Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 101
Filtrar
1.
J Appl Microbiol ; 132(1): 340-350, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33900007

RESUMO

AIMS: Investigate the impact of highly adapted bacterial strains and their ability in waste degradation under a wide range of temperatures. METHODS AND RESULTS: Bacteria isolated from soil and food waste were grown in various media under fluctuated temperatures. After screening for organic compound degradation, the seven strongest bacterial strains have been selected for further experiments. Their enzyme activities were expressed in terms of the size of the hydrolysis zone in a wide temperature range of 2·5-70°C. The enzyme production assay was carried out for each protease, cellulase and amylase. The waste degradation was determined with a maximum 80% decrease in the volume of food waste in 21 days compared to the control in lab scale with enriched bacterial cultures and soil bacteria as additives at room temperature around 18-20°C. CONCLUSION: These seven bacteria are promising candidates for food waste biodegradation in composting especially in the winter without heating expense for maintaining ambient temperature. SIGNIFICANCE AND IMPACT OF THE STUDY: It is necessary to coax the uncultured bacteria from the various environments into the laboratory for investigating their valuable functions. Herein, using enrichment culture of consortium and additive of soil has illustrated the significant mean in food waste degradation.


Assuntos
Compostagem , Eliminação de Resíduos , Bactérias , Biodegradação Ambiental , Alimentos , Solo , Temperatura
2.
Ann Oncol ; 31(7): 902-911, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32320754

RESUMO

BACKGROUND: Immune checkpoint inhibitors (ICIs) have been shown to be beneficial for some patients with advanced non-small-cell lung cancer (NSCLC). However, the underlying mechanisms mediating the limited response to ICIs remain unclear. PATIENTS AND METHODS: We carried out whole-exome sequencing on 198 advanced NSCLC tumors that had been sampled before anti-programmed cell death 1 (anti-PD-1)/programmed death-ligand 1 (PD-L1) therapy. Detailed clinical characteristics were collected on these patients. We designed a new method to estimate human leukocyte antigen (HLA)-corrected tumor mutation burden (TMB), a modification which considers the loss of heterozygosity of HLA from conventional TMB. We carried out external validation of our findings utilizing 89 NSCLC samples and 110 melanoma samples from two independent cohorts of immunotherapy-treated patients. RESULTS: Homology-dependent recombination deficiency was identified in 37 patients (18.7%) and was associated with longer progression-free survival (PFS; P = 0.049). Using the HLA-corrected TMB, non-responders to ICIs were identified, despite having a high TMB (top 25%). Ten patients (21.3% of the high TMB group) were reclassified from the high TMB group into the low TMB group. The objective response rate (ORR), PFS, and overall survival (OS) were all lower in these patients compared with those of the high TMB group (ORR: 20% versus 59%, P = 0.0363; PFS: hazard ratio = 2.91, P = 0.007; OS: hazard ratio = 3.43, P = 0.004). Multivariate analyses showed that high HLA-corrected TMB was associated with a significant survival advantage (hazard ratio = 0.44, P = 0.015), whereas high conventional TMB was not associated with a survival advantage (hazard ratio = 0.63, P = 0.118). Applying this approach to the independent cohorts of 89 NSCLC patients and 110 melanoma patients, TMB-based survival prediction was significantly improved. CONCLUSION: HLA-corrected TMB can reconcile the observed disparity in relationships between TMB and ICI responses, and is of predictive and prognostic value for ICI therapies.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Antígeno B7-H1/genética , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Antígenos HLA , Recombinação Homóloga , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Mutação , Receptor de Morte Celular Programada 1/genética
3.
Phys Rev Lett ; 125(15): 157001, 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33095605

RESUMO

We investigate the pressure effects on the electronic structures and phonon properties of rare-earth-based cubic-Heusler compound LuPd_{2}In, on the basis of ab initio density functional theory. We find the occurrence of intriguing phase transition from the superconducting (SC) to charge-density wave (CDW) state under pressure (P), which is quite unusual in that the pressure is detrimental to the CDW state in usual systems. The SC transition temperature T_{C} of LuPd_{2}In increases first with increasing pressure, up to P_{C}≈28 GPa, above which a quantum phase transition into the CDW state takes place. This extraordinary transition originates from the occurrence of phonon softening instability at a special q=M in the Brillouin zone. We thus propose that LuPd_{2}In is a quite unique material, in which the CDW quantum critical point is realized under the SC dome by applying the pressure.

4.
Br J Surg ; 103(1): 126-35, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26572697

RESUMO

BACKGROUND: This study aimed to investigate whether radiofrequency ablation (RFA) is an alternative to surgical resection for hepatocellular carcinoma (HCC) within the context of current guidelines. METHODS: This retrospective study included patients with normal portal pressure and serum bilirubin level who initially underwent liver resection or RFA for a single HCC of maximum size 3 cm. Between-group differences in cumulative rates of survival and recurrence specific for HCC were analysed in the entire cohort and in a propensity score-matched cohort. RESULTS: A total of 604 patients were enrolled, 273 in the liver resection group and 331 in the RFA group. The 5- and 10-year HCC-specific survival rates for the resection and RFA groups were 87·6 versus 82·1 per cent and 59·0 versus 61·2 per cent respectively (P = 0·214), whereas overall 5- and 10-year recurrence-free survival rates for the corresponding groups were 60·6 versus 39·4 per cent and 37·5 versus 25·1 per cent respectively (P < 0·001). In the propensity score-matched cohort (152 pairs), there were no differences in HCC-specific survival (hazard ratio (HR) 1·03 for RFA versus resection; P = 0·899), whereas recurrence-free survival again differed between the treatment groups (HR 1·75; P < 0·001). RFA was independently associated with poorer outcomes in terms of treatment-site recurrence-free survival (adjusted HR 1·66; P = 0·026), but not non-treatment-site recurrence-free survival (adjusted HR 1·15; P = 0·354). CONCLUSION: Although RFA carries a higher risk of treatment-site recurrence than hepatic resection, it provides comparable overall survival in patients with a single small HCC without portal hypertension or a raised bilirubin level.


Assuntos
Carcinoma Hepatocelular/cirurgia , Ablação por Cateter , Hepatectomia , Neoplasias Hepáticas/cirurgia , Adulto , Idoso , Carcinoma Hepatocelular/mortalidade , Feminino , Seguimentos , Humanos , Neoplasias Hepáticas/mortalidade , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Pontuação de Propensão , Estudos Retrospectivos , Análise de Sobrevida , Resultado do Tratamento
5.
Osteoporos Int ; 27(4): 1559-1568, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26650379

RESUMO

UNLABELLED: Increased fragility has been described in humans with polycythemia vera (PV). Herein, we describe an osteoporotic phenotype associated with decreased osteoblast activity in a mouse model of PV and another mouse of polycythemia and elevated circulating erythropoietin (EPO). Our results are important for patients with PV or those treated with recombinant EPO (rEPO). INTRODUCTION: PV and other myeloproliferative syndromes have been recently associated with an increased risk for fractures. However, the presence of osteoporosis in these patients has not been well documented. EPO, a hormone primarily known to stimulate erythropoiesis, has been shown recently to regulate bone homeostasis in mice. The aim of this study was to examine the bone phenotype of a mouse model of PV and compare it to that of animals with polycythemia caused by elevated circulating EPO. METHODS: Bone mass and remodeling were evaluated by micro-computed tomography and histomorphometry. The JAK2(V617F) knock-in mouse, a model of human PV, manifests polycythemia and low circulating EPO levels. Results from this mouse were compared to wild type (wt) controls and the tg6 transgenic mouse that shows polycythemia caused by increased constitutive expression of EPO. RESULTS: Compared to wt, both JAK2(V617F) and tg6 mice had a decrease in trabecular bone mass. Tg6 mice showed an additional modest decrease in cortical thickness and cortical bone volume per tissue volume (P < 0.01) suggesting a more severe bone phenotype than JAK2(V617F). Decreased osteoblast numbers and bone formation along with normal osteoclast numbers and activity were found in both mice. CONCLUSIONS: This study indicates that PV is associated with low bone mass and decreased osteoblast activity in mice. Our results support future studies of osteoporosis in affected humans. Polycythemia caused by chronically elevated circulating EPO also results in bone loss, and implications on patients treated with rEPO should be evaluated.


Assuntos
Doenças Ósseas Metabólicas/etiologia , Osteoblastos/fisiologia , Policitemia Vera/complicações , Policitemia/complicações , Animais , Densidade Óssea/fisiologia , Doenças Ósseas Metabólicas/diagnóstico por imagem , Doenças Ósseas Metabólicas/fisiopatologia , Remodelação Óssea/fisiologia , Modelos Animais de Doenças , Eritropoetina/sangue , Masculino , Camundongos Knockout , Camundongos Transgênicos , Osteogênese/fisiologia , Policitemia/sangue , Policitemia/fisiopatologia , Policitemia Vera/sangue , Policitemia Vera/fisiopatologia , Microtomografia por Raio-X
6.
Phys Rev Lett ; 116(11): 116401, 2016 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-27035312

RESUMO

To finally resolve the controversial issue of whether or not the electronic structure of YbB_{6} is nontrivially topological, we have made a combined study using angle-resolved photoemission spectroscopy (ARPES) of the nonpolar (110) surface and density functional theory (DFT). The flat-band conditions of the (110) ARPES avoid the strong band bending effects of the polar (001) surface and definitively show that YbB_{6} has a topologically trivial B 2p-Yb 5d semiconductor band gap of ∼0.3 eV. Accurate determination of the low energy band topology in DFT requires the use of a modified Becke-Johnson exchange potential incorporating spin-orbit coupling and an on-site Yb 4f Coulomb interaction U as large as 7 eV. The DFT result, confirmed by a more precise GW band calculation, is similar to that of a small gap non-Kondo nontopological semiconductor. Additionally, the pressure-dependent electronic structure of YbB_{6} is investigated theoretically and found to transform into a p-d overlap semimetal with small Yb mixed valency.

7.
J Eur Acad Dermatol Venereol ; 30(2): 276-81, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26563519

RESUMO

BACKGROUND: Many companies claim that their moisturizers are superior to others based on their ingredients. OBJECTIVE: To compare the efficacy and safety of the most popular moisturizers in the field. METHODS: A randomized, double-blind, controlled study was performed on 80 patients with moderate to severe xerosis. The test agents included the newly developed cream containing topical recombinant human epidermal growth factor (EGF), its vehicle without EGF and four additional therapeutic moisturizers. The study subjects applied the test agents on designated skin areas twice daily for 4 weeks. All of the clinical assessments and non-invasive objective measurements were performed at baseline, and on days 14 and 28 of the study. RESULTS: All of the test agents significantly improved the clinical symptoms of xerosis. The biophysical parameters similarly improved from baseline (P < 0.05). None of the test agents performed significantly better than did another. CONCLUSION: In the treatment of xerosis, consistent and regular moisturizer use is much more important than the moisturizer's particular formulation.


Assuntos
Emolientes/administração & dosagem , Dermatopatias/tratamento farmacológico , Pele/patologia , Perda Insensível de Água/efeitos dos fármacos , Administração Tópica , Adulto , Idoso , Método Duplo-Cego , Composição de Medicamentos/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Pele/efeitos dos fármacos , Dermatopatias/diagnóstico , Adulto Jovem
8.
Int J Cosmet Sci ; 38(3): 286-93, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26564311

RESUMO

OBJECTIVE: The Korean Cosmetic Act regulates the use of functional cosmetics) by the law. Four functional cosmetic groups, whitening, anti-wrinkle, UV protection and combination of whitening and anti-wrinkle, were categorized according to the Korean Cosmetic Act and Functional Cosmetics Codex. In this study, high-performance liquid chromatography (HPLC) coupled with photodiode array detection (DAD) was employed for the simultaneous detection of arbutin (and its decomposition product, hydroquinone), niacinamide, ascorbyl glucoside, ethyl ascorbyl ether and adenosine in functional cosmetic products such as creams, emulsions and lotions. METHODS: Separation by HPLC-DAD was conducted using a C18 column with a gradient elution of 5 mm KH2PO4 buffer (containing 0.1% phosphoric acid) and methanol (containing 0.1% phosphoric acid). The wavelengths for the detection of arbutin, hydroquinone, niacinamide, adenosine, ascorbyl glucoside and ethyl ascorbyl ether were 283, 289, 261, 257, 238 and 245 nm, respectively. RESULTS: This method exhibited good linearity (R(2) ≥ 0.999), precision (expressed as relative standard deviation (RSD) < 2%) and mean recoveries (89.42-104.89%). The results obtained by monitoring 100 market samples showed that the detected levels of the tested materials are within the acceptable authorized concentration. CONCLUSION: The method developed herein is simple and can be used for market survey and quality control of functional cosmetics.


Assuntos
Adenosina/administração & dosagem , Cromatografia Líquida de Alta Pressão/métodos , Cosméticos , Preparações Clareadoras de Pele , Limite de Detecção , Solubilidade , Espectrofotometria Ultravioleta/métodos , Água
9.
Clin Exp Dermatol ; 40(5): 479-84, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25683452

RESUMO

BACKGROUND: Traditionally, the gold standard for diagnosis of onychomycosis has been the combination of direct microscopy with potassium hydroxide (KOH) staining and fungal culture. However, several studies have suggested that periodic-acid-Schiff (PAS) staining of nail-plate clippings may be a very sensitive method for the diagnosis of onychomycosis. AIM: To compare the sensitivities of direct microscopy with KOH, fungal culture and PAS staining of nail-plate clippings, and to define an efficient, high-yield and cost-effective diagnostic strategy for the diagnosis of onychomycosis in the clinical setting. METHODS: We evaluated a total of 493 patients with clinically suspected onychomycosis. Group A comprised 400 patient samples, evaluated using fungal culture and PAS stain, while group B comprised 93 patient samples evaluated using KOH, fungal culture and PAS. Diagnosis of onychomycosis was defined as clinical morphology plus at least one positive test result. RESULTS: In group A, sensitivities of fungal culture and PAS were 49.5% and 93.1% (P < 0.005), respectively. In group B, the most sensitive single test was PAS (88.2%) followed by KOH (55.9%) and fungal culture (29.4%). The combination of fungal culture and PAS (94.1%) was significantly (P < 0.001) more sensitive than that of KOH and culture (72.1%). CONCLUSION: PAS staining of nail clippings is much more sensitive than KOH and fungal culture for the diagnosis of onychomycosis. Based on our results, we propose a diagnostic algorithm for onychomycosis that takes into consideration the sensitivity, cost-effectiveness and necessary time for each test.


Assuntos
Algoritmos , Dermatoses do Pé/diagnóstico , Dermatoses da Mão/diagnóstico , Microscopia/métodos , Onicomicose/diagnóstico , Adulto , Idoso , Feminino , Corantes Fluorescentes , Dermatoses do Pé/microbiologia , Fungos/isolamento & purificação , Dermatoses da Mão/microbiologia , Humanos , Hidróxidos , Indicadores e Reagentes , Masculino , Pessoa de Meia-Idade , Micologia/métodos , Onicomicose/microbiologia , Reação do Ácido Periódico de Schiff , Compostos de Potássio , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Coloração e Rotulagem/métodos
10.
Int J Cosmet Sci ; 37(6): 567-73, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25857400

RESUMO

OBJECTIVE: Arbutin is an effective agent for the treatment of melanin disorders. Arbutin may be converted to hydroquinone under conditions of high temperature, ultraviolet (UV) radiation and dilute acid. The aim of the current study was to develop an analytical method to determine the levels of arbutin and hydroquinone in whitening cosmetic products using high-performance liquid chromatography with photodiode array detection (HPLC-DAD). In addition, we investigated the effects of high temperature and pH on the decomposition of arbutin. METHODS: Samples extracted using two-step sonications were separated on a C18 column using a gradient mobile phase consisting of water and methanol. A 60-mm (40 µL) DAD cell was used to enhance the sensitivity of hydroquinone determination. Thermal decomposition of arbutin was evaluated at temperatures ranging from 60 to 120°C for 1-36 h. RESULTS: The method showed good linearity (R(2) ≥ 0.9997), precision (relative standard deviation, RSD < 5%) and acceptable extraction recovery (90-102.6%). The limits of quantitation for arbutin and hydroquinone were 0.0085 and 0.0119 µg mL(-1) , respectively. One sample of 21 cosmetic products tested contained arbutin at a concentration 1.61 g 100 g(-1) cream and 0.12 g 100 g(-1) cream of hydroquinone. Arbutin (327.18 ppm) decomposed after 6 h at 120°C and produced 10.73 ppm of hydroquinone. CONCLUSION: The developed method is simple to detect both arbutin and hydroquinone simultaneously in cosmetic products, at an adequate level of sensitivity. Notably, temperature and pH did not influence the decomposition of arbutin to hydroquinone in a 2% arbutin cream.


Assuntos
Arbutina/análise , Cromatografia Líquida de Alta Pressão/métodos , Hidroquinonas/análise , Preparações Clareadoras de Pele/química , Espectrofotometria Ultravioleta/métodos , Concentração de Íons de Hidrogênio , Temperatura
11.
Nano Lett ; 13(6): 2738-42, 2013 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-23721106

RESUMO

Measuring local temperature with a spatial resolution on the order of a few nanometers has a wide range of applications in the semiconductor industry and in material and life sciences. For example, probing temperature on the nanoscale with high precision can potentially be used to detect small, local temperature changes like those caused by chemical reactions or biochemical processes. However, precise nanoscale temperature measurements have not been realized so far owing to the lack of adequate probes. Here we experimentally demonstrate a novel nanoscale temperature sensing technique based on optically detected electron spin resonance in single atomic defects in diamonds. These diamond sensor sizes range from a micrometer down to a few tens of nanometers. We achieve a temperature noise floor of 5 mK/Hz(1/2) for single defects in bulk sensors. Using doped nanodiamonds as sensors the temperature noise floor is 130 mK/Hz(1/2) and accuracies down to 1 mK for nanocrystal sizes and therefore length scales of a few tens of nanometers. This combination of precision and position resolution, combined with the outstanding sensor photostability, should allow the measurement of the heat produced by chemical interactions involving a few or single molecules even in heterogeneous environments like cells.

12.
Phys Rev Lett ; 110(24): 247202, 2013 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-25165956

RESUMO

The temperature (T) dependence of the optical conductivity spectra σ(ω) of a single crystal SrRuO(3) thin film is studied over a T range from 5 to 450 K. We observed significant T dependence of the spectral weights of the charge transfer and interband d-d transitions across the ferromagnetic Curie temperature (T(c) ∼ 150 K). Such T dependence was attributed to the increase in the Ru spin moment, which is consistent with the results of density functional theory calculations. T scans of σ(Ω,T) at fixed frequencies Ω reveal a clear T(2) dependence below T(c), demonstrating that the Stoner mechanism is involved in the evolution of the electronic structure. In addition, σ(Ω,T) continues to evolve at temperatures above T(c), indicating that the local spin moment persists in the paramagnetic state. This suggests that SrRuO(3) is an intriguing oxide system with itinerant ferromagnetism.

13.
Nature ; 446(7135): 513-6, 2007 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-17392780

RESUMO

Although the nuclear properties of the late actinides (plutonium, americium and curium) are fully understood and widely applied to energy generation, their solid-state properties do not fit within standard models and are the subject of active research. Plutonium displays phases with enormous volume differences, and both its Pauli-like magnetic susceptibility and resistivity are an order of magnitude larger than those of simple metals. Curium is also highly resistive, but its susceptibility is Curie-like at high temperatures and orders antiferromagnetically at low temperatures. The anomalous properties of the late actinides stem from the competition between itinerancy and localization of their f-shell electrons, which makes these elements strongly correlated materials. A central problem in this field is to understand the mechanism by which these conflicting tendencies are resolved in such materials. Here we identify the electronic mechanisms responsible for the anomalous behaviour of late actinides, revisiting the concept of valence using a theoretical approach that treats magnetism, Kondo screening, atomic multiplet effects and crystal field splitting on the same footing. We find that the ground state in plutonium is a quantum superposition of two distinct atomic valences, whereas curium settles into a magnetically ordered single valence state at low temperatures. The f(7) configuration of curium is contrasted with the multiple valences of the plutonium ground state, which we characterize by a valence histogram. The balance between the Kondo screening and magnetism is controlled by the competition between spin-orbit coupling, the strength of atomic multiplets and the degree of itinerancy. Our approach highlights the electronic origin of the bonding anomalies in plutonium, and can be applied to predict generalized valences and the presence or absence of magnetism in other compounds starting from first principles.

14.
Anaesthesia ; 68(6): 585-90, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23590463

RESUMO

The GlideScope videolaryngoscope is widely used in the management of the difficult airway. However, passing the tracheal tube through the vocal cords can be awkward, and the use of a stylet to guide insertion is recommended. This randomised controlled trial evaluated a forceps-guided tube exchanger as an alternative to the stylet to aid intubation with the GlideScope in patients undergoing anaesthesia, with a simulated difficult airway created by the application of a semi-rigid cervical collar. Data were analysed from 178 patients randomly assigned to undergo intubation using either the stylet (n = 88) or a forceps-guided tube exchanger (n = 90). All intubations were completed successfully, with first attempt rates of 93.2% using the stylet and 94.4% using the exchanger (p = 0.597). The mean (SD) intubation time was 67.8 (28.7) s in the stylet group and 66.1 (15.5) s in the forceps-guided tube exchanger group (p = 0.11). The frequency of sore throat 1 h after extubation was 34.1% in the stylet group and 2.2% in the tube exchanger group (p < 0.001); 24 h after extubation the corresponding figures were 40.0% and 11.1% (p < 0.001). Using a forceps-guided tube exchanger may offer an advantage over a stylet in guiding tracheal intubation when the GlideScope is used.


Assuntos
Intubação Intratraqueal/instrumentação , Laringoscópios , Laringoscopia/instrumentação , Instrumentos Cirúrgicos , Adolescente , Adulto , Idoso , Desenho de Equipamento , Feminino , Humanos , Intubação Intratraqueal/métodos , Masculino , Pessoa de Meia-Idade , Gravação em Vídeo , Adulto Jovem
15.
Phys Rev Lett ; 108(1): 016402, 2012 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-22304274

RESUMO

We address theoretically the evolution of the heavy fermion Fermi surface (FS) as a function of temperature (T), using a first principles dynamical mean-field theory approach combined with density functional theory. We focus on the archetypical heavy electrons in CeIrIn{5}. Upon cooling, both the quantum oscillation frequencies and cyclotron masses show logarithmic scaling behavior [∼ln(T{0}/T)] with different characteristic temperatures T{0}=130 and 50 K, respectively. The enlargement of the electron FSs at low T is accompanied by topological changes around T=10-50 K. The resistivity coherence peak observed at T≃50 K is the result of the competition between the binding of incoherent 4f electrons to the spd conduction electrons at Fermi level (E{F}) and the formation of coherent 4f electrons.

16.
Phys Rev Lett ; 109(5): 050401, 2012 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-23006148

RESUMO

Rabi oscillations in the V(15) single molecule magnet embedded in the surfactant (CH(3))(2)[CH(3)(CH(2))(16)CH(2)](2)N(+) have been studied at different microwave powers. An intense damping peak is observed when the Rabi frequency Ω(R) falls in the vicinity of the Larmor frequency of protons ω(N). The experiments are interpreted by a model showing that the damping (or Rabi) time τ(R) is directly associated with decoherence caused by electron-nuclear cross relaxation in the rotating reference frame. This decoherence induces energy dissipation in the range ω(N) - σ(e) < Ω(R) < ω(N), where σ(e) is the mean superhyperfine field induced by protons at V(15). Weaker decoherence without dissipation takes place outside this window. Specific estimations suggest that this rapid cross relaxation in a resonant microwave field, observed for the first time in V(15), should also take place, e.g., in Fe(8) and Mn(12).

17.
Dermatology ; 224(4): 352-60, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22759782

RESUMO

BACKGROUND: Cathepsin G, a serine protease that is activated by ultraviolet (UV) radiation, increases matrix metalloproteinase-1 (MMP-1) expression in fibroblasts through fibronectin (Fn) fragmentation and promotes the conversion of proMMP-1 to active MMP-1. OBJECTIVES: This study investigated whether [2-[3-[[(1-benzoyl-4-piperidinyl)methylamino]carbonyl]-2-naphthalenyl]-1-(1-naphthalenyl)-2-oxoethyl]-phosphonic acid (KPA), a cathepsin G inhibitor, plays any role in extracellular matrix (ECM) damage in an in vitro 3D dermal equivalent (DE) and an in vivo ultraviolet B (UVB)-irradiated hairless mice. METHODS: We examined the potential ECM-protective effects of a cathepsin G inhibitor in an in vitro 3D DE model and an in vivo UVB-irradiated hairless mouse skin model. RESULTS: Among five known serine protease inhibitors, KPA showed the strongest potency and selectivity against cathepsin G. KPA inhibited the cathepsin G-mediated MMP-1 increase and alleviated the downregulation of mRNAs encoding collagen and tissue inhibitor of matrix metalloproteinase-1 in an in vitro 3D DE model. Most importantly, topical application of KPA (0.025%) to the dorsal skin of hairless mice enhanced collagen expression and attenuated UVB-induced Fn fragmentation and upregulation of MMP-2 and MMP-9 activities. CONCLUSIONS: Cathepsin G inhibitors may be useful for the prevention of UVB-induced photoaging through amelioration of ECM damage and MMP upregulation.


Assuntos
Catepsina G/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Fibronectinas/metabolismo , Naftalenos/farmacologia , Compostos Organofosforados/farmacologia , Piperidinas/farmacologia , Envelhecimento da Pele/efeitos dos fármacos , Pele/efeitos da radiação , Raios Ultravioleta/efeitos adversos , Animais , Western Blotting , Colágeno/metabolismo , Elastina/química , Elastina/metabolismo , Ensaio de Imunoadsorção Enzimática , Feminino , Metaloproteinase 1 da Matriz/metabolismo , Camundongos , Camundongos Pelados , Modelos Animais , Reação em Cadeia da Polimerase em Tempo Real , Pele/metabolismo , Inibidor Tecidual de Metaloproteinase-1/metabolismo
18.
Phys Rev Lett ; 107(12): 126402, 2011 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-22026779

RESUMO

We report the observation of highly anisotropic Dirac fermions in a Bi square net of SrMnBi(2), based on a first-principles calculation, angle-resolved photoemission spectroscopy, and quantum oscillations for high-quality single crystals. We found that the Dirac dispersion is generally induced in the (SrBi)(+) layer containing a double-sized Bi square net. In contrast to the commonly observed isotropic Dirac cone, the Dirac cone in SrMnBi(2) is highly anisotropic with a large momentum-dependent disparity of Fermi velocities of ~8. These findings demonstrate that a Bi square net, a common building block of various layered pnictides, provides a new platform that hosts highly anisotropic Dirac fermions.

19.
J Nanosci Nanotechnol ; 11(7): 6237-40, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22121692

RESUMO

The interaction of antiparallel transverse domain walls in ferromagnetic nanowires was investigated via micromagnetic simulation with systematic variations of the external field strength as well as the wire thickness. The interaction of antiparallel transverse walls after domain wall collision exhibited damped multiple collisions due to the rigid structure of the antiparallel transverse walls. The detailed process during the multiple collisions was analyzed via the Fast Fourier Transform technique, along with a careful examination of the inner spin structures of the colliding domain walls. It was found that a frequency peak of multiple collisions shifted to a higher peak position as the external field strength increases. With a stronger field strength of around a few hundred mT, it was found that two antiparallel transverse walls were finally annihilated with formation of complex antivortex structures.

20.
J Nanosci Nanotechnol ; 11(7): 6122-5, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22121670

RESUMO

Understanding the interaction between the magnetic domain wall and the various artificial defects in ferromagnetic nanowires has been of utmost importance for the future realization of the spintronic devices based on the magnetic domain wall motion in nanowires. In this work, the chirality filter effect of the magnetic domain wall in T-shaped ferromagnetic nanowires with a stray field filter was investigated via micromagnetic simulation. A tapered wire was attached to the flat nanowires to form a potential barrier or well for the domain wall propagating along them. For the domain wall passing through the potential barrier or the potential well, the spin structure of the domain wall and the interaction between the domain wall and the potential barrier/well were investigated in detail. The chirality-dependent translational positioning of the domain wall was intensively examined for the potential barrier and potential well cases. The domain wall chirality transmission on relatively long length scales using a series of potential wells was explored.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA