Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 132
Filtrar
1.
Zhonghua Yi Xue Za Zhi ; 101(37): 2993-2998, 2021 Oct 12.
Artigo em Chinês | MEDLINE | ID: mdl-34638190

RESUMO

Objective: To determinate the block range of lumbar erector spinal plane (ESPB), and investigate the efficacy of ESPB in lumbar spine surgery. Methods: Forty patients who underwent posterior lumbar fusion in the Second Affiliated Hospital of Wenzhou Medical University from November 2019 to August 2020 were randomly divided into two groups (with n=20 in each group) using the random number table: the experimental group (group E) and control group (group C). All the patients received ultrasound-guided bilateral ESPB with 20 ml of 0.375% ropivacaine (group E) or equal volume of normal saline (group C) on each side before induction of general anesthesia. The range of weakened temperature sense in each patient was measured at 10 min, 20 min and 30 min after ESPB, respectively. Dosage of analgesic drug, visual analog scale (VAS), and incidence of adverse events were recorded and compared between the two groups. Results: In group E, the dermatomal distribution and area of weakened temperature sense at 10 min, 20 min, 30 min after ESPB were T9-S1 (222±16) cm2, T8-S2 (352±22) cm2, T8-S3 (481±24) cm2, respectively. The intraoperative dosage of remifentanil in group E was (0.76±0.02) mg, which was significantly lower than that of group C (0.97±0.06) mg (P<0.05). Oxycodone consumption in group E at 0-12 h and 12-24 h after surgery was (4.9±0.4) mg and (8.4±1.2) mg, respectively, which were lower than those in group C [(14.5±2.4) mg and (19.3±2.4) mg, respectively] (both P<0.05). The VAS during rest and movement within 24 h after operation in group E were significantly lower than those in group C (both P<0.05). The passive exercise in bed in group E started at (3.3±0.3) h postoperatively, which was earlier than that in group C (4.6±0.3) h (P<0.05). Conclusion: The blocking effects of T12-S1 segment after ultrasound-guided lumbar ESPB is definite, which can effectively decrease the amounts of analgesics during and after the lumbar fusion surgery, reduce postoperative rest and exercise VAS score, and contribute to a rapid recovery of the patients.


Assuntos
Bloqueio Nervoso , Humanos , Região Lombossacral , Dor Pós-Operatória , Ultrassonografia , Ultrassonografia de Intervenção
2.
Artigo em Chinês | MEDLINE | ID: mdl-31495110

RESUMO

Objective: To analyze Nursing Occupational Risk, the relationship between resilience and job performance, and investigate the mediating effects of resilience on Nursing Occupational Risk and job performance. Methods: 406 nurses from33 clinical departments of Chengdu first-class hospital were recruited by randomsampling method. Thier Nursing Occupational Risk, resilience and job performance were interviewed by nursing occupational risk assessment questionnaire, the Scale of medical staff resilience and the job performance questionnaire, and analyze the relationship between variables. Results: The clinical nurses' resilience is 82.98±10.05, the clinical nurses' job performance is 145.79±23.55; here was a positive correlation between clinical nurses' resilience and job performance (P<0.05) ; three variable of resilience can explain 33.2% of the variation of clinical nurses job performance; in the highest the Nursing Occupational risk, resilience served to mediate the relationship between Nursing Occupational Risk and job performance, which was 56.77% of the total effect respective. Conclusion: resilience are closely related to job performance. Resilience plays mediating role in the relationships between Nursing Occupational Risk and job performance, three dimensions of resilience can predict nurses' job performance. Improving the resilience of nurses can effectively improve their job performance.


Assuntos
Adaptação Psicológica , Satisfação no Emprego , Enfermeiras e Enfermeiros/psicologia , Desempenho Profissional , China , Humanos , Inquéritos e Questionários
3.
Zhonghua Yi Xue Za Zhi ; 97(42): 3297-3300, 2017 Nov 14.
Artigo em Chinês | MEDLINE | ID: mdl-29141373

RESUMO

Objective: To investigate the median effective dose (ED(50)) of hydromorphone and the appropriate concentration of ropivacaine combined with hydromorphone in epidural labor analgesia. Methods: One hundred and forty nulliparous women undergoing labor selected for delivery with epidural analgesia were enrolled in our hospital from January to June 2016. The first of top 50 women received 0.12% ropivacaine plus 20 µg/ml hydromorphone complex solution, then sequential women were used the modified sequential method to determine the ED(50) and ED(95) of hydromorphone. The other 90 women were randomly divided and receieved 0.08% ropivacaine and 15 µg/ml hydromorphone(H1 group), 0.10% ropivacaine and 15 µg/ml hydromorphone (H2 group), 0.12% ropivacaine and 15 µg/ml hydromorphone (group H3) respectively for epidural labor analgesia. In the course of labor, block levels of epidural analgesia, the Bromage scores, analgesia scores and fetal heart rate-uterine concraction were monitored. In addition, onset time of anesthesia, labor time, mode of delivery, cases of increased oxytocin using, neonatal Apgar score, incidence of nausea and vomiting, itching and fetal heart reduction were recorded. Results: The ED(50) and ED(95) values of hydromorphone were 10.49 (95% CI: 8.89-11.79) and 15.15 (95% CI: 13.25-22.25) µg/ml respectively. The onset time in group H1 was significantly longer than those in group H2 and H3((14.23±3.82) , ( 11.32±2.16), (10.83±2.56)min, respectively), the difference was statistically significant (t=5.854, 6.212, all P<0.05). Analgesic VAS score at 30, 60 and 90 min time points in H1 group was significantly higher than that in H2 group and H3 group (all P<0.05). VAS score at withdrawal in H1 group was significantly higher than that in group H3 ( (3.25±0.75) vs (0.27±0.12) ), the difference was statistically significant ( t=9.314, P<0.05). VAS scores at the fourth, fifth, sixth contractions after analgesia in H1 group were significantly higher than those in H2 and H3 groups (all P<0.05). The incidence of motor nerve block in group H3 was higher than that in group H1 and group H2 (26.67%, 6.66%, 3.33%, respectively), the difference was statistically significant (χ(2)=6.413, 4.320, all P<0.05). Conclusions: 0.10% ropivacaine combined with 15 µg/ml hydromorphone has a good analgesic effect, slight motor block, high safety and worthy clinical application for labor analgesia.


Assuntos
Amidas/administração & dosagem , Analgesia Epidural , Analgésicos Opioides/administração & dosagem , Anestésicos Locais/administração & dosagem , Parto Obstétrico , Hidromorfona/administração & dosagem , Analgesia Obstétrica , Feminino , Humanos , Trabalho de Parto , Medição da Dor , Gravidez , Ropivacaina
4.
Andrologia ; 48(7): 824-8, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26762757

RESUMO

We investigated the role of insulin-like growth factor-1 (IGF-1) in spontaneously hypertensive rats with erectile dysfunction. Firstly, we evaluated intracavernous pressure. The bioavailability of IGF-1 at both mRNA and protein levels were measured by quantitative real-time PCR and Western blot respectively. Then, cavernous cyclic guanosine monophosphate concentrations were detected by enzyme-linked immunosorbent assay. The cavernosal pressure was significantly decreased in the hypertensive and the propranolol treatment groups compared to the normal control group (P < 0.01). Cavernous IGF-1 bioavailability and the concentrations of cavernous cyclic guanosine monophosphate were both significantly decreased in the hypertensive and the propranolol treatment groups compared to the normal control group (P < 0.01). This study suggests that an obvious decrease in cavernous IGF-1 levels might play an important role in spontaneously hypertensive rats with erectile dysfunction.


Assuntos
Disfunção Erétil/metabolismo , Hipertensão/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Pênis/fisiologia , RNA Mensageiro/metabolismo , Animais , Anti-Hipertensivos/uso terapêutico , Western Blotting , GMP Cíclico , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Humanos , Hipertensão/tratamento farmacológico , Masculino , Pênis/metabolismo , Propranolol/uso terapêutico , Ratos , Ratos Endogâmicos SHR , Reação em Cadeia da Polimerase em Tempo Real
5.
Andrologia ; 48(1): 59-64, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25879169

RESUMO

It was investigated whether short hairpin ribonucleic acid constructs targeting insulin-like growth factor binding protein-3 (IGFBP-3 shRNA) can rehabilitate dyslipidaemia in streptozotocin-induced diabetic rats. After 12 weeks of intracavernous administration of IGFBP-3 shRNA, intracavernous pressure responses to electrical stimulation of cavernous nerves were evaluated. The concentrations of serum low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride and cavernous cyclic guanosine monophosphate were all detected by enzyme-linked immunosorbent assay. The per cent of smooth muscle in corpus cavernous tissue was also evaluated. It was found that the cavernosal pressure was significantly increased in the IGFBP-3 shRNA treatment group compared to the diabetic control group after 12 weeks of intracavernous administration of IGFBP-3 shRNA (P < 0.01). The concentrations of serum low-density lipoprotein cholesterol and triglyceride were significantly decreased in the IGFBP-3 shRNA treatment group compared to the diabetic control group, while no significant changes of serum high-density lipoprotein cholesterol concentration were found (P < 0.01). At the same time, cavernous cyclic guanosine monophosphate concentrations and the percentage of cavernosal smooth muscle were both significantly increased in the IGFBP-3 shRNA treatment group compared to the diabetic control group (P < 0.01). This study indicated that IGFBP-3 shRNA might rehabilitate erectile function via a decrease in concentrations of serum low-density lipoprotein and triglyceride, an increase in the percentage of cavernosal smooth muscle and an improvement in the nitric oxide-cyclic guanosine monophosphate signalling activities in streptozotocin-induced diabetic rats.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Dislipidemias/genética , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Ereção Peniana/genética , Pênis/metabolismo , Animais , GMP Cíclico/metabolismo , Dislipidemias/metabolismo , Ensaio de Imunoadsorção Enzimática , Disfunção Erétil/genética , Disfunção Erétil/metabolismo , Técnicas de Silenciamento de Genes , Lipoproteínas HDL , Lipoproteínas LDL/metabolismo , Masculino , Músculo Liso/patologia , Óxido Nítrico/metabolismo , Pênis/fisiopatologia , RNA Interferente Pequeno/genética , Ratos , Triglicerídeos/metabolismo
6.
Phys Rev Lett ; 114(13): 137201, 2015 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-25884135

RESUMO

We study the spectral characteristics of spin current nano-oscillators based on the Pt/[Co/Ni] magnetic multilayer with perpendicular magnetic anisotropy. By varying the applied magnetic field and current, both localized and propagating spin wave modes of the oscillation are achieved. At small fields, we observe an abrupt onset of the modulation sidebands. We use micromagnetic simulations to identify this state as a dynamical magnetic skyrmion stabilized in the active device region by spin current injection, whose current-induced dynamics is accompanied by the gyrotropic motion of the core due to the skew deflection. Our results demonstrate a practical route for controllable skyrmion manipulation by spin current in magnetic thin films.

7.
Nature ; 459(7243): 64-7, 2009 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-19424151

RESUMO

The recent discovery of superconductivity in oxypnictides with a critical transition temperature (T(C)) higher than the McMillan limit of 39 K (the theoretical maximum predicted by Bardeen-Cooper-Schrieffer theory) has generated great excitement. Theoretical calculations indicate that the electron-phonon interaction is not strong enough to give rise to such high transition temperatures, but strong ferromagnetic/antiferromagnetic fluctuations have been proposed to be responsible. Superconductivity and magnetism in pnictide superconductors, however, show a strong sensitivity to the crystal lattice, suggesting the possibility of unconventional electron-phonon coupling. Here we report the effect of oxygen and iron isotope substitution on T(C) and the spin-density wave (SDW) transition temperature (T(SDW)) in the SmFeAsO(1 - x)F(x) and Ba(1 - x)K(x)Fe(2)As(2) systems. The oxygen isotope effect on T(C) and T(SDW) is very small, while the iron isotope exponent alpha(C) = -dlnT(C)/dlnM is about 0.35 (0.5 corresponds to the full isotope effect). Surprisingly, the iron isotope exchange shows the same effect on T(SDW) as T(C). This indicates that electron-phonon interaction plays some role in the superconducting mechanism, but a simple electron-phonon coupling mechanism seems unlikely because a strong magnon-phonon coupling is included.

8.
Genet Mol Res ; 14(3): 11063-72, 2015 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-26400336

RESUMO

Bone morphogenetic protein 2 (BMP-2) can promote fracture healing. Although the complex role BMP-2 in bone formation is increasingly understood, the role of endogenous BMP-2 in nonunion remains unclear. Decorin (DCN) can promote the formation of bone matrix and calcium deposition to control bone morphogenesis. In this study, tissue composition and expression of BMP-2 and DCN were detected in different parts of old fracture zones to explore inherent anti-fibrotic ability and osteogenesis. Twenty-three patients were selected, including eight cases of delayed union and 15 cases of nonunion. Average duration of delayed union or nonunion was 15 months. Fracture fragments and surrounding tissues, including bone grafts, marrow cavity contents, and sticking scars, were categorically sampled during surgery. Through observation and histological testing, component comparisons were made between fracture fragments and surrounding tissue. The expression levels of DCN and BMP-2 in different tissues were detected by immunohistochemical staining and real-time polymerase chain reaction. The expression of DCN and BMP- 2 in different parts of the nonunion area showed that, compared with bone graft and marrow cavity contents, sticking scars had the highest expression of BMP-2. Compared with the marrow cavity contents and sticking scars, bone grafts had the highest expression of DCN. The low antifibrotic and osteogenic activity of the nonunion area was associated with non-co-expression of BMP-2 and DCN. Therefore, the co-injection of osteogenic factor BMP and DCN into the nonunion area can improve the induction of bone formation and enhance the conversion of the old scar, thereby achieving better nonunion treatment.


Assuntos
Proteína Morfogenética Óssea 2/metabolismo , Osso e Ossos/metabolismo , Decorina/metabolismo , Fraturas não Consolidadas/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/metabolismo , Proteína Morfogenética Óssea 2/genética , Osso e Ossos/patologia , Decorina/genética , Consolidação da Fratura , Fraturas não Consolidadas/patologia , Expressão Gênica , Humanos , Pessoa de Meia-Idade
9.
Nature ; 453(7199): 1224-7, 2008 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-18528330

RESUMO

Since the discovery of superconductivity in the high-transition-temperature (high-T(c)) copper oxides two decades ago, it has been firmly established that the CuO(2) plane is essential for superconductivity and gives rise to a host of other very unusual properties. A new family of superconductors with the general composition of LaFeAsO(1-x)F(x) has recently been discovered and the conspicuous lack of the CuO(2) planes raises the tantalizing question of a different pairing mechanism in these oxypnictides. The superconducting gap (its magnitude, structure, and temperature dependence) is intimately related to pairing. Here we report the observation of a single gap in the superconductor SmFeAsO(0.85)F(0.15) with T(c) = 42 K as measured by Andreev spectroscopy. The gap value of 2Delta = 13.34 +/- 0.3 meV gives 2Delta/k(B)T(c) = 3.68 (where k(B) is the Boltzmann constant), close to the Bardeen-Cooper-Schrieffer (BCS) prediction of 3.53. The gap decreases with temperature and vanishes at T(c) in a manner consistent with the BCS prediction, but dramatically different from that of the pseudogap behaviour in the copper oxide superconductors. Our results clearly indicate a nodeless gap order parameter, which is nearly isotropic in size across different sections of the Fermi surface, and are not compatible with models involving antiferromagnetic fluctuations, strong correlations, the t-J model, and the like, originally designed for the high-T(c) copper oxides.

10.
Nature ; 453(7196): 761-2, 2008 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-18500328

RESUMO

Since the discovery of high-transition-temperature (high-T(c)) superconductivity in layered copper oxides, extensive effort has been devoted to exploring the origins of this phenomenon. A T(c) higher than 40 K (about the theoretical maximum predicted from Bardeen-Cooper-Schrieffer theory), however, has been obtained only in the copper oxide superconductors. The highest reported value for non-copper-oxide bulk superconductivity is T(c) = 39 K in MgB(2) (ref. 2). The layered rare-earth metal oxypnictides LnOFeAs (where Ln is La-Nd, Sm and Gd) are now attracting attention following the discovery of superconductivity at 26 K in the iron-based LaO(1-x)F(x)FeAs (ref. 3). Here we report the discovery of bulk superconductivity in the related compound SmFeAsO(1-x)F(x), which has a ZrCuSiAs-type structure. Resistivity and magnetization measurements reveal a transition temperature as high as 43 K. This provides a new material base for studying the origin of high-temperature superconductivity.

11.
Phys Rev Lett ; 110(14): 147601, 2013 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-25167036

RESUMO

We utilized microwave spectroscopy to study the magnetization oscillations locally induced in a Permalloy film by a pure spin current, which is generated due to the spin Hall effect in an adjacent Pt layer. The oscillation frequency is lower than the ferromagnetic resonance of Permalloy, indicating that the oscillation forms a self-localized nonpropagating spin-wave soliton. At cryogenic temperatures, the spectral characteristics are remarkably similar to the traditional spin-torque nano-oscillators driven by spin-polarized currents. However, the linewidth of the oscillation increases exponentially with temperature and an additional peak appears in the spectrum below the ferromagnetic resonance, suggesting that the spectral characteristics are determined by interplay between two localized dynamical states.

12.
J Dairy Sci ; 95(5): 2703-6, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22541499

RESUMO

A calf milk replacer (CMR) is designed to replace whole, saleable milk as a lower cost nutrient source for calves while striving to nourish a newborn calf, reduce calf mortality, strengthen immunity, and increase animal life span and productivity. Antioxidants (AO) can enhance immune defense by reducing oxidative damage, but CMR are traditionally not formulated for AO activity. The objective of this study was to compare total AO activities of bovine milk and 6 CMR (A to F) that vary in the amount and source of fat and protein. Calf milk replacers were donated by Milk Products LLC (Chilton, WI). Milk was obtained from the Cornell Dairy Research Farm bulk tank, representing milk produced within 24h by 455 cows. Milk replacers were mixed to 150 g/L with 40°C purified water. All samples were extracted in triplicate. Following hexane lipid extraction, both milk and CMR samples were extracted 5 times with ethyl acetate and then evaporated and reconstituted with 70% methanol:water. Samples were assessed for total AO activity using the peroxyl radical scavenging capacity assay where each sample was diluted to 5 descending concentrations, plated in triplicate. Ascorbic and gallic acids were standards for each plate. Type of protein (soy) had a positive effect on AO activity for CMR A, which exhibited the highest total AO activity. Natural bovine milk had the second highest AO activity. Many factors may explain the difference in AO activity between natural milk and formulated CMR, including fat, vitamin, and mineral contents, enzymatic AO, phenolics, flavonoids, fatty acid profile, and AA composition. When comparing AO activity of CMR, it is important to consider the diversity in feeding recommendations, which will alter the vitamin and mineral content, thus influencing AO activity. The opportunity exists to enhance AO activity of CMR to more closely mimic that of bovine milk. Future research is warranted to compare a broader range of CMR using methods that account for total lipophilic and hydrophilic AO activities, as well as to investigate the effect of additional compounds in milk that may affect AO activity.


Assuntos
Ração Animal/análise , Antioxidantes/análise , Animais , Animais Recém-Nascidos , Bovinos , Sequestradores de Radicais Livres/análise , Leite/química
13.
J Dairy Sci ; 95(11): 6563-70, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22921626

RESUMO

Ferulic acid (FRA), a phenolic compound with antioxidant and anticancer activities, naturally occurs in plants as a lignin precursor. Many veins of research have been devoted to releasing FRA from the lignin complex to improve digestibility of ruminant feeds. Thus, the objective of this research was to investigate the transfer of a given dosage of the free form of FRA into the milk of dairy cattle. Six mid- to late-lactation Holstein cows at the Cornell Research Farm (Harford, NY) were given 14-d adaptation to diet and stall position. Ad libitum access to a total mixed ration based on haylage and maize silage (31.1% neutral detergent fiber containing 5.52 mg of FRA/g) was provided during the study. A crossover design was implemented so that each cow alternated weekly between FRA-dosed and control. On d 1, jugular cannulas and urine catheters were placed in all cows. On d 2, FRA-dosed cows received a single dosage of 150 g of pure FRA powder at 0830 h via their fistula (n=4) or a balling gun for nonfistulated cows (n=2). Plasma, urine, feces, feed, orts, milk, and rumen fluid were sampled intensively for the next 36 h and analyzed for FRA concentration. On d 8, the cows crossed over and the experiment was repeated. When compared with the control, FRA administration did not have an effect on dry matter intake, milk yield, milk fat yield, milk protein yield, somatic cell count, or neutral detergent fiber content of orts and feces. The concentration of FRA in the feces did not change as a result of FRA dosage. As expected, FRA concentration increased dramatically upon FRA dosage and decreased over time until returning to basal levels in rumen fluid (4 h after dosage), plasma (5.5 h after dosage), urine (10 h after dosage), and milk (14 h after dosage). Baseline values for FRA in urine and rumen fluid were variable among cows and had an effect on FRA concentration in FRA-dosed cows. From this study, it is observed that orally ingested FRA can be transported into the milk and that the physiological transfer of FRA occurs from rumen to milk within 6.5 h or the first milking after dosage. Ferulic acid may affect the functionality of milk due to its antioxidant, anticancer, and antibacterial activities. Future research will be required to elucidate whether FRA in milk is bioavailable and bioactive, and to evaluate the complete sensory and microbiological effects of increased FRA and FRA degradation products in milk.


Assuntos
Ácidos Cumáricos/farmacocinética , Animais , Bovinos , Ácidos Cumáricos/análise , Ácidos Cumáricos/sangue , Ácidos Cumáricos/urina , Relação Dose-Resposta a Droga , Fezes/química , Feminino , Lactação/metabolismo , Leite/química , Rúmen/metabolismo
14.
Phys Rev Lett ; 107(6): 067001, 2011 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-21902359

RESUMO

We systematically investigated the in-plane resistivity anisotropy of electron-underdoped EuFe(2-x)Co(x)As(2) and BaFe(2-x)Co(x)As(2) and hole-underdoped Ba(1-x)K(x)Fe(2)As(2). Large in-plane resistivity anisotropy was found in the former samples, while tiny in-plane resistivity anisotropy was detected in the latter ones. When it is detected, the anisotropy starts above the structural transition temperature and increases smoothly through it. As the temperature is lowered further, the anisotropy takes a dramatic enhancement through the magnetic transition temperature. We found that the anisotropy is universally tied to the presence of T-linear behavior of resistivity. Our results demonstrate that the nematic state is caused by electronic degrees of freedom, and the microscopic orbital involvement in the magnetically ordered state must be fundamentally different between the hole- and electron-doped materials.

15.
Nat Mater ; 8(4): 310-4, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19234446

RESUMO

The recent observation of superconductivity with critical temperatures (Tc) up to 55 K in the pnictide RFeAsO(1-x)F(x), where R is a lanthanide, marks the first discovery of a non-copper-oxide-based layered high-Tc superconductor. It has raised the suspicion that these new materials share a similar pairing mechanism to the cuprate superconductors, as both families exhibit superconductivity following charge doping of a magnetic parent material. In this context, it is important to follow the evolution of the microscopic magnetic properties of the pnictides with doping and hence to determine whether magnetic correlations coexist with superconductivity. Here, we present a muon spin rotation study on SmFeAsO(1-x)F(x), with x=0-0.30 that shows that, as in the cuprates, static magnetism persists well into the superconducting regime. This analogy is quite surprising as the parent compounds of the two families have rather different magnetic ground states: itinerant spin density wave for the pnictides contrasted with the Mott-Hubbard insulator in the cuprates. Our findings therefore suggest that the proximity to magnetic order and associated soft magnetic fluctuations, rather than strong electronic correlations in the vicinity of a Mott-Hubbard transition, may be the key ingredients of high-Tc superconductors.

16.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 55(11): 908-914, 2020 Nov 09.
Artigo em Chinês | MEDLINE | ID: mdl-33171567

RESUMO

Objective: To evaluate the effects of fluorinated porcine hydroxyapatite (FPHA) on guided bone regeneration of peri-implant buccal bone defects in canine mandible. Methods: Six male beagle dogs were randomly divided into two groups with different time points (4 weeks and 12 weeks after implants placement), with 3 dogs in each group. Bilateral mandibular second premolars, first molars, and second molars in each dog were extracted. The wounds were allowed to heal for 12 weeks. For each dog, four implant beds were prepared in each side and standardized peri-implant buccal bone defect was created at each implant site. After implants placement, the defect sites were randomly allocated in a split-mouth design to blank control group, deproteinized bovine bone mineral (DBBM), the porcine hydroxyapatite (PHA), FPHA and covered with collagen membranes. The animals were sacrificed 4 or 12 weeks after the surgery. Biopsies of the implant sites were obtained for micro-CT evaluation [bone volume fraction (BV/TV) and bone trabecular separation degree (Tb.Sp)] and histological analysis. Results: Micro-CT results showed that 4 weeks after implants placement, PHA, FPHA and DBBM successfully maintained the contour of alveolar ridge at the buccal aspect of the implants, while the contour of alveolar ridge collapsed in the blank control group. BV/TV in the FPHA group [(24.77±2.20) %] was significantly higher than that in the PHA group [(16.89±1.70)%] and DBBM group [(15.68±3.15)%] (P<0.05). Tb.Sp in the FPHA group (0.70±0.07) was significantly lower than that in the DBBM group (1.03±0.19) (P<0.05). Twelve weeks after implants placement, the alveolar ridge contour of the grafted sites in PHA, FPHA and DBBM group remained stable. The alveolar ridge of the blank control group was still collapsed. There was no significant difference in BV/TV and Tb.Sp between PHA group, FPHA group and DBBM group. The histomorphological analysis showed that 4 weeks after implants placement, in the central area of the defect, the amount and maturity of new bone (NB) around the material particles in FPHA group was higher than that in PHA group and DBBM group. Osseointegration could be observed between the NB and implant surface in all the four groups. Twelve weeks after implants placement, the material particles were surrounded by a large number of mature NB in PHA, FPHA and DBBM group. Conclusions: The incorporation of fluoride ion into PHA could effectively promote the repair of peri-implant bone defects in the early stage of guided bone regeneration.


Assuntos
Substitutos Ósseos , Implantes Dentários , Animais , Regeneração Óssea , Bovinos , Implantação Dentária Endóssea , Cães , Durapatita , Masculino , Mandíbula/cirurgia , Membranas Artificiais , Osseointegração , Suínos
17.
J Phys Condens Matter ; 21(1): 016004, 2009 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-21817241

RESUMO

We have measured susceptibility and angle-dependent magnetoresistance (AMR) on K(0.50)CoO(2) single crystals. A possible magnetic structure similar to that of Na(0.5)CoO(2), a G-type anti-ferromagnetic (AF) structure (both in-plane and inter-plane are AF), is proposed. At âˆ¼20 K, a loop is observed between zero-field-cooled (ZFC) and field-cooled (FC) susceptibility. The absolute value of magnetoresistance (MR) at 20 K is much larger than other cases with H applied within the ab plane. This could arise from the magnetic field being applied in the ab plane, leading to spin-flop of the small magnetic moment of Co(3.5-δ) sites at 20 K to form in-plane ferromagnetic ordering, as observed in Na(0.52)CoO(2).

18.
J Phys Condens Matter ; 21(27): 275601, 2009 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-21828495

RESUMO

The transport properties of Cu(x)NbS(2) (x = 0.09, 0.44 and 0.55) single crystals were systematically studied. The in-plane and out-of-plane resistivities decrease with increasing Cu content, and a transition with hysteresis shows up for the crystals with x = 0.44 and 0.55. The thermopower and Hall coefficient of Cu(x)NbS(2) show opposite signs, indicating that there are two kinds of carriers in this system. The angular dependences of the in-plane magnetoresistance (MR(ab) = (ρ(ab)(H)-ρ(ab)(0))/ρ(ab)(0) × 100%) at different temperatures were also studied. The single crystals with x = 0.44 and 0.55 show a strong anisotropic MR(ab). For the x = 0.55 sample, MR(ab) reaches 80% with a magnetic field of 14 T applied along the c-axis, while MR(ab) is less than 5% for the magnetic field applied within the ab-plane. These results can be well understood in the light of the anisotropic Fermi surface in the multiband system.

19.
J Phys Condens Matter ; 21(14): 142203, 2009 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-21825317

RESUMO

We synthesized the samples Sr(1-x)Sm(x)FFeAs with a ZrCuSiAs-type structure. These samples were characterized by resistivity and susceptibility. It is found that substitution of rare earth metal for alkaline earth metal in this system suppresses the anomaly in resistivity and induces superconductivity. Superconductivity at 56 K in nominal composition Sr(0.5)Sm(0.5)FFeAs is realized, indicating that the superconducting transition temperatures in the iron arsenide fluorides can reach as high as that in oxypnictides with the same structure.

20.
Forensic Sci Rev ; 31(2): 103-140, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31270058

RESUMO

Important events in the history of driving under the influence of alcohol (DUI) and/or other drugs (DUID) are reviewed covering a period of approximately 100 years. This coincides with major developments in the pharmaceutical industry and the exponential growth in motor transportation worldwide. DUID constitutes an interaction between the driver, the motor-driven vehicle, and one or more psychoactive (mind-altering) substances. In this connection, it is important to differentiate between drugs intended and used for medical purposes (prescription or licit drugs) and recreational drugs of abuse (illicit drugs). All chemicals with a mechanism of action in the central nervous system (brain and spinal cord) are potentially dangerous to use when skilled tasks, such as driving, are performed. The evidence necessary to charge a person with drug-impaired driving has evolved over many years and initially rested on a driver's own admissions and observations made about the driving by police officers or eyewitnesses. Somewhat later, all suspects were examined by a physician, whose task was to ask questions about any recent ingestion of alcohol and/or other drugs and to administer various clinical tests of impairment. By the 1940s-1950s, the driver was asked to provide samples of blood, breath, or urine for toxicological analysis, although the test results served only to verify the type of drug causing impairment of the driver. The current trend in DUID legislation is toward zero-tolerance or concentration per se statutes, which are much more pragmatic, because behavioral evidence of impairment is no longer a lynchpin in the prosecution case. This legal framework puts considerable emphasis on the results of toxicological analysis; therefore, the methods used must be accurate, precise, and fit for forensic purposes. Many traffic delinquents charged with DUI or DUID suffer from a substance use and/or personality disorder, with high recidivism rates. In addition to conventional penalties and sanctions for drug-related traffic crimes, many offenders would probably benefit from a medical intervention, such as counseling, rehabilitation, and treatment for substance use disorder, which often coexists with a mental health problem.


Assuntos
Condução de Veículo/legislação & jurisprudência , Dirigir sob a Influência/legislação & jurisprudência , Dirigir sob a Influência/tendências , Consumo de Bebidas Alcoólicas , Humanos , Drogas Ilícitas , Detecção do Abuso de Substâncias , Transtornos Relacionados ao Uso de Substâncias
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA