cssi/SciSciGPT-SciSciNet huggingface dataset:
Hand-assisted laparoscopic radical nephrectomy: the experience of the inexperienced.

Purpose: We retrospectively examined the experience of novice laparoscopic surgeons performing hand-assisted laparoscopic radical nephrectomy. The purpose was to determine if urologists with minimal laparoscopic training could perform hand-assisted laparoscopic nephrectomies in a safe and efficient manner. Materials and Methods: The first six hand-assisted laparoscopic radical nephrectomies performed by four different urology residents at the Chicago Lakeside VA hospital were reviewed. The residents included three chief urology residents and one postgraduate year 3 urology resident. None of the residents had taken any laparoscopic course, and all had limited exposure to the hand-assisted technique. In all cases, the residents performed the entire operation. The patients were evaluated for operative time, tumor size, body mass index, and ASA score. Results: All six procedures were completed without conversion to the open technique. The average operating time was 215.8 minutes, and the time from incision to...
The last step in coenzyme B12 synthesis is localized to the cell membrane in bacteria and archaea

In Salmonella enterica, the last step of the synthesis of adenosylcobamide is catalysed by the cobalamin synthase enzyme encoded by the cobS gene of this bacterium. Overexpression of the S. enterica cobS gene in Escherichia coli elicited the accumulation of the phage shock protein PspA, a protein whose expression has been linked to membrane stress. Resolution of inner and outer membranes of S. enterica by isopycnic density ultracentrifugation showed CobS activity associated with the inner membrane, a result that was confirmed using antibodies against CobS. Computer analysis of the predicted amino acid sequence of CobS suggested it was an integral membrane protein. Results of experiments performed with strains carrying plasmids encoding CobS–alkaline phosphatase or CobS–β-galactosidase protein fusions were consistent with the membrane localization of the CobS protein. Modifications to the predicted model were made based on data obtained from experiments using protein fusions. The function encoded by the cobS orthologue in the methanogenic archaeon Methanobacterium thermoautotrophicum strain ΔH compensated for the lack of CobS during cobalamin synthesis in cobS strains of S. enterica. Cobalamin synthase activity was also detected in a membrane preparation of M. thermoautotrophicum. It was concluded that the assembly of the nucleotide loop of adenosylcobamides in archaea and bacteria is a membrane-associated process. Possible reasons for the association of adenosylcobamide biosynthetic enzymes with the cell membrane are discussed.
Reactive hyperemia following total and subtotal coronary occlusion in the awake dog.

This study examined the reactive hyperemia following total and subtotal coronary artery occlusions. Studies were carried out in awake dogs with electromagnetic flowmeters and hydraulic occluders on the left circumflex coronary artery; the regional distribution of perfusion was examined with radionuclide-labeled microspheres. Reactive hyperemia following total and subtotal occlusions resulted in similar mean blood flow debt repayments of 451±34% and 492±51%, respectively. However, the distribution of perfusion was markedly different, with the ratio of subendocardial to subepicardial blood flow being 1.77±0.22 after total occlusion and 4.14±0.73 after subtotal occlusion (p<0.01). Further examination of the pattern of perfusion during reactive hyperemia demonstrated a direct relationship between the local blood flow debt and blood flow during the subsequent reactive hyperemia. These data demonstrate that coronary reactive hyperemia does not occur uniformly throughout the distribution of the vascular bed served by the previously occluded artery, but rather is coupled to the degree of hypoperfusion during the preceding occlusion.
Geological time, biological events and the learning transfer problem

Comprehension of geologic time does not come easily, especially for students who are studying the earth sciences for the first time. This project investigated the potential success of two teaching interventions that were designed to help non-science majors enrolled in an introductory geology class gain a richer conceptual understanding of the geologic time scale. Our research centered on the results of those interventions since we hypothesized that students who correctly answered exam questions on relative geologic time early in the semester would be able to respond with equal facility to exam questions at the end of the semester that asked them to apply relative geologic time to associated biologic events. The instructor of the course began this study by using the Decoding the Disciplines model (Pace & Middendorf, 1998). During the first step of the model, the instructor identified the place where a majority of students in previous classes had the greatest difficulty; that is, in addressing the relative geologic time scale. Next, the instructor articulated the mental moves an expert geologist makes when solving problems using the geological time scale. During lecture the instructor modeled those very same mental tasks for students. Students were then given the opportunity to practice those mental tasks by creating their own personal timeline. Later in the course students completed the second intervention, a categorization grid that also functioned as a classroom assessment of their learning. Students were given exams after both interventions were completed. Results from the first and second interventions indicated that students were able to understand the conceptual framework of the relative geological time scale. On an exam administered after both interventions were completed, 66% of the students answered correctly the questions about relative geologic time, an indication that they had gained conceptual knowledge of the subject. In contrast, only 36% of students answered correctly the exam questions at the end of the semester that focused on relative geologic time with associated biologic events. Pearson Chi-Square tests with P<0.05 were used to test our hypothesis. Statistically significant results at P=0.00 were attained for all tests, indicating the hypothesis can be rejected. We conclude that a second, more prevalent, underlying problem exists for non-science majors, one that Thorndike and Woodworth (1901), Byrnes (1996), Bransford, Brown, and Cocking (2000) and Bransford and Schwartz (2001) describe as the learning transfer problem. Similar problems have been discussed as a knowledge transfer problem (Graham et al., 2006). Learning transfer is problematic for students using the geological time scale and calls for additional classroom interventions – interventions designed and scaffolded to provide students the opportunity to practice the set of difficult mental moves required to apply biological events to the relative geological timeline.
EFFICIENCY OF MULTISTAGE MARKER-ASSISTED SELECTION IN THE IMPROVEMENT OF MULTIPLE QUANTITATIVE TRAITS

The application of marker-assisted selection (MAS) to breeding programmes depends on its relative cost and the expected economic return compared to conventional phenotypic selection. The relative efficiency of MAS can be increased through a two-stage selection scheme or through marker-based, multiple-trait improvement. However, the effectiveness of these alternatives has not been quantified. In this study, we evaluate the efficiency of MAS relative to conventional phenotypic selection and marker-only selection in multistage selection for the improvement of multiple traits. We further incorporate the costs of obtaining measurements on phenotypic characters and marker loci into the objective function to evaluate the efficiency of MAS with respect to the gain per unit cost. Deterministic analyses indicate that excluding costs, multiple-trait MAS can be used to increase the aggregate breeding values in quantitative characters and is expected to be more effective than conventional selection or single-trait MAS. Two-stage MAS has a slightly reduced gain because of culling in the first stage. If the objective function is to maximize the gain per unit cost, multiple-trait MAS is inferior to phenotypic selection in most of the selection schemes investigated when the cost ratio (r) of obtaining measurements on phenotypic characters to scoring marker loci is less than unity (r≤1.0) and the heritability (h2) is greater than 0.3. The efficiency of MAS increases as r increases and h2 decreases. For MAS to be more effective, it is necessary to decrease further the cost associated with molecular marker assays.
Wound Drainage from Under Full‐thickness Skin Grafts in Dogs Part I. Quantitative Evaluation of Four Techniques

The formation of hematomas or seromas under skin grafts is reported to be the most common cause of graft failure. Several techniques have been developed to prevent fluid accumulation by increasing drainage, but their effectiveness has not been evaluated. In this study, four full-thickness skin grafting procedures were performed on both sides of the chests of 12 dogs, and the amount of wound drainage was quantitated for the first 10 postoperative days. The techniques evaluated were a sheet graft (control), continuous low level suction, piecrust incisions, and nonexpanded mesh graft. Significantly more drainage fluid was removed by continuous low level suction than the other techniques evaluated. Meshing allowed significantly more drainage than the piecrust or sheet grafts but was not as effective as continuous low level suction. Piecrust incisions had no significant effect on wound drainage.
The Student Portfolio in Social Work Education

Abstract The authors focus on the use of portfolios as a pedagogical strategy to encourage students to reflect on and assess their learning experience. The rationale for the use of student portfolios in social work education includes their capacity to foster self-reflection, integrate the learning experience, prepare students for job searches and employment, and help faculty evaluate and improve the curriculum. The authors describe a model for the structure and content of the portfolio, as well as the criteria and process they use for evaluation. They present implications for the use of student portfolios in social work education, including consideration of use for curricular evaluation, positioning within the curriculum and issues in student utilization of the portfolio.
A WKB type analysis of marginal stability in directional solidification

Abstract We propose a simple and physical approach to the marginal stability criterion of pattern selection in directionally solidifying systems. The technique involves a WKB type analysis of instability caused by perturbations on the steady state shape of the cell.
Delay scaling in poisson networks

The local delay, defined as the mean time it takes a node to connect to its nearest neighbor, is a fundamental performance metric in a wireless network. For a network with Poisson distributed nodes, we find its scaling behavior (as a function of the rate of transmission) for different types of nearest-neighbor and the two extreme cases of mobility (infinite mobility and no mobility). Remarkably, it turns out that the level of mobility has hardly any effect on the scaling behavior of the local delay; it affects the pre-constant only.
Innovation, productivity and foreign direct investment-induced R&D spillovers

This article examines the effect of foreign direct investment on innovation and productivity in the host and home countries. I investigate how the flows of knowledge transmitted through FDI affect the production of knowledge in both source and recipient countries, as well as how these flows affect productivity. Using patent citations within FDI as the measure of the degree of ‘access’ that one nation gains to the R&D knowledge of another, and new patents as the measure of innovation, results reveal that there are large differences in the way FDI affects innovation and productivity between countries that are technological leaders, and technological followers. Both inward and outward FDI are found to have a strong positive effect on domestic innovation and productivity in countries that are technological followers. For technological leaders, outward FDI is highly conducive to increased domestic innovation, while inward FDI seems to increase competition between domestic and foreign firms, making it more diff...
Investigation of Inflammation and Tissue Patterning in the Gut Using a Spatially Explicit General-Purpose Model of Enteric Tissue (SEGMEnT)

The mucosa of the intestinal tract represents a finely tuned system where tissue structure strongly influences, and is turn influenced by, its function as both an absorptive surface and a defensive barrier. Mucosal architecture and histology plays a key role in the diagnosis, characterization and pathophysiology of a host of gastrointestinal diseases. Inflammation is a significant factor in the pathogenesis in many gastrointestinal diseases, and is perhaps the most clinically significant control factor governing the maintenance of the mucosal architecture by morphogenic pathways. We propose that appropriate characterization of the role of inflammation as a controller of enteric mucosal tissue patterning requires understanding the underlying cellular and molecular dynamics that determine the epithelial crypt-villus architecture across a range of conditions from health to disease. Towards this end we have developed the Spatially Explicit General-purpose Model of Enteric Tissue (SEGMEnT) to dynamically represent existing knowledge of the behavior of enteric epithelial tissue as influenced by inflammation with the ability to generate a variety of pathophysiological processes within a common platform and from a common knowledge base. In addition to reproducing healthy ileal mucosal dynamics as well as a series of morphogen knock-out/inhibition experiments, SEGMEnT provides insight into a range of clinically relevant cellular-molecular mechanisms, such as a putative role for Phosphotase and tensin homolog/phosphoinositide 3-kinase (PTEN/PI3K) as a key point of crosstalk between inflammation and morphogenesis, the protective role of enterocyte sloughing in enteric ischemia-reperfusion and chronic low level inflammation as a driver for colonic metaplasia. These results suggest that SEGMEnT can serve as an integrating platform for the study of inflammation in gastrointestinal disease.
The Power of the Instructor in the Solo Experience: An Empirical Study and Some Non-Empirical Questions.

Abstract The purpose of this study was to investigate participants' perceptions of an organized solo within a wilderness experience program and the influence that the instructors have on their perception of the solo. More specifically, this research project focused on the role of the instructor in the solo as perceived by the participants while still on solo, at the end of their wilderness experience, and three and a half months following the program. Qualitative data indicated that the instructors do have an influence on the participants' perception of their solo experience through the (a) preparation for, (b) facilitation during and (c) discussion after the solo. Recommendations to enhance the use of the wilderness solo include: (a) understand student expectations prior to the solo, (b) provide a clear rationale for the solo and associated activities, (c) implement an optional instructor/student visit during solo, (d) provide a one-on-one discussion with students prior to a group debrief after the solo,...
Photochemical quartz crystal microbalance study of the nanocrystalline titanium dioxide semiconductor electrode/water interface: Simultaneous photoaccumulation of electrons and protons

Photochemical quartz crystal microbalance (PQCM) studies of nanocrystalline titanium dioxide films show evidence of charge-compensating cation intercalation during photolytically induced accumulation layer formation. The manifestation and magnitude of mass uptake (intercalation) are dependent, respectively, on the illumination and intensity of illumination provided. Isotope experiments performed in H2O and D2O unambiguously identify the cations as protons and deuterons. The experiments extend earlier experiments with dark TiO2 (and other metal oxide semiconductors) that have implicated cation intercalation as the primary process involved in charge compensation under accumulation conditions.
Performance Measurement in Local Economic Development

Despite the trend toward accountability in the public sector, little inferential research exists on the use of accountability tools such as performance measurement. This study identifies factors that affect performance measurement in local economic development and compares the impact of structural determinants such as demographic, socioeconomic, and competitive factors to local community choices such as organizational, political, and community forces. Organizational characteristics of the economic development agency had the greatest impact, though socioeconomic and competitive forces also affected performance measurement. Overall, the findings indicate that in municipal policy making, both structural constraints and local choices matter, but local choices matter more.
Direct Quantification of Calsequestrin-Dependent Buffering in the Calcium Store of Skeletal Muscle

In mouse FDB cells releasing Ca2+ under patch clamp we measured luminal [Ca2+]SR with the novel sensor D4cpv-calsequestrin (Sztretye et al. JGP 2011a) in parallel with SR Ca2+ release flux (derived from the fluorescence of cytosolic X-rhod 1). These simultaneous measurements allowed the dynamic monitoring of Ca2+ buffering power of the SR (BP≡ Δ[Ca]total, SR / Δ [Ca2+]SR). BP started at 180 (SEM 30, 27 cells) and decreased to 89 (SEM 14) as the SR lost Ca2+ upon SR-depleting membrane depolarization (400 ms, +30 mV). The stage of high BP is also characterized by a “hump” in the release flux waveform. Recovery of SR Ca2+ content after the end of depolarization proceeded at the lower BP value (a mismatch that we call “buffer hysteresis”). BP regained slowly its initial value, as demonstrated by persistent low power and absence of hump in the second depolarizing pulse of pairs separated by 600 ms. Full restoration of hump and BP was observed after 2 min rest. In calsequestrin1-null cells BP was a constant 40 during the pulse (3.6, 29 cells), there was neither buffer hysteresis nor flux hump. Therefore, calsequestrin 1 is the time-dependent, hysteretic buffer, and contributes approximately 75% of the SR buffering power. Total releasable Ca2+, however, only decayed by 30% in CSQ-null cells, a paradox explained by a more thorough depletion in the null (Sztretye et al. JGP 2011b). The time dependence and hysteresis of the calsequestrin contribution to Ca2+ buffering is consistent with aggregation changes proposed to accompany Ca2+ binding (e.g. Park et al. JBC 2004). In this view, the hysteresis reflects the time required for the Ca2+ dissociation-induced structural changes in calsequestrin to reverse upon Ca2+ reuptake into the SR.Funded by NIAMS/NIH and MDA.
Biosynthetic studies of the notoamides: isotopic synthesis of stephacidin A and incorporation into notoamide B and sclerotiamide.

The advanced natural product stephacidin A is proposed as a biosynthetic precursor to notoamide B in various Aspergillus species. Doubly 13C-labeled racemic stephacidin A was synthesized and fed to cultures of the terrestrial-derived fungus, Aspergillus versicolor NRRL 35600, and the marine-derived fungus, Aspergillus sp. MF297-2. Analysis of the metabolites revealed enantiospecific incorporation of intact (−)-stephacidin A into (+)-notoamide B in Aspergillus versicolor and (+)-stephacidin A into (−)-notoamide B in Aspergillus sp. MF297-2. 13C-Labeled sclerotiamide was also isolated from both fungal cultures.
Contamination and deterioration of alfalfa sprouts caused by a seedborne isolate of Erwinia herbicola.

A Gram negative, rod-shaped, yellow-pigmented bacterium was recovered from beneath the seed coats of surface-sterilized alfalfa seed from three seed lots used for the commercial production of sprouts. This bacterium was responsible for the deterioration of alfalfa sprouts marketed in film-wrapped plastic containers. Identity of the isolate was confirmed as Erwinia herbicola (Lohnis) Dye (synonym Pantoea agglomerans comb. nov. ). The level of contamination by this bacterium in nonsurface-sterilized seed was 34.7% while in surface-sterilized seed it was 13.2%. No other microorganisms were consistently recovered from surface-sterilized seed samples from these lots, or from other alfalfa seed samples assayed as controls. The bacterium was able to survive for more than three years beneath the seed coats ofcontaminated seed. We recommend that alfalfa sprout companies routinely assay samples for seedborne microorganisms from lots intended for sprouting.
Nanometer Resolution of Cav-Generated Ca2+ Gradients

Diffusion theory predicts that each pA of Ca2+ flux through a voltage-gated Ca2+ channel (CaV) should generate ∼100 μM free [Ca2+] in the channel nanodomain, with steep spatial gradient and little sensitivity to intracellular Ca2+ buffers. This is widely quoted, and bears on synaptic transmission, activity-dependent plasticity, and excitation-contraction coupling. Yet, experimental verification has been difficult because diffusible Ca2+ indicators report space-averaged [Ca2+], and CaV-tethered fluorescent indicators cannot distinguish between active and silent channels. Here, we used Ca2+/calmodulin-dependent inactivation (CDI) of CaV1.3 channels themselves as a nearfield indicator of nanodomain [Ca2+], noting that CDI provides an ionic readout based only on active channels. We calibrated the [Ca2+]-sensitivity of CDI by monitoring the decay of Li+ currents following spatially-uniform Ca2+ uncaging steps. We then ran Ca2+ through the same channels to generate local [Ca2+] gradients, and titrated the external Ca2+ concentration until CDI diminished ∼50%. The corresponding unitary flux was resolved through a combination of single-channel and whole-cell recordings, enabling determination of the relationship between unitary Ca2+ flux and nanodomain [Ca2+]. Contrary to theory, nanodomain [Ca2+] signals are larger and more buffer-sensitive than expected: ∼800 μM/pA in 10 mM intracellular BAPTA, and ∼200 μM/pA in 60 mM BAPTA. These findings indicate that diffusion of free Ca2+ ions is ∼10-fold slower in the nanodomain versus other regions of the cell, and that calmodulin (the Ca2+-sensing subunit for CDI) is ∼7 nm from the channel pore. Our results suggest that the nanodomain is a tortuous environment, where a Ca2+ ion would collide with an obstacle in 9 out of every 10 of its Brownian movements. Under physiological buffering, we predict that CaVs, by virtue of their crowded nanodomains, convert small Ca2+ fluxes into enormous Ca2+ concentrations, ∼1 mM/pA over distances of 10-20 nm.
Marine Phosphorite Deposits and the Nitrogen Cycle

We have attempted to demonstrate a possible relationship between phosphorite deposition and an increase in marine denitrification. The studies of others indicate that major phosphorite deposits are often associated with black shales and accumulated during only a few epochs of geologic history. Some of these epochs were also marked by mass extinctions of organisms. Such events are not as precisely nor as strongly correlated as we would like. Nevertheless, the correlations are strong enough to encourage further consideration of the effects of possible changes in the rate of denitrification within ancient oceans on the origin of phosphorite deposits, the extinctions of marine organisms, variations in the overall level of biological activity, and temporal fluctuations in the organic carbon content of sedimentary rocks (36).
Photonic Crystal Wavelength Division Demultiplexing via Coupling through Variably-Sized Defect Cavities

A four-channel ~1.55 µm wavelength division demultiplexer utilizing a novel coupling mechanism involving resonant defect cavities in a two-dimensional photonic crystal is presented. Finite-difference time-domain simulations produced spectral peaks with 3.4 to 5.2 nm linewidths.
Isolation and purification of bactericides from human tears.

Abstract Three bactericidal components were isolated and purified from human tears by gel filtration and ion exchange chromatographic methods. Lysozyme, specific tear prealbumin and a bactericidal glycoprotein were shown to be active bactericides at, or below, physiological concentrations. The tear factors exerted different molecular effects of Bacillus subtilis, as determined by bactericidal kinetics, inhibition of macromolecular synthetic processes and of oxygen consumption. They were active against other gram-positive including Listeria monocytogenes, Staphylococcus epidermidis or Group D Streptococcus, but not against two gram-negative organisms, Escherichia coli and Salmonella typhimurium. These proteins endow normal tears with an effective system for destroying many potentially harmful micro-organisms.
MUBs, a family of ubiquitin-fold proteins that are plasma membrane-anchored by prenylation.

Abstract Ubiquitin (Ub)-fold proteins are rapidly emerging as an important class of eukaryotic modifiers, which often exert their influence by post-translational addition to other intracellular proteins. Despite assuming a common β-grasp three-dimensional structure, their functions are highly diverse because of distinct surface features and targets and include tagging proteins for selective breakdown, nuclear import, autophagic recycling, vesicular trafficking, polarized morphogenesis, and the stress response. Here we describe a novel family of Membrane-anchored Ub-fold (MUB) proteins that are present in animals, filamentous fungi, and plants. Extending from the C terminus of the Ub-fold is typically a cysteine-containing CAAX (where A indicates aliphatic amino acid) sequence that can direct the attachment of either a 15-carbon farnesyl or a 20-carbon geranylgeranyl moiety in vitro. Modified forms of several MUBs were detected in transgenic Arabidopsis thaliana, suggesting that these MUBs are prenylated in vivo. Both cell fractionation and confocal microscopic analyses of Arabidopsis plants expressing GFP-MUB fusions showed that the modified forms are membrane-anchored with a significant enrichment on the plasma membrane. This plasma membrane location was blocked in vivo in prenyltransferase mutants and by mevinolin, which inhibits the synthesis of prenyl groups. In addition to the five MUBs with CAAX boxes, Arabidopsis has one MUB variant with a cysteine-rich C terminus distinct from the CAAX box that is also membrane-anchored, possibly through the attachment of a long chain acyl group. Although the physiological role(s) of MUBs remain unknown, the discovery of these prenylated forms further expands the diversity and potential functions of Ub-fold proteins in eukaryotic biology.
Cambrian extensional tectonics and magmatism within the Southern Oklahoma aulacogen

Abstract The tectonic evolution of the Southern Oklahoma aulacogen is partially constrained by the petrological consequences of a bimodal igneous suite associated with the Cambrian rift. Mineralogical and compositional layers and erosional surfaces are recognized as initially subplanar, subhorizontal markers. The progressive rotation of these horizons can be explained by uniform-sense normal faulting. Magmatism, confined to the aulacogen trend, elevated the thermal gradient producing a crustal strength-anisotropy. This ensured the localization of the extension throughout the Cambrian rifting event. The presence of a substantial volume of mafic igneous rocks within the crust along the aulacogen's trend suggests that crustal attenuation was compensated for by the addition of mantle derived material during extension.
Engine mass airflow sensor fault detection via an adaptive oxygen fraction observer

In this paper, an adaptive observer, which can simultaneously estimate the oxygen fraction states and unknown intake mass air flow rate, is designed for a Diesel engine equipped with a dual-loop exhaust gas recirculation (EGR) system. A previously developed dynamic model and oxygen fraction observer for the air-path loop of the Diesel engine are introduced as the foundation of this work. As the measurement accuracy of the mass airflow (MAF) sensor may degrade due to aging phenomenon, the impact of MAF signal error on the performance of the previously developed Luenberger-like oxygen fraction observer is investigated through experimental results. To detect the measurement error and to correct the estimation error, the detailed procedure of developing the adaptive observer is presented. The observer's performance is validated against the experimental data.
NAD+/NADH recycling by coimmobilized lactate dehydrogenase and glutamate dehydrogenase

Abstract Most biologically active proteins bind irreversibly to Amberlite XAD-7 in dilute buffer at approximately neutral pH. Small amounts of protein (i.e., ∼4% w/w or less) are adsorbed at the periphery of the porous, spherical, beads where the protein is relatively accessible to external solvent and solvent components. Additional amounts of the same or different proteins up to ∼35% (w/w) absorb to deeper layers of the same beads. The order in which two or more proteins are adsorbed can be used to arrange them in a series of concentric layers on Amberlite XAD-7. An NAD+/NADH recycling system for the synthesis of l -glutamate from ammonia, α-ketoglutarate, and lactate was prepared by coimmobilizing rabbit muscle lactate dehydrogenase (LDH) and bovine liver glutamate dehydrogenase (GDH) in different amounts and in different arrangements on Amberlite XAD-7. The overall efficiency of that immobilized system based on the rates of glutamate production varied with both the ratio of the two enzymes and their arrangement on the polymer beads. Those variations suggest that NADH formation was rate limiting under most conditions and demonstrated the importance of enzyme proximity. The immobilized two-enzyme system, reflecting the pH dependence of its constituent enzymes, had optimal activity at pH ∼8.5 and retained up to 75% of its activity after one week of repeated use.
Angle distortion and conformality

Abstract We offer an alternative to the usual proofs for the equivalence between conformality and analyticity with nonzero derivative. Our proof uses the z-derivative to quantify angle distortion, and thereby foreshadows some important ideas in the study of quasiconformal mappings.
Analytical interpretation of nondiffusive phonon transport in thermoreflectance thermal conductivity measurements

We derive an analytical solution to the Boltzmann transport equation (BTE) to relate nondiffusive thermal conductivity measurements by thermoreflectance techniques to the bulk thermal conductivity accumulation function, which quantifies cumulative contributions to thermal conductivity from different mean free path energy carriers (here, phonons). Our solution incorporates two experimentally defined length scales: thermal penetration depth and heating laser spot radius. We identify two thermal resistances based on the predicted spatial temperature and heat flux profiles. The first resistance is associated with the interaction between energy carriers and the surface of the solution domain. The second resistance accounts for transport of energy carriers through the solution domain and is affected by the experimentally defined length scales. Comparison of the BTE result with that from conventional heat diffusion theory enables a mapping of mean-free-path-specific contributions to the measured thermal conductivity based on the experimental length scales. In general, the measured thermal conductivity will be influenced by the smaller of the two length scales and the surface properties of the system. The result is used to compare nondiffusive thermal conductivity measurements of silicon with first-principles-based calculations of its thermal conductivity accumulation function.
Group desensitization for heterogeneous phobias

Abstract This brief note outlines modifications in group desensitization procedures which make possible the simultaneous desensitization of individuals with heterogeneous anxieties or phobias.
MOLECULAR TYPING OF ISOLATES FROM AN OUTBREAK ASSOCIATED WITH ERYTHROMYCIN-RESISTANT B. PERTUSSIS. • 1030

Between April 30, and October 1, 1994, 75 probable and confirmed cases of pertussis were identified in Yuma County, AZ. A strain of Bordetella pertussis highly resistant to erythromycin (MIC >64 μg/ml, usual MIC range: 0.02 to 0.1 μg/ml) was isolated from a 2-month-old infant during the outbreak. We performed pulsed-field gel electrophoresis (PFGE) typing on 49 isolates obtained from cases in the affected county and the surrounding area during the same period to (1) determine whether the resistant strain was of a unique genetic type. (2) define the distribution of B. pertussis genetic types in the region, and (3) compare the genetic types of isolates from the region with a random sample of isolates from other states in the U.S.. PFGE and antimicrobial susceptibility testing was performed on 7 isolates from Yuma, 24 from other Arizona counties, and 18 from San Diego County, CA. The 49 isolates yielded 12 distinct PFGE patterns. Two PFGE types. C (N=23) and G (N=11) predominated and comprised 69% of all strains. Five of the 7 isolates from Yuma were PFGE type G compared with 6 of 42 isolates from other counties (OR 15.0, 95% CI=1.9-150). Only the isolate from the index case was resistant to erythromycin and was PFGE type G. For comparison, 87 additional B. pertussis strains isolated during 1993-94 in 7 geographically separate states were typed. Only three of 87 strains isolated elsewhere, compared with 11 of 49 strains from southwestern U.S., were identified as type G (OR 8.1, 95% CI=1.9-39). Four type G strains were isolated during 1989-90 in Missouri; none of the 23 Missouri strains from 1994 were type G. Preliminary data suggest that the mechanism of erythromycin resistance in the index isolate may not involve an easily transmissible genetic element and may be associated with alterations in the chromosomal DNA. These data suggest that B. pertussis can develop resistance to erythromycin. This change in phenotype may not be associated with a detectable change in the PFGE pattern of the strain. Additionally, type G was the dominant strain in the outbreak. This genetic type of B. pertussis has circulated in other parts of the U.S. in the past and thus may not have been imported recently from another country.
New quinolones in development

Fluoroquinolones, such as ciprofloxacin and ofloxacin have recently gained wide acceptance for use in the treatment of respiratory tract, skin/soft tissue, sexually transmitted diseases and urinary tract infections. The broad spectrum activity and good oral absorption characteristics of these antimicrobials promotes their use in both community and hospital settings. Despite these favourable properties, ciprofloxacin and ofloxacin have limited potency against some clinically important organsims, such as Streptococcus pneumoniae, enterococci and anaerobes including Bacteroides fragilis and many methicillin-resistant staphylococci. In addition, occasional clinical isolates of Enterobacteriaceae and Pseudomonas aeruginosa have emerged resistant to these compounds following their introduction. In an effort to expand upon the clinical utility of the existing fluoroquinolones, several new agents of this class have been identified and are in various stages of development. Some of these newer fluoroquinolones have...
Distributed friction damping of travelling wave vibration in rods

A ring damper can be affixed to a rotating base structure such as a gear, an automotive brake rotor or a gas turbine's labyrinth air seal. Depending on the frequency range, wavenumber and level of preload, vibration of the base structure can be effectively and passively attenuated by friction that develops along the interface between it and the damper. The assembly is modelled as two rods that couple in longitudinal vibration through spatially distributed hysteretic friction, with each rod having periodic boundary conditions in a manner analogous to an unwrapped ring and disc. As is representative of rotating machinery applications, the system is driven by a travelling wave disturbance, and for that form of excitation, the base structure's and the damper's responses are determined without the need for computationally intensive simulation. The damper's performance can be optimized with respect to normal preload, and its effectiveness is insensitive to variations in preload or the excitation's magnitude when its natural frequency is substantially lower than the base structure's in the absence of contact.
The Dependence of Electrical Resistivity-Saturation Relationships on Multiphase Flow Instability

We investigate the relationship between apparent electrical resistivity and water saturation during unstable multiphase flow. We conducted experiments in a thin, two-dimensional tank packed with glass beads, where Nigrosine dyed water was injected uniformly along one edge to displace mineral oil. The resulting patterns of fluid saturation in the tank were captured on video using the light transmission method, while the apparent resistivity of the tank was continuously measured. Different experiments were performed by varying the water application rate and orientation of the tank to control the generalized Bond number, which describes the balance between viscous, capillary, and gravity forces that affect flow instability. We observed the resistivity index to gradually decrease as water saturation increases in the tank, but sharp drops occurred as individual fingers bridged the tank. The magnitude of this effect decreased as the displacement became increasingly unstable until a smooth transition occurred for highly unstable flows. By analyzing the dynamic data using Archie’s law, we found that the apparent saturation exponent increases linearly between approximately 1 and 2 as a function of generalized Bond number, after which it remained constant for unstable flows with a generalized Bond number less than −0.106.
Sample size requirements for estimating intraclass correlations with desired precision

A method is developed to calculate the approximate number of subjects required to obtain an exact confidence interval of desired width for certain types of intraclass correlations in one-way and two-way ANOVA models. The sample size approximation is shown to be very accurate.
Tests of Significance for Differences in Counts of Rare Events in Two Treatment Groups

Counts of rare events tend to have Poisson or J-shaped distributions that render parametric assumptions questionable. Six different methods for testing the significance of the difference between location parameters for two such distributions are evaluated in this article. A binomial test for the difference between means is known to be the most powerful unbiased test when population distributions are truly Poisson; however, it appears extremely non-robust against departures from the distributional assumption. Robust enough to provide appropriate protection against Type I error, Student's t test was among the most powerful of the tests when applied to counts of rare events in two treatment groups. The Mann-Whitney sum of ranks test also provided superior alpha protection and power even where a large number of tied ranks occurred in the zero-count category of a J-shaped distribution. Finally, a 1 df chi-square test for linear shift in proportional representation across frequency categories of one group as op...
Dynamic Merkle Trees for Verifying Privileges in Sensor Networks

Mobile sinks are already used in static sensor networks to facilitate data collection or network management, but it is possible in such networks for mobile sinks to be compromised and mount various insider attacks. Some schemes have been devised recently to limit the privileges of mobile sinks appropriately, but these are secure only when the number of compromised mobile sinks or sensors is below a network-wide threshold. This threshold is determined by a sensor's memory, and is usually too small. We introduce dynamic Merkle trees, and show how to use them to restrict and verify the privilege of mobile sinks. Unlike current schemes, our scheme allows all sensors in a region to simultaneously verify mobile sink privileges, and does not assume a network-wide limit on the number of node compromises. As our security analysis shows, our approach is safe from fabrication attacks, impersonation attacks and replay attacks. Further, our performance analysis shows that we incur very low communication, computation, and storage overheads.
Fabricating microretarders by CO2 laser heating process technology

We describe an environment-friendly fabrication process for microretarders with a high contrast ratio and well-defined stripe bound- aries. It is shown that by accurately controlling the power, spot size, and scanning speed of a CO2 laser beam, the retardation property of a poly- meric film can be tailored within a localized area without altering that of the untreated areas. The measurements and analyses of the contrast ratios on the microretarders are presented. A microretarder can be used in many applications, especially in stereoscopic displays. © 2001 Society of
Algebraic space-time codes for quasi-synchronous cooperative diversity

Li and Xia have recently investigated the design of space-time codes that achieve full spatial diversity for quasi-synchronous cooperative communications. They show that certain of the binary space-time trellis codes derived from the Hammons-El Gamal stacking construction are delay tolerant and can be used in the multilevel code constructions by Lu and Kumar to produce delay tolerant space-time codes for PSK and QAM signaling. In this paper, we present various generalizations of the Lu-Kumar construction that also preserve the delay tolerance of the underlying constituent codes. We investigate the delay tolerance of short block codes derived from the stacking construction. We identify an algebraic constraint that, if satisfied, is sufficient to guarantee a certain level of delay tolerance and, based on this constraint, exhibit a new construction of short block codes that achieve significant levels of delay tolerance.
Induction of motor neurons by Sonic hedgehog is independent of floor plate differentiation

Abstract Background: The differentiation of floor plate cells and motor neurons in the vertebrate neural tube appears to be induced by signals from the notochord. The secreted protein encoded by the Sonic hedgehog (Shh) gene is expressed by axial midline cells and can induce floor plate cells in vivo and in vitro. Motor neurons can also be induced in vitro by cells that synthesize Sonic hedgehog protein (Shh). It remains unclear, however, if the motor-neuron-inducing activity of Shh depends on the synthesis of a distinct signaling molecule by floor plate cells. To resolve this issue, we have developed an in vitro assay which uncouples the notochord-mediated induction of motor neurons from floor plate differentiation, and have used this assay to examine whether Shh induces motor neurons in the absence of floor plate differentiation. Results Floor plate cells and motor neurons were induced in neural plate explants grown in contact with the notochord, but only motor neurons were induced when explants were separated from the notochord. COS cells transfected with Shh induced both floor plate cells and motor neurons when grown in contact with neural plate explants, whereas only motor neurons were induced when the explants were grown at a distance from Shh -transfected COS cells. Direct transfection of neural plate cells with an Shh -expression construct induced both floor plate cells and motor neurons, with motor neuron differentiation occurring prior to, or coincidentally with, floor plate differentiation. The induction of motor neurons appears, therefore, not to depend on floor plate differentiation. Conclusion The induction of motor neurons by Shh does not depend on distinct floor-plate-derived signaling molecules. Shh can, therefore, initiate the differentiation of two cell types that are generated in the ventral region of the neural tube. These results show that the early development of motor neurons involves the inductive action of Shh, whereas the survival of motor neurons at later stages of embryonic development requires neurotrophic factors.
Probing the folding landscape of the Tetrahymena ribozyme: commitment to form the native conformation is late in the folding pathway

Large, structured RNAs traverse folding landscapes in which intermediates and long-lived misfolded states are common. To obtain a comprehensive description of the folding landscape for a structured RNA, it is necessary to understand the connections between productive folding pathways and pathways to these misfolded states. The Tetrahymena group I ribozyme partitions between folding to the native state and to a long-lived misfolded conformation. Here, we show that the observed rate constant for commitment to fold to the native or misfolded states is 1.9 min ˇ1 (37C, 10 mM Mg 2a ), the same within error as the rate constant for overall folding to the native state. Thus, the commitment to alternative folding pathways is made late in the folding process, concomitant with or after the rate-limiting step for overall folding. The ribozyme forms much of its tertiary structure significantly faster than it reaches this commitment point and the tertiary structure is expected to be stable, suggesting that the commitment to fold along pathways to the native or misfolded states is made from a partially structured intermediate. These results allow the misfolded conformation to be incorporated into a folding framework that reconciles previous data and gives quantitative information about the energetic topology of the folding landscape for this RNA. # 2001 Academic Press
Detection of single fluorescent proteins inside eukaryotic cells using two-photon fluorescence

Imaging single fluorescent proteins in a live cell is a challenging task because of the strong cellular autofluorescence. Autofluorescence can be minimized by reducing fluorescence excitation volume. Total internal reflection fluorescence (TIRF) microscopy has been routinely used to reduce excitation volume and detect single protein molecules in or close to cell membrane. However, the limited penetration depth of evanescent field excludes imaging of single fluorescent proteins that reside deep inside a eukaryotic cell. Here we report detection of single fluorescent proteins inside eukaryotic cells by two-photon fluorescence (TPF) microscopy. TPF has an excitation volume less than 0.1 femtoliter (fL). Cell autofluorescence under TPF is low and thus enables us to detect single enhanced green fluorescent proteins (EGFP) and single monomeric teal fluorescent proteins (mTFP1.0) that reside several microns deep inside the cell. Discrete stepwise photobleaching of TPF was observed for both proteins inside the cell. Quantitative analysis of single-molecule fluorescence trajectories show that mTFP1.0 is about twofold brighter than EGFP, while its fluorescence on-time before bleaching is about 10 fold shorter. These findings demonstrate the sensitivity of TPF for imaging of eukaryotic cells at single-molecule level and will be useful for measurement of protein stoichiometry inside the cell.