Adaptive control of laser-wakefield accelerators driven by mid-IR laser pulses.

There has been growing interest both in studying high intensity ultrafast laser plasma interactions with adaptive control systems as well as using long wavelength driver beams. We demonstrate the coherent control of the dynamics of laser-wakefield acceleration driven by ultrashort (∼ 100 fs) mid-infrared (∼ 3.9 µm) laser pulses. The critical density at this wavelength is 7.3 × 1019 cm-3, which is achievable with an ordinary gas target system. Interactions between mid-infrared laser pulses and such near-critical-density plasma may be beneficial due to much higher absorption of laser energy. In addition, the normalized vector potential of the laser field a0 increases with longer laser wavelength, lowering the required peak laser intensity to drive non-linear laser-wakefield acceleration. Here, MeV level, collimated electron beams with non-thermal, peaked energy spectra are generated. Optimization of electron beam qualities are realized through adaptive control of the laser wavefront. A genetic algorithm controlling a deformable mirror improves the electron total charge, energy spectra, beam pointing and stability at various plasma density profiles. Particle-in-cell simulations reveal that the optimal wavefront causes an earlier injection on the density up-ramp and thus higher energy gain as well as less filamentation during the interaction, which leads to the improvement in electron beam collimation and energy spectra.

The subpolar gyre regulates silicate concentrations in the North Atlantic.

The North Atlantic is characterized by diatom-dominated spring blooms that results in significant transfer of carbon to higher trophic levels and the deep ocean. These blooms are terminated by limiting silicate concentrations in summer. Numerous regional studies have demonstrated phytoplankton community shifts to lightly-silicified diatoms and non-silicifying plankton at the onset of silicate limitation. However, to understand basin-scale patterns in ecosystem and climate dynamics, nutrient inventories must be examined over sufficient temporal and spatial scales. Here we show, from a new comprehensive compilation of data from the subpolar Atlantic Ocean, clear evidence of a marked pre-bloom silicate decline of 1.5-2 µM throughout the winter mixed layer during the last 25 years. This silicate decrease is primarily attributed to natural multi-decadal variability through decreased winter convection depths since the mid-1990s, a weakening and retraction of the subpolar gyre and an associated increased influence of nutrient-poor water of subtropical origin. Reduced Arctic silicate import and the projected hemispheric-scale climate change-induced weakening of vertical mixing may have acted to amplify the recent decline. These marked fluctuations in pre-bloom silicate inventories will likely have important consequences for the spatial and temporal extent of diatom blooms, thus impacting ecosystem productivity and ocean-atmosphere climate dynamics.

Computed tomography assisted determination of optimal insertion points and bone corridors for transverse implant placement in the feline tarsus and metatarsus.

OBJECTIVE: Describe optimal corridors for mediolateral or lateromedial implant placement in the feline tarsus and base of the metatarsus. METHODS: Computed tomographic images of 20 cadaveric tarsi were used to define optimal talocalcaneal, centroquartal, distal tarsal, and metatarsal corridors characterized by medial and lateral insertion points (IP), mean height, width, length and optimal dorsomedial-plantarolateral implantation angle (OIA). RESULTS: Talocalcaneal level: The IP were at the head of the talus and plantar to the peroneal tubercle of the calcaneus and OIA was 22.7° ± 0.3. Centroquartal level: The IP were at the centre of the medial surface of the central tarsal bone and dorsoproximal to the tuberosity of the fourth tarsal bone and OIA was 5.9° ± 0.06. Distal tarsal level: The IP were at the centre of the medial surface of the tarsal bone II and dorsodistal to the tuberosity of the fourth tarsal bone and OIA was 5.4° ± 0.14. Metatarsal level: The IP were at the dorsomedial surface of the proximal end of the metatarsal bone II and at the dorsolateral surface of metatarsal bone V and OIA was 0.5° ± 0.06. Significant positive correlation was found between body weight and the length of each corridor. CLINICAL SIGNIFICANCE: Most of the corridors obtained in this study had a diameter between 1.5 mm and 2 mm with a length of 15 mm to 18 mm, which stresses the importance of their accurate placement.

High-temperature stability and saturation magnetization of superparamagnetic nickel nanoparticles in microporous polysilazane-derived ceramics and their gas permeation properties.

Superparamagnetic Ni nanoparticles with diameters of about 3 nm are formed in situ at room temperature in a polysilazane matrix, forming Ni/polysilazane nanocomposite, in the reaction between a polysilazane and trans-bis(aceto-kO)bis(2-aminoethanol-k(2)N,O)nickel(II). The thermolysis of the Ni/polysilazane nanocomposite at 700 °C in an argon atmosphere results in a microporous superparamagnetic Ni/silicon oxycarbonitride (Ni/SiCNO) ceramic nanocomposite. The growth of Ni nanoparticles in Ni/SiCNO ceramic nanocomposite is totally suppressed even after thermolysis at 700 °C, as confirmed by HRTEM and SQUID characterizations. The analysis of saturation magnetization of Ni nanoparticles in Ni/polysilazane and Ni/SiCNO nanocomposites indicates that the saturation magnetization of Ni nanoparticles is higher than expected values and infers that the surfaces of Ni nanoparticles are not oxidized. The microporous superparamagnetic Ni/SiCNO nanocomposite is shaped as a free-standing monolith and foam. In addition, Ni/SiCNO membranes are fabricated by the dip-coating of a tubular alumina substrate in a dispersion of Ni/polysilazane in THF followed by a thermolysis at 700 °C under an argon atmosphere. The gas separation performance of Ni/SiCNO membranes at 25 and 300 °C is assessed by the single gas permeance (pressure rise technique) using He, H2, CO2, N2, CH4, n-propene, n-propane, n-butene, n-butane, and SF6 as probe molecules. After hydrothermal treatment, the higher increase in the hydrogen permeance compared to the permeance of other gases as a function of temperature indicates that the hydrogen affinity of Ni nanoparticles influences the transport of hydrogen in the Ni/SiCNO membrane and Ni nanoparticles stabilize the structure against hydrothermal corrosion.

Nanostructured SnO2-ZnO heterojunction photocatalysts showing enhanced photocatalytic activity for the degradation of organic dyes.

Nanoporous SnO(2)-ZnO heterojunction nanocatalyst was prepared by a straightforward two-step procedure involving, first, the synthesis of nanosized SnO(2) particles by homogeneous precipitation combined with a hydrothermal treatment and, second, the reaction of the as-prepared SnO(2) particles with zinc acetate followed by calcination at 500 °C. The resulting nanocatalysts were characterized by X-ray diffraction (XRD), FTIR, Raman, X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption analyses, transmission electron microscopy (TEM), and UV-vis diffuse reflectance spectroscopy. The SnO(2)-ZnO photocatalyst was made of a mesoporous network of aggregated wurtzite ZnO and cassiterite SnO(2) nanocrystallites, the size of which was estimated to be 27 and 4.5 nm, respectively, after calcination. According to UV-visible diffuse reflectance spectroscopy, the evident energy band gap value of the SnO(2)-ZnO photocatalyst was estimated to be 3.23 eV to be compared with those of pure SnO(2), that is, 3.7 eV, and ZnO, that is, 3.2 eV, analogues. The energy band diagram of the SnO(2)-ZnO heterostructure was directly determined by combining XPS and the energy band gap values. The valence band and conduction band offsets were calculated to be 0.70 ± 0.05 eV and 0.20 ± 0.05 eV, respectively, which revealed a type-II band alignment. Moreover, the heterostructure SnO(2)-ZnO photocatalyst showed much higher photocatalytic activities for the degradation of methylene blue than those of individual SnO(2) and ZnO nanomaterials. This behavior was rationalized in terms of better charge separation and the suppression of charge recombination in the SnO(2)-ZnO photocatalyst because of the energy difference between the conduction band edges of SnO(2) and ZnO as evidenced by the band alignment determination. Finally, this mesoporous SnO(2)-ZnO heterojunction nanocatalyst was stable and could be easily recycled several times opening new avenues for potential industrial applications.

Canine herpesvirus during pregnancy and non-pregnant luteal phase.

Canine herpesvirus (CHV) is a widespread infection among dogs that typically get latently infected after exposure and can reactivate the infection after stress. The aim of the present study was to study the effects of latent CHV infection during pregnancy on pregnancy outcome, and to study if there are signs of genital viral reactivation during pregnancy or during non-pregnant luteal phase. Twelve mated bitches and eight control bitches were followed and sampled regularly during pregnancy or non-pregnant luteal phase. Blood samples were taken for antibody analysis and vaginal swabs for real-time PCR analysis. Three of the pregnant bitches were vaccinated against CHV during pregnancy. All bitches had antibodies to CHV. Two pregnant bitches that were not vaccinated had a twofold or larger increase in CHV titre, with no negative effects detected on pregnancy. Higher titres were not associated with smaller litters or with vaccination. There was no consistent variation in antibody titres due to pregnancy or non-pregnant luteal phase. Vaginal excretion of CHV was not detected from any of the bitches.

Response to sham and active gamma ventral capsulotomy in otherwise intractable obsessive-compulsive disorder.

This case regards a 34-year-old woman with severe and refractory obsessive-compulsive disorder, who was enrolled in a double-blind, randomized controlled trial of radiosurgery. She was at first submitted to a sham radiosurgical procedure, and 1 year later to an active intervention. Opposite clinical responses were observed in the follow-up of these different phases. During the sham surgery follow-up, no improvements were observed, but a remarkable amelioration was seen a few months after the active procedure. Detailed descriptions of psychopathological changes and neuroimaging findings as well as a discussion regarding the surgical technique are provided.

The 'relics of Joan of Arc': a forensic multidisciplinary analysis.

Archaeological remains can provide concrete cases, making it possible to develop, refine or validate medico-legal techniques. In the case of the so-called 'Joan of Arc's relics' (a group of bone and archaeological remains known as the 'Bottle of Chinon'), 14 specialists analysed the samples such as a cadaver X of carbonised aspect: forensic anthropologist, medical examiners, pathologists, geneticists, radiologist, biochemists, palynologists, zoologist and archaeologist. Materials, methods and results of this study are presented here. This study aims to offer an exploitable methodology for the modern medico-legal cases of small quantities of human bones of carbonised aspect.

Neonatal screening for sickle cell disease in France.

BACKGROUND: As a result of population growth in African-Caribbean regions of overseas France, and now immigration essentially from North and sub-Saharan Africa to mainland France, neonatal screening for sickle cell disease (SCD) has been performed in France since 1985 in Guadalupe and dependencies, as a universal test. After several pilot studies, screening was gradually extended to mainland France in 1996. Since 2000, the test has been performed at national level for all newborns defined as being "at risk" for SCD based on ethnic origin. METHODS: A dry blood sample is obtained by heel stick and analysed by isoelectric focusing as a first-line method, followed by either high-performance liquid chromatography or acid agar electrophoresis for confirmation, whenever a variant haemoglobin is observed on isoelectric focusing. RESULTS: In 2007, 28.45% of all newborns in mainland France were screened for SCD. Since 1996, a total of 3,890 newborns have been found to have SCD, and they have been followed up by reference paediatricians. CONCLUSION: Although screening for SCD at birth in France is not universal, it appears that missed babies are relatively infrequent. Despite obvious sociological problems inherent to the at-risk population, the follow-up of SCD babies is rather successful. Due to the birth prevalence of SCD in France, especially in comparison with other common genetic diseases, screening all newborns regardless of ethnic origin is an issue that is being addressed.

Cerebral histoplasmosis in the azole era: report of four cases and review.

We report four cases of cerebral histoplasmosis and discuss features of six additional cases reported in the medical literature in the past 10 years, when azoles have been available for therapy. Most patients with this disease are immunocompromised or have a history that suggests heavy exposure to Histoplasma capsulatum. Fever and other clinical findings of systemic toxicity caused by disseminated histoplasmosis may be absent; 5 of 10 patients did not manifest these findings. Although the mainstay of treatment for central nervous system histoplasmosis remains amphotericin B, 9 of the 10 patients received itraconazole or fluconazole either as initial therapy or after a course of treatment with amphotericin B.

Starting a successful bariatric surgical practice in the community hospital setting.

BACKGROUND: 3% of the population is morbidly obese and experience many associated medical problems. Surgical procedures have been shown to achieve sustained weight loss not attainable by other measures, lessening the co-morbidities. However, most general surgeons have been reluctant to expand their practice to include bariatric surgery. The current study demonstrates the benefits of including bariatric surgery in a general surgeon's practice in a community hospital. METHODS: Hospital charts of patients undergoing a gastric bypass procedure between 1997 and 2000 were reviewed. Demographic data, co-morbid conditions, intra-operative times, and post-operative weight loss were recorded. Follow-up data was obtained using a mailed survey based on the BAROS survey. RESULTS: 168 patients underwent a Roux-en-Y gastric bypass procedure. Follow-up was obtained for 86 patients. Average pre-operative weight was 141 kg (BMI = 50). There was an average loss of 55% of excess weight by the second post-operative year. Operative times decreased as the number of the procedures performed by the surgeon increased. Over half of the patients surveyed reported improvements for each of the co-morbid conditions that were assessed (i.e., diabetes, back pain, etc.). Five categories of quality of life were assessed, and over 66% of patients reported improvements in all areas. In 44% of the patients, payment was obtained from private insurance and 56% from Medicare or Medicaid. There were no deaths. CONCLUSION: Adding bariatric surgery to a general surgeon's practice in the community setting can be beneficial to patients, intellectually stimulating and emotionally rewarding for the surgeon, and economically feasible for the institution.

Abnormal hemoglobins: laboratory methods.

Laboratory methods allowing the detection and characterization of hemoglobin variants are reviewed. Protein chemistry techniques such as isoelectrofocusing, electrophoreses under various experimental conditions, cation exchange and reversed phase high performance liquid chromatography, are the most frequently used for the detection of variants. When associated with a few additional data they may lead to a presumptive diagnosis. DNA studies are also developed in many laboratories. Final identification of a variant may be achieved either by molecular biology techniques or by protein sequence analysis in which mass spectrometry now occupies a key position.

Aberrant methylation during cervical carcinogenesis.

We studied the pattern of aberrant methylation during the multistage pathogenesis of cervical cancers. We analyzed a total of 73 patient samples and 10 cervical cancer cell lines. In addition, tissue samples [peripheral blood lymphocytes (n = 10) and buccal epithelial cells (n = 12)] were obtained from 22 healthy volunteers. On the basis of the results of preliminary analysis, the cervical samples were grouped into three categories: (a) nondysplasia/low-grade cervical intraepithelial neoplasia (CIN; n = 37); (b) high-grade CIN (n = 17); and (c) invasive cancer (n = 19). The methylation status of six genes was determined (p16, RARbeta, FHIT, GSTP1, MGMT, and hMLH1). Our main findings are as follows: (a) methylation was completely absent in control tissues; (b) the frequencies of methylation for all of the genes except hMLH1 were >20% in cervical cancers; (c) aberrant methylation commenced early during multistage pathogenesis and methylation of at least one gene was noted in 30% of the nondysplasia/low-grade CIN group; (d) an increasing trend for methylation was seen with increasing pathological change; (e) methylation of RARbeta and GSTP1 were early events, p16 and MGMT methylation were intermediate events, and FHIT methylation was a late, tumor-associated event; and (f) methylation occurred independently of other risk factors including papillomavirus infection, smoking history, or hormone use. Although our findings need to be extended to a larger series, they suggest that the pattern of aberrant methylation in women with or without dysplasia may help identify subgroups at increased risk for histological progression or cancer development.

Ancient DNA analysis reveals divergence of the cave bear, Ursus spelaeus, and brown bear, Ursus arctos, lineages.

The cave bear, Ursus spelaeus, represents one of the most frequently found paleontological remains from the Pleistocene in Europe. The species has always been confined to Europe and was contemporary with the brown bear, Ursus arctos. Relationships between the cave bear and the two lineages of brown bears defined in Europe, as well as the origins of the two species, remain controversial, mainly due to the wide morphological diversity of the fossil remains, which makes interpretation difficult [1, 2]. Sequence analysis of ancient DNA is a useful tool for resolving such problems because it provides an independent source of data [3]. We previously amplified a short DNA fragment of the mitochondrial DNA control region (mt control region) of a 40,000-year-old Ursus spelaeus sample [4]. In this paper, we describe the DNA analysis of two mtDNA regions, the control region and the cytochrome b gene. Control region sequences were obtained from ten samples of cave bears ranging from 130,000 to 20,000 years BP, and one particularly well-conserved sample gave a complete cyt b sequence. Our data demonstrate that cave bears split largely before the lineages of brown bears around 1.2 million years ago. Given its abundance, its wide distribution in space and time, and its large morphological diversity, the cave bear is a promising model for direct observation of the evolution of sequences throughout time, extinction periods, and the differentiation of populations shaped by climatic fluctuations during the Pleistocene.

Preterm delivery and the severity of violence during pregnancy.

OBJECTIVE: To determine the severity and consequences of physical violence during pregnancy among participants in a health department prenatal care coordination program. STUDY DESIGN: The prospective cohort study included all program participants from 1994 to 1996. Care coordinators screened participants for physical violence during pregnancy using a validated, systematic assessment protocol three times during prenatal care. The protocol was linked with prenatal records, delivery records and infant records to document complications and infant outcomes. Multiple logistic regression was used to assess the relationship between severe physical violence during pregnancy and pregnancy outcome while controlling for confounding factors. RESULTS: Among the 550 participants, 13.5% reported violence during pregnancy; it included 6.7% severe violence (hitting, kicking, injury with a weapon and abdominal injury) and 6.7% moderate violence (threats, slapping, shoving and sexual abuse). Severe physical prenatal violence was significantly associated with spontaneous preterm labor, preterm delivery, very preterm delivery, very low birth weight, preterm/low birth weight, mean birth weight, mean newborn hospital charges, five-minute Apgar < 7, neonatal intensive care unit admission, and fetal or neonatal death. Body site injured, timing of violence and number of violent incidents were significant factors associated with violence during pregnancy and preterm delivery. CONCLUSION: Because severe physical violence during pregnancy was a significant problem in this population, intervention programs are needed to reduce prenatal violence and its consequences.

Completeness of ascertainment of prenatal smoking using birth certificates and confidential questionnaires: variations by maternal attributes and infant birth weight. PRAMS Working Group. Pregnancy Risk Assessment Monitoring System.

Birth certificate data frequently are used to monitor the prevalence of smoking during pregnancy. The authors used a two-sample capture-recapture method to estimate the completeness of ascertainment of prenatal smoking on birth certificates and on confidential questionnaires in six US states. Completeness of ascertainment was also examined according to maternal attributes and infant birth weight. The samples included white women who delivered a live infant between 1993 and 1995 in one of six states (Alabama, Alaska, Georgia, Maine, South Carolina, or West Virginia) and who responded to a questionnaire mailed to them 2-6 months postpartum as part of the Pregnancy Risk Assessment Monitoring System. State-specific sample sizes ranged from 2,647 to 4,795. The completeness of ascertainment ranged from 70.6% to 82.0% using birth certificates and from 86.2% to 90.3% using confidential questionnaires. In all six states, the birth certificates' completeness of ascertainment varied by maternal education and infant birth weight, and the questionnaires' completeness varied by maternal age. Both birth certificates and questionnaires underestimated the true extent of smoking during pregnancy among these white women. Differential reporting by birth weights recorded on birth certificates would result in an overestimated association between low birth weight and prenatal smoking.

[Management of children with low vision]. / La prise en charge des enfants malvoyants.

Presentation of the Lausanne school for blind and visually impaired children. 38 children were admitted in the school in 1996-1997. 16 have a visual acuity of less than 3/60. Ocular malformations of various origins are the main reason of the handicap, followed by visual lesions of central origin. Comparing the study with those of 1992 and 1993, it seems that the number of retrolental fibroplasia and cataracts (operated or not) is decreasing. The authors present the educational care of these children. At present, the goal is to maintain the children in their own family. Most of them are day pupils and the transportation organisation is therefore very important. In special cases, it is possible to leave the children in a non-specialized school, provided the children receive a good educational support by one of our specialized low-vision teachers.

A conceptual model of occupational health nursing. The resource model.

1. Conceptual models provide an important framework for the development and implementation of a successful occupational health program. The Resource Model incorporates the varied resources available from the worksite, community, and professional realms. 2. Although the domain of the client focuses on the workplace, the concept of "client" may include individuals in the workplace, as well as workers' families, the worksite organization, and the local community. 3. Using a collaborative team process, the occupational health nurse is a leader and coordinator maximizing resources for the most appropriate and realistic health and safety program.