Quantitative matching of crystal structures to experimental powder diffractograms.

The identification and classification of crystal structures is fundamental in materials science, as the crystal structure is an inherent factor of what gives solid materials their properties. Being able to identify the same crystallographic form from unique origins (e.g. different temperatures, pressures, or in silico-generated) is a complex challenge. While our previous work has focused on comparison of simulated powder diffractograms from known crystal structures, herein is presented the variable-cell experimental powder difference (VC-xPWDF) method to match collected powder diffractograms of unknown polymorphs to both experimental crystal structures from the Cambridge Structural Database and in silico-generated structures from the Control and Prediction of the Organic Solid State database. The VC-xPWDF method is shown to correctly identify the most similar crystal structure to both moderate and "low" quality experimental powder diffractograms for a set of 7 representative organic compounds. Features of the powder diffractograms that are more challenging for the VC-xPWDF method are discussed (i.e. preferred orientation), and comparison with the FIDEL method showcases the advantage of VC-xPWDF provided the experimental powder diffractogram can be indexed. The VC-xPWDF method should allow rapid identification of new polymorphs from solid-form screening studies, without requiring single-crystal analysis.

Heisenberg Spin Chains via Chalcogen Bonding: Noncovalent S···O Contacts Enable Long-Range Magnetic Order.

The new radical ligand 5,8-dimethyl-1,4-dioxonaphtho[2,3-d][1,2,3]dithiazolyl (1) is reported. Two crystal polymorphs, 1α and 1ß, differing in their pancake-bonded dimerization motif and S···O contact network, are identified. The self-assembly of Mn(II) metal ions with 1 leads to the formation of [Mn(hfac)2]3(1)2 that exhibits a Mn(II)-radical-Mn(II)-radical-Mn(II) linear arrangement of three Mn(hfac)2 units bridged by two radical ligands (hfac = 1,1,1,5,5,5-hexafluoroacetylacetonato-). Characterization by single-crystal X-ray diffraction of this Mn(II) complex packing structure reveals close noncovalent S···O contacts between the [Mn(hfac)2]3(1)2 units in one dimension along the b-c direction. The magnetic properties of the coordination complex are characterized by dc and ac susceptibility measurements on a microcrystalline solid. The magnetic data down to 4.8 K indicate the presence of effective ferromagnetic interactions (J/kB = +0.16 K) between the molecular ST = 13/2 units along the supramolecular chain involving noncovalent S···O contacts. Below 2.9 K, a non-zero out-of-phase component appears in the ac susceptibility, indicating the presence of a three-dimensional magnetic phase transition.

Advances in Human Placental Biomechanics.

Pregnancy complications are a major clinical concern due to the related maternal and fetal morbidity. Many are caused through defective placentation, but research into placental function is difficult, principally because of the ethical limitations associated with the in-vivo organ and the difficulty of extrapolating animal models. Perfused by two separate circulations, the maternal and fetal bloodstreams, the placenta has a unique structure and performs multiple complex functions. Three-dimensional imaging and computational modelling are becoming popular tools to investigate the morphology and physiology of this organ. These techniques bear the potential for better understanding the aetiology and development of placental pathologies, however, their full potential is yet to be exploited. This review aims to summarize the recent insights into placental structure and function by employing these novel techniques.

Reversible crystal-to-crystal chiral resolution: making/breaking non-bonding SO interactions.

An achiral organic molecule adopts a chiral conformation, crystallizing in two morphologies: a racemic form, stable <70 °C, and a homochiral form, stable ≥70 °C. Upon seeding, crystal-to-crystal phase transitions occur reversibly between the racemic and chiral forms. Liquid-to-solid chiral crystallization is observed >90% of the time from the melt.

Computational modeling of the structure-function relationship in human placental terminal villi.

Placental oxygen transport takes place at the final branches of the villous tree and is dictated by the relative arrangement of the maternal and fetal circulations. Modeling techniques have failed to accurately assess the structure-function relationship in the terminal villi due to the geometrical complexity. Three-dimensional blood flow and oxygen transport was modeled in four terminal villi reconstructed from confocal image stacks. The blood flow was analyzed along the center lines of capillary segments and the effect of the variability in capillary diameter, tortuosity and branching was investigated. Additionally, a validation study was performed to corroborate the simulation results. The results show how capillary variations impact motion of the fetal blood, and how their bends and dilatations can decelerate the flow by up to 80%. Vortical flow is also demonstrated not to develop in the fetal capillaries. The different geometries are shown to dictate the transport of gases with differences of over 100% in the oxygen flux between samples. Capillary variations are key for efficient oxygen uptake by the fetus; they allow the blood to decelerate where the villous membrane is thinnest allowing for a better oxygenation, but also by reducing the vessel diameter they carry the oxygenated blood away fast. The methodology employed herein could become a platform to simulate complicated in-vivo and in-vitro scenarios of pregnancy complications.

The relationship between human placental morphometry and ultrasonic measurements of utero-placental blood flow and fetal growth.

INTRODUCTION: Ultrasonic fetal biometry and arterial Doppler flow velocimetry are widely used to assess the risk of pregnancy complications. There is an extensive literature on the relationship between pregnancy outcomes and the size and shape of the placenta. However, ultrasonic fetal biometry and arterial Doppler flow velocimetry have not previously been studied in relation to postnatal placental morphometry in detail. METHODS: We conducted a prospective cohort study of nulliparous women in The Rosie Hospital, Cambridge (UK). We studied a group of 2120 women who had complete data on uterine and umbilical Doppler velocimetry and fetal biometry at 20, 28 and 36 weeks' gestational age, digital images of the placenta available, and delivered a liveborn infant at term. Associations were expressed as the difference in the standard deviation (SD) score of the gestational age adjusted ultrasound measurement (z-score) comparing the lowest and highest decile of the given placental morphometric measurement. RESULTS: The lowest decile of placental surface area was associated with 0.87 SD higher uterine artery Doppler mean pulsatility index (PI) at 20 weeks (95% CI: 0.68 to 1.07, P < 0.001). The lowest decile of placental weight was associated with 0.73 SD higher umbilical artery Doppler PI at 36 weeks (95% CI: 0.54 to 0.93, P < 0.001). The lowest decile of both placental weight and placental area were associated with reduced growth velocity of the fetal abdominal circumference between 20 and 36 weeks (both P < 0.001). CONCLUSION: Placental area and weight are associated with uterine and umbilical blood flow, respectively, and both are associated with fetal growth rate.

Obesity-dependent metabolic signatures associated with nonalcoholic fatty liver disease progression.

Our understanding of the mechanisms by which nonalcoholic fatty liver disease (NAFLD) progresses from simple steatosis to steatohepatitis (NASH) is still very limited. Despite the growing number of studies linking the disease with altered serum metabolite levels, an obstacle to the development of metabolome-based NAFLD predictors has been the lack of large cohort data from biopsy-proven patients matched for key metabolic features such as obesity. We studied 467 biopsied individuals with normal liver histology (n=90) or diagnosed with NAFLD (steatosis, n=246; NASH, n=131), randomly divided into estimation (80% of all patients) and validation (20% of all patients) groups. Qualitative determinations of 540 serum metabolite variables were performed using ultraperformance liquid chromatography coupled to mass spectrometry (UPLC-MS). The metabolic profile was dependent on patient body-mass index (BMI), suggesting that the NAFLD pathogenesis mechanism may be quite different depending on an individual's level of obesity. A BMI-stratified multivariate model based on the NAFLD serum metabolic profile was used to separate patients with and without NASH. The area under the receiver operating characteristic curve was 0.87 in the estimation and 0.85 in the validation group. The cutoff (0.54) corresponding to maximum average diagnostic accuracy (0.82) predicted NASH with a sensitivity of 0.71 and a specificity of 0.92 (negative/positive predictive values=0.82/0.84). The present data, indicating that a BMI-dependent serum metabolic profile may be able to reliably distinguish NASH from steatosis patients, have significant implications for the development of NASH biomarkers and potential novel targets for therapeutic intervention.

Honeybee colony collapse due to Nosema ceranae in professional apiaries.

Honeybee colony collapse is a sanitary and ecological worldwide problem. The features of this syndrome are an unexplained disappearance of adult bees, a lack of brood attention, reduced colony strength, and heavy winter mortality without any previous evident pathological disturbances. To date there has not been a consensus about its origins. This report describes the clinical features of two professional bee-keepers affecting by this syndrome. Anamnesis, clinical examination and analyses support that the depopulation in both cases was due to the infection by Nosema ceranae (Microsporidia), an emerging pathogen of Apis mellifera. No other significant pathogens or pesticides (neonicotinoids) were detected and the bees had not been foraging in corn or sunflower crops. The treatment with fumagillin avoided the loss of surviving weak colonies. This is the first case report of honeybee colony collapse due to N. ceranae in professional apiaries in field conditions reported worldwide.

Use of supercritical fluid extraction and gas chromatography-mass spectrometry to obtain amino acid profiles from several genetically modified varieties of maize and soybean.

A method using supercritical fluid extraction (SFE) and gas chromatography-mass spectrometry (GC/MS) for obtaining the amino acid profiles of genetically modified maize and soybean is proposed. SFE is carried out in a homemade modular system where amino acids are extracted with carbon dioxide modified with 35% of methanol, in conditions optimized by a central composite design. Once extracted, the amino acids are determined by GC/MS. The method has been applied to three samples of maize derived from MON810, other from NK 603 and a Roundup ready soybean sample. The profiles are compared with those obtained from their corresponding isogenic non-transgenic varieties. Although differences are directly observed in some cases by visual comparison of the chromatograms, the application of ANOVA shows more significant differences. In general terms, isogenic varieties seem to have higher content of several amino acids.

Sample preparation methods to analyze fipronil in honey by gas chromatography with electron-capture and mass spectrometric detection.

Several sample preparation methods have been assayed to analyze residues of fipronil in honey. After diluting the honey, liquid-liquid extraction (LLE) with organic solvents, and solid-phase extraction (SPE) on commercial cartridges or Florisil-packed column have been tested at three concentration levels: 0.01, 0.1 and 1 mg/kg. LLE with n-hexane or SPE on a Florisil column resulted to be the most suitable procedures to analyze fipronil at trace concentrations. Fipronil was quantified by gas chromatography (GC) with electron-capture detection (ECD) or mass spectrometric (MS) detection after conventional or matrix-matched calibration. The detection limit of fipronil in honey samples was below 1 microg/kg. The degradation of fipronil in honey has also been studied, being identified three minor degradation products in the extracts.

Spanish validation of the HIV dementia scale in women.

HIV infection is increasing in minority groups, particularly in African American and Hispanic women. Although the incidence of HIV dementia has decreased since the advent of highly active antiretroviral treatment, prevalence of neurocognitive complications has increased as patients are now living longer. This study's purpose was to determine the psychometric properties of the Spanish-language HIV Dementia Scale (HDS) in a group of HIV-infected women. We recruited 96 women: 60 HIV-seropositive and 36 HIV-seronegative. Modification of the HDS into a Spanish-language version consisted of translating the instructions, substituting four words in Spanish (gato, media, azul, piña), increasing 1 second in the psychomotor speed because the Spanish alphabet has more letters than the English alphabet, and not offering clues for memory recall. Cognitive impairment (CI) was defined according to the modified American Academy of Neurology HIV-dementia criteria including an asymptomatic CI group. Statistical analysis consisted of analysis of variance to determine group differences and receiver operator characteristics (ROC) to determine the optimal cutoff point for the screening of CI. HDS-Spanish total score and subscores for psychomotor speed and memory recall showed significant differences between HIV-seronegative and women with HIV-dementia (p < 0.001) and between HIV-seropositive women with normal cognition and those with HIV-dementia (p < 0.001). The optimal cutoff point of 13 or less had performance characteristics of 87% sensitivity and 46% specificity for HIV-associated CI (50.0% positive predictive value, 85.0% negative predictive value). The HDS-Spanish translation offers a useful screening tool with value for the identification of Hispanic women at risk of developing HIV-associated symptomatic neurocognitive disturbances.

Comparative study of sample preparation procedures to determine fipronil in pollen by gas chromatography with mass spectrometric and electron-capture detection.

Several sample preparation methods have been assayed to analyze residues of fipronil in pollen at trace concentrations. Extraction with organic solvents, solid-phase extraction on either commercial cartridges or a Florisil-packed column and a matrix solid-phase dispersion, also with Florisil as a dispersing agent, have been tested. Determination of fipronil in the extracts has been carried out by GC with electron-capture and mass spectrometric detection. An extraction with acetonitrile followed by a clean-up on ODS or polymeric cartridges was the most suitable procedure to obtain acceptable recoveries and relatively simple chromatograms. The matrix-effects observed in the quantification can be corrected with a matrix-matched calibration.

Educational and health services innovation to improve care for rural Hispanic communities in the USA.

BACKGROUND: Access to comprehensive and quality healthcare services is difficult for socioeonomically disadvantaged groups in rural regions. Barriers to health care for rural Latinos include lack of insurance, language barriers and cultural differences. For the Latino immigrant population in rural areas, barriers to access are compounded. HEALTH NEEDS OF RURAL AREAS: THE CASE OF WALHALLA, SC: The town of Walhalla, South Carolina, USA, is a rural community located in Oconee County, the northwest corner of the state. Disparities exist between rural and urban residents in several health categories, and these disparities illustrate the need to provide competent, appropriate and affordable healthcare to rural populations. The Hispanic population of Oconee has dramatically increased in the past decade, and the majority of these immigrants have no health insurance and have limited access to health services. DESIGNING A PROGRAM TO FIT THE COMMUNITY--THE "WALHALLA EXPERIENCE": The purpose of the Accessible and Culturally Competent Health Care Project (ACCHCP) is to provide care for underserved populations, in Oconee County, South Carolina while providing rural educational opportunities for health services students. Funded by the Health Resources and Services Administration of DHHS, the program is designed to offer culturally appropriate, sensitive, accessible, affordable and compassionate care in a mobile clinic setting. In this interdisplinary program, nurse practitioners, health educators, bilingual interpreters, medical residents and Clemson University students and professors all played key roles. Women in the community also serve as promotoras or lay health advisors. The program is unique in using educational initiatives and innovative strategies for bringing health care to this underserved community and offers important information for rural healthcare initiatives targeting minority groups. This article reports on the challenges and successes in the development and implementation of the ACCHCP program in Walhalla, South Carolina.

Macrophage proteomic fingerprinting predicts HIV-1-associated cognitive impairment.

BACKGROUND: Specific proteins produced from monocytes may be linked to the pathogenesis and aid in the diagnosis of HIV-1-associated dementia (HAD). OBJECTIVE: The authors assessed whether a diagnostic phenomic protein profile could be obtained from monocyte-derived macrophages (MDM) from HIV-1-infected patients with cognitive impairment. METHODS: Twenty-one HIV-1-infected Hispanic women and 10 seronegative controls matched by age and sex were followed at the University of Puerto Rico Medical Sciences Campus, where neuropsychological, immune, and viral parameters were tested. Monocytes were recovered by Percoll gradient centrifugation from peripheral blood mononuclear cells. MDM lysates were prepared after 7 days of cultivation and protein profiles analyzed by surface enhanced laser desorption/ionization (SELDI)-time of flight (TOF) ProteinChip tests. Classification trees were prepared for statistical analyses. RESULTS: A total of 177 protein peaks from 2 to 80 kDa were evaluated in 31 patient MDM lysates by SELDI-TOF ProteinChip assays. Select protein peaks, at 5028 and 4320 Da, separated HIV-1-infected from HIV-1-seronegative subjects with a sensitivity of 100% and a specificity of 80%. Thirty-eight peaks were used to differentiate HIV-1-infected subjects with and without cognitive impairment. A 4348 Da protein separated the two groups with a sensitivity of 100% and a specificity of 75%. CONCLUSIONS: The identification of unique phenomic MDM profiles from cognitively impaired HIV-1-infected patients supports the hypothesis that changes in monocyte function parallel the development of HAD.

An examination of critical care nurses' knowledge and attitudes regarding pain management in hospitalized patients.

The purpose of this study was to determine the effectiveness of an educational intervention focused on pain management. The sample consisted of 30 medical/surgical intensive care nurses (age range, 23 to 62 years) employed in a large metropolitan hospital in the southeastern United States. McCaffery and Ferrell's Nurses' Knowledge and Attitude Survey Regarding Pain was administered at 2 points in time: before and after the educational program. The survey simultaneously measures knowledge and attitude levels regarding pain control. The paired t test was used to test for differences between pre- and posttest scores. The Point-biserial and Spearman's correlation coefficients were computed to examine relationships between selected sociodemographic variables and scores (baseline and change) on the survey. Results revealed a significant increase in scores after the educational intervention (t = 9.60. p = .0005). Additionally, a statistically significant correlation was found between change scores (posttest minus pretest scores) and years of nursing experience (rs = .37, p = .047). However, no significant relationships were found between type of nursing degree and baseline or change scores (rpb = .11, p = .575; rpb = .01, p = .955). These results support previous research findings related to the problem of inadequate pain management in the hospital setting. Further, the findings indicate that education regarding pain control is crucial for current nursing students as well as practicing nurses. The challenge for nurses is to be responsive to and integrate current pain management techniques in an effort to decrease the discomfort of hospitalized patients.

[Triatoma infestans in area under entomological surveillance for Chagas' disease in São Paulo State, Brazil]. / Triatoma infestans em área sob vigilância entomológica para doença de Chagas, Estado de São Paulo, Brasil.

In response to notification of the capture of a winged triatomine bug by local inhabitants, an epidemiological investigation was investigated in the rural area of the Municipality of Paulínia, São Paulo State (Brazil). This led to the collection of 109 specimens of Triatoma infestans from peridomiciliary breeding sites. Local conditions favored colonization by triatomine bugs: many abandoned outbuildings were inhabited by pigeons and sparrows, which meant abundant feed for these bugs. Thus, surveillance is mandatory as long as conditions for triatomine breeding persist. Nevertheless, entomological and serological indicators ruled out immediate concern over vectorial transmission of Chagas' disease in this municipality. All domiciliary units of the region were sprayed with residual-effect insecticides and the triatomine breeding sites were destroyed by the use of mechanical control of bird nests. The importance of reporting the occurrence of triatomine bugs, particularly Triatoma infestans, in this region, is emphasized.

The relationship between spectral characteristics and perceived hypernasality in children.

The purpose of this study was to quantify perceived hypernasality in children. One-third octave spectra of the isolated vowel [i] were obtained from 32 children with cleft palate and 5 children without cleft palate. Four experienced listeners rated the severity of hypernasality of the 37 speech samples using a 6-point equal-appearing interval scale. When the average 1/3-octave spectra from the hypernasal group and the normal resonance group were compared, spectral characteristics of hypernasality were identified as increased amplitudes between F1 and F2 and decreased amplitudes in the region of F2. Based on the findings of the children's speech, 36 speech samples with manipulated spectral characteristics were used to minimize the influences of voice source characteristics on perceived hypernasality. Multiple regression analysis revealed a high correlation (R = 0.84) between the amplitudes of 1/3-octave bands (1 k, 1.6 k, and 2.5 kHz) and the perceptual ratings. Increased amplitudes of bands between F1 and F2 (1 k, 1.6 kHz) and decreased amplitude of the band of F2 (2.5 kHz) was associated with an increasing perceived hypernasality. These results suggest that the amplitudes of the three 1/3-octave bands are appropriate acoustic parameters to quantify hypernasality in the isolated vowel [i].

The influence of acoustic and perceptual factors on perceived hypernasality in the vowel.

The purpose of this study was to examine the influence of acoustic and perceptual factors of speech on listeners' perceived hypernasality in the vowel [i]. The isolated syllable [pi] produced by 22 children with hypernasal speech and 6 noncleft children was rated by 10 listeners. These speech samples were then divided into two groups: (1) the samples (n = 14) that received inconsistent ratings from each listener or variable ratings among listeners (i.e., unreliable ratings) and (2) the samples (n = 14) that received consistent ratings from each listener and similar ratings among listeners (i.e., reliable ratings). These results suggest that the severity of hypernasality was easy to rate in some speech samples and not in others. Voice quality deviation and a particular type of spectral change that related to the severity of hypernasality could be factors that influence perceived hypernasality.