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PubMed2004

Fully automated chip-based mass spectrometry for complex carbohydrate system analysis.

Carbohydrates represent a major class of biopolymers, which occur in nature either as oligosaccharides or glycoconjugates, in which the sugar moiety is linked to proteins or lipids. The significance of mass spectrometry for highly sensitive analysis of complex carbohydrates increased after the introduction of the electrospray ionization and matrix assisted laser desorption/ionization methods and the possibility of tandem MS for sequencing of single molecular species in complex mixtures. Rapid and sensitive characterization of carbohydrates in biological systems by automated nanoscale liquid delivery and chip-based electrospray interface techniques have not been developed so far. In this contribution, the implementation and optimization of a fully automated chip-based nanoelectrospray assembly (NanoMate system), operating in the negative ion mode, in combination with QTOF-tandem MS for mapping/sequencing and computer-assisted structure assignment for carbohydrate components in complex mixtures is presented.

Automation↗
PubMed1999

Ergonomic automated anesthesia recordkeeper using a mobile touch screen with voice navigtion.

OBJECTIVE: To develop an ergonomically designed computerized recordkeeping tool for anesthesiologists that allows the clinician to maintain visual contact with the patient while performing recordkeeping. METHODS: To simplify the human interface software, we developed two general use software components. All purpose menu type 1 (APM1) was used for entering events using a tree structured menu. APM1 was designed to adapt to the limits of human memory, by using Miller's rule of 7 to guide the input process. APM1 can be considered to be a three-dimensional table list consisting of 7 vertical and 7 horizontal choices, which has further 5 tree-structured divergences. APM1 is also completely configurable by the user. All purpose menu 2 (APM2) was used to implement the system-initiated human interface where the system will prompt the user by voice for each entry. When users touch a key on APM1 and APM2, the system was designed to respond with a voice prompt. A touch-screen was also utilized and designed to fit the anesthesia machine. The screen is equipped with a small speaker for voice response and a microphone for voice recognition. The positions of the screen are adjustable supported by a long flexible limb (85 cm). RESULTS: After improving the design, systems were assembled for 10 operating rooms. Of the multiple features of the VOCAAR user interface, the following were well accepted by users and employed daily: touch-screen input, and voice response. The noncompulsory use rate was 87% during the initial 2 weeks, increased to 94% after 2 weeks and 100% after two months. The mean sound emission by voice response (n = 10, mean +/- SD) was 8.2 +/- 2.3 dB at the main anesthetist site (35 cm from the speaker mounted on the touch-screen), 2.2 +/- 1.3 dB at the staff site (1.5 m from the touch-screen), which was only audible for anesthesiologist but for surgeon. DISCUSSION: An EARK system was designed to allow the user to maintain visual contact with the patient while performing recordkeeping tasks. The combination of a mobile touch screen and voice response/recognition facilitated the design goals of the system. Although the system has enjoyed universal clinical acceptance, the voice functions remain too limited to satisfy the needs of a completely handsfree user interface. Enhancements to voice recognition technology will offer the potential for improved functionality. Additional research is also needed to better define the relationship between vigilance and visual contact with the patient.

Anesthesiology↗
PubMed1996

Mutations in the PAY5 gene of the yeast Yarrowia lipolytica cause the accumulation of multiple subpopulations of peroxisomes.

We previously reported the cloning of the PAY5 gene of the yeast Yarrowia lipolytica by complementation of the peroxisome assembly mutant pay5-1 (Eitzen, G. A., Titorenko, V. I., Smith, J. J., Veenhuis, M., Szilard, R. K., and Rachubinski, R. A. (1996) J. Biol. Chem. 271, 20300-20306). The peroxisomal integral membrane protein Pay5p is a homologue of mammalian PAF-1 proteins, which are essential for peroxisome assembly and whose mutation in humans results in peroxisome biogenesis disorders. Mutations in the PAY5 gene result in the accumulation of three distinct peroxisomal subpopulations. These subpopulations are characterized by differences in 1) buoyant density, 2) the relative distribution of peroxisomal matrix and membrane proteins, 3) the efficiency of import of several peroxisomal matrix proteins, and 4) the phospholipid levels of peroxisomal membranes. These data, together with the analysis of temporal changes in the relative abundance of individual peroxisomal subpopulations in pay5 mutants, suggest that these subpopulations represent intermediates in a multistep peroxisome assembly pathway normally operating in yeast cells.

Cell Compartmentation↗
PubMed2005

The unstructured N-terminal tail of ParG modulates assembly of a quaternary nucleoprotein complex in transcription repression.

ParG is the prototype of a group of small (<10 kDa) proteins involved in accurate plasmid segregation. The protein is a dimeric DNA binding factor, which consists of symmetric paired C-terminal domains that interleave into a ribbon-helix-helix fold that is crucial for the interaction with DNA, and unstructured N-terminal domains of previously unknown function. Here the ParG protein is shown to be a transcriptional repressor of the parFG genes. The protein assembles on its operator site initially as a tetramer (dimer of dimers) and, at elevated protein concentrations, as a pair of tetramers. Progressive deletion of the mobile N-terminal tails concomitantly decreased transcriptional repression by ParG and perturbed the DNA binding kinetics of the protein. The flexible tails are not necessary for ParG dimerization but instead modulate the organization of a higher order nucleoprotein complex that is crucial for proper transcriptional repression. This is achieved by transient associations between the flexible and folded domains in complex with the target DNA. Numerous ParG homologs encoded by plasmids of Gram-negative bacteria similarly are predicted to possess N-terminal disordered tails, suggesting that this is a common feature of partition operon autoregulation. The results provide new insights into the role of natively unfolded domains in protein function, the molecular mechanisms of transcription regulation, and the control of plasmid segregation.

Base Sequence↗
PubMedDate not supplied

Modulation of entry of enveloped viruses by cholesterol and sphingolipids (Review).

Enveloped animal viruses infect host cells by fusion of viral and target membranes. This crucial fusion event occurs either with the plasma membrane of the host cells at the physiological pH or with the endosomal membranes at low pH and is triggered by specific glycoproteins in the virus envelope. Both lipids and proteins play critical and co-operative roles in the fusion process. Interactions of viral proteins with their receptors direct which membranes fuse and viral fusion proteins then drive the process. These fusion proteins operate on lipid assemblies, whose physical and mechanical properties are equally important to the proper functioning of the process. Lipids contribute to the viral fusion process by virtue of their distinct chemical structure, composition and/or their preferred partitioning into specific microdomains in the plasma membrane called 'rafts'. An involvement of lipid rafts in viral entry and membrane fusion has been examined recently. However, the mechanism(s) by which lipids as dynamic raft components control viral envelope-glycoprotein-triggered fusion is not clear. This paper will review literature findings on the contribution of the two raft-associated lipids, cholesterol and sphingolipids in viral entry.

Animals↗
PubMed1999

Lactose-containing starburst dendrimers: influence of dendrimer generation and binding-site orientation of receptors (plant/animal lectins and immunoglobulins) on binding properties.

Starburst glycodendrimers offer the potential to serve as high-affinity ligands for clinically relevant sugar receptors. In order to define areas of application, their binding behavior towards sugar receptors with differential binding-site orientation but identical monosaccharide specificity must be evaluated. Using poly(amidoamine) starburst dendrimers of five generations, which contain the p-isothiocyanato derivative of p-aminophenyl-beta-D-lactoside as ligand group, four different types of galactoside-binding proteins were chosen for this purpose, i.e., the (AB)(2)-toxic agglutinin from mistletoe, a human immunoglobulin G fraction, the homodimeric galectin-1 with its two binding sites at opposite ends of the jelly-roll-motif-harboring protein and monomeric galectin-3. Direct solid-phase assays with surface-immobilized glycodendrimers resulted in obvious affinity enhancements by progressive core branching for the plant agglutinin and less pronounced for the antibody and galectin-1. High density of binding of galectin-3 with modest affinity increases only from the level of the 32-mer onwards points to favorable protein-protein interactions of the monomeric lectin and a spherical display of the end groups without a major share of backfolding. When the inhibitory potency of these probes was evaluated as competitor of receptor binding to an immobilized neoglycoprotein or to asialofetuin, a marked selectivity was detected. The 32- and 64-mers were second to none as inhibitors for the plant agglutinin against both ligand-exposing matrices and for galectin-1 on the matrix with a heterogeneous array of interglycoside distances even on the per-sugar basis. In contrast, a neoglycoprotein with the same end group was superior in the case of the antibody and, less pronounced, monomeric galectin-3. Intimate details of topological binding-site presentation and the ligand display on different generations of core assembly are major operative factors which determine the potential of dendrimers for applications as lectin-targeting device, as attested by these observations.

Animals↗
PubMed2004

Dynamics of single polymers in a stagnation flow induced by electrokinetics.

An electrokinetics-induced stagnation flow was created inside a microscale cross-channel. Compared to hydrodynamic-induced microfluidics, this flow system can be readily assembled and the operation is very simple due to a low pressure drop. Through image analysis, a fairly homogeneous, two-dimensional elongational flow was observed. The initial conformation of DNA molecules and residence time inside the flow field play important roles in determining the extent of DNA stretching. A coarse-grain molecular simulation agrees reasonably well with experimental observations.

Computer Simulation↗
PubMed2001

A low-cost transmittance transducer for measurement of blood oxygen saturation in extracorporeal circuits.

Designs for a low-cost dual wavelength transducer based on light transmittance and a disposable cuvette for monitoring oxygen saturation (SO2) in extracorporeal arterial and venous blood are presented. The transducer utilizes red and infrared light-emitting diodes and a large photodiode; it is designed to attach to a flow-through cuvette modified from 3/8-in x3/8-in bypass-circuit connectors. A mock extracorporeal circulation system was assembled to evaluate operation of the transducer at a controlled blood SO2 and the relationship between light transmittance and hemodilution. SO2 was calculated based on multiple linear regression analyses. The results show a high correlation between the SO2 obtained with the equipment designed and values measured with commercial gasometric equipment in the range of 50% to 100% (r2 = 0.976, error <2%). The method presented allows continuous and real time measurement of whole blood SO2 with a low-cost transmittance transducer.

Animals↗
PubMed1988

Occupational cancer in metalworking and transportation equipment industries.

Hazardous chemical exposures may be a more important public health problem in chemical-using industries, such as the metalworking and transportation equipment industries, than in chemical manufacturing plants. Recent studies have identified excess mortality from cancer among groups of workers in model and patternmaking, plating and die-cast, foundry, machining, electronics operations and vehicle assembly plants. The chemical agents or levels of exposure associated with these findings have not previously been thought to pose a cancer risk. Therefore, estimates of the fraction of cancers associated with workplace exposure may understate the importance of exposure in this setting.

Female↗
PubMed2006

Cost-effective assembly of a basic fiber-optic hydrophone for measurement of high-amplitude therapeutic ultrasound fields.

Design considerations, assembly details, and operating procedures of one version of a cost-effective basic fiber-optic probe hydrophone (FOPH) are described in order to convey practical information to groups interested in constructing a similar device. The use of fiber optic hydrophones can overcome some of the limitations associated with traditional polyvinylidene difluoride (PVDF) hydrophones for calibration of acoustic fields. Compared to standard PVDF hydrophones, FOPH systems generally have larger bandwidths, enhanced spatial resolution, reduced directionality, and greater immunity to electromagnetic interference, though they can be limited by significantly lower sensitivities. The FOPH system presently described employs a 100-microm multimode optical fiber as the sensing element and incorporates a 1-W laser diode module, 2 x 2 optical coupler, and general-purpose 50-MHz silicon p-i-n photodetector. Wave forms generated using the FOPH system and a reference PVDF hydrophone are compared, and intrinsic and substitution methods for calibrating the FOPH system are discussed. The voltage-to-pressure transfer factor is approximately 0.8 mV/MPa (-302 dB re 1 V/microPa), though straightforward modifications to the optical components in the FOPH system are discussed that can significantly increase this value. Recommendations are presented to guide the choice of optical components and to provide practical insight into the routine usage of the FOPH device.

Calibration↗
PubMed2002

Gendered bodies: recruitment, management and occupational health in northern Thailand's electronics factories.

This paper explores workers' experiences and understandings of occupational health hazards in the electronics industries of northern Thailand. Women form the bulk of the lower-level workforce as operators responsible for assembling the parts that make up microchip components. Drawing data from 16 months of research in workers' dormitories, formal and informal interviews and questionnaire surveys, in this paper I explore how gender relations are central to the organization and experience of work in these industries. I identify "work process" health hazards resulting from the physical working environment, and "workplace" health hazards relating to the organizational and social pressures of the working environment. Musculoskeletal pain, eye strain, chemical exposure, stress, improper use of safety equipment and accidents all impact upon women workers' health. Additionally, risk behaviors such as amphetamine and alcohol use, and unprotected sex, are associated with the social context of factory work.

Adult↗
PubMed2005

Formulation of a Mueller matrix for modeling of depolarization and scattering of nitrobenzene in a Kerr cell.

We have studied the depolarization of light from nitrobenzene in a Kerr cell. We observed that absorption in nitrobenzene is electric-field dependent. For modeling a nitrobenzene device we formulated a Mueller matrix for the Kerr-cell assembly, and by operating it on a Stokes vector of the input light we obtained a corresponding Stokes vector for the output light. The first parameter of the output Stokes vector corresponds to the intensity transmittance. It was simulated and compared with the measured intensity transmittance for several orientations of the polarizer-analyzer pair with respect to the applied voltages. The measurement of all unknown coefficients in a Mueller matrix consisting of the superposition of nondepolarizing and depolarizing components predicts the depolarization, scattering, and absorption in the nitrobenzene electro-optic device. The output intensities of the orthogonally polarized and cross-coupled depolarizing coefficients are in good agreement for a semi-isotropic medium. The formulated Mueller matrix agrees with the experimentally measured transmittance.

Journal Article↗
PubMedDate not supplied

Catalytic wet oxidation: mathematical modeling of multicompound destruction.

A mathematical model of a three-phase catalytic reactor, CatReac, was developed for analysis and optimization of a catalytic oxidation reactor that is used in the International Space Station potable water processor. The packed-bed catalytic reactor, known as the volatile reactor assembly (VRA), is operated as a three-phase reactor and contains a proprietary catalyst, a pure-oxygen gas phase, and the contaminated water. The contaminated water being fed to the VRA primarily consists of acetic acid, acetone, ethanol, 1-propanol, 2-propanol, and propionic acid ranging in concentration from 1 to 10 mg/L. The Langmuir-Hinshelwood Hougen-Watson (L-H) (Hougen, 1943) expression was used to describe the surface reaction rate for these compounds. Single and multicompound short-column experiments were used to determine the L-H rate parameters and calibrate the model. The model was able to predict steady-state multicomponent effluent profiles for short and full-scale reactor experiments.

Catalysis↗
PubMed1996

Control mechanisms of retinal vein pressure: evaluation in the cat using an in situ infusion micropipette.

OBJECTIVE: Previous work in our laboratory has shown that retinal vein pressure is significantly greater than intraocular pressure in the cat. Our purpose here is to evaluate the potential of an active mechanism being responsible for the control of vein pressure in the cat retina. METHODS: A double-lumen, concentric barrel micropipette assembly designed for operation within the eye of a spontaneously breathing anesthetized cat was developed. The micropipette, initially filled with hypertonic saline for use with a servonull pressure measuring system, was used to determine intravascular pressure. With the tip of the micropipette still situated in the lumen of the vessel the solution in the micropipette was exchanged for papaverine, a potent smooth muscle dilator. Following vasodilation in the distal portion of a major retinal vein, the papaverine was exchanged for hypertonic saline and intravascular pressures were measured in the dilated vessel. RESULTS: Microinjection of papaverine caused visible dilation of the major retinal vein downstream from the site of microinjection. This indicates a relaxation of the smooth muscle yet papaverine caused no change in measured retinal vein pressure. CONCLUSIONS: Vein pressure in the cat retina is maintained above intraocular pressure by mechanisms other than active control. A passive high-resistance segment resides somewhere within the optic nerve possibly within the lamina cribosa or prelaminar region.

Animals↗
PubMed1997

The change of productive skills and human work systems--function of work concept.

The techniques and skills of the age are changing, but the work situation is not corresponding to these changes. Furthermore, this causes problems in human resources development. We have investigated the contents of productive skills, vocational abilities, and work conditions, and as a result, productive skills were divided into two patterns: intellectual-management skills and sensory-motor skills. The contents of intellectual-management skills are divided into measurement, examination, design and arrangement, analysis and judgment, and understanding of technical knowledge. The contents of sensory-motor skills are divided into vision, audition and touch, visual judgment, motion of limbs, judgment by hands, and quality of the product. A sensory-motor skill is defined as one that mainly depends on judgment and memory capabilities. The former includes skills related to traditional handicrafts, processing assembling, and machine operation. The latter includes skills related to programming, designing, and controlling. A connection deeply related to the human being's essence can be found in both skills. When we examine human work systems, it is important to consider this essence.

Efficiency, Organizational↗
PubMed1990

A simple irrigator-aspirator cannula for laparoscopy: the Stewart system.

An irrigator-aspirator cannula (Stewart system) that may be assembled from common operating room supplies is described for use during operative laparoscopy. The unit consists of a disposable three-way stopcock inserted into a standard 5-mm suction probe. One stopcock port is connected to an irrigation fluid source and pressurized with an inflatable cuff; the other stopcock port is attached to wall suction. Flow rates were determined comparing two types of influx tubing, two different heights of the fluid source, and a range of inflatable cuff pressures. The flow rate of this system with urologic irrigation tubing at pressures of 150 mmHg was comparable to that of a commercially available irrigator-aspirator system. The instrument has been used in 15 routine and emergency operative laparoscopy cases and provides adequate aquadissection, rapid and easy maintenance of a clean operative field, smoke evacuation during laser vaporization, and atraumatic suction traction of tissues.

Female↗
PubMed1990

[Significance of angiographic studies in the diagnosis of non-typical epigastric disorders].

The authors analyze the possibilities and importance of angiographic examinations in the clinical differential diagnosis of patients with atypical epigastric complaints. They demonstrate that in congenital anomalies of the arteries tripus Halleri the examinations do not make it possible to assess hypoperfusion of the epigastric organs. Based on data in the literature they point out that there is often disagreement between clinical symptoms and pressure gradients of intravasally angiographically stenoses of the trunk of the coeliac vein found on operation. From hitherto assembled results it may be, however, expected that two-dimensional Doppler ultrasonic evaluation of the blood flow through the blood vessels will contribute towards the objectivization of the assessment of the blood supply of the epigastric organs. The non-invasive examination can be used also during activity of organs or after administration of drugs.

Adult↗
PubMed1997

A simple homemade lighted stylet for neonates and infants: a description and case report of its use in an infant with the Pierre Robin anomalad.

The glossoptosis and micrognathia associated with Pierre Robin anomalad can make tracheal intubation by conventional laryngoscopy quite difficult. Lighted stylets may be helpful in the successful intubation of infants with this anomalad, but those currently available that are small enough to accommodate 3.0 mm ID tracheal tubes have two major drawbacks limiting their utility: an insufficiently rigid stylet component and a nonadjustable, overly bright light. We describe a lighted stylet that can be easily assembled in the operating room which overcomes these problems and allowed us to successfully intubate a six-day-old with severe Pierre Robin anomalad.

Female↗