cssi/SciSciGPT-SciSciNet huggingface dataset:
Online News Coverage of COVID-19 Long Haul Symptoms.

A number of the people who have recovered from the acute effects of COVID-19 are facing long term sequelae from the infection. As the COVID-19 pandemic is still evolving, so is knowledge of the long-term effects of the virus on patients who still experience symptoms. Clearly, news media play a crucial role in distributing information and this distribution of information can, in turn, influence the actions of the public. The purpose of this study was to describe the content of news coverage of COVID-19 long haul symptoms currently posted on the internet. This study utilized Google News, a news aggregator service, and included the first 100 English language pieces of news. Video content and news article content were coded in depth for information on COVID-19 long haul symptoms. A total of 41% of news reports mentioned the length of time that the COVID-19 related symptoms persist. The length of time was reported to range from 1 month to more than 1 year. The symptom most commonly mentioned was tiredness or fatigue (74%), followed by difficulty breathing or shortness of breath (62 cases; 62%), and difficulty thinking or concentrating (50 cases; 50%). Other symptoms were mentioned less frequently. There were no statistically significant differences in any of the content including having video, written news reports, or both video and written news reports by source of the news reports based on consumer, professional, or television or internet-based news (p = .14). More complete coverage by online news media of the long-term effects of COVID-19 enhances public awareness of the post-acute syndromes, augments health providers' awareness of the range of chronic COVID-19 effects and the possibility of a second infection, increases the probability of patients' seeking and obtaining the proper care for their symptoms, and contributes to preventive actions for enhancing public health.
An economic and environmental assessment model for microchannel device manufacturing: part 2 – Application

Microchannel heat exchangers provide large surface area to volume ratios and accelerated heat transfer, leading to compact form factors for application in portable and distributed thermal management and waste heat recovery. The application of microchannel heat exchangers in industry has been slowed by high manufacturing costs. Therefore, efforts are being made to find new ways to manufacture these components. This research investigates the application of a process-based cost and environmental impact assessment model to the evaluation of manufacturing alternatives to produce microchannel heat exchangers. A bottom-up process-based cost modeling method is used to estimate the cost of manufacturing a microchannel heat recovery unit (HRU). Cradle-to-gate life cycle assessment is simultaneously applied to evaluate environmental impact. Both sets of calculations extend from a single common set of data consisting of production and device geometry parameters. An analysis is demonstrated for different manufacturing alternatives for producing the HRU. Among the six manufacturing plans evaluated, the combination of laser cutting and diffusion brazing was found to have the lowest cost but the highest environmental impact, while the combination of photochemical machining and laser welding was found to have the lowest environmental impact with a comparatively high cost. Among the cost categories defined, consumables, capital tooling, and utilities were found to be the primary drivers for cost and environmental impact suggesting these as areas to concentrate in future process capability assessments and technology development.
Validating Landsat-based landscape metrics with fine-grained land cover data

Abstract Context Moderate-grained data may not always represent landscape structure in adequate detail which could cause misleading results. Certain metrics have been shown to be predictable with changes in scale; however, no studies have verified such predictions using independent fine-grained data. Objectives Our objective was to use independently derived land cover datasets to assess relationships between metrics based on fine- and moderate-grained data for a range of analysis extents. We focus on metrics that previous literature has shown to have predictable relationships across scales. Methods The study area was located in eastern Connecticut. We compared a 1 m land cover dataset to a 30 m resampled dataset, derived from the 1 m data, as well as two Landsat-based datasets. We examined 11 metrics which included cover areas and patch metrics. Metrics were analyzed using analysis extents ranging from 100 to 1400 m in radius. Results The resampled data had very strong linear relationships to the 1 m data, from which it was derived, for all metrics regardless of the analysis extent size. Landsat-based data had strong correlations for most cover area metrics but had little or no correlation for patch metrics. Increasing analysis areas improved correlations. Conclusions Relationships between coarse- and fine-grained data tend to be much weaker when comparing independent land cover datasets. Thus, trends across scales that are found by resampling land cover are likely to be unsuitable for predicting the effects of finer-scale elements in the landscape. Nevertheless, coarser data shows promise in predicting fine-grained for cover area metrics provided the analysis area used is sufficiently large.
A novel model of accelerated intimal hyperplasia in the pig iliac artery

There is no good animal model of large artery injury-induced intimal hyperplasia (IH). Those available are reproducible, providing only a few layers of proliferating cells or have the disadvantage of the presence of a metallic stent that complicates histology evaluation. This study was designed to develop a new, simple model of accelerated IH based on balloon injury in conjunction with disruption of the Internal Elastic Lamina (IEL) in pig external iliac arteries. Iliac artery injury (n = 24) was performed in 12 Yorkshire pigs divided in two groups: Group I (n = 10), overdistention injury induced by an oversized non-compliant balloon; Group II (n = 14), arterial wall disruption by pulling back an isometric cutting balloon (CB) followed by stretching with a compliant Fogarty Balloon (FB). At two weeks, arteries were processed for morphometric analysis and immunohistochemistry (IHC) for smooth muscle cells (SMC) and proliferating cell nuclear antigen (PCNA). When comparing the two groups, at 2 weeks, arteries of group II had a higher incidence of IH (100%vs. 50%, P = 0.0059), increased intimal areas (2.54 ± 0.33 mm(2) vs. 0.93 ± 0.36 mm(2) , P = 0.004), increased intimal area/Media area ratios (0.95 ± 0.1 vs. 0.28 ± 0.05; P < 0.0001) and decreased lumen areas (6.24 ± 0.44 vs. 9.48 ± 1.56, P = 0.026). No thrombosis was noticed in Group II. Neointima was composed by proliferating SMC located with the highest concentration in the area of IEL disruption (IHC). Arterial injury by pulling back CB and FB induces significant IH in pig iliac arteries by two weeks without thrombosis. This model is superior to the classical overdistention non-compliant model and should be useful and cost-effective for preclinical testing of procedures designed to inhibit IH in large peripheral arteries.
The Hubble Space Telescope

The Hubble Space Telescope was launched from the Kennedy Space Center on April 24, 1990. Its initial check-out indicates that all sub-systems of the satellite are working very well, with two key exceptions: The line-of-sight pointing is subject to occasional jitter apparently induced by thermal stresses in the solar arrays; this is expected to be overcome. The telescope mirrors are found to contain approximately 0.5 wave rms of spherical aberration which cannot be overcome by any controls on board the satellite. This defect will limit the scientific performance of the telescope in the short run. However, the aberration can be fully corrected in the optical designs of future replacement instruments, and the delivery schedules of these instruments are being accelerated.
Catecholaminergic horizontal and amacrine cells in the ferret retina

Enzymes involved in the synthesis of catecholamines were detected in amacrine and what appeared to be a specific class of horizontal cells in the ferret retina. Antisera directed against the enzymes tyrosine hydroxylase (TH), which converts tyrosine to DOPA, and phenylethanolamine N-methyl-transferase (PNMT), which converts norepinephrine to epinephrine, were used with conventional immunohistochemical techniques. A population of perikarya located at the outer margin of the inner nuclear layer (INL) exhibited TH-like immunoreactivity. The cell bodies were 9–12 micron in diameter and gave rise to stout dendrites that tapered rapidly after emergence from the somata. The processes formed a planar array in the inner half of the outer plexiform layer (OPL) slightly external to the cells of origin. We could not detect any inwardly directed processes. A population of PNMT-positive cells was also observed in the outer tier of cells in the INL. These cells were very similar to those exhibiting TH immunoreactivity. An apparent difference between the 2 populations was that there were areas of intense, somewhat punctate PNMT immunoreactivity in the outer OPL. These were not observed in the TH- stained sections. Examination of horizontal sections showed that each TH-positive cell body gave rise to 4–5 major dendrites that branched to form a roughly circular dendritic field. In the periphery of the retina, an individual cell's dendrites encompassed an area up to 170 micron in diameter. The dendritic fields of cells near the center of the retina were substantially smaller.
Characterizing and modeling the deformation of AA5182 for hot blank - Cold die (HB-CD) stamping

Though warm and hot sheet forming operations enhance the limited formability of aluminium alloys, the high cost and low production rates make them unfit for the demanding automotive sector. A non-isothermal stamping approach, referred to as hot blank — cold die (HB-CD), promises a fast/economic alternative while overcoming the limited formability issues of the material. This, however, necessitates characterizing and modeling the complex material behavior over a wide range of temperatures and strain rates, which is the prime focus of this work. Detailed mechanical testing, aided by digital image correlation (DIC), is carried out on an automotive-grade 5182 aluminium alloy sheet. A phenomenological model is developed and is shown to successfully capture the isothermal behavior of the material over the full temperature/strain rate range for HB-CD stamping.
Online prevention of postpartum depression for Spanish- and English-speaking pregnant women: A pilot randomized controlled trial

Abstract Background Postpartum depression (PPD) is a maternal mental health problem that affects women from all regions of the world. Unfortunately, even in developed countries, half of the cases go undetected and, consequently, untreated. Individuals from low and middle income countries trend toward underutilization of mental health services, partly due to the limited number of available psychological resources. The primary aims of this pilot randomized controlled trial were to adapt to the Internet using the Mothers and Babies Course/Curso Mamas y Bebes, a prevention of PPD intervention, to describe the characteristics of the pregnant women who engaged in the intervention site, and to obtain preliminary data on the efficacy of the Internet intervention to reduce the risk of PPD. Methods Pregnant women, 18 years or older who were interested in using the site for themselves were recruited and randomly assigned to a fully-automated self-help Internet intervention or to an information-only control condition. Randomized participants were invited to complete monthly depression assessments up to six months postpartum. To examine the prevention effects of the Internet intervention, pregnant women who did not meet current criteria for a major depressive episode, who engaged with the study website, and who provided depression data during the postpartum follow-up period were included in the study analyses. Results Participants were 111 predominantly Spanish-speaking (82.9%) and Latino/Hispanic (71.3%) pregnant women residing in 23 countries worldwide. The effect of the prevention intervention condition failed to reach significance at the a priori alpha-level. However, the observed coefficient trended in the hypothesized direction (b = − 0.514, χ2 (1) = 3.43, p = .061; HR = 0.598). The benefits of receiving the e-MB Internet intervention were greater for pregnant women reporting high (vs. low) levels of prenatal depression symptoms (b = − 0.605, χ2 (1) = 5.20, p = .023). Conclusions This study provides preliminary evidence that Internet interventions are a promising method toward expanding the reach of psychological resources to perinatal women at-risk for PPD.
Integrated soft sensors and elastomeric actuators for tactile machines with kinesthetic sense

Abstract Human skin contains highly specialized deformation receptors that allow us to intuitively and effortlessly interpret our surroundings. These sensors help us to localize touch and determine the degree of contact pressure. In addition, the innate understanding of our own body posture is also due to these mechanoreceptors. This work demonstrates a synthetic sensory–motor analog that can be 3D printed, using direct ink writing (DIW) onto soft, fluidic elastomer actuators (FEAs). This 3D printing technique uses two inks–one that is an ionically conductive hydrogel and another that is an electrically insulating silicone–which is then patterned and photopolymerized into stretchable capacitive sensors. In this paper, these sensors are used to enable tactile sensing and kinesthetic feedback in a pneumatically actuated haptic device. This capacitive skin enabled the device to detect a compressive force from a finger press of ∼ 2 N, and an internal pressurization of as low as ∼ 10 kPa.
Three Views of Emotion Regulation and Health

Humans are self-regulating dynamic systems. Health represents an overall state of the system and emotions play a central role. Understanding emotion, self-regulation, and health is complicated by the fact that emotion regulation can be conceptualized in at least three ways: (i) emotions can be seen as one component of a general self-regulatory system that modifies our overall responses in the service of goal-directed behavior, (ii) the emotion system itself operates through internal feedback processes that help to keep our physical and psychological systems in balance and within an optimal range of functioning, and (iii) emotions can become the target of self-regulatory efforts. Each of these views of emotion regulation emphasizes somewhat different connections to health. This review considers the meanings of emotion, regulation, and health and presents research relevant to each of the three views of emotion regulation.
In vitro skin penetration of acetyl hexapeptide-8 from a cosmetic formulation

There is a concern that peptides in cosmetic creams marketed as anti-aging/anti-wrinkle may penetrate into the deep layers of the skin and potentially stimulate biological activity. Claims for one cosmetic peptide, acetyl hexapeptide-8 (Ac-EEMQRR-amide), suggest interference with neuromuscular signaling as its anti-wrinkle mechanism of action. Therefore, the skin penetration of commercially available Ac-EEMQRR-amide from a cosmetic formulation (oil-in-water (O/W) emulsion) was determined in hairless guinea pig (HGP) and human cadaver skin assembled into in vitro diffusion cells. An O/W emulsion containing 10% Ac-EEMQRR-amide was applied to skin at a dose of 2 mg/cm(2). After a 24-h exposure, the skin surface was washed to remove unabsorbed peptide. Skin disks were tape stripped to determine the amount of peptide in the stratum corneum. Removal of the stratum corneum layers was verified by confocal microscopy. The epidermis was heat separated from the dermis and each skin fraction was homogenized. Skin penetration of Ac-EEMQRR-amide was measured in skin layers by hydrophilic interaction liquid chromatography with tandem mass spectrometry using electrospray ionization (ESI) in the positive mode. Stable isotopically labeled hexapeptides were used as internal standards for the quantitation of native hexapeptides to correct for matrix effects associated with ESI. The results (percent of applied dose) showed that the majority of the Ac-EEMQRR-amide was washed from the surface of both HGP and human skin. Ac-EEMQRR-amide that penetrated skin remained mostly in the stratum corneum of HGP (0.54%) and human (0.22%) with the peptide levels decreasing as each layer was removed by tape stripping. Total Ac-EEMQRR-amide found in the epidermis of HGP and human skin was similar at 0.01%. No peptide was detected in the dermis or buffer collected underneath the skin for both human and HGP. There was no hexapeptide metabolite (H2N-EEMQRR-amide) detected in any layers of HGP skin, human skin or buffer collected underneath the skin. This skin penetration data will be useful for evaluating the safety of cosmetic products containing small peptide cosmetic ingredients.
The skeptical critic

This essay responds to a previously published WJSC article by Medhurst in suggesting that the author's personal involvement in the situation led him to abandon the most fundamental office of the critic—he was simply not being critical.
The potential of forgiveness as a response for coping with negative peer experiences

Coping strategies employed by adolescents in response to negative peer experiences are related to their adjustment. This study examines the potential of forgiveness as a coping response for negative peer experiences in early adolescence. Participants were 616 6th through 8th grade students at a middle school (46% girls) who completed self-report measures of bullying and victimization experiences, general coping strategies in response to bullying, social anxiety, self-esteem, and a measure of forgiveness to a self-identified experience of being bullied or hurt by a peer. Forgiveness was positively associated with conflict resolution, advice and support seeking strategies, and negatively associated with revenge seeking. Forgiveness was also positively associated with concurrent self-esteem and negatively associated with social anxiety. Further, forgiveness was related to social anxiety and self-esteem after accounting for bullying behavior and victimization experiences, general coping responses, and gender. Developmental considerations of forgiveness and implications for this response are considered.
Incomplete Excluder Limb Graft Deployment: Cause and Solution

The Excluder stent graft (W.L. Gore and Associates, Flagstaff, AZ) is one of the most frequently used devices for endovascular abdominal aortic aneurysm repair and offers the advantage of a simple and reliable deployment mechanism. We report an unexpected complication during deployment of an Excluder limb graft; the “rip cord” deployment system broke during pulling, most probably because of interference with a previously placed common iliac artery stent, thereby resulting in incomplete graft deployment. This report notes that problems may rarely arise when deploying an Excluder limb graft within already stented iliac arteries and provides technical considerations to manage such events successfully.
Medication Adherence in Patients Who Have Heart Failure: a Review of the Literature

Data indicate that nonadherence plays a major role in preventable rehospitalizations. The first step to improving adherence is determining the affecting factor. This article critically reviews the literature on factors affecting medication adherence in heart failure patients. Findings about effects of age, gender, race, and living status on adherence are quite inconsistent. Patients who believe taking medications is beneficial or who have no side effects are more adherent, as are those highly motivated to improve their well-being. Forgetfulness, social support, and patient-provider relationship are related to adherence. Providers seeking to increase adherence must consider patients' expectations for their health, their environment, their barriers to following prescribed regimen, and their understanding of their condition and how it relates to medication taking.
Encoding and the Durability of Episodic Memory: A Functional Magnetic Resonance Imaging Study

Memories vary in their durability even when encoding conditions apparently remain constant. We investigated whether, under these circumstances, memory durability is nonetheless associated with variation in the neural activity elicited during encoding. Event-related functional magnetic resonance imaging data were acquired while volunteers semantically classified visually presented words. Using the "remember/know" procedure, memory for one-half of the words was tested after 30 min and for the remaining half after 48 h. In several regions, including left hippocampus and left dorsal inferior frontal gyrus (IFG), activity at encoding differed depending on whether items were later recollected regardless of study-test delay. Delay-selective effects were also evident, however. Recollection after 48 h was associated with enhanced activity in bilateral ventral IFG, whereas recollection after 30 min was associated with greater fusiform activity. Thus, there is a relationship between the neural activity elicited by an event as it is encoded and the durability of the resulting memory representation.
Illinois High-Speed Rail Four-Quadrant Gate Reliability Assessment

The United States Department of Transportation’s (USDOT) Research and Innovative Technology Administration’s John A. Volpe National Transportation Systems Center (Volpe Center), under the direction of the USDOT Federal Railroad Administration (FRA) Office of Research and Development (ORD), conducted a reliability analysis of the four-quadrant gate/vehicle detection equipment installed on the potential high-speed rail (HSR) corridor between Chicago and St Louis. A total of 69 highway-rail grade crossings on a 121-mile (195 km) segment of the 280-mile corridor were equipped with four-quadrant gates and inductive loop vehicle detection technology. This segment, between Mazonia and Springfield Illinois, may eventually carry passenger trains at speeds up to 110 mph (177 km/h), including at many of the highway-rail grade crossings. The analysis was based on maintenance records obtained from the Union Pacific Railroad (UPRR), the owner and operator of the rail line. The results were used to assess the impact of the equipment reliability on the proposed HSR timetable. The Volpe Center study showed that the total average delay to the five scheduled daily high-speed passenger roundtrips was an estimated 10.5 minutes, or approximately one minute per train. Overall, extensive analysis of the trouble ticket data showed that the four-quadrant gate and vehicle detection equipment had a minimal direct impact on the frequency and duration of grade crossing malfunctions.© 2010 ASME
Efficacy and adverse effects of drugs used to treat adult cystic fibrosis

Introduction: Cystic fibrosis (CF) is an autosomal recessive disease and is the most commonly seen monogenetic disease in Caucasians. The disease has various manifestations resulting from the abnormal thick secretions, most common being chronic lung infection and airway obstruction. Many new promising drugs have appeared on the horizon over the years. This review here is an attempt to bring together the various treatments being used to prolong and enhance the quality of life of CF patients.Areas covered: A literature review of published as well as ongoing clinical trials, meta-analysis and systematic reviews regarding the drugs used in CF management was carried out using PubMed and Ovid databases.Expert opinion: New concepts have been formed and some positive results in this direction have already led to the approval of cystic fibrosis transmembrane conductance regulator potentiator drug. Gene therapy and stem cell therapy are under development. The current therapies such as dornase alfa and pancreatic en...
Phase I clinical trial of a 3-day divided dose schedule of ifosfamide (NSC 109724)

Abstract Twenty patients with unresectable cancer received ifosfamide as a 30 min i.v. infusion daily for 3 days. Dose limiting toxicity was seen in 6 patients and was genitourinary in 4 , hematologic in 1 , and CNS in 1 . Leukopenia was seen in 10 patients, and microscopic hematuria in all except 4 patients. Divided dose administration enabled a larger total dose of drug to be given per treatment course, but did not change the genitourinary nature of the dose limiting toxicity when compared with a high single dose regimen. Total urinary alkylating activity was slightly less following the divided dose administration. For the 3 day divided dose schedule, a daily dose of 2400 mg/m 2 appears to be the maximally tolerated dose.
Mixing steam with soil increases heating rate compared to steam applied to still soil

Abstract Before development of a new field steam applicator, this study was done to determine whether the application of steam from a source that is mixed with the soil is more efficient than application from a source that does not mix the soil, to aid in the machines' design. A cement mixer, either in motion or still, was used to contain soil or sand as it was treated with steam, and the heat profile of the soil or sand after the steam application was measured. The results indicated that the soil and sand were heated more thoroughly and rapidly from surface to deeper layers when steam was mixed compared to steam applied to the surface of still soil or sand.
Pilot study of noninvasive detection of venous occlusions from central venous access devices in children treated for acute lymphoblastic leukemia

Background. Survivors of childhood acute lymphocytic leukemia (ALL) are at risk of venous occlusion induced by central venous access devices (CVADs). A sensitive, noninvasive screening technique to identify the magnitude of this problem is needed. Ultrasound (US) cannot always adequately image the innominate veins or the superior vena cava. Magnetic resonance angiography (MRA) can be noninvasive and may be useful for screening these patients. Objective. We examined the suitability of US and MRA to identify venous occlusion. Materials and methods. We used MRA and ultrasound to examine 11 pediatric patients previously treated for ALL. CVADs had been in place a median of 2.5 years (range, 0.4–2.8 years) and removed a median of 2.1 years (range, 0.6–2.9 years) previously. We also performed 2D time-of-flight magnetic resonance angiography (TOF MRA) on two healthy young adult women with no history of venous abnormality or CVAD use. Results. MRA suggested central venous abnormalities in 8 of the 11 ALL survivors and in both healthy control subjects. US results were negative in all 11 survivors. Conclusion. Further investigation is warranted to develop a sensitive and specific noninvasive method for identifying venous occlusion caused by prior CVAD use. Such a method would allow prospective studies of this complication in pediatric ALL survivors.
Reactions of OH+ and H2O+ ions with some diatomic and simple polyatomic molecules

Abstract The rate constants and product distributions of the reactions of OH + and H 2 O + with some diatomic and simple polyatomic molecules were studied by ion cyclotron resonance (ICR) mass spectrometric techniques. Reaction rates with CO, NO, O 2 , N 2 , CO 2 , H 2 S, N 2 O, H 2 CO, CH 4 and CD 4 were measured. Charge transfer and proton transfer were generally observed in cases for which the reaction channel is exothermic, but processes involving rearrangement were not found.
A novel approach to prevent 9/11/2001 events using artificial neural networks and decision support systems

The ability to detect objects from image sequences and estimate their trajectory is useful in many applications like satellite tracking, missile guidance and interception. This paper proposes a reliable and an effective application for preventing loss of lives on event of airline crashes similar to the one on 9/11/2001. This contribution uses the MixeD algorithm for object detection, velocity estimation and the trajectory of the moving object in the spatiotemporal domain. The case study of the 9/11 event shows that the proposed method could have helped the authorities alert the people inside the towers far in advance about the hostile situation and could have saved a few more lives.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Effects of trypsin on secretion stimulated by micromolar Ca2+ and phorbol ester in digitonin-permeabilized adrenal chromaffin cells.

1. Catecholamine secretion from digitonin-treated chromaffin cells is stimulated directly by micromolar Ca2+ in the medium. The permeabilized cells are leaky to proteins. 2. In this study trypsin (30–50µg/ml) added to cells after digitonin treatment completely inhibited subsequent Ca2+-dependent catecholamine secretion. The same concentrations of trypsin did not inhibit secretion from permeabilized cells if trypsin was present only prior to cell permeabilization. 3. The data indicate that trypsin entered digitonin-treated chromaffin cells which were capable of undergoing secretion and that an intracellular, trypsinsensitive protein is involved in secretion. Chymotrypsin was less potent but had effects similar to those of trypsin. 4. The enhancement of Ca2+-dependent secretion from permeabilized chromaffin cells induced by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) was inhibited by trypsin added simultaneously with Ca2+ to permeabilized cells at concentrations (3–10µg/ml) which had little or no effect on Ca2+-dependent secretion from cells untreated with TPA. Ca2+-dependent secretion in TPA-treated cells was reduced by trypsin only to the level that would have occurred in cells not treated with TPA. Trypsin reduced the large TPA-induced increment of membrane-bound protein kinase C. 5. The data indicate that Ca2+-dependent secretion in the absence of TPA does not require aTPA-like effect of Ca2+ to activate protein kinase C. Protein kinase C activation by TPA probably enhances Ca2+-dependent secretion by modulating the normal Ca2+-dependent pathway or by activating another Ca2+-dependent pathway which functions in parallel to the normal pathway.
Distance-Independent Charge Recombination Kinetics in Cytochrome c–Cytochrome c Peroxidase Complexes: Compensating Changes in the Electronic Coupling and Reorganization Energies

Charge recombination rate constants vary no more than 3-fold for interprotein ET in the Zn-substituted wild type (WT) cytochrome c peroxidase (CcP):cytochrome c (Cc) complex and in complexes with four mutants of the Cc protein (i.e., F82S, F82W, F82Y, and F82I), despite large differences in the ET distance. Theoretical analysis indicates that charge recombination for all complexes involves a combination of tunneling and hopping via Trp191. For three of the five structures (WT and F82S(W)), the protein favors hopping more than that in the other two structures that have longer heme → ZnP distances (F82Y(I)). Experimentally observed biexponential ET kinetics is explained by the complex locking in alternative coupling pathways, where the acceptor hole state is either primarily localized on ZnP (slow phase) or on Trp191 (fast phase). The large conformational differences between the CcP:Cc interface for the F82Y(I) mutants compared to that the WT and F82S(W) complexes are predicted to change the reorganization ...
Saline water conversion by carrier gas distillation

Abstract A method is described for saline water conversion using carrier gas distillation. Experiments show that the water produced is of high purity. The amount of carrier gas required, and the possible use of hot gases from existing industrial processes, is discussed.
ERK-Mediated Decoding of Calcium Oscillations in Pancreatic Beta Cells

Calcium oscillations are thought to underlie pulsatility of insulin secretion from pancreatic beta-cells, which is necessary for maintaining glucose homeostasis. However, it is still unclear how this calcium signal is ‘decoded’ by other signaling molecules such as protein kinases to modulate functional responses in a context-dependent manner. In this study, we investigated crosstalk between calcium and ERK signaling pathways using FRET-based ERK biosensor, EKAR, and RFP-based calcium biosensor, RCaMP, in live MIN6 pancreatic beta-cells.We observed that different physiological stimuli elicit different dynamics of ERK activity potentially affecting cell function. Amino acid stimulation resulted in simultaneous transient increase in calcium and ERK activity. Membrane-depolarizing agents, however, resulted in calcium oscillations leading to sustained elevation of ERK activity. Further, we observed that artificial imposition of a train of calcium pulses mimicking “low-frequency oscillations” lead to simultaneous low-frequency ERK activity pulses. These results, together with model simulations, suggest that endogenous frequency of calcium oscillations in pancreatic beta-cells may be optimized for sustained ERK activation, potentially leading to efficient insulin gene transcription.Calcium oscillations were also found to lead to sustained activation of Ras, an upstream signaling molecule in the ERK cascade, indicating that “processing” of oscillatory calcium signal was likely mediated by calcium-sensitive RasGEFs and RasGAPs. We show here that calcium-sensitive RasGRF1, RasGRF2 and p120RasGAP are expressed in MIN6 cells which could thus dictate the temporal properties of the signal that is communicated to ERK. Further, we noticed that inhibition of ERK activity resulted in loss of calcium oscillations indicating feedback regulation of input calcium signal by ERK. The presence of this putative feedback loop together with calcium-dependent modulation of ERK activity highlights the intricate cross-regulation of the calcium and ERK signaling pathways in pancreatic beta-cells for precise modulation of functional responses.
The Cardiac Veins and Retrograde Coronary Venous Perfusion

Study of retrograde coronary venous perfusion has been greatly overshadowed in the past decade by the advent and success of direct coronary artery revascularization. Recently there has been renewed interest in retrograde venous perfusion as a possible means of restoring myocardial circulation in selected patients. This paper reviews the anatomy and physiology of the cardiac venous system and the history of retrograde venous perfusion, with emphasis on recent experimental work and clinical trials involving retrograde coronary vein perfusion (RCVP).
Head-elevated laryngoscopy position: improving laryngeal exposure during laryngoscopy by increasing head elevation.

Abstract Study objective: The objective of this study was to determine the effect of increasing head elevation and neck flexion on the quality of laryngeal view during laryngoscopy. Methods: Laryngoscopy with a straight blade was performed on 7 fresh human cadavers. Laryngeal views were recorded with the direct laryngoscopy video system, and the laryngoscopy angle was measured throughout the procedure with an angle finder attached to the handle of the laryngoscope. Each cadaver had laryngoscopy initiated with the head lying flat on the table and with atlanto-occipital extension. The head was then progressively elevated as much as possible (the head-elevated laryngoscopy position), increasing neck flexion and the laryngoscopy angle. Three physicians blinded to the laryngoscopy angle graded the quality of laryngeal view using the percentage of glottic opening (POGO) score. Results: The laryngoscopy angle ranged from a mean of 32°±8° (1 SD) with the head flat on the table to a mean of 67°±8° with the head-elevated laryngoscopy position. The mean midposition laryngoscopy angle was 49°±6°. Comparing the 3 positions, mean POGO scores±1 SD significantly increased from 31%±10% (flat position) to 64%±12% (midposition) to 87%±13% (head-elevated laryngoscopy position). Both the midposition and the head-elevated laryngoscopy position compared with the flat position were statistically significant at a P value of less than.0001. The midposition also differed significantly from the head-elevated laryngoscopy position ( P P Conclusion: Increasing head elevation and laryngoscopy angle (neck flexion) significantly improves POGO scores during laryngoscopy on fresh human cadavers. [ Ann Emerg Med. 2003;41:322-330.]
Interviewing landed elites in post-war Guatemala

Abstract This essay explores the methodological challenges of conducting ethnographic research among economic and managerial elites in Guatemala’s landed sector during the country’s post-war transition. Guatemala’s 34-year civil war ended with peace accords in 1996. From the mid 1990s through 2001, I conducted interviews with leading representatives of the private sector in Guatemala, including the owners and top managers of the country’s sugar plantations. The Guatemalan sugar elite describes itself as the new face of the private sector in Central America, implementing “corporate social responsibility” programs linked to the World Bank and other international agencies. Questions of access and interview dynamics are often discussed in relation to qualitative research on “elites.” Yet, I found the interview process to be less complicated than I anticipated. Of greater concern were the problems of research dissemination and praxis. The experience discussed here raises questions about whether research on particular elite groups can be sustained over long periods of time.
A note on the dynamics of learning alliances: competition, cooperation, and relative scope

Khanna, Gulati, and Nohria (1998) examine the dynamics of alliance learning and develop a conceptual framework designed to capture the tension between cooperation and competition. Based on the concepts of private and common benefits and relative scope, the authors explore firms' learning behavior patterns. This note comments on the framework and suggests that although the framework introduces some interesting concepts, the reliance on simple models from economic theory leaves the framework somewhat disconnected from the process of alliance management. Copyright © 2000 John Wiley & Sons, Ltd.
Fretting fatigue of single crystal/polycrystalline nickel subjected to blade/disk contact loading

Abstract Two bodies are said to be in fretting contact when they are clamped together under the action of a normal force and see an oscillatory motion of small amplitudes at the contact interface due to the effect of shear force and bulk stress. The contact stresses that drive crack nucleation are very sensitive to the shape of the contacting surfaces and the coefficient of friction. To have an understanding of fretting at the contacts in engine components, it is important to simulate similar temperature, load and contact conditions in the laboratory and develop tools to analyze the contact conditions. The efforts made at simulating the temperature and load conditions typical to the engine hardware and the development of a robust mechanics based tool for life prediction are presented. The features of the rig include a combination of an efficient cooling mechanism using water and an insulation mechanism using ceramic blocks and sheets. The rig has been used to conduct an initial set of experiments using single crystal nickel (SCN) specimens and IN100 pads, and was found to function well under the operating temperature and load conditions. Crystallographic orientations contribute significantly to evaluation of the contact stress field. To perform an accurate analysis of anisotropic contact, a clear understanding of the material axes orientations must be maintained. A method for determining axes orientation using a Laue diffraction method is described. Preliminary fractographic observations revealed that the fracture occurs along the 〈 1 1 1 〉 plane. Close observation of the crack initiation site revealed that the crack initiated at the edge of contact on a plane perpendicular to the contact surface.
Interaction of epidermal growth factor with the hypothalamic-pituitary-adrenal axis: potential physiologic relevance.

Epidermal growth factor (EGF), a polypeptide mitogen that participates in wound healing, has ACTH-like activity in ewes. We examined its effects on the primate hypothalamic- pituitary-adrenal (HPA) axis by administering mouse EGF (mEGF) iv (0–100 μg/kg) to rhesus monkeys. mEGF caused dose-dependent elevations of plasma ACTH and cortisol in these animals. To define whether the locus of stimulation was the hypothalamus and/or the pituitary gland we examined the capacity of mEGF to directly stimulate hypothalamic CRH or pituitary ACTH secretion in a rat hypothalamic organ culture system and a rat pituitary cell system, respectively. mEGF stimulated hypothalamic CRH release in a dose-dependent manner, but failed to cause pituitary ACTH release. We conclude that EGF is a stimulator of the HPA axis in primates. Thus, EGF, and/or one of its naturally occurring analogs, may participate in the physiological activation of the HPA axis at times during which the concentrations of these factors are raised in the syste...
Comparison of Polyester Scaffolds for Bioengineered Intestinal Mucosa

Introduction: Biodegradable polyester scaffolds have proven useful for growing neointestinal tissue equivalents both in vitro and in vivo. These scaffolds allow cells to attach and grow in a 3-dimensional space while nutrient flow is maintained throughout the matrix. The purpose of this study was to evaluate different biopolymer constructs and to determine mucosal engraftment rates and mucosal morphology. Hypothesis: We hypothesized that different biopolymer constructs may vary in their ability to provide a good scaffolding onto which intestinal stem cell organoids may be engrafted. Study Design: Eight different microporous biodegradable polymer tubes composed of polyglycolic acid (PGA), polylactic acid, or a combination of both, using different fabrication techniques were seeded with intestinal stem cell clusters obtained from neonatal rats. Three different seeded polymer constructs were subsequently placed into the omentum of syngeneic adult recipient rats (n = 8). Neointestinal grafts were harvested 4 weeks after implantation. Polymers were microscopically evaluated for the presence of mucosal growth, morphology, scar formation and residual polymer. Results: Mucosal engraftment was observed in 7 out of 8 of the polymer constructs. A maximal surface area engraftment of 36% (range 5–36%) was seen on nonwoven, randomly entangled, small fiber PGA mesh coated with aerosolized 5% poly-L-lactic acid. Villous and crypt development, morphology and created surface area were best on PGA nonwoven mesh constructs treated with poly-L-lactic acid. Electrospun microfiber PGA had poor overall engraftment with little or no crypt or villous formation. Conclusion: Intestinal organoids can be engrafted onto biodegradable polyester scaffoldings with restitution of an intestinal mucosal layer. Variability in polymer composition, processing techniques and material properties (fiber size, luminal dimensions and pore size) affect engraftment success. Future material refinements should lead to improvements in the development of a tissue-engineered intestine.
Algorithm to calculate distortion in the common-emitter amplifier with feedback

An algorithm is introduced that makes possible the calculation of distortion in a common-emitter amplifier with feedback. The algorithm is easily programmable and could be incorporated into powerful circuit simulators, such as SPICE. It can be used for calculating the minimum possible amount of feedback necessary to avoid surpassing a pre-specified amount of distortion in the design of high-gain common-emitter amplifiers. The accuracy of the developed algorithm is experimentally verified.
What to Gain from Technical Sophistication

In a recent article in this journal, James McGregor (1993) criticizes political scientists for practicing regression analysis without recognizing the limitations in the regression technique. McGregor argues that the technique is inappropriate for political science research in many cases and suggests that we pay close attention to both the substantive (e.g., linearity and additivity) and statistical aspects of the technique. While acknowledging that many of us have not done enough to meet the statistical assumptions of regression analysis, George Krause (1994) argues that McGregor has underestimated the value of the
Psychological Effects of Musky Compounds: Comparison of Androstadienone with Androstenol and Muscone

Previously, we have shown that delta4,16-androstadien-3-one modulates psychological state, reducing negative mood and increasing positive mood (Jacob and McClintock, 2000; Jacob et al., 2001a). In order to determine whether similar musky compounds also produce these effects, we compared the effects of androstadienone to those of androstenol and muscone, measuring the psychological states of 37 participants. Androstenol and muscone were chosen because they too have a musky odor at high concentrations, while androstenol is a steroid like androstadienone and muscone is not. In a controlled laboratory setting, we conducted a double-blind, within-subject, repeated-measures experiment counterbalanced for order of presentation. Under each participant's nose, a nanomolar amount of each compound was presented, masked by clove oil to minimize perceptible olfactory differences. Participants completed a baseline psychological battery and twice again at 25-min intervals after exposure. Androstadienone's effects on psychological state were unique in comparison with those of androstenol and with muscone. Exposure through passive inhalation, rather than dermal contact, was sufficient for these effects. Although this is additional evidence that androstadienone may be a pheromone, it is yet to be determined whether humans exude concentrations into the air adequate for social communication or process this chemical information within natural social contexts.
A Shifting Specificity Model for Enzyme Catalysis

A new model for general enzyme catalysis challenges the idea that transition state complementarity of enzyme active sites to the reactions they catalyze is the sole source of their catalytic efficacy. The "shifting specificity" model rejects the widely held view that strong interactions of the enzyme with substrate inhibit catalytic efficiency and previously published data are presented which show that a strong interaction of substrate with the enzyme active site actually facilitates its conversion to product. Furthermore, this new model defines a role for the entire enzyme molecule unlike most theories of enzyme catalysis which are concerned only with the interaction of the active site with substrate. This shifting specificity model for general enzyme catalysis may be expressed succinctly as: (i) enzymes have evolved to bind substrates; (ii) enzyme/substrate complexes have evolved to bind transition states; (iii) a stronger interaction of substrate with the enzyme facilitates a more rapid conversion to product. This last effect results from a more efficient modulation of the global enzyme conformation by tight-binding substrates. It is suggested that the addition of atomic mass to the enzyme, which interacts with the enzyme in the same manner in which the enzyme domains interact with one another, must alter the low-frequency, global vibrations of the enzyme to produce a different overall conformation. Nature has selected for that conformational change which shifts the active site complementarity from substrate-specific to transition state-specific. Thus, this model suggests a means for an efficient realization of the substrate-binding energy in the transition state of the reaction. General aspects of this model are discussed in light of the current view of enzyme catalysis.