cssi/SciSciGPT-SciSciNet huggingface dataset:
Reflecting on Growth and Change: The Persistence of the Faculty Academy (2002–2020)

This chapter presents reflections on nearly two decades of membership in the Faculty Academy. The group created a safe space for professional growth and change. My story of Faculty Academy activity draws on Dewey’s notion of the “doing” and “undergoing” (Dewey in Art as experience. Perigee Books, New York, p. 47, 1934/1980) of experience. The metaphoric story involving the literal touchstones of Imagine and Accept frame the rhizomatic growth and change personally experienced and observed in others as members of the Faculty Academy. Flexibility and a relational leadership style emerged as key elements supporting Faculty Academy’s ability to sustain itself through changing times. Learning through experience to both imagine unrealities and accept limitations as a means to persist, grow, and change is realized.
Fresh Osteochondral Allograft Transplantation for Osteochondral Lesions of the Talus: A Systematic Review.

Abstract Osteochondral lesions of the talus (OLTs) are difficult to treat. Despite a multitude of interventions, there are no generally-agreed-upon guidelines regarding treatment. The objective of this study was to conduct a systematic review of clinical outcomes after fresh osteochondral allografts transplantation of the talus. PubMed, the Cochrane Central Register of Controlled Trials, EMBASE, and Medline were searched using PRISMA guidelines. Studies that evaluated outcomes after fresh osteochondral allograft transplantation for OLTs were included. Clinical outcomes, according to standardized scoring systems, such as the American Orthopaedics Foot & Ankle Society (AOFAS) Ankle/Hindfoot Scale and the Visual Analog Scale (VAS) were compared across studies. The literature search yielded 12 eligible studies with a mean Coleman Methodology Score of 68.1 (57-79). A total of 191 patients were included with an average age of 37.5 (17-74) years and average follow-up of 56.8 (6-240) months. The AOFAS Ankle/Hindfoot score was obtained pre- and postoperatively in 6 of the studies and had significant improvements in each (p
Effect of the low glutamate diet on inflammatory cytokines in veterans with Gulf War Illness (GWI): A pilot study.

Abstract Aim To examine the effects of the low glutamate diet on inflammatory cytokines in veterans with Gulf War Illness (GWI). Main methods Forty veterans with GWI were recruited from across the country. Anthropometric measurements and blood samples were collected at baseline and after one month on the low glutamate diet. Dietary adherence was measured with a glutamate food frequency questionnaire (FFQ). Inflammatory cytokines (IL-1β, IL-6, IFN-γ, and TNF-α) were measured in pre- and post-diet serum (N = 34). Improvement was defined as being “much” or “very much” improved on the patient global impression of change scale (PGIC), or as having ≥30% of their symptoms remit. Correlations of the FFQ and the cytokines were calculated, followed by multivariable linear regression for significant findings. Mann Whitney U tests were used to compare cytokine levels according to improvement on the diet, and then logistic regression was used to estimate the association after adjustment for potential confounders. Classification trees were also produced to determine the ability of change in the inflammatory cytokines to predict improvement on the diet. Key findings Dietary adherence was significantly associated with reduction in TNF-α, and PGIC improvement was significantly associated with reduced IL-1β, after adjustment for potential confounders. Classification trees demonstrated that IL-1β, TNF-α, and IL-6 can predict improvement on the diet with 76.5% accuracy. Significance Findings suggest that the low glutamate diet may be able to reduce systemic inflammation in veterans with GWI.
Comparison of Fresh and Frozen Ejaculated Sperm in Sibling Oocyte Recipient Cycles

Abstract Research question Do IVF-ICSI cycles using fresh and frozen ejaculated sperm result in similar pregnancy outcomes in couples with non-male factor infertility? Design In a retrospective cohort study, patients undergoing donor egg recipient cycles in which oocytes from a single controlled ovarian hyperstimulation were split between two recipients were reviewed. Two recipients of the single donor oocyte were paired and categorized based on the type of ejaculated sperm (fresh/frozen). Outcomes included live birth rate (LBR), implantation, pregnancy, pregnancy loss and fertilization rates. Results 408 patients received oocytes from a split donor oocyte cycle. 45 pairs of patients used discrepant types of ejaculated sperm. Fertilization rate was 74.8% in the fresh and 68.6% in the frozen sperm group (p=0.13). Pregnancy rate was 76% in the fresh and 67% in the frozen group. LBR was 69% in the fresh and 44% in the frozen group. Implantation rate was significantly higher at 64% in the fresh and 36% in the frozen group (p=0.04). Rate of pregnancy loss was significantly higher at 5.9% in the fresh and 33% in the frozen group (p = 0.013). Adjusted odds of LBR was 67% lower for patients in the frozen group (95% CI: 0.12, 0.89). Adjusted odds of pregnancy (OR 0.67, 95% CI: 0.20, 2.27) and implantation rates (OR 0.5, 95% CI: 0.12, 2.12) favored the fresh group. Conclusion In this model that controls for oocyte quality by using paired recipients from the same donor, we found that frozen ejaculated sperm resulted in lower live birth rates than those using fresh sperm.
Relative to Whom? Comment on “Relative Education and the Advantage of a College Degree”:

To understand the relative advantage of a bachelor’s degree, we must consider the question: relative to whom? Using the Current Population Survey Annual Social and Economic Supplement, Horowitz (20...
MO-E-213-03: Newer Radiation Protection Requirements in Last Decade

The focus of work of medical physicists in 1980's was on quality control and quality assurance. Radiation safety was important but was dominated by occupational radiation protection. A series of over exposures of patients in radiotherapy, nuclear medicine and observation of skin injuries among patients undergoing interventional procedures in 1990's started creating the need for focus on patient protection. It gave medical physicists new directions to develop expertise in patient dosimetry and dose management. Publications creating awareness on cancer risks from CT in early part of the current century and over exposures in CT in 2008 brought radiation risks in public domain and created challenging situations for medical physicists. Increasing multiple exposures of individual patient and patient doses of few tens of mSv or exceeding 100 mSv are increasing the role of medical physicists. Expansion of usage of fluoroscopy in the hands of clinical professionals with hardly any training in radiation protection shall require further role for medical physicists. The increasing publications in journals, recent changes in Safety Standards, California law, all increase responsibilities of medical physicists in patient protection. Newer technological developments in dose efficiency and protective devices increase percentage of time devoted by medical physicists on radiation protection activities. Without radiation protection, the roles, responsibilities and day-to-day involvement of medical physicists in diagnostic radiology becomes questionable. In coming years either medical radiation protection may emerge as a specialty or medical physicists will have to keep major part of day-to-day work on radiation protection. Learning Objectives: 1.To understand how radiation protection has been increasing its role in day-to-day activities of medical physicist 2.To be aware about international safety Standards, national and State regulations that require higher attention to radiation protection than in past 3.To be aware about possible emergence of medical radiation protection as a specialty and challenges for medical physicists.
The Economics of Biotechnology Regulation

Rational regulations of transgenic products should compare their risks and benefits with the risks and benefits of alternatives. The current regulations ignore the alternatives. Political-economic considerations govern the establishment of regulatory requirements and tend to lead to overregulation. Optimal testing should balance the gains and costs of ex ante testing and ex post monitoring. Emphasis on ex ante testing to control bad products may lead to welfare losses. The ex ante testing of new transgenic products should occur mostly at the trait level. Registration requirements at the varietal level, and even the crop level, may be very costly.
Dorsal stream: from algorithm to neuroscience

The dorsal stream in the primate visual cortex is involved in the perception of motion and the recognition of actions. The two topics, motion processing in the brain, and action recognition in videos, have been developed independently in the field of neuroscience and computer vision. We present a dorsal stream model that can be used for the recognition of actions as well as explaining neurophysiology in the dorsal stream. The model consists of a spatio-temporal feature detectors of increasing complexity: an input image sequence is first analyzed by an array of motion sensitive units which, through a hierarchy of processing stages, lead to position and scale invariant representation of motion in a video sequence. The model outperforms or on par with the state-of-the-art computer vision algorithms on a range of human action datasets. We then describe the extension of the model into a high-throughput system for the recognition of mouse behaviors in their homecage. We provide software and a very large manually annotated video database used for training and testing the system. Our system outperforms a commercial software and performs on par with human scoring, as measured from the ground-truth manual annotations of more than 10 hours of videos of freely behaving mice. We complete the neurobiological side of the model by showing it could explain the motion processing as well as action selectivity in the dorsal stream, based on comparisons between model outputs and the neuronal responses in the dorsal stream. Specifically, the model could explain pattern and component sensitivity and distribution [161], local motion integration [97], and speed-tuning [144] of MT cells. The model, when combining with the ventral stream model [173], could also explain the action and actor selectivity in the STP area. There exists only a few models for the motion processing in the dorsal stream, and these models were not be applied to the real-world computer vision tasks. Our model is one that agrees with (or processes) data at different levels: from computer vision algorithm, practical software, to neuroscience.
Monosaccharide and Chitin Content of Cell Walls of Histoplasma capsulatum and Blastomyces dermatitidis

Cell walls of Histoplasma capsulatum and Blastomyces dermatitidis, obtained by mechanical breakage of yeast- and mycelial-phase cultures, were lipid-extracted and then fractionated with ethylenediamine. Unextracted cell walls, lipid-extracted cell walls, and the three fractions resulting from ethylenediamine treatment were examined for monosaccharide and chitin content. The yeast-phase cell walls of five strains of H. capsulatum fell into two categories, designated chemotypes I and II, one of which, chemotype II, was similar to yeast-phase cell walls derived from three strains of B. dermatitidis. H. capsulatum chemotype I cell walls were characterized by lower content of material soluble in ethylenediamine, higher chitin content, and lower monosaccharide content than H. capsulatum chemotype II or B. dermatitidis cell walls. Approximately 80% of the monosaccharides of chemotype I cell walls was combined in forms susceptible to attack by mild acid hydrolysis, compared with about 50% of the monosaccharides of chemotype II and B. dermatitidis. H. capsulatum and B. dermatitidis yeast-phase cell walls could be distinguished, however, by their susceptibility to attack by a crude enzyme system derived from a Streptomyces sp. incubated with chitin as the only carbon source. Both glucose and acetylglucosamine were released from H. capsulatum cell walls, regardless of chemotype, during enzymatic hydrolysis, whereas only acetylglucosamine was released from B. dermatitidis yeast-phase cell walls. Mycelial-phase cell walls of H. capsulatum and B. dermatitidis were characterized by lower content of material soluble in ethylenediamine, higher proportions of mannose, and lower chitin content than their respective yeast phases. Glucose and acetylglucosamine were both released from all mycelial-phase cell walls, whether H. capsulatum or B. dermatitidis, by the crude enzyme system.
Dynamics of the aurora—VI: Formation of patches and their eastward motion

Abstract The formation of patches in the morning sector occurs about 10 ~30 min after the onset of the auroral substorm in the midnight sector. This phenomenon is examined in detail by using the IGY Alaska-Canada all-sky and magnetic records. Patches drift eastwards and their drift speed is obtained for a number of cases.
How neural interactions form neural responses in the salamander retina.

A wide range of experimental data characterizing propertiesof individual salamander retinal cells and synaptic interactionsare integrated to form a quantitative computational model of visual function in the salamander retina.The model is used to show how specific interactions between neuronsand between networks of neurons can lead to the integratedresponse behavior of individual cells deep in the retina. Themodel is also used to illustrate how the representation of movingand stationary stimuli is encoded in a series of layer-by-layertransformations leading to the final retinal output at the ganglioncell layer.
Voltage-Dependent Neuromodulation of Na+ Channels by D1-Like Dopamine Receptors in Rat Hippocampal Neurons

Activation of D1-like dopamine (DA) receptors reduces peak Na+ current in acutely isolated hippocampal neurons through phosphorylation of the α subunit of the Na+ channel by cAMP-dependent protein kinase (PKA). Here we report that neuromodulation of Na+ currents by DA receptors via PKA is voltage-dependent in the range of −110 to −70 mV and is also sensitive to concurrent activation of protein kinase C (PKC). Depolarization enhanced the ability of D1-like DA receptors to reduce peak Na+ currents via the PKA pathway. Similar voltage-dependent modulation was observed when PKA was activated directly with the membrane-permeant PKA activator DCl-cBIMPS (cBIMPS; 20 μm), indicating that the membrane potential dependence occurs downstream of PKA. PKA activation caused only a small (−2.9 mV) shift in the voltage dependence of steady-state inactivation and had no effect on slow inactivation or on the rates of entry into the fast or slow inactivated states, suggesting that another mechanism is responsible for coupling of membrane potential changes to PKA modulation. Activation of PKC with a low concentration of the membrane-permeant diacylglycerol analog oleylacetyl glycerol also potentiated modulation by SKF 81297 or cBIMPS, and these effects were most striking at hyperpolarized membrane potentials where PKA modulation was not stimulated by membrane depolarization. Thus, activation of D1-like DA receptors causes a strong reduction in Na+ current via the PKA pathway, but it is effective primarily when it is combined with depolarization or activation of PKC. The convergence of these three distinct signaling modalities on the Na+ channel provides an intriguing mechanism for integration of information from multiple signaling pathways in the hippocampus and CNS.
Biodegradation of 2,4-D and related xenobiotic compounds

Abstract Organisms capable of degrading 2,4-D and related compounds have been studied in pure and mixed cultures. Most studies have been conducted under aerobic conditions. Some of the environmental factors identified to be significant in determining biodegradation rates include pH, temperature, aeration, supplemental nutrient supplies, culture enrichment and substrate concentration range. The Monod model appears to be most applicable to xenobiotic degradation in low substrate concentration ranges, where inhibition effects are not significant. The Haldane model provides a more complete description over a broad range of substrate concentrations because it takes substrate inhibition into account. Inhibitory effects caused by biodegradation products need to be modelled in some applications. Modelling of cometabolism is necessary to describe microbial degradation at very low concentrations. Several models are examined to determine their applicability in correlating physicochemical properties to biodegradation rate constants that can be applied to either cometabolic or growth associated substrate utilization.
Correlation of symptoms with location and severity of pelvic organ prolapse.

Abstract Objective: The purpose of this study was to compare the symptoms that are related to pelvic floor dysfunction with the location and severity of the coexisting prolapse. Study Design: Two hundred thirty-seven consecutive patients with symptomatic pelvic organ prolapse came to Johns Hopkins Medicine during a 24-month period beginning in July 1998 and completed a symptom-specific Likert scale questionnaire that included standardized questions that were compiled from commonly used validated instruments. All questionnaires were completed by the patients before they were seen by a physician. Further evaluation included a standardized physical examination that included the International Continence Society's system for grading uterovaginal prolapse. Symptoms were categorized according to both severity and associated anatomic compartment. Symptoms that were related to urinary and anal incontinence and voiding, defecatory, sexual, and pelvic floor dysfunction were analyzed with respect to location and severity of pelvic organ prolapse with the use of the nonparametric correlation coefficient, Kendall's tau-b. Results: The mean age of the women was 57.2 years (range, 23-93 years); 109 of the women (46%) had undergone hysterectomy. Overall, stage II was the most common pelvic organ prolapse (51%) that was encountered. In 77 patients (33%), anterior compartment pelvic organ prolapse predominated; 46 patients (19%) demonstrated posterior compartment prolapse, whereas 26 patients (11%) had apical prolapse. In 88 patients (37%), no single location was more severe than another. Voiding dysfunction that was characterized by urinary hesitancy, prolonged or intermittent flow, and a need to change position was associated with the increasing severity of anterior and apical pelvic organ prolapse. Pelvic pressure and discomfort along with visualization of prolapse were strongly associated with worsening stages of pelvic organ prolapse in all compartments. Defecatory dysfunction characterized by incomplete evacuation and digital manipulation was associated with worsening posterior compartment pelvic organ prolapse. Impairment of sexual relations and duration of abstinence were strongly associated with worsening pelvic organ prolapse. An inverse correlation was observed between increasing severity of pelvic organ prolapse and urinary incontinence and enuresis. Conclusion: Women with pelvic organ prolapse experience symptoms that do not necessarily correlate with compartment-specific defects. Increasing severity of pelvic organ prolapse is weakly to moderately associated with several specific symptoms that are related to urinary incontinence and voiding, defecatory, and sexual dysfunction. (Am J Obstet Gynecol 2001;185:1332-8.)
Water limitation and plant inter-specific competition reduce rhizosphere-induced C decomposition and plant N uptake

Plants can affect soil organic matter decomposition and mineralization through litter inputs, but also more directly through root-microbial interactions (rhizosphere effects). Depending on resource availability and plant species identity, these rhizosphere effects can be positive or negative. To date, studies of rhizosphere effects have been limited to plant species grown individually. It is unclear how belowground resources and inter-specific interactions among plants may influence rhizosphere effects on soil C decomposition and plant N uptake. In this study, we tested the simple and interactive effects of plant diversity and water availability on rhizosphere-mediated soil C decomposition and plant N uptake. The study was conducted in the greenhouse with five semi-arid grassland species (monocultures and mixtures of all five species) and two water levels (15 and 20% gravimetric soil moisture content). We hypothesized that microbial decomposition and N release would be less in the low compared to high water treatment and less in mixtures compared to monocultures. Rhizosphere effects on soil C decomposition were both positive and negative among the five species when grown in monoculture, although negative effects prevailed by the end of the experiment. When grown in mixture, rhizosphere effects reduced soil C decomposition and plant N uptake compared to monocultures, but only at the low-water level. Our results suggest that when water availability is low, plant species complementarity and selection effects on water and N use can decrease soil C decomposition through rhizosphere effects. Although complementarity and selection effects can increase plant N uptake efficiency, plant N uptake in the mixtures was still lower than expected, most likely because rhizosphere effects reduced N supply in the mixtures more than in the monocultures. Our results indicate that rhizosphere effects on C and N cycling depend on water availability and inter-specific plant interactions. Negative rhizosphere effects on soil C decomposition and N supply in mixtures relative to monocultures of the component species could ultimately increase soil C storage and possibly influence how plant communities in semi-arid grasslands respond to global climate change.
Anesthesia for the patient with liver disease

Summary Patients with liver disease are at increased risk for complications after surgery. 1–5 In those patients with chronic disease, risk correlates with Child's or Pugh's class and the location of surgery. In those patients with acute disease (excluding FHF), risk is less quantified but prudence dictates a conservative approach to proceeding with surgery. Careful anesthetic management may make a difference in patient outcome. This includes optimizing the patient preoperatively, appropriate invasive monitoring, meticulous attention to metabolic and electrolyte abnormalities, rational selection of agents, and careful titration of drugs to clinical effect. End organ disease associated with liver disease affects every major organ system and may be as important or even more so than the liver disease per se. An index of suspicion must be kept for these disease processes during preoperative evaluation and appropriate work-up sought. A low threshold for invasive monitoring should be adopted particularly for the patient with end-stage disease. Successful care of these patients demands that the anesthesiologist accommodate a large group of medical needs when forming his or her anesthetic plan.
Visual Language: The Development of Format and Page Design in English Renaissance Technical Writing

Studies in the history of technical writing have only recently begun to study the development of technical writing. Pollard and Redgrave's Short-Title Catalogue, 1475-1640 contains a number of English Renaissance technical books that reveal that Renaissance printers and authors were aware of the need for readability and visual access in technical reference and information books. An examination of these books shows evolving use of many contemporary page design techniques: partition, clearly worded headings, visual aids, enumeration and listing devices, and choice of font for emphasis.
Study of Efflorescence Produced on Ceramic Wicks by Masonry Mortars

Ceramic wicks (Efflorwicks) were partly embedded in cylinders of masonry mortars of various compositions, and the hardened mortars were alternately wetted and dried, which produced various amounts of efflorescence on the wicks. Portland cement in mortars contributed significantly to efflorescence. The alkaline material of the cementing substance of the mortars appeared to be an important source of the efflorescence.
Effects of feeding endophyte-infected fescue seed on reproductive traits of male mice divergently selected for resistance or susceptibility to fescue toxicosis.

Our objective was to determine whether consumption of endophyte-infected fescue seed affected male reproduction differently in a mouse line previously selected for susceptibility (S) to fescue toxicosis than in a line previously selected for fescue toxicosis resistance (R). For 8 weeks following weaning, 48 males per line were provided diets containing 50% of either endophyte-infected (E+) or endophyte-free (E−) fescue seed. Each male was then paired with a female for 1 week, with litter size and weight recorded from subsequent births. Males were then killed, testes and seminal vesicles were weighed, cauda epididymal sperm were collected and testis cross-sections were fixed. The E+ diet reduced litter size by 0.5 in mates of S males but increased it by 1.0 in mates of R males (line by diet interaction P=0.05). Testis traits were not affected by diet or the line by diet interaction. Sperm integrity was adversely affected by the E+ diet (P<0.01) but did not differ significantly between lines, nor were line by diet interactions important. In earlier work, the E+ diet reduced long-term reproduction by a larger amount in S- than in R-line mated pairs. Because the E+ diet had similar effects on reproductive traits in R and S males in the current experiment, we infer that the differential impact previously reported acted primarily through traits expressed in females.
FORD WHITMAN HARRIS'S ECONOMICAL LOT SIZE MODEL

Abstract Here we celebrate the centennial of Ford Whitman Harris's model for determining economical lot sizes, which was published in the A.W. Shaw Company's magazine Factory, The Magazine of Management in February 1913. The square-root formula derived by Harris has become one of the most cited and applied results in production and operations management. We examine the circumstances under which this result was derived, and explore the probable causes for the later obscurity of Harris's paper, which was forgotten for many years.
Direct Measurement of Internal Flow Velocities in a Star-Slot Model

This paper presents the results of a cold flow experiment to make direct measurements of the velocity distribution in a model of a solid rocket motor star grain propellant slot. The experimental procedure utilizes a multi-component laser Doppler velocimeter (LDV) and an apparatus for seeding the flow with aluminum particles to determine the velocity components at various discrete locations within the star slot. The test article used in this investigation was a one-tenth scale, cold flow model based on the geometry of the Space Shuttle solid rocket motor head-end section. The results obtained for the direct measurements of velocity are compared to velocities calculated from measured pressure distributions to data obtained from oil smear experiments and flow visualization videos, and to heat transfer calorimeter data.
Isolation, characterization, and transplantation of bone marrow-derived hepatocyte stem cells.

Recently it was shown that a population of cells in the bone marrow-expressing hematopoietic stem cell antigens could differentiate into hepatocytes. However, explicitly committed hepatocyte progenitors, which exhibit highly differentiated liver functions, immediately upon isolation, have not yet been isolated from bone marrow. After studying common antigens on blast-like cells in fetal and adult regenerating cholestatic rat livers and human regenerating and malignant livers, we hypothesized that beta-2-microglobulin-negative (beta(2)m(-)) cells might represent dedifferentiated hepatocytes and/or their progenitors. Utilizing a two-step magnetic bead cell-sorting procedure, we show that in bone marrow from rat and human, beta(2)m(-)/Thy-1(+) cells consistently express liver-specific genes and functions. After intraportal infusion into rat livers, bone marrow-derived hepatocyte stem cells (BDHSC) integrated with hepatic cell plates and differentiated into mature hepatocytes. In a culture system simulating liver regeneration and containing cholestatic serum, these cells differentiated into mature hepatocytes and metabolized ammonia into urea. This differentiation was dependent on a yet nondescript humoral signal existing in the cholestatic serum. Transmission electron microscopy and three-dimensional digital reconstruction confirmed hepatocyte ultrastructure of cultured BDHSC.
Rethinking about guessing attacks

Although various past efforts have been made to characterize and detect guessing attacks, there is no consensus on the definition of guessing attacks. Such a lack of generic definition makes it extremely difficult to evaluate the resilience of security protocols to guessing attacks.To overcome this hurdle, we seek a new definition in this paper to fully characterize the attacker's guessing capabilities (i.e., guessability). This provides a general framework to reason about guessing attacks in a symbolic setting, independent of specific intruder models. We show how the framework can be used to analyze both passive and active guessing attacks.
Cytoplasmic ribosomal RNA of hamster-mouse hybrid cells.

Abstract When hamster-mouse hybrid 13B was incubated for 11h with [ 3 H]uridine, followed by 20 h in medium without isotope and an excess of non-radioactive uridine, about 46 % of the labeled cytoplasmic rRNA was of hamster type. If 13B was incubated for 4 h with [ 3 H]uridine, about 81 % of the radioactive rRNA was of hamster type. In contrast, in hybrid 8A the hamster/mouse ratio of 3 H-labeled rRNA remained essentially the same between 4 and 53 h after addition of [ 3 H]uridine. Both in 13B and 8A the hamster/mouse ratio of cytoplasmic rRNA from polysomes was similar to that of non-polysomal ribosomes.
On understanding proton transfer to the biocatalytic [Fe―Fe]H sub-cluster in [Fe―Fe]H2ases: QM/MM MD simulations

Abstract Proton transfer to the [Fe―Fe] H sub-cluster in the Desulfovibrio desulfuricans (DdH) and Clostridium pasteurianum (CpI) [Fe―Fe] hydrogenases was investigated by a combination of first principles and empirical molecular dynamics simulations. Pathways that can be inferred from the X-ray crystal structures of DdH and CpI, i.e., (Glu159 → Ser198 → Glu156 → water460 → Cys178 → DTMA([Fe―Fe] H ) and (Glu282 → Ser319 → Glu279 → water612 → Cys299), respectively, were considered. Proton transfer from Cys178 to DTMA in the [Fe―Fe] H sub-cluster in DdH was readily observed in our results, specifically when [Fe―Fe] H was in the reduced state ([Fe I ―Fe I ]) or in the mixed valence state for the protonated distal iron Fe d ([Fe I ―Fe II ―H − ] H ). A concerted mechanism is proposed, where proton transfer in DdH from Glu159 to Glu156 via Ser198 and Glu156 to Cys178 via water460 readily occurred, as well as from Glu282 to Glu279 via Ser319 and Glu279 to Cys299 via water612 in CpI. The theoretical prediction of the proton transfer characteristics is consistent with the assumed biocatalytic mechanism of the [Fe―Fe] hydrogenases in which the proton binds at Fe d , providing confirmation that has not been explored so far. The computational results were qualitatively validated by the agreement with experimental hydrogen production activity data for mutated CpI enzymes, relative to the wild-type protein. Finally, the insight provided by the simulations, combined, in part, with experimental validation, are important for establishing an approach in future exploration of proton transfer to the active site in this class of enzymes, and possibly also for biomimetic analogs.
Radiation doses to ERCP patients are significantly lower with experienced endoscopists

Background Patients undergoing ERCP receive nontrivial doses of radiation, which may increase their risk of developing cancer, especially young patients. Radiation doses to patients during ERCP correlate closely with fluoroscopy time. Objective The aim of this study was to determine whether endoscopist experience is associated with fluoroscopy time. Design Retrospective analysis of a prospectively collected database. Setting Data from 69 providers from 6 countries. Patients 9,052 entries of patients undergoing ERCP. Main Outcome Measurements Percent difference in fluoroscopy time associated with endoscopist experience and fellow involvement. Results For procedure types that require less fluoroscopy time, compared with endoscopists who performed > 200 ERCPs in the preceding year, endoscopists who performed 200 ERCPs in the preceding year, endoscopists who performed Limitations Database used is a voluntary reporting system, which may not be generalizable. Data is self-reported and was not verified for accuracy. Conclusions Fluoroscopy time is shorter when ERCP is performed by endoscopists with more years of performing ERCP and a greater number of ERCPs in the preceding year. These findings may have important ramifications for radiation-induced cancer risk.
Travelling wave solutions of diffusive Lotka-Volterra equations

We establish the existence of travelling wave solutions for two reaction diffusion systems based on the Lotka-Volterra model for predator and prey interactions. For simplicity, we consider only 1 space dimension. The waves are of transition front type, analogous to the travelling wave solutions discussed by Fisher and Kolmogorov et al. for a scalar reaction diffusion equation. The waves discussed here are not necessarily monotone. For any speed c there is a travelling wave solution of transition front type. For one of the systems discussed here, there is a distinguished speed c* dividing the waves into two types, waves of speed c < c* being one type, waves of speed c ⩾ c* being of the other type. We present numerical evidence that for this system the wave of speed c* is stable, and that c* is an asymptotic speed of propagation in some sense. For the other system, waves of all speeds are in some sense stable. The proof of existence uses a shooting argument and a Lyapunov function. We also discuss some possible biological implications of the existence of these waves.
The Dynamic Clamp Induced Pacing in Single and Coupled Cells

The dynamic clamp is a method whereby an arbitrary current, a function of time and membrane potential, is applied to a preparation to create hybrid circuits of real and virtual cells.We tested the ability to add electronically two membrane currents, the inward rectifier current (IK1) and the pacemaker current (If), which contribute to myocyte pacemaker activity. Injection of computer-simulated If in addition to IK1 under current-clamp conditions into an isolated canine ventricle myocyte and/or HEK293 cell stably expressing SCN5a initiated pacing activity. The pacing rate and action-potential (AP) duration were modified by changing If and IK1 amplitudes.We also examined whether coupling of a source cell with If and IK1 to another cell creates a two-cell pacing unit. HEK293 cells were co-cultured either with HEK293/SCN5a cells or acutely isolated adult canine ventricular myocytes. Injecting If and IK1 currents into one cell of a pair generated sustained pacing in a coupled ventricular myocyte or HEK293/SCN5a cell once a critical level of electrical cell-cell coupling between the If+IK1 source cell and the neighboring cell was exceeded. Application of the gap-junction blocker carbenoxolone stopped pacing activity in the coupled myocyte and/or HEK293/SCN5a cell; washout of carbenoxolone restored activity. Hence, the currents from a If+IK1-injected cell delivered to a cardiac myocyte (or another cell type) via gap junctions can generate spontaneous APs allowing the cell pair to function as a pacemaker unit.Pacing activity also was investigated artificially by electrically connecting two separate single cells via a dual-cell dynamic clamp, permitting varying of coupling conductance while modulating If and/or IK1 within either or both of the two coupled cells.These results demonstrate that the dynamic clamp can be used to study the determinants of pacemaker activity.Supported by HL28958, GM88180, GM088181.
Biological and metabolic response in STS-135 space-flown mouse skin.

There is evidence that space flight condition-induced biological damage is associated with increased oxidative stress and extracellular matrix (ECM) remodeling. To explore possible mechanisms, changes in gene expression profiles implicated in oxidative stress and in ECM remodeling in mouse skin were examined after space flight. The metabolic effects of space flight in skin tissues were also characterized. Space Shuttle Atlantis (STS-135) was launched at the Kennedy Space Center on a 13-day mission. Female C57BL/6 mice were flown in the STS-135 using animal enclosure modules (AEMs). Within 3-5 h after landing, the mice were euthanized and skin samples were harvested for gene array analysis and metabolic biochemical assays. Many genes responsible for regulating production and metabolism of reactive oxygen species (ROS) were significantly (p 1.5 compared to AEM control. For ECM profile, several genes encoding matrix and metalloproteinases involved in ECM remodeling were significantly up-/down-regulated following space flight. To characterize the metabolic effects of space flight, global biochemical profiles were evaluated. Of 332 named biochemicals, 19 differed significantly (p < 0.05) between space flight skin samples and AEM ground controls, with 12 up-regulated and 7 down-regulated including altered amino acid, carbohydrate metabolism, cell signaling, and transmethylation pathways. Collectively, the data demonstrated that space flight condition leads to a shift in biological and metabolic homeostasis as the consequence of increased regulation in cellular antioxidants, ROS production, and tissue remodeling. This indicates that astronauts may be at increased risk for pathophysiologic damage or carcinogenesis in cutaneous tissue.
BACH1 is a DNA repair protein supporting BRCA1 damage response

The link between defects in BRCA1 and breast cancer development may be best understood by deciphering the role of associated proteins. BRCA1 associated C-terminal helicase (BACH1) interacts directly with the BRCA1 C-terminal BRCT repeats, which are important for BRCA1 DNA repair and are mutated in the majority of BRCA1 familial cancers. Thus, BACH1 is a likely candidate for mediating BRCA1 DNA repair and tumor suppression functions. Although previous evidence using overexpression of a dominant negative BACH1 has suggested that BACH1 is involved in BRCA1-DNA repair function, our results using BACH1 deficient cells provide direct evidence for involvement of BACH1 in DNA repair as well as for localizing BRCA1. Following DNA damage BACH1 is modified by phosphorylation, displays a BRCA1-like nuclear foci pattern and colocalizes with γ-H2AX. Given that the BACH1/BRCA1 complex is unaltered by DNA damage and the intensity of BRCA1 foci is diminished in BACH1 deficient cells, BACH1 may serve to not only facilitate DNA repair, but also maintain BRCA1 in DNA damage foci.
Lateral and z-axial resolution in laser optoacoustic imaging with ultrasonic transducers

Our studies are directed towards the development of a pulsed laser based optoacoustic technique to visualize absorbed light distribution in irradiated tissues. Optoacoustic technique utilizes the time-resolved detection of laser-induced stress transients to visualize absorbed laser fluence distribution in opaque and heterogeneous tissues. The acoustic signal induced under confined stress conditions of irradiation by an Nd:YAG laser pulse displays Z-axial light distribution and may be used for imaging the tissue layers where a temperature-rise of about 1 degree(s)C is achieved. Scanning of the acoustic transducer along the tissue surface line by line until entire surface of interest is tested, permits reconstruction of a 3D optoacoustic image of the irradiated tissue. Z-axial resolution of optoacoustic imaging is defined as a product of the temporal resolution of piezoelectric transducer and the speed of sound in tissues. Lateral (radial) resolution of optoacoustic images is a funtion of piezoelectric detector diameter, the diameter of laser-induced acoustic wave, and a depth of optoacoustic probing (acoustic diffraction factor). The role of various parameters, such as tissue optical properties, tissue thickness, laser beam diameter, and diameter of piezoelectric element, were evaluated for imaging resolution in lateral direction. The results of our studies demonstrated that a broad- band acoustic transducer may become a useful tool for in vivo diagnostic imaging and feed- back information during clinical laser procedures. First in vivo measurements were performed and found to be in agreement with tissue histology. This study is a very first step in the basic design of optoacoustic tomographic technology for light absorbing tissues.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
DNA electrochemical biosensors for environmental monitoring. A review

Abstract DNA sensing protocols, based on different modes of nucleic acid interaction, possess an enormous potential for environmental monitoring. This review describes recent efforts aimed at coupling nucleic acid recognition layers with electrochemical transducers. It considers DNA hybridization sensors for sequences related to microbial or viral pathogens, and DNA-modified carbon electrodes for monitoring low molecular weight priority pollutants interacting with the surfaceconfined DNA. Carbon strip or paste electrode transducers, supporting the DNA recognition layer, are used with a highly sensitive chronopotentiometric transduction of the DNA analyte recognition event. Factors influencing the performance of these new environmental biosensors are discussed, and their environmental utility is illustrated. While the use of DNA biosensors is at a very early stage, these and similar developments are expected to have a profound effect on environmental analysis.
A Multistate Capture–Recapture Modeling Strategy to Separate True Survival from Permanent Emigration for a Passive Integrated Transponder Tagged Population of Stream Fish

Abstract Robust estimates of survival and movement are important for informing the recovery of fish populations as well as for the study of life history, behavior, and population ecology. We present a multistate capture–recapture model that allows separate and simultaneous estimation of true survival and fidelity to the study reach in the presence of imperfect recapture and detection probabilities. The key study design element that permitted this separation was the use of a multiple-antenna array to detect passive integrated transponder (PIT) tagged individuals as they emigrated from the study area. The modeling approach incorporated live recapture data during discrete sampling occasions with observational data on antenna detections of tagged individuals as they exited the study area between sampling occasions. The multistate emigration model was applied to empirical data from a stream-dwelling, PIT-tagged cohort of Atlantic salmon Salmo salar for which emigration was continuously monitored by using a pai...
Effects of analytic variations in creatinine measurements on the classification of renal disease using estimated glomerular filtration rate (eGFR).

BACKGROUND This study uses the Isotope Dilution Mass Spectrometer-Traceable Modification of Diet in Renal Disease (MDRD) equation to evaluate the effects of analytic variation of serum creatinine on estimated glomerular filtration rate (eGFR). The equation was inverted to provide critical creatinine levels corresponding to eGFRs equal to 15, 30, and 60 mL/min/1.73 m(2). METHODS eGFRs were calculated for two populations of patients representing clinic outpatients and hospitalized inpatients. Simulation studies evaluated the effects of analytic bias for these populations. Differences between creatinine tests ordered on consecutive blood draws were analyzed for within-subject eGFR variation. Finally, propagation of error techniques established the relationship between creatinine imprecision and eGFR imprecision. RESULTS eGFR of 60 mL/min/1.73 m(2) corresponds to creatinine levels of 80-156 micromol/L. A 20-micromol/L negative shift of creatinine approximately doubles the percentage of patients classified in various stages of decreased renal function, whereas a positive shift approximately halves the percentage. The central 95% limits for within-subject variation of eGFR are 33% for outpatients, 38% for inpatients and 40% across the groups. eGFR imprecision is approximately 15%-20% higher than creatinine imprecision. CONCLUSIONS Small analytic changes in serum creatinine create major shifts in the distributions of eGFR, which can cause large differences in the classification of patients. The within-subject variations in eGFR over time, especially between hospital and clinic measurements, can be large. Therefore, tight control of laboratory analysis is important.
Clinicopathologic analysis of HER-2/neu immunoexpression among various histologic subtypes and grades of osteosarcoma

Overexpression of the HER-2/neu oncogene appears to have prognostic significance in breast cancer. Recently, some have reported a relationship between increased immunohistochemical expression in osteosarcoma and poor clinical outcome. Despite limited data, a pilot trial of Herceptin, which targets the oncogene product, has been initiated for the therapy of some metastatic osteosarcomas (CCG-P9852). Archival formalin-fixed, paraffin-embedded tissue obtained from 41 patients diagnosed with osteosarcoma was examined immunohistochemically by 2 antibodies against the HER-2/neu oncogene product: CB-11 (monoclonal, 1/100) and Oncor (polyclonal, 1/200). All but one tumor (case of recurrent dedifferentiated parosteal osteosarcoma) represented primary tumor samples; when applicable, only prechemotherapy biopsies were analyzed. The study sample included the full spectrum of histologic subtypes and grades of osteosarcoma (25 conventional high grade; 3 telangiectatic; 1 small cell; 6 parosteal; 1 periosteal; and 5 low-grade intramedullary). A case of metastatic breast cancer with known overexpression of the HER-2/neu oncogene served as the positive control. Complete membranous positivity, considered prognostically significant in breast cancer, was not seen in any of our osteosarcoma cases. At least focal cytoplasmic positivity was documented in 40 (98%) tumors using the CB11 antibody and in 34 (83%) using the Oncor antibody. The intensity of the cytoplasmic staining (0, 1–3+) did not correlate with histologic subtype/grade, response to chemotherapy (<90% versus ≥90% necrosis), metastasis, or survival. Immunohistochemical overexpression of the HER-2/neu oncogene, defined as complete membranous positivity, is not present in our series of osteosarcomas. Cytoplasmic positivity is observed in most osteosarcomas, irrespective of histologic subtype/grade, and is not associated with response to preoperative chemotherapy or disease progression.