cssi/SciSciGPT-SciSciNet huggingface dataset:
Delta bonds and rotational barriers in 4d and 5d metal-porphyrin dimers

This review summarizes the contribution made to the field of delta bonds by Collman and co-workers. The delta (σ) bond is unique to metal-metal multipty bonded systems and has been the subject of several reviews (F. A. Cotton and R.A. Walton,Multiple Bomls Between Metal Atoms (Oxford University Press, New York, 1993), and references therein). Our contribution to this field is the measurement of the barrier to rotation about the axis of the metal-metal bond for a series of Mo and W porphyrin dimers. (J. P. Collman and L K. Woo (1984).Proc. Natl. Acad. Sci. USA 81, 2592-2596; J. P. Collman, J. M. Garner, R.T. Hembre, and Y. Ha (i992).J. Am. Chem. Soc. 114, 1292–1301). The barriers to rotation for the porphyrin dimers are as follows: ΔG: rot,=9.8 to 10.7±0.5 kcal/mol for a series of [M(OEP-X)]2 dimers (X=CHO, NCO), ΔG: rot,= 10.5±0.5 kcal/mol for [Mo(TOEP)]2 and ΔG: rot= 12.9∓0.1 kcal/mol for [W(TOEP)], Each of these barriers reflects both the strength of the delta bond and steric interactions. The steric component is estimated to be small ( <5 kcal/mol); hence the barrier can be used as an estimate for the delta bond strength. These studies constitute the firstdirect experimental probe of the strength of delta bonds. These data for the rotational barriers in Mo and W dimers are of the same order of magnitude as the estimate of the 6 bond strength obtained using a generalized valenee bond treatment (6±3 kcal/mol) (D. C. Smith and W. A. Goddard 1II (1987).J. Am. Chem. Soc. 109, 5580-55831 and are in agreement with the recent estimate of the delta bond strength (⊃10kcal/mol) (M.D. Hopkins, H.B. Gray, and V.M. Miskowski (1987).Polyhedron 6, 705—714). In addition, this study demonstrates that the W (5d)σ bond is significantly stronger (⊃ 20%) than the anatogous Mo (4d)σ bond; this is consistent with the assertion that the greater radial expansion of 5 d orbitals can result in 5d-5d bonds which arestronger eren though they may belonger.
Measuring preference-based quality of life using the EuroQol EQ-5D in patients with cerebral aneurysms.

OBJECTIVE Cerebral aneurysms can adversely affect quality of life (QOL) via mass effect, subarachnoid hemorrhage, anxiety, or treatment sequelae. The EuroQol EQ-5D is a popular generic 5-item multiple-choice survey questionnaire that measures preference-based QOL on a 0 to 1 scale. We assessed the validity and reliability of the EQ-5D in patients with cerebral aneurysms. METHODS We collected data from 178 neurosurgery clinic patients with cerebral aneurysms. Patients were assigned Glasgow Outcome Scale, Rankin scale, Barthel index, and Physical Performance Test scores, and completed the Short-Form 12, Hospital Anxiety and Depression scale, and the EQ-5D. We assessed the construct validity of the EQ-5D by comparing the EQ-5D and the other scales using rank-order methods and multivariate linear regression. Reliability was assessed with Cronbach's alpha. RESULTS Patients had a mean age of 54.7 years (standard deviation, 12.6 years), 131 (74%) were women, and 98 (55%) had survived a subarachnoid hemorrhage. The mean EQ-5D score was 0.80 (standard deviation, 0.19). Construct validity of the EQ-5D was confirmed by statistically significant associations between EQ-5D and Glasgow Outcome Scale, Rankin scale, Barthel index, Physical Performance Test, Short-Form 12 Physical Component Summary, and Hospital Anxiety and Depression scores (for all, P < or = 0.05). Multivariate regression showed that the EQ-5D scores were independently associated with the Barthel index, Short-Form 12 Physical Component Summary, and Hospital Anxiety and Depression scale anxiety and depression subscales (pseudo R = 0.40). Reliability was demonstrated by Cronbach's alpha of 0.70. CONCLUSION The EQ-5D is a valid and reliable instrument for measuring QOL in patients with cerebral aneurysms. The EQ-5D provides a single QOL value incorporating functional status, physical functioning, and mental health.
On efficient simulations of systolic arrays by random-access machines

We give efficient simulations of systolic arrays by unit-cost random-access machines (RAM’s). For example, we show that a one-dimensional systolic array operating in linear time can be simulated by a RAM in $O({{n^2 } / {\log ^2 n}})$ time. For the case of a two-dimensional systolic array, the simulation time is $O({{n^3 } / {\log ^{{3 / 2}} n}})$.
Radiology's role in the battle against pediatric cancers.

Like most medical disciplines, radiology is relentlessly forward looking, always tending to focus on the latest innovations. Journal articles and continuing medical education courses are replete with the latest developments in imaging science and technology, outlining their implications for the daily practice of radiology. This is both natural and good. However, there are risks in gazing only in the forward direction and never pausing to reflect on where we have been. For one thing, we cannot draw lessons from our mistakes and successes unless we reflect on our past. Moreover, understanding the contributions of predecessors can enhance our appreciation for the value of the capabilities we currently enjoy, ensuring that we do not take them for granted. Above all, we cannot see our current location and trajectory unless we understand where we have come from. One of the most remarkable stories in medicine in the latter half of the 20th century was the successful battle against many pediatric cancers. For example, about 3000 children each year are diagnosed with acute lymphoblastic leukemia. In the 1950s as today, a child 3 to 5 years of age would present to a physician’s office with complaints of pallor, shortness of breath, bruising, headaches, and lack of appetite. A blood smear would show a large number of lymphocytic blasts. In 1950, effective treatments were unavailable, and the question was not whether the patient would die, but how soon. Today, patients diagnosed with acute lymphoblastic leukemia enjoy a 90% survival rate. Happily, such progress has not been restricted to leukemias, and the overall survival rate of US children diagnosed with cancers of all types has risen from approximately 10% in 1950 to >80% today. Cancer in childhood is relatively uncommon, accounting for only 13,000 of the 1.3 million new US cancer diagnoses each year. This being said, however, children’s cancers have served as important models for the management of cancers
Synthesis, receptor binding and tissue distribution of 17α-E[125I]iodovinyl-11β-ethyl-estradiol

Abstract In this study we prepared and evaluated a derivative of estradiol with an ethyl group at the 11β-position and an E-iodovinyl group at the 17α-position. This new ligand binds to the estrogen receptor with an affinity slightly less than estradiol (RBA = 43%) at 0 °C but much greater (RBA = 890%) at 25 °C. The 125 I-labeled derivative was obtained by radioiododestannylation of the tri- n -butylstannyl precursor in good radiochemical yield with a specific activity exceeding 1500Ci/mmol. The tissue distribution in immature female rats was evaluated over a 48 h period to determine uterine uptake and selectivity. Peak uterine uptake at 2 h was 6% ID/g and was significantly greater than that of [ 3 H]estradiol, 2.4% ID/g. Substantial uptake in the uterus was still present at 48 h (2.4% ID/g). Co-administration of estradiol reduced the uptake at 2 and 24 h by 85%. Uterus-to-plasma ratios increased with time, from about 25:1 at 2 h to nearly 90:1 at 48 h. The affinity, ease of radiosynthesis and tissue distribution of the 17α-E-[ 125 I]iodovinyl-11β-ethyl-estradiol suggest that further evaluation of this agent as an imaging agent for estrogen-receptor-positive breast cancer is warranted.
A Half Dozen Puzzles Regarding Intrinsic Attitudinal Hedonism

But the main reasons I enjoyed the paper are that Fred's presentation and defense of attitudinal hedonism is interesting and that it's been great fun puzzling over various aspects of his view for the past several weeks. Some of the puzzles might rise to the level of objections, but others really are just puzzles-I'm unsure what we should say. In these comments I'll try to describe a half dozen puzzles that I have been able to think up without trying to organize them around any unifying theme.
The Epidemiology of Behavior Disorders in Children

A COMPARATIVE review of research into children's behavior disorders brings into sharp focus the major problems in such studies. Variability in the definitions and methods used by different investigators makes it difficult to select the more valid findings among the discrepant data reported. An aspect of the dilemma is illustrated by Goldfarb's study1of the relative ability of school teachers and psychiatrists to identify psychiatric cases among school children. He found that these two professional groups disagreed on the identification of specific children with mental health problems and concluded that the teachers required further training to increase their sensitivity to psychiatric cases. The assumption that the correct definition of a psychiatric case is a secure part of the psychiatrist's armamentarium is open to question when psychiatric diagnosis still lacks the means for objective validation. Far more than in other medical fields, psychiatric diagnosis is known to vary with the
A new computer-oriented approach to molecular mechanics

A new dynamical theory for atomic and molecular dynamics is formulated and discussed. The associated nonlinear differential system is derived from general atomic and molecular stability properties and from aspects of modern particle theory, especially as it relates to the structure of the electron. Computer experiments are described for developing a new model of the water molecule.
Streptococcus milleri Group Cutaneous Abscess Associated With Insulin Injection to Distal Lower Extremity in an Insulin-Dependent Diabetic Man

Purpose: We report a case of Streptococcus milleri group (SMG)–associated cutaneous abscess in an older diabetic man. The infection developed after subcutaneous insulin injection to the distal lower extremity. This is the first known account of SMG-associated abscess secondary to insulin administration.Summary: A 60-year-old Caucasian insulin-dependent diabetic male developed a severe cutaneous infection including abscess and surrounding cellulitis at the site of a self-administered insulin glargine injection on the medial portion of his right lower leg. The infection developed rapidly within 1 day following the injection. Cultures from purulent drainage were positive for SMG. The infection resolved rapidly with an antibiotic regimen including 1 dose of clindamycin followed by intravenous pipercillin/tazobactam plus vancomycin and concluded with outpatient treatment with sulfamethoxazole/trimethoprim. Organisms belonging to SMG are increasingly recognized as pyogenic pathogens responsible, most commonly, ...
Defectivity in Laterally Confined Lamella-Forming Diblock Copolymers: Thermodynamic and Kinetic Aspects

We use self-consistent field theory (SCFT) to study the directed self-assembly of laterally confined diblock copolymers. In this study, we focus on systems in which the self-assembled lamellae are oriented parallel to selective sidewalls in a channel. While well-ordered, perfect lamellae are observed in narrow channels both experimentally and numerically, undesirable defective structures also emerge. We therefore investigate the energetics of two categories of isolated defects (dislocations and disclinations) for various segregation strengths and channel dimensions, and establish conditions that favor the formation of defects. We also determine the energy barrier and the transition path between defective and perfect states using the string method. We find that only a few kT of energy are necessary to overcome the kinetic barrier and remove a defect, sharply contrasting with the large gain in free energy (many tens of kT) that is necessary for the formation of a defect from the pristine state.
Chaotic adiabatic energy diffusion and the Fermi mechanism

Abstract Energy diffusion in chaotic adiabatic systems is illustrated with a model depicting the Fermi mechanism for cosmic ray acceleration.
A sterically demanding iminopyridine ligand affords redox-active complexes of aluminum(III) and gallium(III).

The combination of an electrophilic metal center with a redox active ligand set has the potential to provide reactivity unique from transition metal redox chemistry. In this report, substituted iminopyridine complexes containing monoanionic and dianionic MeIPMes ligands have been characterized structurally and electronically. Green (MeIPMes–)AlCl2 (1), (MeIPMes–)AlMe2 (2), and (MeIPMes–)GaCl2 (5) have a doublet spin state which results from the anion radical form of MeIPMes. Purple (MeIPMes2–)AlCl(OEt2) (3), (MeIPMes2–)AlMe(OEt2) (4), and (MeIPMes2–)GaCl(OEt2) (6) are each diamagnetic. We have also investigated the solvent dependence of the decomposition of the MeIPMes anion radical. Complexes 1 and 2 can be obtained from benzene and hexanes whereas the use of ether solvents results in the formation of undesirable (CH2IPMes–)AlCl2 (1a) and (CH2IPMes–)AlCl2 (2a) formed by loss of a hydrogen atom from the MeIPMes– ligand. Electrochemical measurements indicate that 1, 2, and 5 are redox active.
Validation (not just verification) of deep space missions

Verification & validation (VV validation proves it is the right design" is rather vague. And while verification is a reasonably well standardized systems engineering process, validation is a far more abstract concept and the rigor and scope applied to it varies widely between organizations and individuals. This is reflected in the findings in recent mishap reports for several NASA missions, in which shortfalls in validation (not just verification) were cited as root- or contributing-factors in catastrophic mission loss. Furthermore, although there is strong agreement in the community that test is the preferred method for V&V, many people equate "V&V" with "test", such that analysis and modeling aren't given comparable attention. Another strong motivator is a realization that the rapid growth in complexity of deep-space missions (particularly planetary landers and space observatories given their inherent unknowns) is placing greater demands on systems engineers to "get it right" with validation.
THE FORMATION OF ETTRINGITE AT ELEVATED TEMPERATURE

Abstract The formation of ettringite was investigated by isothermal calorimetry over the range of temperature from 50 to 70°C. Ettringite was formed using three sources of alumina: tricalcium aluminate, high alumina cement and calcium aluminate sulfate. In accord with a diffusionally controlled reaction mechanism, the kinetics of ettringite formation exhibit minimal temperature dependence over this range. C 4 A 3 S and HAC evolve comparable amounts of heat in ettringite formation while the heat evolved when the alumina-containing reactant is C3A is significantly higher.
Light-scattering technique for the study of dynamic thickness fluctuations in thin liquid films

We describe a light-scattering technique capable of probing the dynamics of thickness fluctuations in lipid bilayers. The technique, which we call reflectance fluctuation spectroscopy (RFS), is keenly sensitive to light scattered from the squeeze modes of motion in a thin liquid film, and insensitive to light scattered from the bend modes. A laser beam is focused to a small spot on the film, and the power in the specularly reflected beam is recorded in real time. Thickness fluctuations associated with the squeeze modes of motion give rise to fluctuations in the power of the specularly reflected light. The frequency spectrum of the fluctuations in detected power (RFS spectrum) can be analyzed to yield values for the film viscosity and thickness compressibility. We present two independent theoretical derivations of the RFS spectrum and show that scattering from the bend mode can be neglected. The theoretical expression for the RFS spectrum is compared with experimental spectra obtained from glycerylmono-oleate--decane bilayers. The fit of the theory to the data is excellent and the values deduced for the film viscosity and thickness compressibility are reasonable.
Optimal design of wing structures with substructuring

Abstract An iterative method for optimal design of large scale structures that incorporates the concept of substructuring is extensively applied to wing-type structures to demonstrate its generality, effectiveness and efficiency. Optimum designs for several wing-type structures are obtained and compared with results available in the literature. It is shown that considerable efficiencies can be achieved by integration of the substructuring concept into a structural optimization algorithm.
17β-Estradiol- and 4-hydroxytamoxifen-induced transactivation in breast, endometrial and liver cancer cells is dependent on ER-subtype, cell and promoter context

The pattern of transcriptional activation by 17beta-estradiol (E2) and 4-hydroxytamoxifen (4-OHT) was determined in ZR-75 and MDA-MB-231 breast, ECC1 and HEC1A endometrial and HepG2 liver cancer cell lines cotransfected with E2-responsive constructs and wild-type estrogen receptor alpha (ER alpha) or ER beta (ER beta) or variant forms of ER alpha expressing activation function 1, AF1 (ER alpha-AF1) or activation function 2, AF2 (ER alpha-AF2). The E2-responsive constructs contained promoter inserts from the human complement C3 (pC3), human cathepsin D (pCD) and rat creatine kinase B (pCKB) genes. Minimal ER beta-dependent transactivation (<2.5-fold induction) was observed for E2 only in ECC1 and MDA-MB-231 cells transfected with pCKB or pC3, whereas 4-OHT was inactive as an ER beta agonist for all promoters in the four cell lines. The ER alpha agonist and/or antagonist activities for E2 and 4-OHT were highly variable and the transactivation was dependent on ER subtype, ER alpha variant expressed, gene promoter, and cell context. For example, E2 did not activate pCD in HepG2 cells transfected with wild-type or variant ER alpha, whereas E2 activated reporter gene activity in the four endometrial and breast cancer cell lines transfected with ER alpha and pCD, pCKB or pC3. Hormone activation of these constructs by ER alpha-AF1 or ER alpha-AF2 was highly variable among the different cell lines and even in the same cell line transfected with the three E2-responsive constructs. Similar variability was observed for 4-OHT. For example, 4-OHT activates pC3 in HepG2 cells transfected with ER alpha or ER alpha-AF1, and pCKB in HEC1A cells. However, AF1-dependent activation by 4-OHT is not observed for pCKB in ECC1 cells or for pC3 and pCD in HEC1A or ECC1 endometrial cancer cells. The results of this study suggest that transcriptional activation by E2 and 4-OHT induces recruitment of different transcription factor complexes that are dependent on the cell type and also the gene promoter.
Analysis of flight effects on noise radiation from dual-flow coaxial jets

A theoretical study has been made of the effects of flight on noise from dual-flow coaxial jets. The theory is based on an instability free, vortex sheet flow model. It is shown that the flight effects are more favorable (and hence produce less forward-arc amplification) for coaxial jets than for single-stream jets. Further, the theory predicts that, like the single-stream jet case, flight effects induce noise amplification in the forward quadrant and attenuation in the aft quadrant and have virtually no effect at theta = 90 deg to the jet axis, where theta is the angle between the directions of convection and emission at the retarded time. Amplification in the forward quadrant diminishes as the inner flow velocity increases and becomes optimum when the outer-to-inner velocity ratio is about 0.5. The theory also shows that the higher the outer-to-inner area ratio, the lower the forward-arc amplification due to flight.
Chordal graphs, interval graphs, and wqo

Let precedes, equal to be the induced-minor relation. It is shown that, for every t, all chordal graphs of clique number at most t are well-quasi-ordered by precedes, equal to. On the other hand, if the bound on clique number is dropped, even the class of interval graphs is not well-quasi-ordered by precedes, equal to. © 1998 John Wiley & Sons, Inc. J Graph Theory 28: 105–114, 1998
P-selectin blockade fails to improve acute lung injury in sheep

Accumulation of neutrophils in the lung contributes to the endothelial damage in the tissue associated with acute respiratory distress syndrome. This initial recruitment of neutrophils within the pulmonary microvasculature may involve P-selectin. Thus we hypothesized that an antibody against P-selectin would reduce pulmonary damage. Sheep were chronically instrumented and prepared. The first group received 40% body surface area third-degree burns with 48 breaths of cotton smoke and 1 mg/kg of anti-(P-selectin) antibody (termed 3D4) 1 h post injury (n fl 5). The second group (non-treated) received the same injury but no antibody treatment (n fl 6). The third group comprised of sham animals without any injury or antibody treatment (n fl 6). Sheep were studied for 48 h during which they were uniformly resuscitated with Ringer’s lactate solution by following the Parkland formula. All the animals were mechanically ventilated. In the non-treated injured group, the arterial partial pressure of O2 (‘PaO2’)/inspired fraction of O2 (‘FiO2’) ratio dropped to 168‡30 at 48 h, whereas the lung lymph flow increased to an average of 46‡9 ml/h (10-fold of baseline). These changes were not prevented by an anti-(P-selectin) antibody. The plasma and lymph nitrate/nitrite levels were lower in the antibody-treated group than in the non-treated group. The lymph conjugated dienes were significantly lower in the treated animals. However, lung myeloperoxidase activity and lung tissue conjugated dienes were significantly increased in the treated animals compared with the non-treated injured controls. In conclusion, although the anti-(P-selectin) antibody did not protect against lung injury during the initial 48 h of burn and smoke, it decreased some aspects of injury in the peripheral microcirculation.
Photodecomposition of 2,4-dichlorophenoxyacetic acid

Abstract Three types of reactor operation, flow-differential, flow-integral, and batch-recycle were employed to study the kinetics of the photolysis and oxidation of 2,4-dichlorophenoxyacetic acid (2,4-D). The flow-through annular reactor was irradiated with a polychromatic lamp located at the axis of the annulus. Using aqueous solutions of pollutant-level concentrations (5-50 ppm), the initial rate was found proportional to the light abosrbed and otherwise independent of 2,4-D and dissolved oxygen concentrations. Using thin-layer chromatographic and spectroscopic analytical methods, 2,4-dichlorophenol (2,4-DCP) was identified as one of the photolysis products. Measurements were also made of the initial rate and rate at finite conversions for 2,4-DCP. The results were consistent with a rate equation based upon a photo-activation process followed by formation of peroxides. Of particular significance was the autocatalytic effect of intermediates on the rate of disappearance of 2,4-D. One such catalytic agent was 2,4-DCP. Carbon dioxide was produced as the final oxidation product when either 2,4-D or 2,4-DCP was the reactant. The amount of CO 2 formed proved that the aromatic ring was ruptured. This suggests the possibility of employing photochemical oxidation for reducing refractory, aromatic pollutants into fragments more susceptible to biological oxidation.
Hydrogen purification: MOF membranes put to the test

Membranes are key components for the removal of greenhouse gases during fuel generation processes, such as hydrogen production, but simultaneous permeability and selectivity is difficult to obtain. This has now been achieved in ultrathin membranes that use the size-selective porosity of metal–organic frameworks to separate CO2 from H2.
Why are some plant genera more invasive than others

Determining how biological traits are related to the ability of groups of organisms to become economically damaging when established outside of their native ranges is a major goal of population biology, and important in the management of invasive species. Little is known about why some taxonomic groups are more likely to become pests than others among plants. We investigated traits that discriminate vascular plant genera, a level of taxonomic generality at which risk assessment and screening could be more effectively performed, according to the proportion of naturalized species which are pests. We focused on the United States and Canada, and, because our purpose is ultimately regulatory, considered species classified as weeds or noxious. Using contingency tables, we identified 11 genera of vascular plants that are disproportionately represented by invasive species. Results from boosted regression tree analyses show that these categories reflect biological differences. In summary, approximately 25% of variation in genus proportions of weeds or noxious species was explained by biological covariates. Key explanatory traits included genus means for wetland habitat affinity, chromosome number, and seed mass.
On the cone of positive semidefinite matrices

Abstract A survey of some general properties of the cone of positive semidefinite matrices, its faces, two isometric isomorphisms, and linear transformations on it is given.
ABSCISSION AGENT EFFECTS ON ORANGE JUICE FLAVOR

The flavor quality of juice products from early- (Hamlin), mid- (Pineapple) and late-season (Valencia) oranges sprayed with abscission chemicals to aid in mechanical harvesting, was evaluated and compared with that of similar juice products from untreated fruit. Four commercially available abscission agents were included in this study: Acti Aid®, Release®, Pik-Off® and ethephon. An expert taste panel distinguished experimental from control juice samples in most tests and generally preferred juice products made from control oranges.
Schumpeter, product innovation and public policy: the case of cigarettes

Perhaps the most fundamental proposition advanced by Joseph Schumpeter is that competition drives innovation and innovation drives progress. Strangely, although “competition” was a key ingredient to the processes of his capitalistic world, Schumpeter was not concerned about private monopolies and evidently had little stomach for the antitrust policy practiced over the past 50 years in the United States, or for the rather aggressive policy that is emerging currently in the European Common Market.1 At the same time, a careful reading of his writings discloses that Schumpeter’s benign view of monopolies and restraints of trade was limited to product markets; he expressed a definite concern about monopoly and restraints of trade in R & D-innovation markets. Schumpeter also displayed a very prophetic insight about R & D/innovation and public policy, observing: “... Surely nothing can be more plain or even more trite common sense than the proposition that innovation ... is at the center of practically all the phenomena, difficulties, and problems of economic life in capitalist society.”2 As keen a vision as Schumpeter displayed about economic processes and public policy, he could not have imagined that his theories of innovation and “creative destruction” would become a centerpiece during the 1990s for the widespread antitrust prosecutions by several states against U.S. tobacco companies alleging a conspiracy in restraint of trade and other types of unlawful conduct, and for recovery
Formation of fine nanocrystalline microstructure in bulk Fe-28Al-2Cr

Abstract Deformation induced grain refinement was examined in ≈100 nm Fe-28Al-2Cr intermetallic produced by ingot-metallurgical processing. Grain refinement to ≈7 nm (after room temperature compressive deformation) was observed in a small fraction of ingot-metallurgically processed 100 nm Fe-28Al-2Cr. As a first approach, it was demonstrated that fine nano crystalline microstructure can be produced in Fe-28Al-2Cr by a processing technique that does not require powder precursors.
Affair-Proofing Relationships: Discussion Questions for Couples

In this article, we present an activity that couple educators and couple therapists can use to help couples prevent and/or address infidelity. The activity involves a series of discussion questions that can be used to complement existing couple education programs or used separately in the context of couple therapy. By helping couples discuss and explore these questions, a couple educator or therapist can identify behaviors and attitudes that can help couples prevent or deal more effectively with infidelity.
Management of esophageal varices in children by endoscopic variceal ligation

Endoscopic variceal sclerotherapy (EVS) has been considered the mainstay of therapy for bleeding esophageal varices in adults. However, recent data have shown that endoscopic variceal ligation (EVL) is just as efficacious and has fewer complications than EVS. Although there are many reports concerning EVL in adults, only a few studies have been done in children. This report describes experience with EVL in 22 children with esophageal variceal hemorrhage. Eighty-seven EVL procedures were performed during a 9-year period in 22 children. The causes of portal hypertension were biliary atresia (10), portal vein thrombosis (8), chronic active hepatitis (1), cirrhosis secondary to cystic fibrosis (2), and primary sclerosing cholangitis (1). The age range at the onset of variceal bleeding was 8 months to 19 years. Twelve patients had EVS before EVL treatment was begun. Distal esophageal varices (one to four per session) were mechanically ligated using an elastic band ligature device attached to a flexible endoscope. The aim of therapy was obliteration of distal esophageal varices by EVL, every 2 to 4 weeks, until eradication. Subsequent EVL was dictated by the status of the varices. Outcome was assessed with respect to survival, rebleeding, status of varices, and complications. The patients underwent a mean of four sessions of EVL (range, one to eight). Four patients subsequently underwent liver transplantation. Of the 18 patients remaining (average follow-up period, 5.3 years), 12 had their varices eradicated (average of four EVL sessions), four are still in treatment, one has not been evaluated in the past 4 years, and one died of liver failure. Complications included bleeding between sessions (6 patients), cervical esophageal perforation (1 patient), and transient fever (2 patients). No child has experienced symptoms of esophageal stenosis or gastroesophageal reflux. Two patients died of liver disease, unrelated to bleeding from portal hypertension. EVL is effective in controlling variceal hemorrhage in children with portal hypertension, regardless of etiology. The complication rate is low, and EVL is an acceptable and perhaps preferable alternative to EVS in children with esophageal varices.
Mother-Child Conversation in Different Social Classes and Communicative Settings.

30 working-class and 33 upper-middle-class mothers were videotaped in dyadic interaction with their 18-29-month-old children in 4 settings--mealtime, dressing, book reading, and toy play. Samples of the mothers' adult-directed speech also were collected. There were significant social class differences in the mothers' child-directed speech and some parallel social class differences in the mothers' adult-directed speech. These findings suggested that some social class differences in child-directed speech may be instances of more general class differences in language use. There also were main effects of communicative setting on mothers' child-directed speech and interaction effects in which setting moderated the size of the class differences in maternal speech. These findings suggested that the amount of time mothers spend interacting with their children in different contexts may be at least as important an influence on children's linguistic experience as are average characteristics of their mothers' speech.
Elephantiasis nostras 1984

Elephantiasis nostras is a rare condition that usually presents as a persistent swelling of the lower extremity secondary to recurrent lymphangitis. We present a patient, originally referred for "angioneurotic edema of the lip," who presented with a history of several months of persistent swelling of the upper lip. There was probable evidence for recent infection of the lip that is consistent with the diagnosis of elephantiasis nostras. This disease should be included in the differential diagnosis of chronic persistent angioedema of the lip.
The Effects of Technology Innovativeness and System Exposure on Student Acceptance of E-Textbooks.

The efforts of educators in the last three decades have, among other things, focused on the use of information technology (IT) in education. It has become commonplace to view information systems both as an effective carrier of course content as well as a cost-effective tool to improve student learning outcomes. One of such technologies is the e-book. Decision-makers in the education field need make sense of this technological transformation. However, despite the growing popularity of e-books in higher education, its adoption by students is yet to be crystalized. This study exploits the technology acceptance model (TAM) framework to examine student acceptance of e-textbooks as “internally” impacted by technology innovativeness and “externally” influenced by system exposure. The results showed that students’ technology innovativeness is associated with student acceptance of e-textbooks and that system exposure was a strong moderator of the TAM relationships. The findings suggest that students’ openness to new technology, in general, is likely to positively affect the adoption of a specific new instructional technology. Additionally, system exposure was found to be a significant moderator of the TAM relationships. It is concluded that students’ technology innovativeness and system exposure must therefore be factored into instructional technology usage decision-making models.
Usefulness of Basal Cell Cocktail (34βE12 + p63) in the Diagnosis of Atypical Prostate Glandular Proliferations

We evaluated the diagnostic usefulness of the 34betaE12-p63 cocktail, compared with 34betaE12 and p63 used alone, in 34 prostate needle biopsy (NBXs) and 3 transurethral resection specimens containing atypical glandular proliferations and in 18 NBXs containing unequivocal prostate carcinoma (PCa). Staining intensity; percentage of basal cells staining in benign, atypical, and malignant glands; number of benign glands lacking basal cell staining; and staining variance were analyzed. All NBXs with unequivocal PCa were negative with all 3 markers. Diagnoses were as follows for the atypical cases after staining for the 3 markers: PCa, 9; postatrophic hyperplasia, 12; high-grade prostatic intraepithelial neoplasia (HGPIN), 5; atypical adenomatous hyperplasia, 6; benign atypical proliferations, 4; and HGPIN with adjacent small atypical acinar proliferation suggestive of PCa, 1. The cocktail demonstrated consistently strong staining intensity and improved basal cell staining in morphologically benign and benign atypical glands compared with p63 and 34betaE12 alone; it had the smallest staining variance compared with 34betaE12 (F < 0.0001) and p63 (F = 0.31), although its advantage for resolving individual atypical cases was limited compared with 34betaE12 and p63 alone. Of 37 atypical cases, 1 (3%) additionally was resolved as benign using the cocktail and p63. Because the diagnosis of PCa is supported by lack of basal cell staining, the immunohistochemical analysis with highest possible sensitivity and lowest possible variability is critical to ensure that a negative reaction is true. The cocktail provides a simple, cost-effective improvement in basal cell immunohistochemical analysis of difficult prostate lesions.
Quantum black holes in two dimensions

We show that a whole class of quantum actions for dilaton gravity, which reduce to the Callan-Giddings-Harvey-Strominger theory in the classical limit, can be written as a Liouville-like theory. In a subclass of this, the field space singularity observed by several authors is absent, regardless of the number of matter fields, and in addition it is such that the dilaton-gravity functional integration range (the real line) transforms into itself for the Liouville theory fields. We also discuss some problems associated with the usual calculation of Hawking radiation, which stem from the neglect of back reaction. We give an alternative argument incorporating back reaction but find that the rate is still asymptotically constant. The latter is due to the fact that the quantum theory has no lower bound in energy and Hawking radiation takes positive Bondi (or Arnowitt-Deser-Misner) mass solutions to an arbitrarily large negative mass.
Bronchial thermoplasty for severe asthma

Bronchial thermoplasty (BT) is a novel treatment of patients with severe asthma who continue to be symptomatic despite maximal medical treatment. It aims to reduce the smooth muscle mass in the airways by delivering controlled thermal energy to the airway walls during a series of three bronchoscopies. Randomized controlled clinical trials of BT in severe asthma have not been able to show a reduction in airway hyperresponsiveness or change in FEV1 but have suggested an improvement in quality of life, as well as a reduction in the rate of severe exacerbations, emergency department visits, and days lost from school or work. Strict inclusion and exclusion criteria of these trials resulted in the elimination of patients with severe asthma who experienced more than three exacerbations per year. Therefore, the generalizability of this treatment to the broader severe asthma population still needs to be determined. The short-term adverse events consist primarily of airway inflammation and occasionally more severe ...
Modeling of charge transport in thin film silicon solar cells using light generation distribution from full wave EM simulations

The continuity and Poisson equations were modeled in different layers of thin film silicon solar cells using finite difference method. In each layer the system of equations were solved numerically. The mesh size was chosen to be smaller than the Debye length. Different parameters like energy bands, electron and hole concentrations, electric field, voltage, current densities etc. were calculated at each mesh point. Cell parameters were calculated using the generation rate obtained from optical modeling.
Tablet-level origin of toughening in abalone shells and translation to synthetic composite materials

Nacre, the iridescent material in seashells, is one of many natural materials employing hierarchical structures to achieve high strength and toughness from relatively weak constituents. Incorporating these structures into composites is appealing as conventional engineering materials often sacrifice strength to improve toughness. Researchers hypothesize that nacre's toughness originates within its brick-and-mortar-like microstructure. Under loading, bricks slide relative to each other, propagating inelastic deformation over millimeter length scales. This leads to orders-of-magnitude increase in toughness. Here, we use in situ atomic force microscopy fracture experiments and digital image correlation to quantitatively prove that brick morphology (waviness) leads to transverse dilation and subsequent interfacial hardening during sliding, a previously hypothesized dominant toughening mechanism in nacre. By replicating this mechanism in a scaled-up model synthetic material, we find that it indeed leads to major improvements in energy dissipation. Ultimately, lessons from this investigation may be key to realizing the immense potential of widely pursued nanocomposites.
Patient compliance with orthodontic retainers in the postretention phase.

Introduction Retention is an important, even critical, component of orthodontic treatment. There is little research on practice protocols and patient compliance with long-term or short-term retention. This lack of information leaves our specialty with many opinions and practice protocols. The purposes of this study were to evaluate and quantify orthodontic retainer wear according to several variables, including patient age, sex, time in retention, and retainer type, and to identify predictors of compliance and reasons for noncompliance with removable orthodontic retainers. Methods Questionnaires were mailed to patients who finished full fixed appliance therapy in either the orthodontic graduate clinic or the orthodontic faculty practice at the University of Kentucky within the past 6 years. Of the 1085 questionnaires mailed, 280 were returned (25.8%). A logistic regression model that described the probabilities of retainer wear was created (P Results Patient compliance was greater with vacuum-formed retainers (VFRs) for the first 2 years after debonding. However, compliance with VFRs decreased at a much faster rate than with Hawley retainers. Because of this, patient compliance was greater with Hawley retainers at any time longer than 2 years after debonding, and patient compliance overall was greater with Hawley retainers. Conclusions This evidence disagrees with the current anecdotal trend of orthodontists who favor switching from Hawley retainers to VFRs. An unexpected finding was that patients reported few esthetic concerns about retainers, and the few that were reported were equally distributed between Hawley retainers and VFRs.
Model-based predictive control of an Electro-Pneumatic exhaust valve for Internal Combustion engines

Variable valve actuation of internal combustion (IC) engines is capable of significantly improving their performance. Variable valve actuation can be divided into two main categories: variable valve timing with cam shaft(s) and camless valve actuation. For camless valve actuation, research has been centered in electro-magnetic, electro-hydraulic, and electro-pneumatic valve actuators. This research studies the control of the electro-pneumatic valve actuator. The modeling and control of intake valves for the Electro-Pneumatic Valve Actuators (EPVA) was shown in early publications and this paper extends the EPVA modeling and control development to exhaust valves for both valve timing and lift control. The control strategy developed utilizes model-based predictive techniques to overcome the randomly variable in-cylinder pressure against which the exhaust valve opens.
Improving Breast Cancer Control Among Latinas: Evaluation of a Theory-Based Educational Program:

The study evaluated a theory-based breast cancer control program specially developed for less acculturated Latinas. The authors used a quasi-experimental design with random assignment of Latinas into experimental (n = 51) or control (n = 37) groups that completed one pretest and two posttest surveys. The experimental group received the educational program, which was based on Bandura's self-efficacy theory and Freire's empowerment pedagogy. Outcome measures included knowledge, perceived self-efficacy, attitudes, breast self-examination (BSE) skills, and mammogram use. At posttest 1, controlling for pretest scores, the experimental group was significantly more likely than the control group to have more medically recognized knowledge (sum of square [SS] = 17.0, F = 6.58, p < .01), have less medically recognized knowledge (SS = 128.8, F = 39.24, p < .001), greater sense of perceived self-efficacy (SS = 316.5, F = 9.63, p < .01), and greater adeptness in the conduct of BSE (SS = 234.8, F = 153.33, p < .001). Cancer control programs designed for less acculturated women should use informal and interactive educational methods that incorporate skill-enhancing and empowering techniques.
Effects of inspiratory muscle training on heart rate variability

iv Acknowledgements v List of List of Tables and Figures viii List of Appendices ix Chapter I: The problem and its scope Introduction 1 Purpose of the Study 2 Hypotheses 3 Significance of the Study 3 Limitations of the Study 3 Definition of Terms 4 Chapter II: Review of Literature Introduction 8 Physiology of Heart Rate Variability 8 Measurement of Heart Rate Variability 11 Heart Rate Variability in Clinical Conditions 14 Physiological influences on HRV 15 Age 15 Short term stability of HRV 18 Aerobic exercise training 19 Resistance training 23 Modulatory Effect of Respiration on HRV 24 Genesis of respiratory sinus arrhythmia 25 Effect of respiration rate and pattern on HRV 26 Inspiratory Muscle Training 29 Inspiratory muscle training and autonomous nervous system 33 Summary 37
Uncooled Infrared Photodetector Utilizing PbSe Nanocrystals

Lead selenide nanocrystals were coupled with the interdigital gold electrodes to create a dissimilar material that is used for detecting near-infrared light at room temperature. The photoluminescence spectrum of the nanocrystals showed a narrow peak at 1.6 μm. A device with 10-μm electrode spacing exhibits excellent photoresponse with an onset at 1.8 μm and detectivity in the order of 3 × 109 cmHz0.5/W at 5 V bias. The recovery time constant of the device was calculated from the time-resolved photocurrent curve and found to be 0.16 s. The photoresponse spectrum comprises of three distinct peaks in the near-infrared region creating a wavelength selectivity feature.
Supramolecular Gelation of Rigid Triangular Macrocycles through Rings of Multiple C–H···O Interactions Acting Cooperatively

When equimolar solutions of the enantiomeric naphthalenediimide-based highly rigid triangles R-Δ and S-Δ in ClCH2CH2Cl are mixed, the racemate rac-Δ forms an organogel that is composed of interwoven fibers, resulting from the columnar stacking of the triangles in an alternating R-Δ/S-Δ fashion. Under identical conditions, the pure enantiomers do not form organogels. Density functional theory calculations reveal that the racemic RS dimer is more stable than the RR dimer as a result of the enantiomeric relationship between R-Δ and S-Δ, allowing them to act as two complementary rings comprised of 12 [C–H···O] interactions with an unprecedented and uninterrupted circular ADDAADDAADDA·DAADDAADDAAD alignment of hydrogen bond donors (D) and acceptors (A), in contrast with the square-wave manner in which the RR dimer forms a complementary yet interrupted ADADAD·DADADA circular sequence of six longer [C–H···O] hydrogen bonds. It follows that gelation is favored by weak interactions acting cooperatively in rings un...
Magnetic resonance elastography of slow and fast shear waves illuminates differences in shear and tensile moduli in anisotropic tissue

Mechanical anisotropy is an important property of fibrous tissues; for example, the anisotropic mechanical properties of brain white matter may play a key role in the mechanics of traumatic brain injury (TBI). The simplest anisotropic material model for small deformations of soft tissue is a nearly incompressible, transversely isotropic (ITI) material characterized by three parameters: minimum shear modulus (µ), shear anisotropy (ϕ=µ1µ-1) and tensile anisotropy (ζ=E1E2-1). These parameters can be determined using magnetic resonance elastography (MRE) to visualize shear waves, if the angle between the shear-wave propagation direction and fiber direction is known. Most MRE studies assume isotropic material models with a single shear (µ) or tensile (E) modulus. In this study, two types of shear waves, "fast" and "slow", were analyzed for a given propagation direction to estimate anisotropic parameters µ, ϕ, and ζ in two fibrous soft materials: turkey breast ex vivo and aligned fibrin gels. As expected, the speed of slow shear waves depended on the angle between fiber direction and propagation direction. Fast shear waves were observed when the deformations due to wave motion induced stretch in the fiber direction. Finally, MRE estimates of anisotropic mechanical properties in turkey breast were compared to estimates from direct mechanical tests.