Electronic densities and valence bond wave functions.

Valence bond (VB) wave functions are studied from the density point of view. The density is plotted as a difference with the quasi-state built on the same orbitals. The densities of the components of the VB wave function are also shown. The breathing orbital effect leads to small modifications of the density. It is shown that while the densities of ionic and covalent components are the same, their coupling ends-up in modifications of the electronic density.

Subchondral bone circulation in osteoarthritis of the human knee.

OBJECTIVE: The hypothesis of this study is that human subchondral bone exhibits abnormal patterns of perfusion in osteoarthritis (OA) that can be characterized by kinetic parameters of blood flow using dynamic contrast enhanced (DCE) MRI. DESIGN: Fifteen subjects with advanced OA of the knee and seven control subjects without OA were studied at 1.5 T with DCE-MRI. Region of interest (ROIs) analysis of pharmacokinetic perfusion parameters were used to examine initial uptake and washout of the contrast agent in the lateral tibial plateau. RESULTS: Arterial and venous perfusion kinetics were abnormal in subchondral OA bone compared to those of normal controls. Time-intensity curves (TIC) exhibited delayed contrast clearance in OA knees compared to normal. Quantitatively, changes were observed in the kinetic parameters, kep, Akep, and kel. The mean kep and Akep were reduced in OA, compared to normal bone, indicating a reduction of arterial inflow and delayed signal enhancement. The kel in OA bone was lower than in normal bone, the negative kel indicating a reduction in venous outflow. The area under the TIC (AUC60) indicated greater residual contrast in OA bone. CONCLUSIONS: DCE-MRI can quantitatively assess subchondral bone perfusion kinetics in human OA and identify heterogeneous regions of perfusion deficits. The results are consistent with venous stasis in OA, reflecting venous outflow obstruction, and can affect intraosseous pressure, reduce arterial inflow, reduce oxygen content, and may contribute to altered cell signaling in, and the pathophysiology of, OA.

Management of labour and delivery in congenitally corrected transposition of great arteries.

A descriptive case report of the labour and delivery management of a 28-year-old woman who presented with congenitally corrected transposition of great arteries, dextrocardia, systemic ventricular dysfunction and junctional tachycardia. Patients with congenitally corrected transposition have a thin-walled morphological right ventricle as the systemic circulatory pump. The stress of increased cardiac output can lead to congestive heart failure, systemic atrioventricular valve regurgitation and arrhythmias. We used minimally invasive continuous cardiac output monitoring, fluid balance optimization and good maternal pain control to prevent decompensation and achieve vaginal delivery with a good maternal and neonatal outcome.

Estimating ON and OFF contributions to the photopic hill: normative data and clinical applications.

BACKGROUND: With progressively brighter stimuli, the amplitude of the b-wave of the human photopic electroretinogram (ERG) first increases to a maximal value (Vmax) and then decreases to finally reach a plateau, a phenomenon known as the photopic hill (PH). A mathematical model combining a Gaussian (G) and a logistic (L) growth function was previously proposed to fit this unusual luminance-response curve, where the G and L functions were suggested to represent, respectively, the OFF and ON retinal pathway contributions to the building of the PH. METHOD: The PHs of patients presenting stationary diseases affecting specifically the ON (3 CSNB-1) or OFF (4 CPCPA) retinal pathways as well as patients affected with retinitis pigmentosa (14 RP) of different stages or etiology were analyzed using this mathematical model and compared to the PHs of a group of 28 normal subjects. RESULTS: The PH of the CSNB-1 patients had a much larger contribution from the G function compared to normal subjects, whereas the opposite was observed for the CPCPA patients. On the other hand, analysis of data from RP patients revealed variable G-L contributions to the building of their PH. CONCLUSION: In this study, we confirm the previous claim that the luminance-response function of the photopic ERG b-wave can be decomposed into a Gaussian function and a logistic growth function representing, respectively, the OFF and ON retinal pathways. Furthermore, our findings suggest that this mathematical decomposition could be useful to further segregate and potentially follow the progression of retinopathies such as RP.

Micropatterns of cell adhesive proteins with poly(ethylene oxide)-block-Poly(4-vinylpyridine) diblock copolymer.

Control of cell shape and behavior through the micropattern technique by spatial immobilization of adhesive proteins on a surface has provided novel insights in several aspects of cell biology, such as tissue morphogenesis, cell growth and cell differentiation, and apoptosis. In this work, we present the use of poly(ethylene oxide-block-poly(4-vinylpyridine) (PEO-b-P4VP) as a non-adhesive background to construct micropatterns of cell adhesive proteins. In the method presented, PEO-b-P4VP is used for its antifouling properties and at the same time, as a photosensitive material to define the micropatterns. The irradiation of PEO-b-P4VP with a short wavelength UV light through photolithographic mask, causes the polymer to crosslink and immobilize in the areas exposed. In the areas non-exposed the polymer can be removed. These areas can be subsequent back filled with the adhesive protein of interest to produce the final micropatterned cell chips.

A Systematic Evaluation of Mobile Health Applications for the Prevention of Suicidal Behavior or Non-suicidal Self-injury.

People with suicidal ideation and non-suicidal self-injury (NSSI) behavior face numerous barriers to help-seeking, which worsened during the COVID-19 pandemic. Mobile health applications (MHA) are discussed as one solution to improve healthcare. However, the commercial app markets are growing unregulated and rapidly, leading to an inscrutable market. This study evaluates the quality, features, functions, and prevention strategies of MHA for people with suicidal ideation and NSSI. An automatic search engine identified MHA for suicidal behavior and NSSI in the European commercial app stores. MHA quality and general characteristics were assessed using the Mobile Application Rating Scale (MARS). MHA of high quality (top 25%) were examined in detail and checked for consistency with established suicide prevention strategies. Of 10,274 identified apps, 179 MHA met the predefined inclusion criteria. Average MHA quality was moderate (M = 3.56, SD = 0.40). Most MHA provided emergency contact, but lacked security features. High-quality MHA were broadly consistent with the best-practice guidelines. The search revealed apps containing potentially harmful and triggering content, and no randomized controlled trial of any included MHA was found. Despite a large heterogeneity in the quality of MHA, high-quality MHA for suicidal behavior and NSSI are available in European commercial app stores. However, a lack of a scientific evidence base poses potential threats to users.

[Seroprevalence of cytomegalovirus infection in puerperal women and its impact on their newborns]. / Seroprevalencia de la infección por citomegalovirus en puérperas y su impacto neonatal.

INTRODUCTION: Cytomegalovirus (CMV) is the most frequent etiologic agent associated with perinatal infections. The incidence of this infection is higher in developing countries. The seroprevalence of CMV infection among pregnant women and its impact on newborns have not been studied in Panama and there are a few publications on this health problem in Latin America. OBJECTIVE: The purpose of this study was to determine the seroprevalence of CMV infection in puerperal women and CMV-related morbidity in the neonates of seropositive mothers. PATIENTS AND METHODS: A total of 316 blood samples from puerperal women and 317 urine samples from their newborns were obtained to determine CMV IgG and the polymerase chain reaction CMV test respectively. Risk factors such as parity, socioeconomic status and educational level were analyzed. RESULTS: The seroprevalence of CMV was 84 % and the incidence of congenital CMV infection in the newborns of seropositive women was 0.8 %. Two cases of congenital CMV infection were diagnosed, one of which showed clinical signs at birth, but neither of the newborns showed neurological or audiological sequels in the first 11 months of life. There were no correlations between positive serology and parity, socioeconomic status or educational level in the mothers studied. CONCLUSIONS: Although neither of the newborns diagnosed with congenital CMV infection showed clinical signs at the time of this report, we believe that the incidence of 0.8 % found in this study should be kept in mind with a view to evaluating the possibility of including CMV diagnostic tests in neonatal screening and introducing measures to prevent seronegative mothers from becoming infected.

Automated radioxenon monitoring for the comprehensive nuclear-test-ban treaty in two distinctive locations: Ottawa and Tahiti.

In preparation for verification of the Comprehensive Nuclear-Test-Ban-Treaty, automated radioxenon monitoring is performed in two distinctive environments: Ottawa and Tahiti. These sites are monitored with SPALAX (Systeme de Prelevement d'air Automatique en Ligne avec l'Analyse des radioXenons) technology, which automatically extracts radioxenon from the atmosphere and measures the activity concentrations of (131m,133m,133,135)Xe. The resulting isotopic concentrations can be useful to discern nuclear explosions from nuclear industry xenon emissions. Ambient radon background, which may adversely impact analyser sensitivity, is discussed. Upper concentration limits are reported for the apparently radioxenon free Tahiti environment. Ottawa has a complex radioxenon background due to proximity to nuclear reactors and medical isotope facilities. Meteorological models suggest that, depending on the wind direction, the radioxenon detected in Ottawa can be characteristic of the normal radioxenon background in the Eastern United States, Europe, and Japan or distinctive due to medical isotope production.

Mechanism of toxicity of 3-methyladenine for bacteriophage T7.

Treatment of bacteriophage T7 with methyl methanesulfonate perturbed phage-specific genetic expression in both repair-proficient and repair-deficient Escherichia coli cells. In wild-type cells (AB1157), the time course of protein synthesis was slowed down but an entire complement of phage proteins was synthesized. In cells (BK2114, tag-) unable to repair 3-methyladenine, the toxic lesion produced by methyl methanesulfonate, alkylated phage produced only early (class I) proteins. These results suggested that late transcription was inhibited in infected tag- cells. These cells were shown to contain a significant amount of active T7 RNA polymerase, a class I protein. Thus, the cause of inhibition appeared to be the inability of T7 RNA polymerase to use unrepaired DNA as template. In vitro transcription assays with alkylated T7 DNA as template supported this proposal. T7 RNA polymerase proved to be very sensitive to the presence of alkylation lesions. In addition, the phage enzyme was much more sensitive to these lesions than was its bacterial counterpart, E. coli RNA polymerase. These results suggest that 3-methyladenine exerts its toxic action, in the T7 system, at the level of transcription by T7 RNA polymerase. To further characterize the reduced activity of the T7 enzyme, an in vitro transcription assay using linearized plasmid DNA with one T7 promoter was devised. Gel electrophoresis revealed that only one transcript of well-defined length was synthesized by T7 RNA polymerase on this template. Alkylation of the template did not alter the size of the transcript produced. Simultaneous measurement of chain initiation and chain elongation confirmed this result by showing that both steps were reduced to the same extent by alkylation of template DNA. Thus T7 RNA polymerase does not appear to be blocked by 3-methyladenine. Rather the lesion must hinder translocation of T7 RNA polymerase along the DNA template during chain elongation.

Effect of abasic sites on bacteriophage T7 protein synthesis.

We have examined protein synthesis directed by bacteriophage T7 which had been alkylated with methyl methanesulfonate so as to produce apurinic sites in its DNA in vivo. Both repair-proficient and repair-deficient (xth nfo mutant) strains of Escherichia coli served as host cells. In repair-proficient cells, all three classes of phage proteins were synthesized, although with significant delays. In mutant cells, only class I proteins were produced and their synthesis was delayed and reduced, demonstrating a perturbation of protein synthesis and providing the first in vivo indication that transcription is inhibited by abasic sites. However, the proposed effects of abasic sites on transcription appear to be weaker than those on replication.

Statistical inference, the bootstrap, and neural-network modeling with application to foreign exchange rates.

We propose tests for individual and joint irrelevance of network inputs. Such tests can be used to determine whether an input or group of inputs "belong" in a particular model, thus permitting valid statistical inference based on estimated feedforward neural-network models. The approaches employ well-known statistical resampling techniques. We conduct a small Monte Carlo experiment showing that our tests have reasonable level and power behavior, and we apply our methods to examine whether there are predictable regularities in foreign exchange rates. We find that exchange rates do appear to contain information that is exploitable for enhanced point prediction, but the nature of the predictive relations evolves through time.

Semiparametric ARX neural-network models with an application to forecasting inflation.

We examine semiparametric nonlinear autoregressive models with exogenous variables (NLARX) via three classes of artificial neural networks: the first one uses smooth sigmoid activation functions; the second one uses radial basis activation functions; and the third one uses ridgelet activation functions. We provide root mean squared error convergence rates for these ANN estimators of the conditional mean and median functions with stationary beta-mixing data. As an empirical application, we compare the forecasting performance of linear and semiparametric NLARX models of US inflation. We find that all of our semiparametric models outperform a benchmark linear model based on various forecast performance measures. In addition, a semiparametric ridgelet NLARX model which includes various lags of historical inflation and the GDP gap is best in terms of both forecast mean squared error and forecast mean absolute deviation error.

Computerized videokeratography of keratoconus kindreds.

OBJECTIVE: To assess the role of heredity in the development of keratoconus. DESIGN: Prospective study. SETTING: Eye clinic providing secondary and tertiary ophthalmic care in Toronto. PATIENTS: Thirty-nine patients with keratoconus (57 eyes) and 48 relatives of 11 patients with keratoconus. The corneal topography of the family members was compared with that of a group of 68 volunteer control subjects (136 eyes) without clinical evidence or a family history of keratoconus. OUTCOME MEASURES: Three quantitative measures derived from computerized videokeratography: the relative steepness of the inferior cornea versus the superior cornea, central corneal power and the difference in central corneal power between the two eyes. All the data were statistically analysed with the use of nonparametric discriminant analysis. RESULTS: Fifteen family members who were believed to be clinically normal on the basis of refraction, keratometry and slit-lamp examination has statistically significant topographic abnormalities suggestive of early or mild keratoconus. CONCLUSIONS: The presence of these findings in family members of patients with keratoconus may represent the incomplete expression of a gene contributing to the development of the condition. Pedigree analysis suggested an autosomal dominant inheritance pattern in 9 of the 11 families. Our results underline the value of videokeratography for accurate family pedigree analysis and the diagnosis of keratoconus.

The Hawaii Poison Center: what's it worth to you?

Benefits of the Hawaii Poison Center (HPC) to the public, providers, and third party payers are enumerated. Financial advantages to third party payers during 1996-7 were quantified by comparing costs for the home management of poisonings with alternative sources of care reported by callers, if the HPC were closed. The value for third party payers exceeded $2.5 million, greater than eight times the investment in operating the HPC, similar to national data. Since third party payers are the most visible beneficiary of cost savings, a case is made for their financial support of the HPC.

Severe hypothermia in infants.

In countries with low socio-economical conditions and cold winters, life threatening hypothermia in newborns and infants represents a frequent medical emergency. In such a country, during a particularly cold winter, 38 infants with rectal temperature of less than 33 degrees C were admitted to hospital. With the usually recommended method of progressive rewarming, lethality was very high (70%). However, with a method of quick core and external rewarming, the death rate decreased to 33%.

[protein synthesis in alkylated bacteriophage T7]. / Etude de la synthèse protéique chez le bactériophage T7 alkylé.

We have studied the toxic effects of alkylating agents with a well characterized model: phage T7. Treatment of bacteriophage T7 with methyl methanesulfonate led to perturbation of phage-specific protein synthesis. Synthesis of class I and II proteins was prolonged, while production of class II and III proteins was delayed. This delay increased for proteins coded by genes located further to the right on the T7 genetic map. In extracts prepared from cells infected by alkylated phage, the specific activity of T7 RNA polymerase was decreased. These results suggest that the toxic action of methyl methanesulfonate is directed towards viral transcription.

Alkylation of T7 bacteriophage blocks superinfection exclusion.

Alkylation of T7 bacteriophage by methyl methane sulfonate blocked superinfection exclusion. This blockage could be correlated with a delay in the synthesis of phage-specific proteins. Therefore we conclude that protein synthesis directed by the primary infecting phage is required for efficient exclusion of superinfecting phage particles.

FOXO1 and c-jun transcription factors mRNA are modulated in endometriosis.

Endometriosis is a polygenic gynaecological condition affecting 5-15% of women of childbearing age. Major symptoms of the disease are pelvic pain and infertility. No clear link has been established between symptoms and the stage of the disease. Although some aspects have begun to be clarified, clinical understanding of endometriosis remains partial at the molecular level. In this perspective, we targeted isolation of differentially expressed genes in the eutopic endometrial tissue. Our assumption was that the endometrial cells of patients presented an unusual gene expression profile, allowing their implantation and survival in an ectopic site, leading to endometriotic lesions. Here, we report that mRNA steady-state levels of two key transcription factors are modulated in endometriosis. FOXO1 (also known as FKHR) levels were 1.6-fold lower in endometriosis compared to the control group at the onset of the secretory phase (day 15-21), while c-jun mRNA was present at higher amounts in endometriosis (1.5-fold) at the proliferative phase of the menstrual cycle. These results were derived from a large sample composed of 157 control subjects and 209 patients with endometriosis. Gene profiling was conducted by real-time quantitative PCR, and data were quality controlled before statistical analysis. Whether protein levels are affected as well remains to be investigated.