1,577 research outputs found
Distribution of Complex and Core Lipids within New Hyperthermophilic Members of the Archaea Domain
Core and complex lipids of several new hyperthermophilic archaeal isolates were analyzed. The organisms belong to the Sulfolobales,Archaeoglobus, Pyrobaculum, and Methanococcus. A detailed structural investigation of complex lipids of Pyrobaculum species is reported. The different lipid structures are of help for
a rapid and simple phylogenetic classification of the new isolates. They are in agreement with the classification based on other features
System and method for calibrating a rotary absolute position sensor
A system includes a rotary device, a rotary absolute position (RAP) sensor generating encoded pairs of voltage signals describing positional data of the rotary device, a host machine, and an algorithm. The algorithm calculates calibration parameters usable to determine an absolute position of the rotary device using the encoded pairs, and is adapted for linearly-mapping an ellipse defined by the encoded pairs to thereby calculate the calibration parameters. A method of calibrating the RAP sensor includes measuring the rotary position as encoded pairs of voltage signals, linearly-mapping an ellipse defined by the encoded pairs to thereby calculate the calibration parameters, and calculating an absolute position of the rotary device using the calibration parameters. The calibration parameters include a positive definite matrix (A) and a center point (q) of the ellipse. The voltage signals may include an encoded sine and cosine of a rotary angle of the rotary device
Connector pin and method
An electrical connector and method includes a connector and a conforming element proximate to or in contact with the mating end of the connector so as to prevent distortion of a matable end. The matable end of the connector may be of a female or male type and may be of a post, tube, blade, pin, or other configuration. An element made of conforming material, for example, an elastomer, epoxy or rubber type material, is configured and positioned in contact with the matable end of the connector, providing support during assembly to prevent distortion of the matable end. The conforming element may be rectangular, wedge, cylindrical, conical, annular, or of another configuration as required to provide support to the connector pin. The conforming element may be fastened with an adhesive to the matable end to further prevent distortion
Functioning and disability in multiple sclerosis from the patient perspective
Multiple sclerosis (MS) has a great impact on functioning and disability. The perspective of those who experience the health problem has to be taken into account to obtain an in-depth understanding of functioning and disability. The objective was to describe the areas of functioning and disability and relevant contextual factors in MS from the patient perspective. A qualitative study using focus group methodology was performed. The sample size was determined by saturation. The focus groups were digitally recorded and transcribed verbatim. The meaning condensation procedure was used for data analysis. Identified concepts were linked to International Classification of Functioning, Disability and Health (ICF) categories according to established linking rules. Six focus groups with a total of 27 participants were performed. In total, 1327 concepts were identified and linked to 106 ICF categories of the ICF components Body Functions, Activities and Participation and Environmental Factors. This qualitative study reports on the impact of MS on functioning and disability from the patient perspective. The participants in this study provided information about all physical aspects and areas of daily life affected by the disease, as well as the environmental factors influencing their lives
Sequence-Independent Cloning and Post-Translational Modification of Repetitive Protein Polymers through Sortase and Sfp-Mediated Enzymatic Ligation
Repetitive protein-based polymers are important for many applications in biotechnology and biomaterials development. Here we describe the sequential additive ligation of highly repetitive DNA sequences, their assembly into genes encoding protein-polymers with precisely tunable lengths and compositions, and their end-specific post-translational modification with organic dyes and fluorescent protein domains. Our new Golden Gate-based cloning approach relies on incorporation of only type IIS BsaI restriction enzyme recognition sites using PCR, which allowed us to install ybbR-peptide tags, Sortase c-tags, and cysteine residues onto either end of the repetitive gene polymers without leaving residual cloning scars. The assembled genes were expressed in Escherichia coli and purified using inverse transition cycling (ITC). Characterization by cloud point spectrophotometry, and denaturing polyacrylamide gel electrophoresis with fluorescence detection confirmed successful phosphopantetheinyl transferase (Sfp)-mediated post-translational N-terminal labeling of the protein-polymers with a coenzyme A-647 dye (CoA-647) and simultaneous sortase-mediated C-terminal labeling with a GFP domain containing an N-terminal GG-motif in a one-pot reaction. In a further demonstration, we installed an N-terminal cysteine residue into an elastin-like polypeptide (ELP) that was subsequently conjugated to a single chain poly(ethylene glycol)-maleimide (PEG-maleimide) synthetic polymer, noticeably shifting the ELP cloud point. The ability to straightforwardly assemble repetitive DNA sequences encoding ELPs of precisely tunable length and to post-translationally modify them specifically at the N- and C- termini provides a versatile platform for the design and production of multifunctional smart protein-polymeric materials
Hydrothermal, catalyst-free production of a cyclic dipeptide from lysine
The formation of cyclic dipeptides, 2,5-diketopiperazines (DKP), from lysine in aqueous solution was investigated at hydrothermal conditions (250 to 350 °C) without the addition of catalyst. The products obtained were analyzed by GC–MS combined with extensive H,C NMR analysis, after purification via preparative chromatography. The main product of the conversion of lysine, octahydrodipyrido[1,2-a:1\u27,2\u27-d]pyrazine-6,12(2H,6aH)-dione, was successfully isolated and identified. The purification/separation protocol is rapid, environmentally friendly, and highly efficient with excellent selectivity (81 wt%) in the oils obtained from the conversion of lysine at 300 °C. Performing the conversion step at higher temperatures or lysine concentrations led to the formation of complicated side products. Based on the evolution of key compounds during hydrothermal conversion of lysine, we propose a tentative mechanism for the formation of diketopiperazine. The technique presented in this work provides a novel catalyst-free pathway for the synthesis of DKP
Forming Human-Robot Teams Across Time and Space
NASA pushes telerobotics to distances that span the Solar System. At this scale, time of flight for communication is limited by the speed of light, inducing long time delays, narrow bandwidth and the real risk of data disruption. NASA also supports missions where humans are in direct contact with robots during extravehicular activity (EVA), giving a range of zero to hundreds of millions of miles for NASA s definition of "tele". . Another temporal variable is mission phasing. NASA missions are now being considered that combine early robotic phases with later human arrival, then transition back to robot only operations. Robots can preposition, scout, sample or construct in advance of human teammates, transition to assistant roles when the crew are present, and then become care-takers when the crew returns to Earth. This paper will describe advances in robot safety and command interaction approaches developed to form effective human-robot teams, overcoming challenges of time delay and adapting as the team transitions from robot only to robots and crew. The work is predicated on the idea that when robots are alone in space, they are still part of a human-robot team acting as surrogates for people back on Earth or in other distant locations. Software, interaction modes and control methods will be described that can operate robots in all these conditions. A novel control mode for operating robots across time delay was developed using a graphical simulation on the human side of the communication, allowing a remote supervisor to drive and command a robot in simulation with no time delay, then monitor progress of the actual robot as data returns from the round trip to and from the robot. Since the robot must be responsible for safety out to at least the round trip time period, the authors developed a multi layer safety system able to detect and protect the robot and people in its workspace. This safety system is also running when humans are in direct contact with the robot, so it involves both internal fault detection as well as force sensing for unintended external contacts. The designs for the supervisory command mode and the redundant safety system will be described. Specific implementations were developed and test results will be reported. Experiments were conducted using terrestrial analogs for deep space missions, where time delays were artificially added to emulate the longer distances found in space
Method and apparatus for electromagnetically braking a motor
An electromagnetic braking system and method is provided for selectively braking a motor using an electromagnetic brake having an electromagnet, a permanent magnet, a rotor assembly, and a brake pad. The brake assembly applies when the electromagnet is de-energized and releases when the electromagnet is energized. When applied the permanent magnet moves the brake pad into frictional engagement with a housing, and when released the electromagnet cancels the flux of the permanent magnet to allow a leaf spring to move the brake pad away from the housing. A controller has a DC/DC converter for converting a main bus voltage to a lower braking voltage based on certain parameters. The converter utilizes pulse-width modulation (PWM) to regulate the braking voltage. A calibrated gap is defined between the brake pad and permanent magnet when the brake assembly is released, and may be dynamically modified via the controller
Aldehydes and ketones in pyrolysis oil: analytical determination and their role in the aging process
Aldehydes and ketones are known to play a role in the aging process of pyrolysis oil and generally, aldehydes are known for their high reactivity. In order to discern in pyrolysis oil the total aldehyde concentration from that of the ketones, a procedure for the quantification of aldehydes by H-NMR was developed. Its capability is demonstrated with a hardwood pyrolysis oil at different stages of the aging process. It was treated by the Accelerated Aging Test at 80 °C for durations of up to 48 h. The aldehyde concentration was complemented by the total concentration of carbonyls, quantified by carbonyl titration. The measurements show, that the examined hardwood pyrolysis oil contained 0.31–0.40 mmol g aldehydes and 4.36–4.45 mmol g ketones. During the first 24 h, the aldehyde concentration declined by 23–39% and the ketone concentration by 9%. The rate of decline of aldehyde concentration slows down within 24 h but is still measureable. In contrast, the total carbonyl content does not change significantly after an initial decline within the first 4 h. Changes for vinylic, acetalic, phenolic and hydroxyl protons and for protons in the α-position to hydroxy, ether, acetalic and ester groups were detected, by H-NMR. In the context of characterizing pyrolysis oil and monitoring the aging process, H-NMR is a reliable tool to assess the total concentration of aldehydes. It confirms the reactivity of aldehydes and ketones and indicates their contribution to the instability of pyrolysis oil
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