricle/transposition of great arteries_ventricular septal defect_pulmonary stenosis/pulmonary atresia_ventricular septal defect/others) in 21, and univentricular hearts in 11, patients. Hypoplastic left heart syndrome patients were excluded. Two procedures required cardiopulmonary bypass. Median shunt size was 3.5 (3-4) mm and median shunt size/kg body weight was 1.2 (0.9-1.7) mm/kg. Reduction in shunt size was necessary in 5 of 32 (16%) patients. RESULTS Three of 32 (9%) patients died after 3 (1-15) days due to cardiorespiratory decompensation. Lower body weight (P = 0.04) and bigger shunt size/kg of body weight (P = 0.004) were significant risk factors for mortality. Acute shunt thrombosis was observed in 3 of 32 (9%), none leading to death. Need for cardiac decongestive therapy was associated with univentricular hearts (P < 0.001), bigger shunt size (P = 0.054) and longer hospital stay (P = 0.005). Twenty-eight patients have undergone a successful shunt takedown at a median age of 5.5 (0.5-11.9) months, without late mortality. CONCLUSIONS Palliation with a modified BT shunt continues to be indicated despite increased thrust on primary corrective surgery. Though seemingly simple, it is associated with significant morbidity and mortality. Effective over-shunting and acute shunt thrombosis are the lingering problems of shunt therap

Dynamics of UF[6] Desublimation with the Influence of Tank Geometry for Various Coolant Temperature

Mathematical model of UF[6] desublimation in a vertical immersion tank is presented in the article. Results of calculations of the filling dynamics of the tanks with 1m3 volume at various coolant temperatures, with and without ellipticity of the end walls are given. It is shown that allowance for the ellipticity of the end walls of the tanks leads to a significant increase in the time of desublimation of UF[6]

Management and outcome of Ebstein's anomaly in children

Abstract Objectives To assess clinical presentation, treatment, and outcome of children with Ebstein's anomaly. Background Data on long-term outcome of children with Ebstein's anomaly are scarce. Methods Retrospective analysis of all children with Ebstein's anomaly treated between February, 1979 and January, 2009 in a single tertiary institution. Primary outcomes included patient survival and need for intervention, either cardiac surgery or catheter intervention. Results A total of 42 patients were diagnosed with Ebstein's anomaly at a median age of 5 days ranging from 1 day to 11.7 years. Symptoms included cyanosis, heart murmur, and/or dyspnoea. Associated cardiac anomalies occurred in 90% of the patients. Average follow-up was 9.5 plus or minus 7.0 years. The overall mortality rate was 14%. Of the six patients, three died postnatally before treatment. Cardiac surgery and/or catheter-guided interventions were required in 33 patients (79%). Cardiac surgery was performed in 21 (50%) patients at a median age of 9.1 years (range 0.1-16.5 years), including biventricular repair in 13 (62%), one-and-a-half chamber repair in seven (33%), and a staged single-ventricle repair in one. Peri-operative mortality was 4%. Catheter-guided interventions consisted of device closure of an atrial septal defect in three cases and radiofrequency ablation of accessory pathways in nine patients. The estimated 10-year survival was 85.3 plus or minus 5.6%. Conclusion In children, Ebstein's anomaly is usually diagnosed in the first year of age. Even though children with Ebstein's anomaly often require an intervention, their peri-operative mortality is low and long-term survival is good. Symptomatic newborns requiring an intervention may have a worse outcom

Leipziger und Schkeuditzer Gewässer: 24 Fließgewässer im Portrait

Der Auwald und seine Gewässer schlängeln sich wie grüne und blaue Bänder durch die Stadt Leipzig und ihre Umgebung

Para além da racionalidade: outras dimensões da ação entre organizações familiares de produção agrícola: uma discussão a partir da realidade de famílias de agricultores no sul de Santa Catarina

The discussion surrounding the rationale guiding the actions of organizations has highlighted the duality between instrumental and substantive rationalities. “Beyond rationality” seeks to understand other dimensions of action in the context of the organization of agricultural production, through the meanings shared by family organizations of farmers. A qualitative study was carried out involving the participation of 13 families, living in locations characterized by a strong presence of descendants of immigrants who settled in southern Brazil. The authors performed the observation of family organizations, whose members shared agricultural production activities in small rural holdings in the south of Santa Catarina State. In the three modes of organizing agricultural production identified as integrated, semi-integrated and nonintegrated. The shared meanings showed evidence of action guided by affection and tradition, extending beyond the dimensions of action guided by rationality of an instrumental and/or substantive nature. It was noted that affective relations and productive practices based on traditions play an important role in the modes of organizing and are associated with the substantive character of social relations, according to the adopted theoretical frameworks. It is understood that the dimensions of action, rejected in the discussion on rationality, are in fact relevant and should be considered with regards to family organizations involved in agricultural production activities