Associations between breast implants and postpartum lactational mastitis in breastfeeding women: retrospective study.

OBJECTIVE: To examine the putative associations between breast implants and postpartum lactational mastitis. DESIGN: Observational retrospective study. SETTING: Digital database of Maccabi Healthcare Services, integrated health maintenance organisation in Israel. POPULATION: Breastfeeding mothers from 2003 to 2016 based on an initial health maintenance organisation data set of 28 383 singleton live births in Israel. METHODS: Multivariate analysis and propensity score matching were used to test the extent to which breast implants were associated with lactational mastitis during the 6-month postpartum period in breastfeeding mothers. Analyses for potential confounders were adjusted for socio-economic status, smoking and parity. MAIN OUTCOME MEASURE: Lactational mastitis among breastfeeding women with breast implants compared with women without breast implants. RESULTS: Mothers with breast implants (n = 6099) were significantly (P < 0.001) more likely to be diagnosed with postpartum mastitis (8.3%) than mothers with no breast implants(n = 22 284) (6.6%) at an odds ratio of 1.22 (95% CI 1.09-1.35) after adjusting for confounders. CONCLUSION: Breast augmentation is associated with an increased risk of postpartum lactational mastitis in the 6-month postpartum period. In light of these findings, it is important for health professionals to instruct women who have undergone breast augmentation on correct breastfeeding techniques, ways to avoid risk factors, and to be alert to signs permitting the early detection of lactational mastitis. TWEETABLE ABSTRACT: A study of over 28,000 breastfeeding women has shown that breast augmentation is associated with an increased risk of postpartum lactational mastitis in the six-month postpartum period.

A multifunctional matching algorithm for sample design in agricultural plots.

Collection of accurate and representative data from agricultural fields is required for efficient crop management. Since growers have limited available resources, there is a need for advanced methods to select representative points within a field in order to best satisfy sampling or sensing objectives. The main purpose of this work was to develop a data-driven method for selecting locations across an agricultural field given observations of some covariates at every point in the field. These chosen locations should be representative of the distribution of the covariates in the entire population and represent the spatial variability in the field. They can then be used to sample an unknown target feature whose sampling is expensive and cannot be realistically done at the population scale. An algorithm for determining these optimal sampling locations, namely the multifunctional matching (MFM) criterion, was based on matching of moments (functionals) between sample and population. The selected functionals in this study were standard deviation, mean, and Kendall's tau. An additional algorithm defined the minimal number of observations that could represent the population according to a desired level of accuracy. The MFM was applied to datasets from two agricultural plots: a vineyard and a peach orchard. The data from the plots included measured values of slope, topographic wetness index, normalized difference vegetation index, and apparent soil electrical conductivity. The MFM algorithm selected the number of sampling points according to a representation accuracy of 90% and determined the optimal location of these points. The algorithm was validated against values of vine or tree water status measured as crop water stress index (CWSI). Algorithm performance was then compared to two other sampling methods: the conditioned Latin hypercube sampling (cLHS) model and a uniform random sample with spatial constraints. Comparison among sampling methods was based on measures of similarity between the target variable population distribution and the distribution of the selected sample. MFM represented CWSI distribution better than the cLHS and the uniform random sampling, and the selected locations showed smaller deviations from the mean and standard deviation of the entire population. The MFM functioned better in the vineyard, where spatial variability was larger than in the orchard. In both plots, the spatial pattern of the selected samples captured the spatial variability of CWSI. MFM can be adjusted and applied using other moments/functionals and may be adopted by other disciplines, particularly in cases where small sample sizes are desired.

Does the presence of AGG interruptions within the CGG repeat tract have a protective effect on the fertility phenotype of female FMR1 premutation carriers?

PURPOSE: While FMR1 premutation carriers (CGG 55-200) were shown to have reduced success with IVF treatment (lower oocyte yield), studies reporting on the association between the number of CGG repeats and patients' response to controlled ovarian hyperstimulation (COH) are inconsistent. In the present study, we aim to explore whether the number of CGG repeats in women with premutation in FMR1 gene, undergoing COH for IVF, correlates with COH variables and whether the number of AGG interruptions may function as a "protective factor" by improving the ovarian response to COH. METHODS: Retrospective study, in an academic IVF-PGD unit. Fifty-seven consecutive FMR1 premutation carriers who underwent 285 IVF treatment cycles were included. The numbers of CGG repeats and AGG interruptions were retrieved and correlated to the demographics and COH variables. RESULTS: There were no significant association between the numbers of CGG or the AGG interruptions and the number of oocyte retrieved or the peak estradiol levels. The lack of association was also observed when including all the IVF treatment cycles or only the first or last IVF treatment cycle. Moreover, no associations were found between the number of CGG repeats or AGG interruptions and other COH variables, i.e., duration of stimulation, the total dose of gonadotropin used, or the number of top-quality embryos. CONCLUSIONS: No associations were observed between the number of CGG repeats or AGG interruptions and any of the COH variables. Further studies are required to identify early biomarkers of POI to empower FMR1 premutation carriers with risk assessment tools to consider procedures such as fertility preservation.

Choice of anaesthesia for category-1 caesarean section in women with anticipated difficult tracheal intubation: the use of decision analysis.

A predicted difficult airway is sometimes considered a contra-indication to rapid sequence induction of general anaesthesia, even in an urgent case such as a category-1 caesarean section for fetal distress. However, formally assessing the risk is difficult because of the rarity and urgency of such cases. We have used decision analysis to quantify the time taken to establish anaesthesia, and probability of failure, of three possible anaesthetic methods, based on a systematic review of the literature. We considered rapid sequence induction of general anaesthesia with videolaryngoscopy, awake fibreoptic intubation and rapid spinal anaesthesia. Our results show a shorter mean (95% CI) time to induction of 100 (87-114) s using rapid sequence induction compared with 9 (7-11) min for awake fibreoptic intubation (p < 0.0001) and 6.3 (5.4-7.2) min for spinal anaesthesia (p < 0.0001). We calculate the risk of ultimate failed airway control after rapid sequence induction to be 21 (0-53) per 100,000 cases, and postulate that some mothers may accept such a risk in order to reduce potential fetal harm from an extended time interval until delivery. Although rapid sequence induction may not be the anaesthetic technique of choice for all cases in the circumstance of a category-1 caesarean section for fetal distress with a predicted difficult airway, we suggest that it is an acceptable option.

Variables Associated with Severity of Bacterial Canker and Wilt Caused by Clavibacter michiganensis subsp. michiganensis in Tomato Greenhouses.

Clavibacter michiganensis subsp. michiganensis, the causal agent of bacterial canker and wilt of tomato, is considered to be one of the most important bacterial pathogens worldwide. In the year 2000 there was an increase in the number of infected greenhouses and in the severity of the disease in Israel. As part of the effort to cope with the disease, a comprehensive survey was conducted. Scouts recorded disease severity monthly in 681 production units. At the end of the season the scouts met with the growers and together recorded relevant details about the crop and cultural practices employed. The results suggested an absence of anisotropy pattern in the study region. Global Moran's I analysis showed that disease severity had significant spatial autocorrelation. The strongest spatial autocorrelation occurred within a 1,500 m neighborhood, which is comparable to the distance between production units maintained by one grower (Farm). Next, we tested three groups of variables including or excluding the Farm as a variable. When the Farm was included the explained variation increased in all the studied models. Overall, results of this study demonstrate that the most influential factor on bacterial canker severity was the Farm. This variable probably encompasses variation in experience, differences in agricultural practices between growers, and the quality of implementation of management practices.

Cryogenic-temperature electron microscopy direct imaging of carbon nanotubes and graphene solutions in superacids.

Cryogenic electron microscopy (cryo-EM) is a powerful tool for imaging liquid and semiliquid systems. While cryogenic transmission electron microscopy (cryo-TEM) is a standard technique in many fields, cryogenic scanning electron microscopy (cryo-SEM) is still not that widely used and is far less developed. The vast majority of systems under investigation by cryo-EM involve either water or organic components. In this paper, we introduce the use of novel cryo-TEM and cryo-SEM specimen preparation and imaging methodologies, suitable for highly acidic and very reactive systems. Both preserve the native nanostructure in the system, while not harming the expensive equipment or the user. We present examples of direct imaging of single-walled, multiwalled carbon nanotubes and graphene, dissolved in chlorosulfonic acid and oleum. Moreover, we demonstrate the ability of these new cryo-TEM and cryo-SEM methodologies to follow phase transitions in carbon nanotube (CNT)/superacid systems, starting from dilute solutions up to the concentrated nematic liquid-crystalline CNT phases, used as the 'dope' for all-carbon-fibre spinning. Originally developed for direct imaging of CNTs and graphene dissolution and self-assembly in superacids, these methodologies can be implemented for a variety of highly acidic systems, paving a way for a new field of nonaqueous cryogenic electron microscopy.

Conservative management of preterm premature rupture of membranes beyond 32 weeks' gestation: is it worthwhile?

We aimed to investigate whether conservative management of preterm premature rupture of membranes (PPROM) at 32-34 weeks' gestation improves outcome. In this retrospective analysis of singleton pregnancies, the study group included patients with PPROM at 28-34 weeks' gestation and the control group included patients presented with spontaneous preterm delivery at 28-34 weeks' gestation. Both groups were subdivided according to gestational age - early (28-31 weeks' gestation) versus late (32-34 weeks' gestation). Adverse neonatal outcome included neonatal death, intraventricular haemorrhage grade 3/4, respiratory distress syndrome, periventricular leucomalacia and neonatal sepsis. The study and control groups included 94 and 86 women, respectively. The study group had a lower incidence of adverse neonatal outcome at the earlier weeks (28-31), compared with the control group at the same gestational age. In contrast, at 32-34 weeks' gestation no difference in the risk for adverse neonatal outcome was noticed. Additionally, within the study group, chorioamnionitis rate was significantly higher among those who delivered at 32-34 weeks' gestation (p < 0.01). No advantage for conservative management of PPROM was demonstrated beyond 31 weeks' gestation. Moreover, conservative management of PPROM at 32-34 weeks' gestation may expose both mother and neonate to infectious morbidity.

Direct experimental observation of a new mechanism for sputtering of solids by a large polyatomic projectile: velocity-correlated cluster emission.

We have measured kinetic energy distributions of Ta(n)C(n)(+) (n=1-10) and Ag(n)(+) (n=1-9) cluster ions sputtered off Ta and Ag targets, following impact of C(60)(-) at 14 keV kinetic energy. A gradual increase of the most probable kinetic energies with increased size of the emitted cluster was observed (nearly the same velocity for all n values). This behavior is in sharp contrast to that reported for cluster emission induced by the impact of a monoatomic projectile. Our observation is in good agreement with a mechanism based on the new concept of a superhot moving precursor as the source of the emitted clusters.

Exposure of fallopian tube epithelium to follicular fluid mimics carcinogenic changes in precursor lesions of serous papillary carcinoma.

OBJECTIVES: Ovulation-related inflammation is suspected to have a causal role in ovarian carcinogenesis, but there are no human models to study the molecular pathways. Our aim is to develop such an ex-vivo model based on human fallopian tube (FT) epithelium exposed to human follicular fluid (FF). METHODS: FT epithelium was dissociated from normal surgical specimens. FF was obtained from donors undergoing in-vitro fertilization. The cells were cultured on collagen-coated Transwells and incubated with FF for various periods of time. The transcriptomic changes resulting from FF treatment were profiled using Affymetrix expression arrays. Specific characteristics of the FT pre-cancerous lesions were studied using immunohistochemistry, immunofluorescence, RT-PCR and XTT assay. RESULTS: We show that FF exposure causes up-regulation of inflammatory and DNA repair pathways. Double stranded DNA breaks are induced. There is a minor increase in cell proliferation. TP53, which is the hallmark of the precursor lesion in-vivo, is accumulated. Levels of expression and secretion of Interleukin-8 are significantly increased. CONCLUSIONS: Our model addresses the main non-genetic risk factor for ovarian cancer, namely the impact of ovulation. This study demonstrates the biological implications of in-vitro exposure of human FT epithelial cells to FF. The model replicates elements characterizing the precursor lesions of ovarian cancer, and warrants further investigation of the linkage between repeated exposure to ovulation-related damage and accumulation of neoplastic changes.

Enhanced imaging of developed fingerprints using mass spectrometry imaging.

Latent fingermarks are invisible to the naked eye and normally require the application of a chemical developer followed by an optical imaging step in order to visualize the ridge detail. If the finger deposition is poor, or the fingermark is aged, it can sometimes be difficult to produce an image of sufficient quality for identification. In this work, we show for the first time how mass spectrometry imaging (in this case time-of-flight secondary ion mass spectrometry, ToF-SIMS) can be used to enhance the quality of partially recovered fingermarks. We show three examples of how chemical imaging can be used to obtain enhanced images of fingermarks deposited on aluminium foil, glass and the handle of a hand grenade compared with conventional development techniques.

Host Preference of Mating Type in Pseudoperonospora cubensis, the Downy Mildew Causal Agent of Cucurbits.

The A2 mating type of Pseudoperonospora cubensis was first discovered in Israel in May 2010 on butternut gourd (Cucurbita moschata) (1). We monitored the occurrence of the A2 mating type of P. cubensis in isolates collected during May 2010 through September 2012 from downy mildew-infected cucurbit crops growing along the coastal plain of Israel. Mating type was determined by oospore production in melon leaf discs co-inoculated with sporangia of a test isolate mixed with sporangia of A1 or A2 tester isolates (2). The A1 and A2 tester isolates were maintained at 14°C (14 h light/day) by repeated inoculation of detached leaves of cucumber and pumpkin, respectively. The 29 isolates that were collected from cucumber (Cucumis sativum) were all A1. Of the 33 isolates collected from pumpkin (Cucurbita maxima), squash (C. pepo), or butternut gourd (C. moschata), 88% were A2 and 12% were A1. The host preference of mating type in P. cubensis was monitored at Bar-Ilan University farm during April to July 2012, among about 800 plants of eight cucurbit species (~100 plants per species) that were grown side-by-side in three adjacent net-houses (two 6 × 50 m and one 6 × 100 m) and exposed to natural infection. Downy mildew developed on cucumber, melon, pumpkin, squash, and butternut gourd, but not on watermelon, sponge gourd (Luffa cylindrica), or Momordica balsamina. Three-hundred and three isolates of P. cubensis were collected and tested for mating type: 123 from cucumber, 53 from melon, 30 from pumpkin, 48 from butternut gourd, and 41 from squash. The cucumber isolates expressed A1, A2, and A1A2 at a ratio of 94.3%, 3.3%, and 2.4%, respectively; the melon isolates 58.5%, 26.4%, and 15.1%; the pumpkin isolates 0%, 96.7%, and 3.3%; the butternut isolate 7.3%, 87.3%, and 5.5%; and the squash isolates 2.4%, 97.6%, and 0%, respectively. A1A2 isolates produce oospores when crossed with either A1 or A2 tester isolates. This is the first evidence suggesting a preference of A1 isolates to Cucumis spp. and of A2 isolates to Cucurbita spp. similar preference was recently observed among Chinese isolates of this pathogen (unpublished data). The mechanism(s) controlling this preference is not known. Classical genetics is currently employed to P. cubensis in order to understand if it derives from true linkage. The practical implication for downy mildew management is that growing cucumber/melon in close proximity to pumpkin/squash/butternut gourd should be avoided as it may enhance oospore production in nature. Oospores in soil were recently shown to serve as a primary source of downy mildew infection in cucumber (3). References: (1) Y. Cohen, A. E. Rubin, and M.Galperin. Plant Dis. 95:874, 2011; (2) Y. Cohen and A. E. Rubin. Eur. J. Plant Pathol. 132:577, 2012; (3) Y. J. Zhang et al. J. Phytopathol. 160:469, 2012.

First Report on the Occurrence of A2 Mating Type of the Cucurbit Downy Mildew Agent Pseudoperonospora cubensis in China.

Pseudoperonospora cubensis is a foliar pathogen of cucurbits. In cucumber, it produces chlorotic, angular lesions with dark sporangia on their under-surface. The distribution of pathotypes and mating types of P. cubensis were investigated in seven provinces in China. Twenty-nine isolates were obtained from Guangdong, Anhui, Hubei, Sichuan, Shandong, Beijing, and Harbin, one to six isolates from each province. They were collected from cucumber during summer 2011, except those from Harbin, which were collected from cucumber in summer 2012. Isolates were tested for pathogenicity and mating type. Pathogenicity was tested by inoculation of detached leaves of: cucumber (Cucumis sativum cvs. Bet-Alpha, SMR18), melon (Cucumis melo reticulatus cv. Ananas-Yokneam), pumpkin (Cucurbita maxima cv. Tripoli), squash (Cucurbita pepo, cv. Beruti), butternut gourd (Cucurbita moschata cv. Waltham), watermelon (Citrullus lanatus, cv. Malali), and sponge gourd (Luffa cylindrica, cultivar unknown). Mating type was determined by oospore production in melon leaf discs inoculated with mixed sporangia of a test isolate and A1 or A2 tester isolates, as recently described (2). The results showed that 22 isolates belonged to pathotype 3, sporulating on cucumber and melon; five isolates belonged to pathotype 6, sporulating on cucumber, melon, pumpkin, squash, and butternut gourd; one isolate belonged to pathotype 5, sporulating on the above five species and watermelon (1), and one isolate was capable of sporulating on the mentioned five species and sponge gourd, herein called pathotype 7. Of the 29 isolates tested, 22 belonged to the A1 mating type, six to the A2 mating type, and one did not produce oospores with either testers. Of the six A2 isolates, two originated from Sichuan, one from Beijing, and three from Harbin. All 22 isolates belonging to pathotype 3 were A1, whereas the other six isolates (four pathotype 6, one pathotype 5, and one pathotype 7) were A2. Crosses made between Chinese isolates belonging to opposite mating types resulted in the formation of abundant oospores in detached melon or cucumber leaves. The results prove that the A2 mating type of P. cubensis occurs in China. This explains the abundant occurrence of oospores of P. cubensis in nature in China (4). The data corroborate with Runge et al. (3), who suggested that the recent changes in the population structure of P. cubensis around the world resulted from the migration of a new genotype of P. cubensis from the Far East to Europe and the U.S.A. In Israel, a new pathotype attacking both Cucumis and Cucurbita appeared in 2002 (1), and A2 mating type first appeared in 2010 (2). References: (1) Y. Cohen et al. Phytoparasitica 31:458, 2003. (2) Y. Cohen and A. E. Rubin. Eur. J. Plant Pathol. 132:577, 2012. (3) F. Runge et al. Eur. J. Plant Pathol. 129:135, 2011. (4) Y. J. Zhang et al. J. Phytopathol. 160:469, 2012.

First Report of the Occurrence and Resistance to Mefenoxam of Peronospora belbahrii, Causal Agent of Downy Mildew of Basil (Ocimum basilicum) in Israel.

Downy mildew in basil was first reported from Uganda in 1933 (4). In 2004, it was reported from Italy (3) and, thereafter, from other countries around the world. In Israel, the disease was first observed in November 2011 in two greenhouses located in the northern part of the Jordan Valley. Within a month, second and third outbreaks of the disease occurred simultaneously near the southwest and southeast borders of Israel, 250 km from the initial disease outbreak. By the summer of 2012, the disease had appeared throughout the country, causing major economic damage. The causal agent, identified as Peronospora belbahrii (see below), produced chlorotic lesions on leaf blades with sporangia developing on the lower leaf surfaces. Lesions gradually turn necrotic, and infected leaves abscised. Sporangia were dark purple, oval, 30.4 ± 2.9 µm long × 21.4 ± 1.7 µm wide. Sporangiophores emerged from stomatal openings in a saturated atmosphere, were hyaline, 400 to 600 µm long, dichotomously branched, with three to five branches per sporangiophore, and bore a single sporangium on each branchlet tip. Oospores, seldom seen, were brown, round, and 46.2 ± 2.8 µm in diameter. Sporangia germinated directly, each producing a single germ tube that penetrated the periclinal wall of epidermal cells. PCR assays using sporangia and infected leaves as the template, and specific BAZ primers (1), produced a 134-bp band typical of P. belbahrii (1,2). Twenty isolates, collected from 12 locations in Israel from December 2011 to September 2012, were all sensitive to mefenoxam as the isolates did not cause symptoms on 15-leaf, potted basil plants (cv. Peri, Volcani Center, Israel) that were sprayed with 10 µg mefenoxam/ml (Ridomil Gold 48%, Syngenta, Basel, Switzerland) prior to inoculation. However, one isolate collected in early October 2012 from a severely infected plant in a greenhouse at Rehov in Bet-Shaan Valley, in which the plants had been treated with mefenoxam, was resistant to mefenoxan, showing abundant sporulation on leaves of potted basil plants that had been sprayed with 1,000 µg of mefenoxam/ml prior to inoculation. To our knowledge, this is the first report of the occurrence of downy mildew in basil in Israel. This is also the first global report of resistance to mefenoxam in P. belbahrii. References: (1) L. Belbahri et al. Mycol. Res. 109:1276, 2005. (2) R. Djalali et al. Mycol. Progress 11:961, 2012. (3) A. Garibaldi et al., Plant Dis. 89:683, 2004. (4) C. G. Hansford. Rev. Appl. Mycol. 12:421, 1933.

Deontological Guilt and Moral Distress as Diametrically Opposite Phenomena: A Case Study of Three Clinicians.

Feelings of guilt are human emotions that may arise if a person committed an action that contradicts basic moral mores or failed to commit an action that is considered moral according to their ethical standards and values. Psychological scholarship distinguishes between altruistic guilt (AG) and deontological guilt (DG). AG results from having caused harm to an innocent victim, either by acting or failing to act, whereas DG is caused by violating a moral principle. Although physicians may be expected to experience frequent feelings of guilt in their demanding and intensive work, it is surprising to find that this issue has not been explored in the professional literature on medical ethics. To that end, we conducted a qualitative study that included personal in-depth interviews with Sunni Muslim gynaecologists. These doctors provide underground infertility care and perform religiously forbidden treatments involving sex selection and gamete donation. They opened their hearts and spoke about the emotionally taxing pangs of conscience they suffer. Analysing their narratives led us to characterize their feelings of guilt as DG. We discuss the causes for their plight and the way they cope with it, compare DG to the concept of moral distress, and call for future research on clinicians' feelings of guilt and pangs of conscience.

A functional role for the ventrolateral prefrontal cortex in non-spatial auditory cognition.

Spatial and non-spatial sensory information is hypothesized to be evaluated in parallel pathways. In this study, we tested the spatial and non-spatial sensitivity of auditory neurons in the ventrolateral prefrontal cortex (vPFC), a cortical area in the non-spatial pathway. Activity was tested while non-human primates reported changes in an auditory stimulus' spatial or non-spatial features. We found that vPFC neurons were reliably modulated during a non-spatial auditory task but were not modulated during a spatial auditory task. The degree of modulation during the non-spatial task correlated positively with the monkeys' behavioral performance. These results are consistent with the hypotheses that the vPFC is part of a circuit involved in non-spatial auditory processing and that the vPFC plays a functional role in non-spatial auditory cognition.

Environmental SARS-CoV-2 contamination in hospital rooms of patients with acute COVID-19.

OBJECTIVE: Data on the transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) remain conflicting. Airborne transmission is still debated. However, hospital risk control requires better understanding of the different modes of transmission. This study aimed to evaluate the frequency of, and factors associated with, environmental air and surface contamination in the rooms of patients with coronavirus disease 2019 in the acute phase of the disease. METHODS: Sixty-five consecutive patients were included in this study. For each patient, seven room surfaces, air 1 m and 3 m from the patient's head, the inner surface of the patient's mask, and the outer surface of healthcare workers' (HCW) masks were sampled. Environmental contamination was assessed by quantitative reverse transcription polymerase chain reaction (RT-qPCR) for SARS-CoV-2 RNA on surfaces, air and masks. A viral isolation test was performed on Vero cells for samples with an RT-qPCR cycle threshold (Ct) ≤37. RESULTS: SARS-CoV-2 RNA was detected by RT-qPCR in 34%, 12%, 50% and 10% of surface, air, patient mask and HCW mask samples, respectively. Infectious virus was isolated in culture from two samples among the 85 positive samples with Ct ≤37. On multi-variate analysis, only a positive result for SARS-CoV-2 RT-qPCR for patients' face masks was found to be significantly associated with surface contamination (odds ratio 5.79, 95% confidence interval 1.31-25.67; P=0.025). CONCLUSION: This study found that surface contamination by SARS-CoV-2 was more common than air and mask contamination. However, viable virus was rare. The inner surface of a patient's mask could be used as a marker to identify those at higher risk of contamination.

Formation and emission of gold and silver carbide cluster ions in a single C60- surface impact at keV energies: experiment and calculations.

Impact of fullerene ions (C(60)(-)) on a metallic surface at keV kinetic energies and under single collision conditions is used as an efficient way for generating gas phase carbide cluster ions of gold and silver, which were rarely explored before. Positively and negatively charged cluster ions, Au(n)C(m)(+) (n = 1-5, 1 ≤ m ≤ 12), Ag(n)C(m)(+) (n = 1-7, 1 ≤ m ≤ 7), Au(n)C(m)(-) (n = 1-5, 1 ≤ m ≤ 10), and Ag(n)C(m)(-) (n = 1-3, 1 ≤ m ≤ 6), were observed. The Au(3)C(2)(+) and Ag(3)C(2)(+) clusters are the most abundant cations in the corresponding mass spectra. Pronounced odd/even intensity alternations were observed for nearly all Au(n)C(m)(+/-) and Ag(n)C(m)(+/-) series. The time dependence of signal intensity for selected positive ions was measured over a broad range of C(60)(-) impact energies and fluxes. A few orders of magnitude immediate signal jump instantaneous with the C(60)(-) ion beam opening was observed, followed by a nearly constant plateau. It is concluded that the overall process of the fullerene collision and formation∕ejection of the carbidic species can be described as a single impact event where the shattering of the incoming C(60)(-) ion into small C(m) fragments occurs nearly instantaneously with the (multiple) pickup of metal atoms and resulting emission of the carbide clusters. Density functional theory calculations showed that the most stable configuration of the Au(n)C(m)(+) (n = 1, 2) clusters is a linear carbon chain with one or two terminal gold atoms correspondingly (except for a bent configuration of Au(2)C(+)). The calculated AuC(m) adiabatic ionization energies showed parity alternations in agreement with the measured intensity alternations of the corresponding ions. The Au(3)C(2)(+) ion possesses a basic Au(2)C(2) acetylide structure with a π-coordinated third gold atom, forming a π-complex structure of the type [Au(π-Au(2)C(2))](+). The calculation shows meaningful contributions of direct gold-gold bonding to the overall stability of the Au(3)C(2)(+) complex.

Correlation between risk factors and musculoskeletal disorders among classical musicians.

BACKGROUND: Musculoskeletal disorders in humans may originate from biomechanical, environmental, psychosocial and personal risk factors encountered in the working environment. These disorders in musicians are designated as playing related musculoskeletal disorders (PRMD). AIMS: To investigate the correlation between biomechanical, environmental, psychosocial and personal risk factors and potential incidence of PRMD arising in professional classical musicians. METHODS: Fifty-nine orchestral classical musicians were observed: They also filled out questionnaires providing information regarding musculoskeletal symptoms, psychosocial factors and demography. RESULTS: Clinical observation using the Rapid Upper Limb Assessment (RULA) showed significantly higher scores in string musicians compared with woodwind and brass players (right RULA score F = 4.77, P < 0.05; left RULA score, F = 3.90, P < 0.05). A multivariate regression model showed statistical significance for five of the six dependent variables regarding prevalence of painful joints, severity of musculoskeletal symptoms and functional limitation. The regression analysis revealed that biomechanical risk factors, perceived physical environment risk factors, instrument weight and average playing hours per week, were the main predictors of PRMD. CONCLUSIONS: The biomechanical risk factors that predict PRMD are mainly associated with the upper limbs. A high association between PRMD and clinical observation emphasizes the need for further investigation of these risk factors and to study possible implementations in order to define 'prevention strategies' for musical routines and patterns, as used by classical musicians.