RESUMEN
The intertwining between spin, charge, and lattice degrees of freedom can give rise to unusual macroscopic quantum states, including high-temperature superconductivity and quantum anomalous Hall effects. Recently, a charge density wave (CDW) has been observed in the kagome antiferromagnet FeGe, indicative of possible intertwining physics. An outstanding question is that whether magnetic correlation is fundamental for the spontaneous spatial symmetry breaking orders. Here, utilizing elastic and high-resolution inelastic x-ray scattering, we observe a c-axis superlattice vector that coexists with the 2[Formula: see text]2[Formula: see text]1 CDW vectors in the kagome plane. Most interestingly, between the magnetic and CDW transition temperatures, the phonon dynamical structure factor shows a giant phonon-energy hardening and a substantial phonon linewidth broadening near the c-axis wavevectors, both signaling the spin-phonon coupling. By first principles and model calculations, we show that both the static spin polarization and dynamic spin excitations intertwine with the phonon to drive the spatial symmetry breaking in FeGe.
RESUMEN
The Ca2MnReO6double perovskite is a spin-orbit-assisted Mott insulator with exotic magnetic properties, including a largely non-collinear Mn2+spin arrangement and nearly orthogonal coupling between such spins and the much smaller Re 5dmagnetic moments. Here, the electron-doped compound Ca1-xYxMnReO6(x= 0.1, 0.2 and 0.3) is reported and a detailed investigation is conducted forx= 0.3. Neutron and x-ray powder diffraction confirm that nearly full chemical order is maintained at the Mn and Re sites under the Y substitution at the Ca site. X-ray absorption measurements and an analysis of the Mn-O/Re-O bond distances show that the Mn oxidation state remains stable at +2 whereas Re is reduced upon doping. The electron doping increases the magnetic ordering temperature fromTc= 121 to 150 K and also enhances significantly the ferromagnetic component of the Mn spins at the expense of the antiferromagnetic component at the base temperature (T= 3 K). The lattice parameter anomalies atTcobserved in the parent compound are suppressed by the electron doping. The possible reasons for the enhanced magnetism and the suppressed magnetoelastic coupling in Ca1.7Y0.3MnReO6are discussed.
RESUMEN
We report the electronic and magnetic properties of stoichiometric CeAuBi2 single crystals. At ambient pressure, CeAuBi2 orders antiferromagnetically below a Néel temperature (TN ) of 19 K. Neutron diffraction experiments revealed an antiferromagnetic propagation vector τ ^ = [ 0 , 0 , 1 ∕ 2 ] , which doubles the paramagnetic unit cell along the c axis. At low temperatures several metamagnetic transitions are induced by the application of fields parallel to the c axis, suggesting that the magnetic structure of CeAuBi2 changes as a function of field. At low temperatures, a linear positive magnetoresistance may indicate the presence of band crossings near the Fermi level. Finally, the application of external pressure favors the antiferromagnetic state, indicating that the 4f electrons become more localized.
RESUMEN
Preliminary data of a follow-up study on effectiveness of mechanical devices for patients handling are shown. Main study results highlight a statistical significant decrease for subjective referred episodes of acute low back pain during the previous 12 months, a decrease in perceived effort and Borg scale score in the subgroup who received any sort of mechanical devices. However no difference was found regarding to proportion of subjects positive at symptom questionnaire for low back pain and mean length of absenteeism for disease was similar even after the introduction of mechanical devices.
Asunto(s)
Personal de Salud , Elevación/efectos adversos , Dolor de la Región Lumbar/prevención & control , Enfermedades Profesionales/prevención & control , Pacientes , Adulto , Algoritmos , Femenino , Humanos , Estudios Longitudinales , Dolor de la Región Lumbar/etiología , Masculino , Encuestas y CuestionariosRESUMEN
In the present experiments we planned to ascertain whether an abnormal production of nitric oxide (NO) by human CHP100 neuroblastoma cells in culture following stimulation of N-methyl-D-aspartate (NMDA) receptors, produced lethal effects in co-cultured human BMEL melanoma cells. Human BMEL melanoma cells in culture were found to be positive to the nicotinamide adenine dinucleotide phosphate diaphorase (NADPH diaphorase) histochemical reaction and produced NO as revealed by measurements of nitrite under basal culture conditions. Exposure for 50 min to aspartate (1-2 mM) or to NMDA (0.5-1.5 mM) did not evoke significant melanoma cell death. The dose of 1.0 mM NMDA applied for 1 min to BMEL cell cultures did not increase significantly nitrite concentrations in comparison to controls. Incubation for 50 min of human CHP100 neuroblastoma cells with NMDA (0.5-1.5 mM) elicited dose-dependent death of BMEL melanoma cells co-cultured in trans-wells. Under these experimental conditions, nitrite levels in cell culture-inserts containing melanoma cells increased by 120% 1 min after application of the excitotoxin (1 mM) to CHP100 neuroblastoma cultures. The lethal effects produced in BMEL cell culture-inserts by application of NMDA (1.0 mM) to CHP100 cultures were prevented by pretreatment of neuroblastoma cultures with MK801 (200 nM). Similar protection was also afforded by N omega-nitro-L-arginine methyl ester (L-NAME; 0.2 mM) and N omega-monomethyl-L-arginine (L-NMMA; 0.2 mM), two inhibitors of nitric oxide synthase, and by haemoglobin (10 microM), a nitric oxide trapping agent.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Melanoma Experimental/metabolismo , N-Metilaspartato/farmacología , Neuroblastoma/metabolismo , Óxido Nítrico/biosíntesis , Arginina/análogos & derivados , Arginina/farmacología , Muerte Celular/efectos de los fármacos , Maleato de Dizocilpina/farmacología , Histocitoquímica , Humanos , Melanoma Experimental/enzimología , NADPH Deshidrogenasa/metabolismo , NG-Nitroarginina Metil Éster , Neuroblastoma/enzimología , Óxido Nítrico/antagonistas & inhibidores , Nitroprusiato/farmacología , Células Tumorales Cultivadas , omega-N-MetilargininaRESUMEN
The pharmacokinetics of carboplatin in cerebrospinal fluid (CSF) and plasma was studied in five children with brain tumors (four medulloblastomas and one ependimoblastoma) who underwent preirradiation treatment with carboplatin. Carboplatin pharmacokinetics was studied following the administration of 600 mg/m2 as a 1-h infusion. Four children were treated a few weeks after surgery, whereas one child with an unresectable tumor was treated prior to surgery. All patients had a ventricular-peritoneal CSF shunt connected to a subcutaneous reservoir. Total platinum and free carboplatin were measured. The mean AUC values for free carboplatin in CSF and plasma were 2.29 +/- 1.20 and 8.18 +/- 1.27 mg ml-1 min, respectively. The mean ratio of CSF AUC to plasma AUC was 0.28 (range, 0.17-0.46). Both plasma peak levels and AUC values showed limited interpatient variability. On the other hand, carboplatin levels in CSF showed substantial interpatient variability, with a greater than 5-fold difference in peak levels and a 3-fold difference in AUC values being recorded. The interpatient difference in CSF pharmacokinetics may have been related at least in part to the different anatomical alterations induced by the surgical procedures or by the presence of a large tumor mass. In the four evaluable patients exhibiting macroscopic residual tumor, we observed one complete remission (CR) and two partial remissions (PR) following two cycles that consisted of two doses of 600 mg/m2 carboplatin given on 2 consecutive days (total dose, 1200 mg/m2) and were separated by a 1-month interval. These results may give some indication as to the optimal dose and schedule for carboplatin administration in the treatment of primitive neuroectodermic tumors (PNET).
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Neoplasias Encefálicas/líquido cefalorraquídeo , Cisplatino/líquido cefalorraquídeo , Neoplasias Encefálicas/sangre , Niño , Preescolar , Cisplatino/sangre , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Lactante , Infusiones Intravenosas , MasculinoRESUMEN
Evidence suggests that nitric oxide (NO) may mediate, at least in part, excitotoxic effects of excessive N-methyl-D-aspartate (NMDA) receptor activation both in vivo and in vitro. In the present experiments, NMDA-induced excitotoxicity has been studied in CHP100 neuroblastoma cell cultures. Application of NMDA (0.25-1.5 mM) produced concentration-dependent cell death. These effects were antagonized by co-application of dizocilpine (MK801), a selective and non-competitive NMDA receptor complex antagonist. Protection from NMDA-induced lethal effects was also afforded by N omega-nitro-L-arginine methyl ester, a potent NO-synthase inhibitor, and by hemoglobin, a NO-trapping agent. In addition, substitution of L-arginine, normally present in the exposure solution with its D-isomer, abolished the cell death induced by the excitotoxin. In conclusion, the present experiments support the suggestion that excitotoxic effects induced by NMDA receptor stimulation involve L-arginine-NO pathway activation.
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Arginina/metabolismo , Neoplasias Encefálicas/fisiopatología , N-Metilaspartato/farmacología , Neuroblastoma/fisiopatología , Óxido Nítrico/metabolismo , Aminoácido Oxidorreductasas/antagonistas & inhibidores , Aminoácido Oxidorreductasas/metabolismo , Arginina/análogos & derivados , Arginina/farmacología , Biotransformación , Muerte Celular/efectos de los fármacos , Maleato de Dizocilpina/farmacología , Humanos , NG-Nitroarginina Metil Éster , Óxido Nítrico Sintasa , Células Tumorales CultivadasRESUMEN
In industrialised countries, carpal tunnel syndrome (CTS) is considered an epidemic work-related disease. We have set up the MODS (Malattie Occupazionali Da Sovraccarico biomeccanico, biomechanical overload-related occupational diseases) collaborative group, formed by epidemiologists, ergonomists and occupational physicians to investigate CTS in Italy, applying the methods that epidemiologists commonly use to understand epidemics. Several studies are already ongoing. Two different descriptive studies based on current hospitalisation data are in the reporting phase. A pilot case-control multicentre study (260 cases and 520 controls in 13 centres) is in the final phase of data collection. A longitudinal study on a cohort of 3000 subjects exposed to different risk factors has reached the third year of follow-up. Moreover, a surveillance system has been set up to cover selected districts of the Emilia Romagna region. These studies will generate new information about the prevalence and incidence of CTS in Italy, along with identification of regional, high-risk job titles and work sectors, and the relative influence of non-occupational factors.
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Síndrome del Túnel Carpiano , Enfermedades Profesionales , Adolescente , Adulto , Anciano , Síndrome del Túnel Carpiano/epidemiología , Estudios de Casos y Controles , Humanos , Italia , Estudios Longitudinales , Persona de Mediana Edad , Enfermedades Profesionales/epidemiología , Encuestas y CuestionariosRESUMEN
The aim of the study was to generate hypotheses on what could be the ISTAT (National Institute of Statistics) job classes with a major risk of carpal tunnel syndrome in order to plan more specific analytic epidemiology studies and apply more correct ergonomic solutions. A case-control cross-sectional survey without matching was carried out. The source of data were the computerized medical records of a large regional hospital: 833 carpal tunnel syndrome cases (mean age 48, SD 9.33) and 3222 controls (mean age 43.5, SD 13.22) hospitalized for other diseases, were selected. The odds ratio (OR) and 95% confidence limits, controlled for age and gender by a logistic linear regression model, were calculated as measures of association for the comparison between non-exposed managerial/administrative staff and industrial workers. The analysis showed a statistically significant risk for some ISTAT job classes, in particular class 53 (spinners, weavers, dyers and similar jobs) (OR = 2.65; C.L. 1.52-4.62) class 54 (knitters, tailors, hatmakers, upholsterers and similar jobs) (OR = 1.69; C.L. 1.06-2.71), 55 (tanners, shoemakers, leather manufacture workers and similar jobs) (OR = 2.74; C.L. 1.66-4.53) and group 742 (Hotel and restaurant cooks) (OR = 2.99; C.L. 1.45-6.13). Job classes 45 (carpenters, welders and similar jobs). 62 (electricians, electrotechnicians, radio engineers and similar jobs), 63 (gasfitters, plumbers, heating engineers and similar jobs) and 85 (porters and other jobs involving manual handling of loads) showed ORs higher than 2 but without statistical significance. The results are valid for planning further studies, especially in the textile and shoe and leather manufacturing sectors.
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Síndrome del Túnel Carpiano/epidemiología , Enfermedades Profesionales/epidemiología , Adulto , Distribución por Edad , Síndrome del Túnel Carpiano/etiología , Estudios de Casos y Controles , Intervalos de Confianza , Estudios Transversales , Femenino , Humanos , Italia/epidemiología , Modelos Lineales , Masculino , Persona de Mediana Edad , Enfermedades Profesionales/etiología , Ocupaciones/estadística & datos numéricos , Oportunidad Relativa , Factores de Riesgo , Distribución por SexoRESUMEN
The wide-spread use of video display units in many work places has led to an increase in ophthalmologic examinations of the operators. For this reason, instruments for visual test screening (for example Visotest) have become widely used. Nevertheless, the literature does not seem to offer any clarification about the utility of these instruments as epidemiological tools. The costs and benefits of visual screening programmes were estimated in relation to specific visual deficit prevalence in a differently age-structured population. Via epidemiological calculation, it was demonstrated that positive and negative predictive values, which are directly related to deficit prevalence, are more important than sensitivity and specificity calculations. In view of the disorders screened, a visual test with a low positive predictive value is more expensive than one with a low negative predictive value. A visual test for visual deficits screening does not appear to be advisable in young populations, where the true positives/false positives ratio is 1:4, whereas in older populations the ratio is 2:1.
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Tamizaje Masivo/estadística & datos numéricos , Enfermedades Profesionales/epidemiología , Trastornos de la Visión/epidemiología , Adulto , Análisis Costo-Beneficio , Humanos , Italia/epidemiología , Tamizaje Masivo/economía , Persona de Mediana Edad , Enfermedades Profesionales/economía , Enfermedades Profesionales/prevención & control , Prevalencia , Pronóstico , Sensibilidad y Especificidad , Trastornos de la Visión/economía , Trastornos de la Visión/prevención & control , Pruebas de Visión/economía , Pruebas de Visión/estadística & datos numéricosRESUMEN
Data concerning all accidents with absence from work exceeding three days were analysed in a cohort of 5000 workers (all employees of a Local Health Unit). A total of 1062 accidents were recorded in the file from 1987 to 1989, 118 coded as "low-back injury". A case-control study design was used to detect the main causes of these accidents, using accidents coded as other than low-back injury as controls. The odds ratios and related confidence limits were calculated in order to assess the degree of association, taking account of potentially confounding factors. A significant relationship was observed between hospital wards and other health service departments rated as "high exposure" and low-back injury (OR high exposure versus low exposure = 2.13; 95% C.L. 1.06-4.29). Selection bias and its influence on the results is also discussed.
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Dolor de Espalda/etiología , Personal de Salud , Enfermedades Profesionales , Adolescente , Adulto , Estudios de Casos y Controles , Femenino , Humanos , MasculinoRESUMEN
We analyzed the occupational health activities of physicians in a public occupational health service using the Method of Organizational Congruences (MOC). Occupational health activities are changing in Italy with the application of the European Community Directives (Decreto Legislativo 626/94). We identified four major organizational constraints: a lack and difficult in interdisciplinary work, absence of worker control on the activities, limitations in planning specific industrial area studies, increased conflict between prevention and control activities. We predict for the future an increase of these constraints with a reduction in the professional level of the physicians employed in the state system of local occupational health units.
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Enfermedades Profesionales/prevención & control , Medicina del Trabajo , Humanos , Italia , Medicina del Trabajo/legislación & jurisprudencia , Recursos HumanosRESUMEN
The etiology and frequency of low back pain among health care personnel have been widely studied by means of cross sectional studies. The aim of our study was to calculate low back pain incidence in a prospective cohort of nursing students. A population of 344 subjects (72 males and 272 females) was involved in this investigation. Every student was submitted to a clinical and functional examination of the spine before beginning training and was checked in two following steps by a specific questionnaire for epidemiological studies of spinal disorders in working communities. 197 subjects (57.3%)(41 males and 156 females) completed follow-up. The low back pain incidence was similar at the end of two exposure periods (12.1% and 13.1%). The cumulative incidence was 22.5% throughout the study period. The longitudinal study allowed good control of selection bias and confounding factors; more over it showed that compared to other measurements of occurrence the cumulative incidence was between other occurrence measures, more informative, in our case, than prevalence and incidence rates. A cumulative incidence of low back pain over 20% after only two years of exposure in a young and healthy population of nursing students, requires implementation of ergonomic measures for patient handling tasks.
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Dolor de la Región Lumbar/epidemiología , Enfermedades Profesionales/epidemiología , Estudiantes de Enfermería/estadística & datos numéricos , Adulto , Femenino , Humanos , Incidencia , Italia/epidemiología , Estudios Longitudinales , Masculino , Persona de Mediana EdadRESUMEN
An evaluation was made of the degree of exposure to risk and the frequency of disorders attributable to biomechanical overload of the upper limb in workers performing finishing operation on ceramic vases and cups in a ceramics factory. The risks were first evaluated against a checklist, then subsequently an assessment was made of the tasks found to feature the highest risks, using an ergonomic analysis method, which identified activities associated with a large number of actions per minute (> 50). The 22 female workers performing the tasks in question underwent a risk-targeted physical examination which included an electroneurographic test using surface electrodes. The clinical test detected an extremely high frequency of carpal tunnel syndrome cases, in addition to other upper limb disorders. In particular, nine female workers (41%) were found to be suffering from carpal tunnel syndrome, and five (22%) from other pathologies of the upper limbs (4 scapulo-humeral periarthritis, 1 epicondylitis). As a result of the findings arising out of this study, immediate preventive measures were adopted; moreover, it has become evident that further epidemiological studies on larger sample populations are needed.
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Brazo , Cerámica , Trastornos de Traumas Acumulados/epidemiología , Enfermedades Musculoesqueléticas/epidemiología , Enfermedades Profesionales/epidemiología , Exposición Profesional/efectos adversos , Adulto , Fenómenos Biomecánicos , Síndrome del Túnel Carpiano/diagnóstico , Síndrome del Túnel Carpiano/epidemiología , Trastornos de Traumas Acumulados/diagnóstico , Femenino , Humanos , Enfermedades Musculoesqueléticas/diagnóstico , Enfermedades Profesionales/diagnóstico , Postura , Medición de RiesgoRESUMEN
An evaluation was made of the degree of exposure to risk and the frequency of disorders attributable to biomechanical overload of the upper limb in workers employed on packaging in an ice cream factory. The risks were first evaluated against a checklist, then subsequently an assessment was made of the tasks found to feature the highest risks, using an ergonomic analysis method. The method identified several jobs, such as placing ice cream coupes and such like in boxes, as requiring a large number of actions per minute (> 30) and considerable muscular strength. The 59 female workers performing the packaging operations were given a risk-targeted physical examination. The clinical test detected an extremely high frequency of carpal tunnel syndrome, (7.1%) epicondylitis (5.2%) and scapulo-humeral periarthritis (3.5%) in the over 35 years age group, with respect to a control population not exposed to risk. The authors conclude that the repetitiveness of the actions, the use of gloves due to prolonged contact with frozen products and the effects of the low temperatures themselves, may have favoured the spread of the disorders that appeared in this population of workers. These findings must be further supported by more in-depth epidemiological studies.
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Brazo , Trastornos de Traumas Acumulados/epidemiología , Embalaje de Alimentos , Enfermedades Musculoesqueléticas/epidemiología , Enfermedades Profesionales/epidemiología , Exposición Profesional/efectos adversos , Adulto , Fenómenos Biomecánicos , Trastornos de Traumas Acumulados/clasificación , Femenino , Humanos , Enfermedades Musculoesqueléticas/clasificación , Enfermedades Profesionales/clasificación , Prevalencia , Medición de RiesgoRESUMEN
Back pain is a major health and economic problem for preventive medicine. It has been found to be significantly associated with nursing. The present paper reviews a number of epidemiological studies on back pain in nurses and examines the main confounding factors. The different approaches to back pain prevention are briefly discussed.
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Dolor de Espalda/epidemiología , Personal de Salud , Enfermedades Profesionales/epidemiología , Dolor de Espalda/prevención & control , Humanos , Enfermedades Profesionales/prevención & controlRESUMEN
Interest in occupational mental illness has increased as a result also of the technological changes at the workplace. A total of 22 epidemiological studies on this topic were reviewed on the following basis: subject of the study, epidemiological design, type of psychometric scale, results. The authors discuss the methods and constraints of these studies, especially the lack of knowledge on occupational exposure and its relationship to mental health. The need for further studies in order to improve prevention of mental illness at the workplace is stressed.
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Trastornos Mentales , Enfermedades Profesionales , Estudios Cruzados , Documentación , Humanos , Italia , Estudios Longitudinales , MEDLINE , Trastornos Mentales/diagnóstico , Trastornos Mentales/epidemiología , National Institute for Occupational Safety and Health, U.S. , Enfermedades Profesionales/diagnóstico , Enfermedades Profesionales/epidemiología , Estados UnidosRESUMEN
An evaluation was made of the posture risk and occurrence of alterations of the spine in a sample of female sewing machine operators in the clothing industry. The results revealed a greater risk for sewing operators of contracting spinal disorders compared with a control population matched for sex and age. The cause of these disorders appears to be due to the fact that the work station cannot be adjusted to the anthropometric requirements of the individual subject, and also because the seated position is maintained for long periods.
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Vestuario , Enfermedades Profesionales/etiología , Postura , Enfermedades de la Columna Vertebral/etiología , Adolescente , Adulto , Femenino , Humanos , Italia/epidemiología , Persona de Mediana Edad , Enfermedades Profesionales/epidemiología , Prevalencia , Enfermedades de la Columna Vertebral/epidemiologíaRESUMEN
In February 2007, three organs from an human immunodeficiency virus (HIV)-positive donor were transplanted at two hospitals in the Tuscany Regional Health Care Service, owing to a chain of errors during the donation process. The heart-beating donor was a 41-year-old woman who died as a result of head trauma. The patient's history did not highlight any risky behavior. The available data on previous hospital admissions reported a negative result on HIV testing. During the donation process, the result of the lab test performed for evaluation of organ suitability was mistakenly transcribed from positive to negative. This wrong negative result was then included in the donation record without any cross-check. Therefore, the Regional Transplant Center allocated the liver and both kidneys. The patient also donated tissues, and a second laboratory conducted an evaluation of suitability for the tissue banks. During this process, only 5 days after the successful transplantation procedures, the positive HIV result was fed back to the Regional Transplant Center and the previous error discovered. Transplanted patients were immediately assessed and then treated with antiretroviral medications. A national commission soon performed a systems analysis of the adverse event. Besides the active error committed during the manual transcription for the HIV lab test result, the commission also identified technological factors, such as the lack of integration between the lab machine, the laboratory information system (LIS), and the donor record, as well as organizational factors, such as the distribution to two different labs of the suitability evaluation for organs and tissues. Recommendations included: automatic transmission of lab test results from the lab machine to the LIS and to the donor record, centralization of lab tests for suitability evaluation of organs and tissues, a training program to develop a proactive quality and safety culture in the regional network of donation and transplantations.