cssi/SciSciGPT-SciSciNet huggingface dataset:
Modal abundances of pyroxene, olivine, and mesostasis in nakhlites: Heterogeneity, variation, and implications for nakhlite emplacement

Nakhlites, clinopyroxenite meteorites from Mars, share common crystallization and ejection ages, suggesting that they might have been ejected from the same place on Mars by the same ejection event (impact) and are different samples of the same thick volcanic flow unit or shallow sill. Mean modal abundances and abundance ranges of pyroxene, olivine, and mesostasis vary widely among different thin-sections of an individual nakhlite. Lithologic heterogeneity is the main factor contributing to the observed modal-abundance variations measured in thin-sections prepared from different fragments of the same stone. Two groups of nakhlites are distinguished from one another by which major constituent varies the least and the abundance of that constituent. The group consisting of Nakhla, Lafayette, Governador Valadares, and the Yamato nakhlite pairing group is characterized by low modal mesostasis and pyroxene-olivine covariance, whereas the group consisting of the Miller Range nakhlite pairing group and Northwest Africa 5790 is characterized by low modal olivine and pyroxene-mesostasis covariance. These two groups sample the slowest-cooled interior portion and the chilled margin, respectively, of the nakhlite emplacement body as presently understood, and appear to be also related to recently proposed nakhlite groups independently established using compositional rather than petrographic observations. Phenocryst modal abundances vary with inferred depth in the nakhlite igneous body in a manner consistent with solidification of the nakhlite stack from dynamically sorted phenocryst-rich magmatic crystal-liquid mush.
Anatomic considerations in therapeutic arteriogenesis for cerebral ischemia.

Response We very much appreciate Dr Liebeskind’s letter. We fully agree that the collateral circulation in the brain is far more complex than in the peripheral vasculature. Indeed, in the first part of our study, we carefully characterized the response of the circle of Willis to 3-vessel occlusion (3-VO, ipsilateral carotid and bilateral vertebral artery ligation) both short term (1-week survival) and long term (3-week survival). These data were published1 before our investigation on the therapeutic effects of granulocyte-macrophage colony-stimulating factor and actually deal with the questions raised by Dr Liebeskind. We examined the diameter of the anterior and middle cerebral arteries, the internal carotid artery, and Heubner’s dorsal leptomeningeal anastomoses after 1 and 3 weeks of 3-VO. We expected that arteriogenic growth would also take place in regions of smaller arteriolar connections, as described by Wei and coworkers 2 in rats after stroke. However, after 1 week, the only significant difference in vessel diameter was observed in the ipsilateral posterior cerebral artery (PCA). After 3 weeks, a significant increase in vessel size was also detected in the ipsilateral anterior cerebral artery and the contralateral PCA. At this time, the diameter of the ipsilateral PCA had increased significantly from 18727 to 32250 m (plus 72%), that of the contralateral PCA from 19629 to 26138 m (plus 33%), and that of the ipsilateral anterior cerebral artery from 25137 to 32242 m (plus 28%). Other supplying arteries did not change in diameter during the observation period. Heubner’s leptomeningeal anatomoses did not change either; in control animals, the mean diameter was ipsi- and contralateral 374 m; after 3-VO, it was 382 m on the ipsilateral and 373 mo n the contralateral side; and after granulocyte-macrophage colonystimulating factor treatment, it insignificantly changed on the ipsilateral side to 396 m and on the contralateral side to 364 m. In summary, our study demonstrates that the basal cerebral arteries respond more to 3-VO than Heubner’s dorsal leptomeningeal anastomoses, but this effect may be adequate to protect the brain against ischemia arising from vascular stenosis. Collateral growth is closely linked to the location of blood pressure gradients within the vascular system. Thus, any experimental brain ligation model can only partially reflect the complex pattern of brain arteriogenesis.
Treatment of MS patients with BG-12 results in a decline in circulating memory T and B lymphocytes (HUM1P.317)

BG-12 (Tecfidera®) is a recently approved oral treatment for multiple sclerosis that has shown remarkable efficacy. The mechanisms by which BG-12 acts on the human immune system are poorly defined. In the current study, we analyzed the effects of BG-12 treatment on subsets of circulating human T and B lymphocytes using multicolor flow cytometry. Patients treated for four months with BG-12 had decreased total numbers of lymphocytes in their blood that did not reach significance, and no changes in their overall percentages of CD4+ T cells, CD8+ T cells, or CD19+ B cells compared to pretreatment levels. Significant differences were observed when subsets of T and B cells were evaluated. BG-12 treatment resulted in a decrease in percentages of circulating CD4+CD45RO+CD45RAneg memory TH cells and CD8+CD45RO+CD45RAneg memory CTL. Treatment with BG-12 also resulted in significant decreases in circulating CD27+CD19+ memory B cells, and a relative increase in the levels of CD24highCD38highCD19+ regulatory B cells. A CD27+CD24lowCD19+ B cell subset was present in the circulation of some MS patients prior to treatment, but returned to the very low levels found in healthy controls following four months of BG-12 treatment. The data suggest that BG-12 has in vivo down regulatory effects on some lymphocyte subsets, particularly memory T and B cells. Ongoing experiments are focused on measuring functional differences in T and B cell cytokine production in BG-12 treated patients.
Anisotropy in an ambiguous kinetic depth effect.

A set of animated stimuli (Lissajous figures), each element of which is physically consistent with two different 3D shapes undergoing rigid rotations about orthogonal axes is presented. Predictions of which shape will be seen are made by utilizing an adaptation of Hildreth's smoothest-velocity-field computation. Results indicate that the ambiquity in 2D visual motion, i.e., the aperture problem, is not resolved before the interpretation of the 3D structure.
Use of palliative sedation for intractable symptoms in the palliative care unit of a comprehensive cancer center

There is wide variation in the frequency of reported use of palliative sedation (PS) to control intractable and refractory symptoms in terminally ill patients. The aim of this study was to determine the frequency and outcomes of PS use and examine patterns of practice after establishment of a policy for the administration of midazolam for PS in our palliative care unit (PCU). This retrospective study reviewed PCU admissions for 2004 and 2005 and pharmacy records to identify patients who received chlorpromazine, lorazepam, or midazolam for PS in the PCU. Data on indication for PS, drug used, and discharge outcome were assessed for each patient. During the period studied, there were 1,207 PCU admissions. Of these patients, 186 (15%) received PS; and 143 (41%) of the 352 patients who died in the PCU received PS. The median age of PS patients was 58 (range, 20–84) years, and 106 (57%) were male. The most common indications for PS were delirium, 153 cases (82%); dyspnea, 11 (6%); and multiple indications, 12 (6%). Midazolam was used in 18 PS cases (10%). Six (55%) of 11 patients with dyspnea received midazolam for PS, compared with 12 (7%) of 175 patients with other indications for PS (p < 0.001). Forty-three (23%) of 186 PS patients were discharged alive, compared with 812 (80%) of 1,021 patients who did not receive PS (p < 0.001). PS was required in 15% of PCU admissions, and 23% of PS patients were discharged alive. Our findings suggest a potential for significant underreporting of overall PS. If our institution’s policy on midazolam use for PS were less restrictive, midazolam use might increase. More research is needed to define the optimal agent for inducing rapid, effective, and easily reversible PS.
Saccharide Polymer Brushes To Control Protein and Cell Adhesion to Titanium

Attaining control over the surface chemistry of titanium is critical to its use in medical implants, especially to address complications such as infection and loosening of implants over time, which still present significant challenges. The surface-initiated atom transfer radical polymerization (SI-ATRP) of a saccharide-substituted methacrylate, 2-gluconamidoethyl methacrylate (GAMA), affords dense polymer brushes that resist protein adsorption and cell adhesion. We further tailored the nature of the surfaces by covalent attachment of an adhesion peptide to afford control over cell adhesion. Whereas unmodified poly(GAMA) brushes prevent cell adhesion, brushes with a tethered GFOGER-containing peptide sequence promote the deposition of confluent well-spread cells. The presentation of adhesion proteins on a robust bioresistive background in this fashion constitutes a versatile approach to the development of new biomaterials.
Did magma ascent rate control the explosive-effusive transition at the Inyo volcanic chain, California?

Rhyolitic eruptions often begin explosively and then shift to extrusions of lava. It is widely believed that the style of eruption is dependent on magma flow rate within the conduit, fast ascent leading to explosive eruption and slow ascent favoring effusive behavior. Currently, the velocity of rhyolite magma flowing in a conduit is unknown, and therefore eruption models remain untested against geologic evidence of magma ascent. We show that explosively erupted rhyolite magma from the Inyo volcanic chain ascended slowly (centimeters per second), at same rates as the dome-building phases. We propose that the explosive-effusive transition sub-Plinian rhyolite eruptions is governed by the alleviation of exsolved volatile pressure in the shallow conduit rather than the magma flow rate.
Subxiphoid incisional hernias after median sternotomy.

Background Subxiphoid incisional hernias are notoriously difficult to repair and are prone to recurrence. The few reports on subxiphoid hernia published over the last two decades have not fully addressed the etiology, pathology, treatment, and outcome of this problem. This review was performed to analyze the published experience and increase the understanding of these difficult hernias.
Standard molar enthalpies of formation of PdAl, PtAl, ScAl1.78, YAl2 and LaAl2

Abstract The standard molar enthalpies of formation of PdAl, PtAl, ScAl 1.78 , YAl 2 and LaAl 2 have been determined using a high temperature calorimeter at 1473 ± 2 K: ΔH j o ( PdAl ) = −182.5 ± 9.3 kJ mol −1 , ΔH j o ( PtA 1)=−195.1 ± 10.1 kJ mol −1 , ΔH j o ( ScAl 1.78 )= −132.6 ± 2.6 kJ mol −1 , ΔH j o ( YA 1 2 ) = −151.2 ± 3.8 kJ mol −1 and ΔH j o ( LaA 1 2 ) = −149.6 ± 6.2 kJ mol −1 . Comparisons are made with some available data and with predicted values.
Relationship between birefringence and neurotubule density in the primate retinal nerve fiber layer

The relationship between retinal nerve fiber layer (RNFL) birefringence (Dn) and neurotubule density (NTD, retinal ganglion cell (RGC) neurotubules per unit RNFL area) was investigated by correlating measurements of these two parameters in 1 eye of a healthy cynomolgus monkey. Phase retardation per unit depth (PR/UD, proportional to Dn) was measured at 5.6-15 o intervals around the optic nerve head (ONH) with an enhanced polarization-sensitive optical coherence tomography (EPS-OCT) instrument. Transverse tissue sections containing 3 RGC nerve fiber bundles from each peripapillary RNFL octant were imaged with a transmission electron microscope (TEM). Morphological measurements taken in TEM images were used by a novel algorithm to estimate NTD. Registered PR/UD and NTD data were then correlated using single- and multi-level models, yielding correlation coefficients in the range 0.49 l r l 0.61 (0.06 l P l 0.11). It was found that in order for the single-level correlation coefficient (r = 0.61) to be statistically significant (P l 0.05) and powerful (Power g 80%), NTD measurements in at least 16, rather than 8, RNFL sectors were needed. Interestingly, a single-level correlation coefficient of r = 0.81 (P = 0.01) was calculated between octant-averaged PR/UD and RGC axoplasmic area (A x , axon area less non-cytoskeletal organelle area) mode. A x represents a RGC axon's neurotubule-inhabitable area. Intuitively, a strong relationship should exist between A x and neurotubule number if neurotubules provide the primary structural support for RGC axons and structural requirements are the same in all RGC axons. If this relationship exists, error resulting from NTD estimation methods or preservation artifacts may have caused lower observed correlations of PR/UD with NTD than with A x mode, and more accurate methods of measuring in vivo NTD may be required to determine an accurate relationship between RNFL birefringence and NTD.
Size effects in the structural phase transition of VO 2 nanoparticles

We have observed size effects in the structural phase transition of submicron vanadium dioxide precipitates in silica. The ${\mathrm{VO}}_{2}$ nanoprecipitates are produced by the stoichiometric coimplantation of vanadium and oxygen and subsequent thermal processing. The observed size dependence in the transition temperature and hysteresis loops of the semiconductor-to-metal phase transition in ${\mathrm{VO}}_{2}$ is described in terms of heterogeneous nucleation statistics with a phenomenological approach in which the density of nucleating defects is a power function of the driving force.
The effect of prestraining in simple tension and biaxial tension on flow and fracture behaviour of a low carbon deep-drawing steel sheet

Abstract The effect of prestraining in tension in the rolling direction of a fully killed deep drawing steel sheet has been determined in subsequent tension at 0°, 22.5°, 45°, 67.5° and 90° to the rolling direction. The effect of prestraining under biaxial tension, using a circular and an elliptical bulge tester, has been determined in subsequent tension at 0° and 45° to the original rolling direction. The initial anisotropy of the material satisfied orthotropic symmetry, and is not affected by the prestrain. After prestraining under biaxial tension, or upon changing the direction of straining after prestraining in tension, the initial flow stress is greater than that predicted by the effective stress-strain concept, the strain-hardening coefficient is decreased, and, beyond a prestrain of 0.095 effective strain, the maximum load upon retesting is reached after approximately 0.01 strain. The angle between specimen axis and fracture surface is not affected by the prestrain, and is found to be approximately 50°, which is in agreement with the computed value of 51° for the rolling and transverse directions for the type of anisotropy found.
Differential effects of cyclic nucleotides and their analogs and various agents on cyclic GMP-specific and cyclic AMP-specific phosphodiesterases purified from guinea pig lung.

The differential effects of various compounds on the activities of cyclic GMP-specific phosphodiesterase (cyclic GMP-PDE) and cyclic AMP-specific phosphodiesterase (cyclic AMP-PDE) purified from the guinea pig lung were examined. Cyclic IMP, 2'-deoxy cyclic GMP and 2'-O-monobutyryl cyclic GMP were found to be the most potent inhibitors of the cyclic GMP-PDE, with I50 (concentrations of the compounds inhibiting 50 per cent of the activity) values of 1.5, 4.5 and 35 μM respectively. These compounds, however, were at least 30–600 times less potent in inhibiting the cyclic AMP-PDE. In contrast, 2'-O-monobutyrul cyclic AMP and 2'-deoxy cyclic AMP were the most potent inhibitors of cyclic AMP-PDE, with I50 values of 10 and 45 μM respectively; these compounds, however, were at least 30–100 times less potent in inhibiting cyclic GMP-PDE. Ethanol (13%, v/v) stimulated cyclic GMP-PDE 80 per cent while conversely inhibiting cyclic AMP-PDE 75 per cent. Most of the phosphodiesterase inhibitors studied were found to be more selective for cyclic AMP-PDE, with the possible exception of 1-methyl-3-isobutylxanthine, which was more specific for inhibiting cyclic GMP-PDE. The differential inhibition of the two classes of phosphodiesterases by a wide variety of compounds shown in the present study suggests a possibility of selective regulation of the tissue levels of respective cyclic nucleotides through specific or preferential inhibition of their enzyme activities.
Explicating the Role of Mathematical Tasks in Conceptual Learning: An Elaboration of the Hypothetical Learning Trajectory

Simon's (1995) development of the construct of hypothetical learning trajectory (HLT) offered a description of key aspects of planning mathematics lessons. An HLT consists of the goal for the students' learning, the mathematical tasks that will be used to promote student learning, and hypotheses about the process of the students' learning. However, the construct of HLT provided no framework for thinking about the learning process, the selection of mathematical task, or the role of the mathematical tasks in the learning process. Such a framework could contribute significantly to the generation of useful HLTs. In this article we demonstrate how an elaboration of reflective abstraction (i.e., reflection on activity-effect relationships), postulated by Simon, Tzur, Heinz, and Kinzel (in press), can provide such a framework and thus a theoretical elaboration of the HLT construct.
Do angiotensin-converting enzyme inhibitors prolong life in patients with heart failure treated in clinical practice?

Angiotensin converting enzyme (ACE) inhibitors have emerged as a significant advance in the treatment of heart failure; yet only a minority (i.e., 30% to 40%) of eligible patients are being treated with these drugs, and even among treated patients, the doses used in clinical practice are substantially lower than those used in the clinical trials that established the efficacy and safety of these agents. The preference for low doses is based on the belief that low and high doses exert similar benefits but that high doses produce more side effects. Yet, most studies indicate that large doses of ACE inhibitors produce greater hemodynamic and clinical effects than small doses, with no additional toxicity. However, it is uncertain whether the survival effects of these drugs are also related to dose. To address this question, a large multinational, double-blind clinical trial (Assessment of Treatment With Lisinopril and Survival [ATLAS]) was launched to compare the effects of low and high doses of the ACE inhibitor lisinopril on the survival of patients with heart failure. If the study demonstrates that large doses are needed to produce optimal effects on mortality, then the low dose strategies that are now widely used in clinical practice may be inadvertently nullifying the enormous potential benefits that ACE inhibitors might otherwise have on public health.
Protein Adsorption Modalities on Polyelectrolyte Multilayers

Protein adsorption on polyelectrolyte multilayers (PEMUs) was evaluated using a combination of synthetic polyelectrolytes and proteins, including serum albumin, fibrinogen, and lysozyme. Variables such as surface and protein charge, polymer hydrophobicity, and hydrophilic repulsion were introduced to probe interaction mechanisms. Quantitative analysis with reflectance Fourier transform infrared spectroscopy, optical waveguiding, and UV−vis absorption, together with qualitative information from atomic force microscopy, provided a coordinated picture for what drives protein adsorption and how the molecules are disposed on the multilayer surface. It was found that multilayers bearing a particular surface charge sorbed biomolecules if they were of opposite charge, yielding significant loadings within the bulk PEMU. Adsorption of like-charged proteins, as surface aggregates, occurred to a much lower extent, driven by nonelectrostatic forces. A diblock copolymer comprising a hydrophilic poly(ethylene oxide) blo...
Cumulative pregnancy analysis of one-tube versus two-tube tubal anastomosis.

Abstract Objective: To determine the prognosis for pregnancy when tubal anastomosis can be performed on only one tube. Design: Prospective collection of demographic and clinical data. Setting: University medical center. Patient(s): One hundred twenty-six women undergoing elective sterilization reversal. Intervention(s): Sterilization reversal was performed by five reproductive endocrine surgeons. In 35 cases, only one tube could be treated surgically. In all cases, this was because of a previous salpingectomy or inadequate distal tubal segment. Main Outcome Measure(s): Cumulative probability of pregnancy in the two groups (one tube or two tubes) was analyzed by survival analysis and logistic regression. Survival curves were compared by log-rank testing. Result(s): Comparison of survival curves revealed no difference between the logistic regression curves for probability of conception after anastomosis of one tube versus two tubes. Logistic regression revealed a similar cumulative probability of conception with a two-tube (0.76) and a one-tube anastomosis (0.63). The monthly fecundity rates were 0.032 and 0.034 for a two-tube and one-tube anastomosis, respectively. There were no differences between the groups with respect to age, gravidity, or parity. Virtually all pregnancies occurred within 2 years of surgery. Conclusion(s): The prognosis for conception after one-tube anastomosis was the same as for two-tube anastomosis.
Inhibition of protein synthesis by antagonists of calmodulin in Ehrlich ascites tumor cells

Several recent publications indicate that Ca2+ is required for protein synthesis in mammalian cells, including the Ehrlich ascites tumor cell. The present communication examines whether the effects of Ca2+ might be mediated through calmodulin or a related protein. Four calmodulin antagonists belonging to different chemical categories were used to provide evidence of calmodulin involvement. Three of the antagonists inhibited protein synthesis in intact cells; 50% inhibitory concentrations were 10 μM calmidazolium, 12 μM N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W7) and 17.5 μM trifluoperazine (TFP). Initiation was preferentially inhibited as indicated by an increase in the 80S monomers accompanied by a significant disaggregation of polyribosomes. All the antagonists also inhibited protein synthesis initiation in the cell-free protein-synthesizing system; 50% inhibitory concentrations for compound 48/80, calmidazolium, TFP, and W7 were 10 μM, 125 μM, 300 μM and 500 μM, respectively. A weak analogue of W7 inhibited only 20% at 1000 μM. Inhibition in the cell-free system was reversed by the addition of exogenous calmodulin in all four cases. The levels of 43S complexes were significantly elevated with all four antagonists, indicating a block in the utilization of 43S complexes. The similarity of the effects of four distinct classes of antagonists and their ready reversal by exogenous calmodulin leads us to suggest that there may be a role for calmodulin or a very similar calcium-binding protein in protein synthesis.
Risk factors for small bowel bacterial overgrowth and diagnostic yield of duodenal aspirates in children with intestinal failure: a retrospective review.

Abstract Background Children with intestinal failure (IF) are at risk for small bowel bacterial overgrowth (SBBO) because of anatomical and other factors. We sought to identify risk factors for SBBO confirmed by quantitative duodenal culture. Methods A single-center retrospective record review of children who had undergone endoscopic evaluation for SBBO (defined as bacterial growth in duodenal fluid of >10 5 colony-forming unit per mL) was performed. Results We reviewed 57 children with median (25th-75th percentile) age 5.0 (2.0-9.2) years. Diagnoses included motility disorders (28%), necrotizing enterocolitis (16%), atresias (16%), gastroschisis (14%), and Hirschsprung disease (10.5%). Forty patients (70%) had confirmed SBBO. Univariate analysis showed no significant differences between patients with and without SBBO for the following variables: age, sex, diagnosis, presence of ileocecal valve, and antacid use. Patients receiving parenteral nutrition (PN) were more likely to have SBBO (70% vs 35%, P = .02). Multiple logistic regression analysis confirmed that PN administration was independently associated with SBBO (adjusted odds ratio, 5.1; adjusted 95% confidence interval, 1.4-18.3; P = .01). SBBO was not related to subsequent risk of catheter-related bloodstream infection (CRBSI). Conclusion SBBO is strongly and independently associated with PN use. Larger prospective cohorts and more systematic sampling techniques are needed to better determine the relationship between SBBO and gastrointestinal function.
CONGENITAL MEGALOURETHRA : A CASE REPORT

We describe a case of a male infant with a scaphoid megalourethra. A physical examination showed a large, flabby phallus with bilateral undescended testes. The corpus spongiosum was absent with normal corpora cavernosa. Urethrography showed a crescent-shaped dilatation of the anterior urethra. Further examination revealed an association with concomitant urogenital anomalies, right renal hypoplasia-dysplasia, bilateral vesicoureteral reflux and the prune-belly syndrome. A urethroplasty with resection of the excess urethral tissue and reconstruction of the urethra was performed. There was a satisfactory surgical result and the patient now voids without difficulty.
Overeating after midbrain 6-hydroxydopamine: Prevention by central injection of selective catecholamine reuptake blockers

Abstract Earlier research from this laboratory showed that 6-hydroxydopamine (6-OHDA) injected into the ventral midbrain of rats causes overeating and the gradual development of obesity in association with extensive depletion of forebrain norepinephrine. It was proposed that depletion of norepinephrine or epinephrine was the cause of the behavioral abnormality. This was questioned on the basis of experiments showing that 6-OHDA can cause non-selective lesions and also that non-selective neurotoxins can cause hyperphagia. To help resolve this question, the present experiments used 191 rats in 28 groups to test 3 doses of 6-OHDA and 3 different pretreatments with reuptake blockers, amphetamine, desmethylimipramine and benztropine. The result of midbrain 6-OHDA alone was hyperphagia that was highly correlated with the dose. Pretreatment with intraperitoneal desmethylimipramine (DMI) caused gastric distress, and systemic amphetamine cuased delayed overeating, but these unwanted side effects were avoided by injecting the drugs directly into the midbrain 15 min before the 6-OHDA. DMI and amphetamine partially prevented catecholamine depletion in the forebrain and totally prevented subsequent hyperphagia and obesity. Benztropine prevented dopamine depletion, but had no effect on hyperphagia. We conclude that some of the neurons protected by local injection of amphetamine and DMI are probably norepinephrine or epinephrine fibers that ascend through the ventral midbrain and have as one of their functions the inhibition of food intake. These neurons could also play a role in the control of body weight.
A qualitative exploration of the experiences of lesbian and heterosexual patients with breast cancer.

PURPOSE/OBJECTIVES To explore similarities and differences between lesbian and heterosexual survivors of breast cancer regarding cancer experiences, medical interactions related to cancer treatment, and quality of life (QOL). DESIGN Qualitative study using focus groups. SETTING Urban, community-based health center. SAMPLE A convenience sample of lesbians (n = 13) and heterosexual women (n = 28) with a diagnosis of breast cancer within the past five years. Participants were recruited via posted advertisements. METHODS Focus groups were conducted as part of a larger study exploring coping and adjustment in lesbian survivors of breast cancer. Transcribed focus group data were analyzed through thematic and representative case study methods. MAIN RESEARCH VARIABLES Broad aspects of medical interactions and the patient-provider relationship that may be associated with improved QOL of lesbian and heterosexual patients with cancer. FINDINGS Data suggested similarities between lesbians and heterosexual women in their overall QOL. However, differences did emerge between the groups. Lesbians reported higher stress associated with diagnosis, lower satisfaction with care received from physicians, and a trend toward lower satisfaction with the availability of emotional support. CONCLUSIONS Study findings have important implications for future research on adjustment and coping among lesbian patients with breast cancer and for the improvement of their mental and physical healthcare services. IMPLICATIONS FOR NURSING Study findings may help improve healthcare services for lesbians with cancer.
Dislocation reduction in GaAs crystal grown from the Czochralski process

Abstract The dislocation density in the gallium arsenide (GaAs) crystal is generated by excessive thermal stresses during the Czochralski (CZ) growth process. A constitutive equation which couples the dislocation density with the plastic deformation is employed to simulate the dislocation density in the crystal. The temperature distribution in the crystal during the growth process is obtained by solving the quasi-steady-state (QSS) heat-transfer equation. The thermal stresses induced by the temperature distribution are calculated using the finite-element method. The crystal is assumed to be an axisymmetrical ingot. The resolved shear stress (RSS) in each slip system is obtained by stress transformation. The RSS in each slip system is no longer axisymmetric. The dislocation motion and multiplication in each slip system are simulated using the constitutive equation. The total dislocation density in the crystal is obtained by summing the dislocation densities in all of the slip systems. Since the thermal stresses are sensitive to the temperature gradients and the dislocations move faster at a higher temperature, the dislocation densities are generated most near to the solid-melt interface. The dislocation density is also found to be affected by the growth orientation, growth speed, ambient temperature and the radius of the crystal. The dislocation density in GaAs crystals grown with the different growth orientation, growth speed, and crystal radius at various ambient temperatures has been calculated so that the influence of these growth parameters on the dislocation density can be understood. Consequently, the growth parameters can be controlled to reduce the dislocation density generated in the crystal during the CZ growth process.
Modeling population density across major US cities: a polycentric spatial regression approach

A common approach to modeling population density gradients across a city is to adjust the specification of a selected set of mathematical functions to achieve the best fit to an urban place’s empirical density values. In this paper, we employ a spatial regression approach that takes into account the spatial autocorrelation latent in urban population density. We also use a Minkowskian distance metric instead of Euclidean or network distance to better describe spatial separation. We apply our formulation to the 20 largest metropolitan areas in the US according to the 2000 census, using block group level data. The general model furnishes good descriptions for both monocentric and polycentric cities.
Histochemical changes in ATPase activity during regeneration of adult skeletal muscle fibers

Abstract Developing skeletal muscle fibers (myotubes) and fully differentiated (adult) muscle fibers can be distinguished according to their histochemical “myofibrillar” ATPase reaction. Myotubes stain darkly for the ATPase reaction at pH 9.4 following preincubation of sections in either alkali (pH 10.4) or acid (pH 4.35). This staining is exclusively localized to the myofibrils of these embryonic fibers. In the soleus muscle of the guinea pig, a progressive conversion to the adult staining pattern is completed 1 month following birth; fibers then stain lightly after alkaline-preincubation and darkly following acid-preincubation when staining is intermyofibrillar as well as myofibrillar. Thus the staining reaction can be used to follow developmental alterations in muscle fibers, and in the present study it was used to determine whether the regenerating fibers in an injured, fully differentiated muscle repeat the developmental changes. Fibers were transected in fully differentiated soleus muscles of guinea pigs, and at periodic intervals these injured muscles were examined histochemically. The sequence of histochemical and morphological changes in the regenerating muscle fibers essentially repeated normal development. Since regenerating fibers go through the same stages as during normal development, the restoration process probably involves the elaboration and fusion of undifferentiated myogenic cells or dedifferentiated muscle cells.
DISTRIBUTED CONTROL OF A MULTIPLE TETHERED MOBILE ROBOT SYSTEM FOR HIGHWAY MAINTENANCE AND CONSTRUCTION

The development of a distributed control system for a multiple mobile robot system is described. The mobile robots considered have been termed tethered mobile robots (TMRs). The TMRs are differentially steered, wheeled mobile robots tethered to a support vehicle, and they have been designed for automating highway maintenance and construction. The control system consists of a network of a host computer and several real-time dynamic controllers running under Windows for Workgroups and DOS operating systems, respectively. Advanced industrial embedding technology is applied to the hardware design, and the system's fault-tolerance is achieved from a distributed architecture and overall condition monitoring. The object-oriented and hardware-independent software programming provides a graphic user interface and flexibility for a large number of highway maintenance and construction tasks. It also provides convenience for any other mobile robotics research applications.
Phonon-assisted transition rates I. Optical-phonon-assisted hopping in solids

Abstract An extensive calculation of the optical-phonon-assisted transition rates for non-adiabatic electronic hopping motion in a solid is presented. Holstein's Molecular Crystal Model is used as a basis for study and the computation involves no restrictions on either the magnitude of the electron-lattice coupling strength, the temperature, or the difference between the electronic energies of the initial and final sites. In the strong-coupling small-polaron regime, the jump rates, associated d.c. conductivity, a.c. conductivity, and electric-field dependence of the d.c. conductivity, for a crystal are all calculated. These transport properties manifest qualitatively distinct behaviours corresponding to whether the temperature is above or well below the optical-phonon temperature. In the low-temperature regime the energy-conserving processes which involve the absorption of the minimum amount of vibrational energy provide the dominant contribution to the thermally activated jump rates. At sufficiently high...
Recovery of prostacyclin synthesis in human vascular endothelial cells following intermittent or continuous exposure to indomethacin.

Abstract Indomethacin is a potent prostaglandin synthesis inhibitor, which is widely used in treating arthritis and other inflammatory conditions. This study investigated the effect of physiological levels of indomethacin on synthesis of the antiplatelet substance prostacyclin, by human vascular endothelial cells in culture. The nature of the inhibition and its reversibility following removal of indomethacin were characterized. Almost complete inhibition of prostacyclin synthesis was obtained at concentrations of 5.6 μM indomethacin, which were within physiological blood levels (1.4–16.8 μM) attained during routine indomethacin therapy. Inhibition was essentially irreversible for all exposure periods in excess of one minute. Following inactivation by brief (5 minute) exposure to indomethacin, partial recovery of prostacyclin synthesis to between 45% and 60% of control values was attained 24 hours after indomethacin removal. Prolonged (24 hours) exposure of cells to indomethacin did not further impair subsequent recovery of prostacyclin synthesis and did not affect cell viability. Recovery of enzyme was much more rapid in confluent quiescent monolayers of endothelial cells than in dividing cultures. The results indicate that continuous or intermittent exposure to indomethacin may significantly impair vascular prostacyclin synthesis in vascular endothelium, but that substantial recovery may occur within 24 hours of drug removal.
Airborne infrared and visible sensors used for law enforcement and drug interdiction

Throughout the 1980's, airborne infrared and visible band sensors have played an increasing role in the fields of law enforcement and drug interdiction. In the 1990's, as more enforcement agencies avail themselves of existing and evolving sensor technologies, a family of issues peculiar to airborne sensor applications for search and rescue, boarder patrol, security, surveillance and intelligence gathering will be addressed by a rapidly growing industry. Increasingly, single payload gimbals are being replaced by multiple role sensor assemblies, capable of two and even three waveband imaging, target designation and illumination. The ability to provide these multi-function sensor pods and integrate, anal'ze and store the resultant imagery and data will be a necessary requisite to continue servicing the law enforcement community. This paper discusses some of the applications of visible and IR sensors in law enforcement and the issues peculiar to their use in that community. Sensor technology which is currently available will be described, as well as new sensor developments which will become deployed throughout the 1990's. Particular emphasis will be given to IR and visible sensors, lasers and sensor fusion. A short videotape of JR and visible imagery used in law enforcement will be shown.
Pulmonary complications in bone marrow transplantation: a practical approach to diagnosis and treatment.

Hematopoietic stem cell transplantation (HSCT)has become the standard technique of bone marrowtransplantation (B M T ); nearly 20,000 procedureswere performed in North America during 1998 [1] .The donor source may be the patient (autologous), asibling or unrelated person (allogeneic), an identicaltwin (syngeneic), or a genetically-unrelated umbilicalcord blood sample [2] . Although syngeneic grafts donot develop graft-versus-host disease (GVHD) andhave low er treatm ent-related m ortality com paredwith allogeneic transplants, the advantages are oftencounterbalanced by a greater risk of malignant re-lapse. Thus, overall mortality is similar for syngeneicand allogeneic BMT .T he process of H S C T involves three stages:(1 ) conditioning of the recipien t, (2) inf usion ofhematopoietic stem cells, and (3) engraftment. Con-ditioning may involve cytoreductive therapy with orwithout total body irradiation (TBI). For solid tumors,high-dose cytoreductive chemotherapy may be usedin an attempt to achieve complete tumor ablation.Some chemoth erape utic age nts (eg, cyc lophosp ha-mide and busulfan) are direct pulmonary toxins thatcan lead to the development of drug-induced lunginjury and interstitial pneumonitis [3] . TBI also maybe used during the conditioning phase to prevent therelapse of the primary disease and graft failure. Dose-related, radiation-induced lung injury is reflected bya reduc tion in diffusing capac ity of the lung [4] .Furthermore, the combination of high-dose chemo-therapy and TBI synergistically increases the inci-dence and the severity of pulmonary complications[5] . In fact, idiopathic pneumonia syndrome (IPS)may be a direct consequence of radiation- and chemo-therapy-induced lung injury [6] .Th e hema topoi etic stem ce lls can be coll ect edfro m bon e marr ow , peri pher al blood , plac enta , orumbilical cord blood (T able 1) . Peripheral blood hasbecome the preferred source of stem cells for autolo-gous recipients because iteliminates the need for gen-eral anesthesia that is associated with bone marrowas piration. He m atopo ietic stem cells that are har-vested from the patientO s peripheral blood after treat-m ent with gra nul ocy te colo ny Ð stim ulat ing factor(G-CSF) or granulocyte-macrophage colony Ð stimu-lating factor (GM-CSF) are being used increasingly inautologous recipients. F or alloge ne ic H S CT , tech-niques, such as removal of T lymphocytes from thedonor graft, have lowered the incidence of GVHD.N onetheless, recipients are still prone to develop-ment of cytomegalovirus (CMV) infection, invasivefungal infections, and Epstein-Barr virus Ð associatedposttransplantation lymphoproliferative disease. Morerecently , hematopoietic stem cells from placental orumbilical cord blood were used to perform allogeneictransplants. This technique also is associated with alower incidence of graft rejection and GVHD [7] .Engraftment is defined as an absolute neutrophilcount that is greater than 0.5 ! 10
Radiance enhancement of the 16-Mum CF4 laser.

The spectral radiance and quantum yield of the CF4 laser operating at 16 μm have been increased more than an order of magnitude by narrowing the frequency bandwidth of the CO2 pump laser and by telescopically matching the pump radiation to the lowest-order mode of the 16-μm resonator. The temporal and spectral characteristics of the radiation, as well as the optical gain of the laser, have been determined.
The binocular contribution to monocular optokinetic nystagmus and after nystagmus asymmetries in humans

Stereoblind subjects show marked monocular asymmetries in both OKN and OKAN, while normal subjects produce more balanced nystagmus. There is a negative relationship between the magnitude of the asymmetries and the magnitude of a binocular contribution to OKN production as measured with dichoptic, strobe illumination. A second experiment with normal subjects corroborated this relationship, revealing a small, but significant asymmetry in these subjects' OKAN. Further, there was no correlation between the monocular nystagmus asymmetries and stereoacuity. The results are explained in terms of subcortical binocular mechanisms.
Identification of the metal-binding sites of restriction endonucleases by Fe2+-mediated oxidative cleavage.

Fenton chemistry [Fenton (1894) J. Chem. Soc. 65, 899-910] techniques were employed to identify the residues involved in metal binding located at the active sites of restriction endonucleases. This process uses transition metals to catalytically oxidize the peptide linkage that is in close proximity to the amino acid residues involved in metal ligation. Fe2+ was used as the redox-active transition metal. It was expected that Fe2+ would bind to the endonucleases at the Mg2+-binding site [Liaw et al. (1993) Biochemistry 32, 7999-4003; Ermacora et al. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 6383-6387; Soundar and Colman (1993) J. Biol. Chem. 268, 5264-5271; Wei et al. (1994) Biochemistry 33, 7931-7936; Ettner et al. (1995) Biochemistry 34, 22-31; Hlavaty and Nowak (1997) Biochemistry 36, 15515-15525). Fe2+-mediated oxidation was successfully performed on TaqI endonulease, suggesting that this approach could be applied to a wide array of endonucleases [Cao and Barany (1998) J. Biol. Chem. 273, 33002-33010]. The restriction endonucleases BamHI, FokI, BglI, BglII, PvuII, SfiI, BssSI, BsoBI, EcoRI, EcoRV, MspI, and HinP1I were subjected to oxidizing conditions in the presence of Fe2+ and ascorbate. All proteins were inactivated upon treatment with Fe2+ and ascorbate. BamHI, FokI, BglI, BglII, PvuII, SfiI, BssSI, and BsoBI were specifically cleaved upon treatment with Fe2+/ascorbate. The site of Fe2+/ascorbate-induced protein cleavage for each enzyme was determined. The Fe2+-mediated oxidative cleavage of BamHI occurs between residues Glu77 and Lys78. Glu77 has been shown by structural and mutational studies to be involved in both metal ligation and catalysis [Newman et al. (1995) Science 269, 656-663; Viadiu and Aggarwal (1998) Nat. Struct. Biol. 5, 910-916; Xu and Schildkraut (1991) J. Biol. Chem. 266, 4425-4429]. The sites of Fe2+/ascorbate-induced cleavage for PvuII, FokI, BglI, and BsoBI agree with the metal-binding sites identified in their corresponding three-dimensional structures or from mutational studies [Cheng et al. (1994) EMBO J. 13, 3297-3935; Wah et al. (1997) Nature 388, 97-100; Newman et al. (1998) EMBO J. 17, 5466-5476; Ruan et al. (1997) Gene 188, 35-39]. The metal-binding residues of BglII, SfiI, and BssSI are proposed based on amino acid sequencing of their Fe2+/ascorbate-generated cleavage fragments. These results suggest that Fenton chemistry may be a useful methodology in identifying amino acids involved in metal binding in endonucleases.
Tracer dispersal by mid-ocean mesoscale eddies. Part I. Ensemble statistics

Abstract The rate at which, and the processes by which, a passive tracer is stirred and mixed in a turbulent mesoscale eddy field are examined for environmental parameters characteristic of a homogeneous mid-ocean region. The simulated, time-dependent eddy field is obtained by direct integration of the forced/damped barotropic vorticity equation; the dispersal of a spatially localized, instantaneous release of tracer (a “tracer spot”) within the evolving velocity field is subsequently computed from the advective-diffusive equation. An ensemble of 10 independent releases is used to determin the average spreading properties of the tracer spot. On an f-plane, the ensemble-averaged dispersal is approximately isotropic, and is associated with an effective diffusion rate substantially greater than that supported in the absence of turbulent advection. Quantitatively, the effective ensemble-averaged diffusivity is shown to be 0(UL), where U and L are characteristic velocity and length scales of the turbulent flow. This estimate is consistent with the traditional mixing length hypothesis. With the addition of β, the simulated flow field has substantial zonal anisotropy. Ensemble-averaged dispersal of tracer spots is similarly anisotropic, and the overall rate of tracer dispersal is substantially reduced over its f-plane value. Both with and without β, the initial rate at which maximum tracer concentration and total tracer variance decay are given by the approximate law exp[− αγt] where γ is the RMS rate of strain, and α is approximately constant at a value of 0.5. The heightened rate of variance loss over that associated with pure (subgridscale) diffusion is shown to be accommodated by the rapid transfer of tracer variance from the largest to the shortest scale tracer features, that is, by the rapid sharpening of tracer gradients by turbulent advection. A detailed examination of the dispersal of individual tracer realizations, and the associated question of tracer streakiness, is given in part II of this work (Keffer and Haidvogel, in preparation).
Short-term alcohol administration alters KiSS-1 gene expression in the reproductive hypothalamus of prepubertal female rats.

Background Kisspeptins bind to the G protein coupled receptor (GPR54), to activate hypothalamic luteinizing hormone releasing hormone (LHRH) secretion at the time of puberty. Alcohol (ALC) causes depressed prepubertal LHRH release, resulting in depressed luteinizing hormone (LH) secretion and delayed puberty. Because KiSS-1 and GPR54 are important to the onset of puberty, we assessed the effects of chronic ALC administration on basal expression of these puberty related genes within the reproductive hypothalamus, as well as hormones and transduction signaling pathways contributing to their activity.