cssi/SciSciGPT-SciSciNet huggingface dataset:
Computational Study of the HCCO + NO Reaction: ab Initio MO/vRRKM Calculations of the Total Rate Constant and Product Branching Ratios

Accurate thermochemistry for major product channels of the HCCO + NO (R1) reaction was established at the CCSD(T)/6-311+G(3df,2p) and QCISD(T)/6-311+G(3df,2p) levels of theory based on the potential energy surface (PES) calculated by density functional B3LYP/6-311G(d,p) method. Two barrierless entrance pathways forming trans- and cis-nitrosoketene (1 and 2) have been mapped out following the minimum energy paths. Using isodesmic reaction analysis, the standard enthalpy of formation for 1 is found to be 17.8 ± 1.7 kcal/mol. The recently reported PES of the nitrosoketene decomposition (Vereecken, L.; Sumathy, R.; Carl, S. A.; Peeters, J. Chem. Phys. Lett. 2001, 344, 400) has been appended with two additional pathways to form HCNO + CO (R1a) and HCN + CO2 (R1b) products. A lower-energetic transition state for the decomposition of 2 to HCNO + CO has been found, and a new stepwise pathway for the decomposition of 1,2-oxazet-4-one (3) to HCN + CO2 has been considered in competition with a more favorable concert...
Both electrical and chemical synapses mediate fast network oscillations in the olfactory bulb.

Odor perception depends on a constellation of molecular, cellular, and network interactions in olfactory brain areas. Recently, there has been better understanding of the cellular and molecular mec...
Influences of clay minerals on sandstone cementation and pressure solution

The authors investigate hypotheses concerning observed associations between clay minerals and sandstone pressure solution and cementation. By use of a quantitative reaction-transport-deformation model that the authors set forth earlier, simulations of diagenetic interactions in clay-bearing sandstones in time and space show that different combinations of kinetic mechanisms acting as quartz grain-free faces and contacts produce characteristic spatial patterns in clay content, quartz-overgrowth abundance, porosity, and amount of pressure solution-related compaction. Comparison of simulation results to existing data from sandstones provides constraints on the operating diagenetic processes. The authors conclude that thin clay coatings on sand grains sufficiently retard development of quartz overgrowth by slowing precipitation kinetics, intracontact clay minerals promote water-film diffusion pressure solution, and free-face pressure solution operates within clay-free sand-grain boundaries.
Differences in feedback use for correct and incorrect responses

Feedback's effects on behavior during learning are not well understood. Recent research results suggest feedback on incorrect responses may affect cognitive processes and behavior differently than feedback on correct responses (Butler, Karpicke, & Roediger, 2007; Pashler, Cepeda,Wixted, & Rohrer, 2005). In the current study we investigated how feedback on different types of response accuracies affected learning in a simple rule based task under varying difficulty levels. Feedback was manipulated by being provided after correct responses only, incorrect responses only, or all responses. Results suggested feedback on incorrect responses was used differently than feedback on correct responses and was influenced by the difficulty of the task. Specifically, feedback on incorrect responses resulted in more learning than feedback on correct responses when task difficulty was higher; however, this effect was eliminated when task difficulty was lower. Language: en
PICOSECOND FLUORESCENCE STUDIES OF EXCITON MIGRATION AND ANNIHILATION IN PHOTOSYNTHETIC SYSTEMS. A REVIEW

. In this paper we review picosecond fluorescence studies of exciton dynamics in photosynthesis. We discuss some of the exciton interactions that led to artifacts in early picosecond data and outline procedures for avoiding their presence. In the case of high intensity single pulse excitation (> 1013 photons cm2), the dominant mechanism is singlet-singlet fusion, manifesting itself by a decrease in the observed lifetime and quantum efficiency of fluorescence. The manner in which excitons interact in vivo provides an indicator of the topology of the photosynthetic unit (PSU). The shape of the fluorescence quenching curve, as a function of intensity, in particular, can be used to test various models. In addition to fluorescence quenching curves, we also report the results of fluorescence decay following ps laser flashes, using an ultrafast streak camera in four types of systems: (1) organic crystal anologues, (2) chromatophores of various mutants of the photosynthetic bacteria, Rhodopseudomonas sphaeroides, (3) intact cells of the green alga, Chlorella and (4) chloroplasts of higher plants (e.g. spinach).
Surgical treatment of anorectal complications in Crohn's disease

Abstract Background. The purpose of our study was to elucidate features, surgical procedures, and long-term results in patients with anorectal complications of Crohn's disease. Methods. Physical findings, surgical treatment, and long-term outcome were recorded prospectively for 224 patients who had anorectal complications of Crohn's disease between October 1984 and May 1999. Results. Presenting complications included abscess (n = 36), fistula-in-ano (n = 51), rectovaginal fistula (n = 20), anal stenosis (n = 40), anal incontinence (n = 11), or a combination of features (n = 66). Twenty-four patients did not undergo surgical treatment; the remaining 200 patients underwent 284 procedures. Ultimately, 139 patients (62%) retained anorectal function; reasons for proctectomy in the remaining 85 patients included disease (n = 66), extensive fistular disease (n = 15), fecal incontinence (n = 2), and tight anal stenosis (n = 1). Patients with rectal disease had a significantly higher rate of proctectomy than patients with rectal sparing (77.6% vs 13.6%, respectively, P
Shape-selective reactions with zeolite catalysts. IV: Alkylation of toluene with ethylene to produce p-ethyltoluene

Abstract Reaction of toluene with ethylene over HZSM-5 zeolite gave a mixture of ethyltoluenes which contained meta isomer as the major product. Coking of the catalyst increased the percentage of para isomer in the ethyltoluenes from 29 to 47%. Over HZSM-5 modified with phosphorus and a variety of metal oxides, ethyltoluenes were produced which contained 90–99% para isomer. A comparison of the isomers produced by toluene disproportionation to produce p -xylene (and benzene) with toluene alkylation to produce ethyltoluene, revealed that with the same catalyst, ethyltoluene formation is more para -selective than xylene formation. It is proposed that this is due to the presence of the larger ethyl group on the aromatic ring, relative to methyl, which gives rise to enhanced steric effects and diffusional discrimination among the product isomers in the shape-selective catalysts.
Counting Skulls: Comment on the Aztec Cannibalism Theory of Harner‐Harris

Harner (1977) and Harris (1977) propose a cultural materialist explanation for the large number of sacrifices carried out by the Aztecs by stating that these provided raw material for cannibalism. Cannibalism, in turn, was needed to provide the protein missing in Aztec diets. The magnitude of these sacrifices was given at 15,000 annually in Tenochtitlan and 250,000 in Central Mexico. Harner argues that the overwhelming majority of the victims were eaten. He describes the sacrificial ritual as follows:
Phase Separation in Quenched Noncrystalline Poly(vinylidene fluoride)/Poly(methyl methacrylate) Blends.

The dielectric characterization was carried out in poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) blends quenched from the melts. In the quenching of 60/40 PVDF/PMMA, the phase separation between the PVDF phase and the mixed PVDF-PMMA amorphous phase was observed in apparently completely noncrystalline blends. The dielectric behaviors for this PVDF phase separated were the same as those of the PVDF crystal-amorphous interphase. The PVDF phase/mixed amorphous phase separation was explained by forming incipient crystallites of PVDF.
Recommendations for the ethical use and design of artificial intelligent care providers.

Abstract Objective This paper identifies and reviews ethical issues associated with artificial intelligent care providers (AICPs) in mental health care and other helping professions. Specific recommendations are made for the development of ethical codes, guidelines, and the design of AICPs. Methods Current developments in the application of AICPs and associated technologies are reviewed and a foundational overview of applicable ethical principles in mental health care is provided. Emerging ethical issues regarding the use of AICPs are then reviewed in detail. Recommendations for ethical codes and guidelines as well as for the development of semi-autonomous and autonomous AICP systems are described. The benefits of AICPs and implications for the helping professions are discussed in order to weigh the pros and cons of their use. Results Existing ethics codes and practice guidelines do not presently consider the current or the future use of interactive artificial intelligent agents to assist and to potentially replace mental health care professionals. AICPs present new ethical issues that will have significant ramifications for the mental health care and other helping professions. Primary issues involve the therapeutic relationship, competence, liability, trust, privacy, and patient safety. Many of the same ethical and philosophical considerations are applicable to use and design of AICPs in medicine, nursing, social work, education, and ministry. Conclusion The ethical and moral aspects regarding the use of AICP systems must be well thought-out today as this will help to guide the use and development of these systems in the future. Topics presented are relevant to end users, AI developers, and researchers, as well as policy makers and regulatory boards.
A planning and evaluation model for programs in hospitality management (foodservice management program used as illustration).

A curriculum model is proposed for planning and evaluation of hospitality management programs. The model distinguishes four phases of an educational program: (1) mission of the program, (2) program goals, (3) competency-based objectives, and (4) learning activities. The fourphases of the model are then divided according to what was intended (planning) or what was assessed from observation (evaluation). The model provides a framework for the planners and evaluators to investigate the success or failure of an individual program in terms of logical contingency and congruency. Contingency in the planning stage refers to the theory that if the mission, goals, competencies and learning activities were planned through a deductive and sequential process, then logical contingency follows. Congruency in the evaluation stage refers to symmetry between what is intended (planning) and what is observed (evaluation). A well planned quality program meets both the contingency and congruency requirements of the curriculum ...
The invasive plant species Centaurea maculosa alters arbuscular mycorrhizal fungal communities in the field.

While several recent studies have described changes in microbial communities associated with exotic plant invasion, how arbuscular mycorrhizal fungi (AMF) communities respond to exotic plant invasion is not well known, despite the salient role of this group in plant interactions. Here, we use molecular methods (terminal restriction fragment length polymorphism analyses based on the large subunit of the rRNA gene) to examine AMF community structure in sites dominated by the invasive mycorrhizal forb, Centaurea maculosa Lam. (spotted knapweed), and in adjacent native grassland sites. Our results indicate that significant AMF community alteration occurs following C. maculosa invasion. Moreover, a significant reduction in the number of restriction fragment sizes was found for samples collected in C. maculosa-dominated areas, suggesting reduced AMF diversity. Extraradical hyphal lengths exhibited a significant, on average 24%, reduction in C. maculosa-versus native grass-dominated sites. As both AMF community composition and abundance were altered by C.maculosa invasion, these data are strongly suggestive of potential impacts on AMF-mediated ecosystem processes. Given that the composition of AMF communities has the potential to differentially influence different plant species, our results may have important implications for site restoration after weed invasion.
Surgical management of atherosclerotic renovascular disease

Abstract Objective: This review describes the clinical outcome of surgical intervention for atherosclerotic renovascular disease in 500 consecutive patients with hypertension. Methods: From January 1987 to December 1999, 626 patients underwent operative renal artery (RA) repair at our center. A subgroup of 500 patients (254 women and 246 men; mean age, 65 ± 9 years) with hypertension (mean blood pressure, 200 ± 35/104 ± 21 mm Hg) and atherosclerotic RA disease forms the basis of this report. Hypertension response was determined from preoperative and postoperative blood pressure measurements and medication requirements. Change in renal function was determined with estimated glomerular filtration rates (EGFRs) calculated from serum creatinine levels. Proportional hazards regression models were used for the examination of associations between selected preoperative parameters, blood pressure and renal function response, and eventual dialysis-dependence or death. Results: Two hundred three patients underwent unilateral RA procedures, 297 underwent bilateral RA procedures, and 205 patients underwent combined renal and aortic reconstruction. After surgery, there were 23 deaths (4.6%) in the hospital or within 30 days of surgery. Significant and independent predictors of perioperative death included advanced age ( P P =.013; HR, 3.05; 95% CI, 1.26 to 7.34). Among the patients who survived surgery, hypertension was considered cured in 12%, improved in 73%, and unchanged in 15%. For the entire group, renal function increased significantly after operation (preoperative versus postoperative mean EGFR, 41.1 ± 23.9 versus 48.2 ± 25.5 mL/min/m 2 ; P P P =.007; HR, 2.14; 95% CI, 1.15 to 3.97), prior stroke ( P =.042; HR, 1.50; 95% CI, 1.02 to 2.22), and severe aortic occlusive disease ( P =.003; HR, 1.69; 95% CI, 1.19 to 2.31) showed significant and independent associations with death or dialysis during the follow-up examination period. After operation, blood pressure cured ( P =.014; HR, 0.52; 95% CI, 0.30 to 0.88) and improved renal function ( P =.011; HR, 0.40; 95% CI, 0.19 to 0.81) showed significant and independent associations with improved dialysis-free survival rate. All categories of function response and time to death or dialysis showed significant interactions with preoperative EGFR. Conclusion: The surgical correction of atherosclerotic renovascular disease resulted in blood pressure benefit and retrieval of renal function in selected patients with hypertension. The patients with cured hypertension or improved EGFR after operation showed increased dialysis-free survival as compared with other patients who underwent surgery. (J Vasc Surg 2002;35:236-45.)
Reductive Elimination of Alkylamines from Low-Valent, Alkylpalladium(II) Amido Complexes

A series of three-coordinate norbornylpalladium amido complexes ligated by bulky N-heterocyclic carbene (NHC) ligands were prepared that undergo reductive eliminations to form the alkyl–nitrogen bond of alkylamine products. The rates of reductive elimination reveal that complexes containing more-electron-donating amido groups react faster than those with less-electron-donating amido groups, and complexes containing more-sterically bulky amido groups undergo reductive elimination more slowly than complexes containing less-sterically bulky amido groups. Complexes ligated by more-electron-donating ancillary NHC ligands undergo reductive elimination faster than complexes ligated by less-electron-donating NHC ligands. In contrast to the reductive elimination of benzylamines from bisphosphine-ligated palladium amides, these reactions occur with retention of configuration at the alkyl group, indicating that these reductive eliminations proceed by a concerted pathway. The experimentally determined free energy bar...
The CURRY chip

The CURRY chip is • ¢ombintor reduction machine in VLSI. Normal order evaluation is implemented using a pointer reversal scheme that stores the stack in the celia representing the function. Program eval- uation maps an input stream to an output stream, Methods used to write elable programs for the chip are given, along with experience gained using super combinators.
Factors predicting success of endoscopic variceal ligation for secondary prophylaxis of esophageal variceal bleeding.

Introduction: Endoscopic obliteration of esophageal varices by endoscopic variceal ligation (EVL) is an effective form of secondary prophylaxis. However, there is no consensus regarding the technical aspects of EVL for secondary prophylaxis. The present study compares the technical aspects of EVL (frequency of sessions, number of sessions and number of bands used) in patients who rebled following secondary prophylaxis of esophageal varices by EVL compared to those who did not rebleed. Methods: All patients who underwent EVL for treatment of acute variceal bleeding followed by EVL for secondary prophylaxis and who subsequently developed recurrent variceal bleeding at Mayo Clinic, Rochester between January 1995 and May 2003 were identified. A control group of patients undergoing EVL for secondary prophylaxis who did not rebleed was identified. Results: During the study period, 216 patients with acute esophageal variceal hemorrhage underwent emergent EVL treatment with follow-up EVL for secondary prophylaxis, of whom 20 (9.3%) subsequently rebled. Both rebleeding and non-rebleeding patient groups were well-matched with respect to liver function (Child–Pugh class), number and size of variceal trunks, endoscopic stigmata of hemorrhage and beta-blocker usage. The median interval between EVL sessions in the rebleeding group (2 weeks, interquartile range 0–2 weeks) was significantly shorter compared to the non-rebleeding group (5 weeks, interquartile range 3–7 weeks; P = 0.004). Adjusting for age, gender, and Child–Pugh class, interbanding interval ≥ 3 weeks was associated with increased likelihood of not rebleeding, hazard ratio 3.84 (95% confidence interval: 1.69–11.79; P = 0.0007). Conclusions: These findings demonstrate the importance of technical aspects of EVL on patient outcome, suggesting the benefit of longer interbanding intervals. Future prospective studies are required to define the optimal intersession interval. Standardizing procedural aspects of EVL will aid in objectively evaluating the benefit of this procedure when compared to other modalities such as medical treatment.
Piezoelectric Characterization of Bulk and Thin Film Ferroelectric Materials using Fiber Optics

In this study, the use of a fiber optic technique for the measurement of the piezoelectric properties of ferroelectric bulk and thin film samples was investigated. The strain and piezoelectric properties (namely the d 33 coefficients) were measured using the MTI-2000 Fotonic Sensor, which uses the principle of the optical lever to resolve very small changes in sample displacement (1 A). Using this technique, we were able to detect the very small strains associated with the converse piezoelectric effect for PVDF films and bulk PZT samples, and correlate the results with data acquired from direct piezoelectric effect measurement. Comparison of the data sets prove that the optical lever would be a useful optical technique for measuring of the d 33 values of ceramic thin films, such as BaTiO 3 , ZnO, and PZT.
No fear: University of Minnesota Robotics Day Camp introduces local youth to hands-on technologies

Women and minorities are underrepresented in the IT field at the high school, university, and industry levels. Efforts to address this imbalance are often too late to solve underlying problems such as perceived ineptitude and actual inexperience. By designing and hosting a program for these underrepresented students in the middle grades, the Center for Distributed Robotics at the University of Minnesota hopes to establish a successful annual robotics day camp which would inspire both women and minorities to pursue careers in technology. Detailed accounts of the goals and methodology are provided. Initial survey results reveal a very positive response from the campers as well as strengths and weaknesses which would be useful in designing or refining similar camps
Structural Health Monitoring of Composite Structures With Piezoelectric Wafer Active Sensors

Piezoelectric wafer active sensors (PWAS) are lightweight and inexpensive enablers for a large class of structural health monitoring (SHM) applications such as: (a) embedded guided-wave ultrasonics, i.e., pitch-catch, pulse-echo, phased arrays; (b) high-frequency modal sensing, i.e., the electro-mechanical (E/M) impedance method; (c) passive detection (acoustic emission and impact detection). The focus of this paper will be on the challenges and opportunities posed by the composite structures as different from the metallic structures on which this methodology was initially developed. After a brief introduction, the paper discusses damage modes in composites. Then, it reviews the PWAS-based SHM principles. It follows with a discussion of guided wave propagation in composites and PWAS tuning effects. Finally, the paper presents some experimental results with damage detection in composite specimens. The paper ends with conclusions and suggestions for further work.© 2010 ASME
Neurological outcome after resection of intramedullary spinal cord tumors in children.

Objective With modern surgical advances, radical resection of pediatric intramedullary spinal cord tumors (IMSCT) can be achieved with preservation of long-term neurological function. Clinical and radiographic risk factors predictive of postoperative neurological outcome may serve as a guide for surgical risk stratification. Materials and methods We prospectively reviewed the outcomes of 16 consecutive cases of pediatric IMSCT resection at a single institution. Clinical, radiographic, and operative variables were analyzed as predictors of postoperative neurological function defined by the modified McCormick score (MMS). Results Sixteen children 10±5 years old presented with median (interquartile range) MMS score of 2 (1–2) with IMSCTs (eight cervical, eight thoracic) involving 4±2 levels. Pathology revealed astrocytoma in 12 cases (three pilocytic, four grade II, three gradeIII, two GBM), gangliogliomas in two, ependymoma in one, and gliosis in one case. At median follow-up of 7 months, six (38%) patients experienced improved neurological function, eight (50%) remained stable, one (6%) experienced a delayed decrease in neurological function (GBM progression), and one (6%) died (GBM progression). Five (31%) patients developed persistent dysesthetic symptoms. Four (80%) patients with cystic tumors experienced neurological improvement compared to only two (18%) patients with noncystic tumors, p<0.05. Preoperative steroid use (odds ratio, OR [95% confidence interval, CI]=18.0 [1.24– 260.1], p=0.03) and cystic tumor (OR [95%CI]=18.0 [1.24–260.1], p=0.03) predicted neurological improvement after surgery. Conclusion Radical resection of pediatric IMSCTs can be achieved with low incidence of neurological injury. Sensory syndromes frequently occur after pediatric IMSCT resection and frequently affect patient’s quality of life. Tumors with compressive cysts may identify patients more likely to experience improved neurological function after surgical resection.
Studies in Lithium Oxide Systems: XII, Li2O‐B2O3‐Al2O3

Phase relationships in the system Li2O, B2O3-B2O3 were studied by the quenching method using twenty compositions. The crystalline phases encountered were (a) Li2O, B2O3, which melts congruently at 849°± 2°C., (b) Li2O.-2B2O3, which melts congruently at 917°± 2°C., (c) a new compound, 2Li2O-5B2O3, which melts incongruently at 856°± 2°C. and dissociates below 696°± 4°C., (d) Li2O.3B2O3, which melts incongruently at 834°± 4°C. and dissociates below 595°± 20°C., and (e) probably Li2O.4B2O3, which melts incongruently at 635°± 10°C. Reactions were sluggish at temperatures near 600°C., resulting in metastable relations. Hence phase equilibrium data relating to the lower stability limit of Li2O.3B2O3 and to the upper stability limit of Li2O.4B2O3 are considered to be tentative. Properties of the glasses and crystalline phases were studied. The refractive index of the glasses increased with the addition of Li2O up to 22%, but further additions up to 40% had no substantial effect. Glasses containing less than 30% Li2O were water soluble. Limited data on the density and thermal expansion of the glasses are presented. Li2OB2O3 was euhedral, lath-shaped, length-fast, biaxial negative (2V = 27°), with nα= 1.540, nβ= 1.612, nγ= 1.616. Li2O.2B2O3 was uniaxial negative, with ne= 1.560, nw= 1.605. Li2O.3B2O3 was biaxial negative (2V = 75° to 80°), with nα= 1.576, nβ= 1.602, nγ= 1.605. X-ray powder diffraction data for the five crystalline compounds are presented. Thermal expansion data for Li2O-B2O3 and Li2O.2B2O3 and limited data on the fluorescent properties of the compounds are given. X-ray diffraction data are also presented for Li2O.B2O3.4H2O and Li2O.-5B2O3. 10H2O. Li2O B2O3 was obtained by heating the first hydrate at 450° to 680° C. X-ray diffraction showed Li2O.4B2O3 and Li2O-3B2O3 to be the crystalline products obtained during heating the decahydrate at 500°C. and 600°C., respectively.
Risk of Falling in Older Women

We propose a weighted average approach to measure the risk of falling in older women. We consider four causal variables of falling, namely serum 25-OHD levels, medication use, fracture, and age. We use five methods to derive linear equations with these four factors as independent variables in the linear equations with risk of falling as the dependent variable.
Hide and Seek: Costly Consumer Privacy in a Market with Repeat Purchases

When a firm can recognize its previous customers, it may use information about their past purchases to price discriminate. We study a model with a monopolist and a continuum of heterogeneous consumers, where consumers have the ability to maintain their anonymity and avoid being identified as past customers, possibly at a cost. When consumers can freely maintain their anonymity, they all individually choose to do so, which results in the highest profit for the monopolist. Increasing the cost of anonymity can benefit consumers but only up to a point, after which the effect is reversed. We show that if the monopolist or an independent third party controls the cost of anonymity, it often works to the detriment of consumers.
Voltage-clamp studies of transient inward current and mechanical oscillations induced by ouabain in ferret papillary muscle.

1. We studied the effects of a toxic concentration of ouabain on transmembrane electrical activity and on mechanical behaviour of right ventricular papillary muscles from ferrets in a single sucrose-gap using current clamp and voltage clamp. 2. Ouabain (1·4-1·8 μM) induced oscillatory after-potentials and after-concentrations in current-clamp experiments. Voltage clamp showed that the oscillatory after-potential was caused by a transient inward current, similar to that in Purkinje fibres. 3. The transient current had a sigmoidal dependence on the preceding (activating) voltage step V1, with a treshold around -13 mV and a plateau between +10 and 20 mV. There was a decline in current amplitude for more positive clamps. When activated by a fixed V1 voltage step, and measured at different repolarization levels V2, the transient current manifested an inverse dependence on V2 between -50 and -10 mV. No outward transient current could be detected. Total replacement of Na in the bathing medium by Tris or by sucrose abolished the transient current. 4. Ouabain caused an increase of phasic (twitch) tension responses to voltage steps at all potentials without shifting the curve relating these variables on the voltage axis. The drug evoked an even greater increase in the tonic tension responses. 5. After prolonged exposure, oscillatory mechanical responses were frequently recorded during positive voltage steps. Unlike the after-contraction, these mechanical fluctuations were not consistently damped and were not accompanied by detectable synchronous current fluctuations. Catecholamines and dibutyryl cyclic AMP markedly reduced the amplitude of the tonic contraction and the mechanical oscillations but increased their frequency. Caffeine had no effect on the tonic contraction amplitude but abolished the fluctuations. 6. These results support the proposal that Ca is transiently released from the overloaded sarcoplasmic reticulum in ouabain-intoxicated muscle and may evoke oscillatory responses in nearby contractile fibrils. When these transient increases of sarcoplasmic free Ca are large enough, they may induce the transient transmembrane current described above.
BONE CHANGES IN ACUTE AND CHRONIC SCURVY

1. Protracted scurvy in guinea pigs is characterized by a suppression of the entire growth zone leading eventually to complete cessation of enchondral ossification in animals whose ascorbic-acid intake is sufficiently restricted. 2. Calcified cartilage columns do not accumulate in the metaphysis as a "lattice" in guinea pigs as, according to the report of Park, Guild, Jackson, and Bond, they do in human cases of protracted scurvy. 3. The activity of osteoblasts and chondroblasts is suppressed, partly or completely, according to the vitamin-C intake. In early acute lesions of chronic scurvy, osteoblasts are present in increased numbers, but do not lay down bone.
Quantifying fracture geometry with X-ray tomography: Technique of Iterative Local Thresholding (TILT) for 3D image segmentation

This paper presents a new method—the Technique of Iterative Local Thresholding (TILT)—for processing 3D X-ray computed tomography (xCT) images for visualization and quantification of rock fractures. The TILT method includes the following advancements. First, custom masks are generated by a fracture-dilation procedure, which significantly amplifies the fracture signal on the intensity histogram used for local thresholding. Second, TILT is particularly well suited for fracture characterization in granular rocks because the multi-scale Hessian fracture (MHF) filter has been incorporated to distinguish fractures from pores in the rock matrix. Third, TILT wraps the thresholding and fracture isolation steps in an optimized iterative routine for binary segmentation, minimizing human intervention and enabling automated processing of large 3D datasets. As an illustrative example, we applied TILT to 3D xCT images of reacted and unreacted fractured limestone cores. Other segmentation methods were also applied to provide insights regarding variability in image processing. The results show that TILT significantly enhanced separability of grayscale intensities, outperformed the other methods in automation, and was successful in isolating fractures from the porous rock matrix. Because the other methods are more likely to misclassify fracture edges as void and/or have limited capacity in distinguishing fractures from pores, those methods estimated larger fracture volumes (up to 80 %), surface areas (up to 60 %), and roughness (up to a factor of 2). These differences in fracture geometry would lead to significant disparities in hydraulic permeability predictions, as determined by 2D flow simulations.
Usability Methods at the Millennium: How We Got Here and Where We Might Be Going

This paper proposes that usability methods can be organized into a three-dimensional space. The dimensions of this method space are (1) the genesis of the method, (2) the function of the method, and (3) the point(s) in the design that the method is typically used. The paper exemplifies and explains each dimension by discussing where on the dimension certain methods might fall. The future of usability methods is discussed by examining (1) how new methods might be developed within the space defined by the three dimensions (inner space methods) or (2) how new methods might require extending a dimension (outer space methods).
Disruption of microtubules alters polarity of basement membrane proteoglycan secretion in epithelial cells

Basement membrane proteins such as the heparan sulfate proteoglycan (HSPG) are secreted in a polarized fashion from the basolateral membrane of epithelial cells. We have used the microtubule-disrupting drug colchicine to study the role of the microtubule network in directing constitutive secretion to the basolateral membrane of LLC-PK1 renal epithelial cells. Microtubule depolymerization induced by colchicine resulted in fragmentation and redistribution of fluorescently labeled trans-Golgi membranes. Increased immunofluorescent staining of HSPG was associated with these dispersed Golgi cisternae. The biosynthetic processing of HSPG was not significantly altered by the loss of microtubules or by the dispersal of the Golgi elements. The most striking effect of microtubule disruption was the loss of polarity of HSPG secretion. Immunoprecipitation studies showed that HSPG was secreted from both apical and basolateral surfaces of LLC-PK1 cells treated with colchicine, and a similar result was found for the delivery of laminin, another basement membrane protein. In contrast, there was no change in the distribution of an integral basolateral membrane protein, Na(+)-K(+)-ATPase, following colchicine treatment. Our results provide the first demonstration that microtubules are involved in the constitutive trafficking of basolateral secretory proteins. These data also suggest that there may be an inherent difference in the targeting or delivery of membrane and secretory proteins to the basolateral cell surface.
Direct and maternal genetic effects on preweaning characters of Brahman, Hereford and Brahman-Hereford crossbred cattle.

Birth weight, preweaning gain and weaning weight (adjusted 180-d weight) data, collected at McGregor, Texas, were analyzed for genetic differences. Breedtypes represented in the data were Brahman, Hereford and various Brahman-Hereford crosses. Preweaning gain was calculated as adjusted 180-d weight less birth weight. All statistical models included effects of dam age, year, season and sex. Analyses were performed using a breedtype model and a regression model that redefined breedtype as direct additive, direct heterotic, maternal additive and maternal heterotic effects. Brahman dams produced calves with lightest birth weights. Brahman-sired calves were heaviest at birth compared with those by other sire breedtypes. The estimated Brahman direct additive effect on birth weight was 4.6 kg greater than Hereford. The Brahman maternal additive effect was 7.5 kg less than Hereford. Direct and maternal heterotic effects on birth weight were 2.2 and .6 kg, respectively. Calves from F1 dams had larger preweaning gains than those of the other breedtypes. The Brahman direct additive effect on preweaning gain was 17.7 kg less than Hereford and the Brahman maternal additive effect was 20 kg greater than Hereford. Direct and maternal heterotic effects on preweaning gain were 19.6 and 19.5 kg, respectively. Results of weaning weight analyses were similar to preweaning gain analyses. The largest effects on weaning weight were direct and maternal heterosis, which were 21.6 and 19.8 kg, respectively.
Stability of Osaka Mutant and Wild-Type Fibril Models

Single amino acid mutations in amyloid-beta (Aβ) peptides can lead to early onset and increased severity of Alzheimer's disease. An example is the Osaka mutation (Aβ1-40E22D), which is more toxic than wild-type Aβ1-40. This mutant quickly forms early stage fibrils, one of the hallmarks of the disease, and these fibrils can even seed fibrilization of wild-type monomers. Using molecular dynamic simulations, we show that because of formation of various intra- and intermolecular salt bridges the Osaka mutant fibrils are more stable than wild-type fibrils. The mutant fibril also has a wider water channel with increased water flow than the wild type. These two observations can explain the higher toxicity and aggregation rate of the Osaka mutant over the wild type.
Binding and permeabilization of model membranes by amphipathic peptides.

Measurement of binding and activity of antimicrobial and cytolytic amphipathic peptides on membranes is essential to understanding their function and cell specificity. The use of model systems has provided a wealth of information on the interactions of amphipathic peptides with membranes. Binding of peptides to membranes can be monitored by measuring Forster resonance energy transfer from a Trp residue on the peptide to a lipid fluorophore incorporated in the membrane. Especially for peptides that perturb or disrupt the membrane, it is advantageous to perform these measurements as a function of time, rather than in steady state. The activity of these amphipathic peptides toward model membranes is usually measured by dye efflux kinetics. One of those methods, based on self-quenching of carboxyfluorescein, is described here, together with a discussion of caveats and pitfalls of the corresponding analysis and interpretation.
Chronic Exertional Compartment Syndrome

Chronic exertional compartment syndrome is characterized by pain that is associated with exercise or physical training that commonly necessitates cessation of the inciting activity and can therefore be of significant concern for athletes. Classically a condition of runners, it is caused by an increase in pressure within a fascial compartment that results from muscular function during exercise. Chronic exertional compartment syndrome should be on the differential for any athlete presenting with chronic exercise-induced pain of the leg; proper clinical history, physical exam, and diagnostic work-up will differentiate it from other etiologies of this common presenting complaint. This topic has historically been characterized by some degree of debate with regard to the specific indications and varying methods of both diagnostic management and treatment. As conservative measures have proved largely ineffective, the mainstay of treatment for this condition is surgical release of the fascial compartment involved. There are several techniques for this procedure described in the literature that have proven successful.
The Role of Composition in Ultrafine-Grain Ceramics

The importance of composition and impurities to the behavior of ultrafine-grain ceramics is discussed with emphasis on: (1) significance of large grain boundary area per unit volume; (2) nature and distribution of impurities; (3) source and elimination of impurities; and (4) analysis of impurities.
Agents of Political Socialization Through the Life Course

At any point in people’s lives, the influences of their families, teachers, clergy, co-workers, and so on can be re-enforcing or contradictory. Some of those have greater overall effect than do others. Some are more influential at different periods in people’s lives. The structures, dynamics, messages, and prevalence of the various sources of political orientations change over time. Further, the politically relevant experiences of individuals within their families, schools, churches, voluntary associations as well as their patterns of media use vary by gender, race, ethnicity, and social class. The chapter systematically examines research detailing this complexity.
Igneous or metamorphic? Hornblende phenocrysts as greenschist facies reaction cells in the Half Dome Granodiorite, California

The Half Dome Granodiorite, Yosemite National Park, California, is recognized in the field by euhedral, fresh-looking, black hornblende phenocrysts up to 2 cm in length. This variety of granodiorite typifies intermediate-age hornblende-phyric units of Cretaceous nested plutonic suites in the Sierra Nevada batholith. Although only inclusions of feldspar are evident in hand samples, the phenocrysts are riddled with up to 50% inclusions of every major mineral found in the host granodiorite plus metamorphic minerals formed during cooling. Amphibole compositions within single phenocrysts vary from actinolite with less than 1 wt% Al 2 O 3 to magnesiohornblende with over 8 wt%. Elemental zoning within the amphibole is highly irregular on the micrometer scale, showing patches and polygonal zones with dramatically different compositions separated by sharp to gradual transitions. The chemical compositions of entire phenocrysts are equivalent to hornblende plus a small proportion of biotite, suggesting that the non-biotite inclusions are the result of metamorphism of the phenocrysts. Backscattered electron imaging shows evidence of brecciation that may have been the result of volume changes as hornblende was converted to actinolite. Pressure calculations using the Al-in-hornblende barometer show unreasonably wide variations on the micrometer scale that cannot have been produced by temperature or pressure variations during crystallization. These hornblende phenocrysts would thus be unsuitable for geobarometry, and caution must be used to avoid similarly zoned phenocrysts in the application of the Al-in-hornblende geobarometer.
The role of CTCF and DNA methylation in telomerase hTERT gene regulation

4321 Telomerase, which is involved in the regulation of the replicative life span by its maintaining telomere length, is activated in germ and stem cells, repressed in normal somatic cells and reactivated in a large majority of tumor cells. The expression of the catalytic subunit (hTERT) represents the limiting factor for telomerase activity. The hTERT promoter region is located in a CpG island and we observed that, in a majority of telomerase-positive cells, methylation of the hTERT promoter seems necessary for its transcription (Int J Cancer 101:335-341, 2002). This correlation is in stark contrast to the general model of regulation by DNA methylation. To understand how DNA methylation can lead to hTERT gene expression, several experiments were performed which showed that: 1) Strong activation of the hTERT minimal promoter is necessary but not sufficient to hTERT activation in vivo. 2) The strong inhibitory effect of the proximal exonic region was also investigated. We demonstrated that the inhibitory effect of this region is not promoter and cell dependent. 3) This inhibition is mainly due to the chromatin insulator protein CCCTC binding factor (CTCF), which binds in two sites in the hTERT proximal exonic region. ChiP experiments revealed that CTCF binds to the unmethylated hTERT exonic region (normal telomerase-negative cells) but not to the methylated one (telomerase-positive cells). 4) In transient or even stable transfection experiments, CTCF knockdown with siRNA resulted in a significant increasing activity of hTERT promoter in luciferase reporter constructs containing the hTERT promoter and the proximal exonic region. This indicates that activation of the unmethylated hTERT gene can be achieved by inhibition of CTCF. According to our data, a new model for hTERT gene regulation could be proposed. In telomerase-negative normal tissues and in some of telomerase-negative tumors, hypomethylation of the hTERT promoter allows CTCF to bind to the proximal exonic region and leads to hTERT transcription inhibition. In contrast, in telomerase-positive samples (normal or tumor tissues), hypermethylation of the hTERT gene prevents the methylation-sensitive CTCF inhibitor to bind and thus, lead to a weak but significant level of hTERT transcription.
Measurement of instantaneous flame spread rate over solid fuels using image analysis

Abstract Spread rate is an overall property of flame propagation that characterizes the condition of a flame better than any other property. As a result, prediction and measurement of spread rate is central to flame spread studies over solid fuels. Significant amount of data have been collected over last four decades of research on flame spread over various fuels under different conditions. In most of these studies, however, only average spread rate is reported which is adequate for steady phenomena. Given that a flame may not face the same conditions during the spread, it is possible for the spread rate to change during the duration of the spread continually. In this work a methodology for image analysis is presented with the goal of evaluating instantaneous spread rate to study time-dependent phenomena. The parameters that control the error and time resolution of the flame spread history are identified, and a sensitivity study is carried out to validate the results of a scale analysis. A MATLAB-based Flame Image Analyzer (FIA) package is developed and applied to flame spread videos recorded in several experiments in different regimes of opposed-flow flame spread. An expression for the error in spread rate for a given time resolution is expressed in terms of the imaging parameters. The two parameters that are found most important are the pixel resolution and the frame rate. A non-dimensional imaging parameter is identified that is shown to govern the quality of imaging for spread rate measurement. Theoretical prediction from the error analysis is confirmed by doing various case studies using the Analyzer.
Quantitative DNA determinations of nuclear transplant triploid Rana pipiens.

Abstract Quantitative Feulgen spectrophotometry of control diploid and nuclear transplant triploid frogs indicates that DNA of the two types of frogs is related approximately as 2:3. An essentially unimodal distribution of DNA values among the experimental triploid frogs indicates that they are probably not constructed of cells of any polyploid class other than triploid.
Hydrolysis of Ribulose-1,5-Bisphosphate Carboxylase by Partially Purified Endoproteinases of Senescing Primary Barley Leaves

Ribulose-1, 5-bisphosphate carboxylase (RuBPCase) is the protein responsible for fixation of CO2 in photosynthetic organisms. In many higher plants RuBPCase also appears to serve as a storage protein that is hydrolyzed during leaf senescence (Huffaker et al., 1978). This provides a source of reduced N that can be transported to newly developing leaves or fruits (Dalling et al., 1976). RuBPCase is a large protein (MW ∿ 550 kD) consisting of 8 large subunits (50–57 kD) and 8 small subunits (13–15 kD). The large subunit is coded on chloroplast DNA and is synthesized within the chloroplast (Blair et al., 1973; Chan et al., 1972; Criddle et al., 1970; Kung, 1976). The small subunit is coded on nuclear DNA (Kung, 1976), synthesized as a precursor protein in the cytoplasm (Criddle et al., 1970; Highfield et al., 1978), and then processed at or in the chloroplast. The native protein is assembled in the chloroplast and the active enzyme is localized in the stroma. The synthesis of RuBPCase occurs predominantly during the greening of etiolated leaf tissue (Kleinkopf et al., 1970; Smith et al., 1974) or leaf expansion (Friedrich and Huffaker, 1980). The cellular concentration of RuBPCase (which can constitute 50–70% of the total soluble leaf protein) then remains nearly constant for several days; little or no apparent turnover takes place (Huffaker, 1979; Peterson et al., 1973). During senescence, protein is rapidly degraded, and RuBPCase is the predominant protein lost during the initial stages (Friedrich and Huffaker, 1980; Peterson and Huffaker, 1975). A1- though there is much data concerned with the synthesis of RuBPCase, information about the control of its degradation and turnover is lacking. Exo—and endoproteinases in green and senescing leaf tissue have been described (Dalling et al., 1976; Huffaker and Miller, 1978; Martin and Thimann, 1972; Peterson and Huffaker, 1975; Sopanen and Lauriere, 1976; Thomas, 1978; Wittenbach, 1978) but very little is known about their role in senescence or in normal cellular protein turnover.