RESUMO
Over the years, numerous gold and silver artifacts have been excavated from the tombs of the Tang dynasty, which give evidence of the sophisticated metalworking techniques at that time. Few of the artifacts were thoroughly studied and their manufacturing processes were barely known. The present investigation concerns a metal headgear from a newly excavated tomb of a female in Xi'an of the Tang dynasty (618-907 A.D.), using advanced techniques in a complementary way, especially performing a detailed analysis of the corrosion products and alloying processes. The combined state-of-the-art methods and instrumentation used for the corrosion study included spectroscopy, diffraction, electron microscopy, synchrotron and their versions for specific measurements and sample preparation. The investigated headgear metal consists of a copper-based core, which is gilded by a thin gold layer, consisting of an Au-Hg alloy with a thin layer of about 400 nm. The technique used for shaping and hammered embellishments led to the creation of nanosized grains on the side that would eventually be the interior of the headgear. It was gilded using the mercury-amalgamation process, and the liquid diffusion caused the development of intermetallic compounds. This is the first recorded instance of these nano-scale and eutectic phases being observed on objects from an archaeological context. The crystallographic analysis offered valuable insights into the formation of needle-like malachite crystals growing on a layer of cuprite found on the surface of the corroded piece. The results highlight that the artisans utilized advanced methods in the creation of funerary items during the Tang dynasty.
RESUMO
AIM: To identify factors contributing to Greek nursing students' stress and the coping strategies used. BACKGROUND: Stress experienced by nursing students in the context of ongoing economic recession is as yet unexplored. DESIGN: A cross-sectional study . METHODOLOGY: Undergraduate nursing students (n = 424) completed the Student Nurse Stress Index (short version) and the Brief COPE questionnaires during the year 2017. RESULTS: Most of the participants stated that their current financial status (81.7%) contributed towards their experience of stress, and they had higher scores on the interface worries subscale (p < 0.001). Female gender (p < 0.001) seniority (p = 0.005) and stress of transportation from home to university (p = 0.019) significantly increased the SNSI total score as well as most of the stress subscales scores. As far as coping subscales were concerned, higher means were shown in active/positive coping (mean 2.95), seeking support (mean 2.84), expression of negative feelings (mean 2.71) and avoidance (2.47). However, the use of higher maladaptive coping strategies was noted in cases presenting higher SNSI Total score, interface worries and personal problems. CONCLUSION: The introduction of stress management training and conflict management skills ought to be considered. Fund raising initiatives should be considered to provide financial assistance to those in need.
Assuntos
Bacharelado em Enfermagem , Estudantes de Enfermagem , Adaptação Psicológica , Estudos Transversais , Recessão Econômica , Feminino , Grécia , Humanos , Estresse Psicológico , Inquéritos e QuestionáriosRESUMO
Poly (methyl methacrylate) (PMMA) bone cement is widely used for anchoring joint arthroplasties. In cement brands approved for these procedures, micron-sized particles (usually barium sulphate, BaSO4) act as the radiopacifier. It has been postulated that these particles act as sites for crack initiation and subsequently cement fatigue. This study investigated whether alternative radiopacifiers, anatase titanium dioxide (TiO2) and yttria-stabilised zirconium dioxide (ZrO2), could improve the in vitro mechanical, fatigue crack propagation and biological properties of polymethyl methacrylate (PMMA) bone cement and whether their coating with a silane could further enhance cement performance. Cement samples containing 0, 5, 10, 15, 20 and 25%w/w TiO2 or ZrO2 and 10%w/w silane-treated TiO2 or ZrO2 were prepared and characterised in vitro in terms of radiopacity, compressive and bending strength, bending modulus, fatigue crack propagation, hydroxyapatite forming ability and MC3T3-E1 cell attachment and viability. Cement samples with greater than 10%w/w TiO2 and ZrO2 had a similar radiopacity to the control 10%w/w BaSO4 cement and commercial products. The addition of TiO2 and ZrO2 to bone cement reduced the bending strength and fracture toughness and increased fatigue crack propagation due to the formation of agglomerations and voids. Silane treating TiO2 reversed this effect, enhancing the dispersion and adhesion of particles to the PMMA matrix and resulted in improved mechanical properties and fatigue crack propagation resistance. Silane-treated TiO2 cements had increased nucleation of hydroxyapatite and MC3T3-E1 cell attachment in vitro, without significantly compromising cell viability. This research has demonstrated that 10%w/w silane-treated anatase TiO2 is a promising alternative radiopacifier for PMMA bone cement offering additional benefits over conventional BaSO4 radiopacifiers.
Assuntos
Cimentos Ósseos/química , Materiais Revestidos Biocompatíveis/química , Polimetil Metacrilato/química , Titânio/química , Zircônio/química , Animais , Sulfato de Bário/química , Cimentos Ósseos/farmacologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/farmacologia , Força Compressiva , Camundongos , Tamanho da Partícula , Silanos/química , Estresse Mecânico , Ítrio/químicaRESUMO
BACKGROUND: To investigate possible differences in emotional/behavioral problems and cognitive function in children with nephrotic syndrome compared to healthy controls and to examine the effect of disease-specific and steroid treatment-specific characteristics on the abovementioned variables. METHODS: Forty-one patients with nephrotic syndrome (23 boys, age range: 4.4-15.2 years) and 42 sex- and age-matched healthy control subjects (20 boys, age range: 4.1-13.4 years) were enrolled in the study. Disease (severity, age of diagnosis, duration) and steroid treatment (total duration, present methylprednisolone dose and duration of present dose) data were collected. In order to assess children's emotional/behavioral problems, the Child Behavior Checklist was administered. The Wechsler Intelligence Scale for Children - Third Edition was administered to assess Full-Scale, Verbal, and Performance intelligence quotient (IQ) scores. RESULTS: The patients presented with more internalizing problems (P = 0.015), including withdrawal (P = 0.012) and somatic complaints (P = 0 .011), but not more anxiety/depression or externalizing problems. A significant association was found between severity of disease and somatic complaints (P = 0.017) as well as externalizing problems (P = 0.030). Years of illness were significantly more in those presenting with abnormal anxiety/depression (P = 0.011). Duration of steroid medication was significantly higher among those presenting with abnormal anxiety/depression (P = 0.011) and externalizing problems (P = 0.039). IQ was not associated significantly with disease or steroid treatment variables. CONCLUSIONS: Psychosocial factors and outcomes may be important correlates of children's nephrotic syndrome and potential targets of thorough assessment and treatment.