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1.
J Prev Alzheimers Dis ; 11(5): 1260-1269, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39350371

RESUMEN

BACKGROUND: Global prevalence and incidence of dementia continue to rise at a rapid rate. There is a need for new Alzheimer's disease (AD) treatments globally. Aducanumab is a human monoclonal antibody that selectively targets aggregated soluble amyloid beta oligomers and insoluble amyloid beta fibrils. In June 2021, aducanumab was approved by the US Food and Drug Administration for the treatment of AD under the accelerated approval pathway. OBJECTIVES: We evaluated the efficacy, safety, biomarker and pharmacokinetics (PK) of aducanumab in Japanese subgroups in EMERGE and ENGAGE studies. DESIGN: EMERGE and ENGAGE were two randomized, double-blind, placebo-controlled, global, phase 3 studies of aducanumab in patients with early AD (mild cognitive impairment due to AD or mild AD dementia). SETTING: These studies involved 348 sites in 20 countries. PARTICIPANTS: Participants enrolled in Japan included 121 (7.4% of total 1638 in EMERGE) and 100 (6.1% of total 1647 in ENGAGE) patients (aged 50-85 years with confirmed amyloid pathology) who met clinical criteria for mild cognitive impairment due to AD or mild AD dementia. INTERVENTION: Participants were randomly assigned 1:1:1 to receive aducanumab low dose (3 or 6 mg/kg target dose), high dose (6 or 10 mg/kg target dose) or placebo via IV infusion once every 4 weeks over 76 weeks. MEASUREMENTS: The primary outcome measure was change from baseline to Week 78 on the Clinical Dementia Rating Sum of Boxes (CDR-SB), an integrated scale that assesses both function and cognition. Other measures included safety assessments; secondary and tertiary clinical outcomes that assessed cognition, function, and behavior; biomarker endpoints (amyloid PET and plasma p-tau181); serum PK profiles and immunogenicity. RESULTS: Results from the Japanese subgroup analyses were generally consistent with those of the overall study population across endpoints, while a lower mean body weight (kg) and a smaller proportion of ApoE ε4 carriers were observed in the Japanese subgroup population. A treatment effect was observed in favor of aducanumab on the primary and secondary efficacy endpoints at Week 78 in EMERGE, but not ENGAGE. The incidence and type of adverse events in the Japanese subgroups were generally comparable to those observed in the overall study population; amyloid related imaging abnormalities (ARIA) were common treatment-related adverse events that appeared to be related to the aducanumab dose. ARIA incidence was generally lower in the Japanese subgroup compared with the overall population. Consistent with the overall data set, a robust dose-dependent decrease in amyloid beta levels as assessed with amyloid-PET and plasma p-tau181 was observed. Serum PK profiles and immunogenicity of aducanumab in Japanese population were consistent with the non-Japanese population. CONCLUSION: Efficacy, safety, biomarker, and PK profiles of aducanumab were consistent between the Japanese subgroup and the overall population. A positive treatment effect of aducanumab on efficacy endpoints was observed in EMERGE, but not in ENGAGE.


Asunto(s)
Enfermedad de Alzheimer , Anticuerpos Monoclonales Humanizados , Humanos , Enfermedad de Alzheimer/tratamiento farmacológico , Anticuerpos Monoclonales Humanizados/uso terapéutico , Anticuerpos Monoclonales Humanizados/farmacocinética , Anciano , Masculino , Femenino , Método Doble Ciego , Japón , Anciano de 80 o más Años , Persona de Mediana Edad , Disfunción Cognitiva/tratamiento farmacológico , Biomarcadores/sangre , Péptidos beta-Amiloides/metabolismo , Pueblos del Este de Asia
2.
Pharmazie ; 77(5): 162-164, 2022 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-35655379

RESUMEN

Vincristine (VCR) is an important drug used in R-CHOP regimens for the treatment of non-Hodgkin's lymphoma. The purpose of this study was to examine whether the administration method affects the incidence of VCR-induced peripheral neuropathy. We investigated the ratio of VCR-induced peripheral neuropathy during rapid intravenous infusion and intravenous drip infusion. A total of 71 patients who had received six or more courses of R-CHOP from January, 2015 to December, 2016 at Komaki City Hospital and Ogaki Municipal Hospital were retrospectively investigated. Peripheral neuropathy was observed in 27/39 patients (69 %) and 24/32 (75 %) in rapid intravenous infusion and intravenous drip infusion of VCR, respectively (P = 0.79). Peripheral neuropathy was observed at a high frequency in this study. Additionally, there was no difference in frequency of peripheral neuropathy due to the difference in administration method. In both groups, the degree of peripheral neuropathy was grade 1 and grade 2 in most patients. However, in rapid intravenous infusion, grade 3 peripheral neuropathy was observed. Some cases required dose reduction and discontinuation in rapid intravenous infusion. In contrast, there were no discontinuing patients in the intravenous drip infusion. Therefore, it was suggested that intravenous drip infusion of VCR reduced serious peripheral neuropathy because the ratio requiring dose reduction and discontinuation was less than that in the rapid group. In conclusion, this study is informative as there are few reports focusing on the administration method of vincristine.


Asunto(s)
Linfoma no Hodgkin , Enfermedades del Sistema Nervioso Periférico , Doxorrubicina/efectos adversos , Humanos , Infusiones Intravenosas , Linfoma no Hodgkin/tratamiento farmacológico , Enfermedades del Sistema Nervioso Periférico/inducido químicamente , Enfermedades del Sistema Nervioso Periférico/tratamiento farmacológico , Enfermedades del Sistema Nervioso Periférico/patología , Estudios Retrospectivos , Vincristina/efectos adversos
3.
Pharmazie ; 76(5): 239-242, 2021 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-33964999

RESUMEN

We retrospectively evaluated the incidence of skin immune-related adverse effects (irAEs) in patients treated with pembrolizumab (PMB) and explored and the relationship between skin irAEs and PMB efficacy. Thirty-two patients with non-small cell lung cancer treated with PMB between April 2017 and May 2018 were enrolled. The patients were separated into two groups, namely, skin irAEs and no-skin irAEs group. We investigated the ratio and degree of express skin irAEs, period of skin irAEs and treatment, and the PFS between the two groups. Additionally, we evaluated the PFS between the irAE and no-irAEs groups. The median patient age was 76.5 (range 56-92) years. The European Cooperative Oncology Group Performance Status (ECOG PS) score of 26, 5, and 1 was 0-1, 2, and 3, respectively. The male/female ratio was 23/9. In terms of clinical stages, 6, 21, and 5 patients were in stages III and IV, and postoperative relapse, respectively. Skin irAEs were observed in 10 patients (31%). The progression-free survival of patients with skin irAEs (median, 390 days) was longer than that of patients without skin irAEs (median, 128.5 days). Overall, we suggested a significant association between skin irAEs and the efficacy of PMB in treating non-small cell lung cancer. As skin irAEs can be an indicator of treatment efficacy, it is important for medical staff, including pharmacists, to closely observe these adverse events.


Asunto(s)
Anticuerpos Monoclonales Humanizados/efectos adversos , Anticuerpos Monoclonales Humanizados/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/inmunología , Anomalías Cutáneas/etiología , Anciano , Anciano de 80 o más Años , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Piel/inmunología , Resultado del Tratamiento
4.
Anticancer Res ; 40(11): 6221-6228, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33109559

RESUMEN

BACKGROUND/AIM: Malignant peripheral nerve sheath tumor (MPNST) is a rare soft-tissue tumor, and its diagnosis is usually made histopathologically. The effectiveness of chemotherapy and radiotherapy has not been established. We elucidated prognostic factors, diagnostic markers, and therapeutic targets. MATERIALS AND METHODS: Cases of MPNST were studied using next-generation sequencing. A total of 24 tumor samples, 11 from von Recklinghausen's disease-associated MPNST (vRH-MPNST), 11 from sporadic non-vRH MPNST, and two neurofibroma (NF) cases were retrieved, on which next-generation sequencing and survival analysis were performed. RESULTS: We identified NF1 gene mutations, including three mutations in two NFs, and 10 mutations in eight MPNSTs (five vRH-MPNSTs and three sporadic MPNSTs). Meningioma 1 (MN1) gene alteration was detected in six cases of vRH-MPNST. It is considered that MN1 gene alteration is related to the tumorigenesis of vRH-MPNST. CONCLUSION: MN1 gene mutation was detected in more than half of our cases, it may have potential for use as a therapeutic target in vRH-MPNST.


Asunto(s)
Mutación/genética , Neoplasias de la Vaina del Nervio/genética , Neoplasias de la Vaina del Nervio/patología , Transactivadores/genética , Proteínas Supresoras de Tumor/genética , Apoptosis/genética , Genes de Neurofibromatosis 1 , Humanos , Neurofibroma/genética , Neurofibromatosis 1/genética , Proteínas Proto-Oncogénicas c-bcl-2/genética , Análisis de Supervivencia
5.
Pharmazie ; 74(5): 305-309, 2019 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-31109402

RESUMEN

The main objective of this study is to conduct a disproportionality analysis of adverse events in the Japan Adverse Event Report (JADER) database and evaluate the risk of the DPP-4 inhibitor induced autoimmune disorder, the secondary objective is risk assessment of sex difference and age difference. The proportional reporting ratio (PRR) of frequency-based statistics and Bayesian estimates of the information components (IC) were calculated as a measure of signal detection. Sex difference and age difference were evaluated using signal score calculated from the PRR and the Chi-square. In patients taking DPP-4 inhibitors, 94 reports of autoimmune disorders were detected with both signals; PRR: 4.09, chi-square: 158.26 and IC: 1.66, 95 % confidence interval: 1.32-2.00). For other antidiabetic drugs, no signals were detected. The signal of males was PRR: 4.53, chi-square: 110.91 and signal score: 6.22, the signal of female was PRR: 3.53, chi-square: 47.65 and signal score: 5.12. About age difference, the signal scores were 6.71 for patients over 60 years and 0.56 for patients under 60 years old. This study suggests that the DPP-4 inhibitors, unlike other antidiabetic drugs, were associated with autoimmune disorders. Signals of the DPP-4 inhibitors induced autoimmune disorders were detected in both male and female, but no sex difference was observed, but age difference was observed. Especially attention should be paid to patients over 60 years old.


Asunto(s)
Enfermedades Autoinmunes/inducido químicamente , Inhibidores de la Dipeptidil-Peptidasa IV/efectos adversos , Adulto , Sistemas de Registro de Reacción Adversa a Medicamentos/estadística & datos numéricos , Factores de Edad , Anciano , Anciano de 80 o más Años , Enfermedades Autoinmunes/enzimología , Enfermedades Autoinmunes/epidemiología , Minería de Datos , Inhibidores de la Dipeptidil-Peptidasa IV/administración & dosificación , Humanos , Japón/epidemiología , Persona de Mediana Edad , Factores Sexuales
6.
Skin Res Technol ; 24(4): 630-635, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-29707828

RESUMEN

BACKGROUND: The intradermal (ID) route for vaccination represents an effective alternative to subcutaneous (SC)/intramuscular administration to induce protective immunity. However, a critical issue associated with ID vaccination is the precise delivery of solution in the upper dermis, which ensures enhanced immunity. METHODS: We fabricated a hollow microneedle unit made of poly-glycolic acid by injection molding and bonding, and created a dedicated prototype injector. To ensure ID delivery of solution, the injected site was macroscopically and microscopically examined. Serum immunoglobulin G antibody production was measured by enzyme immunoassay and compared in groups of rats following either ID delivery with microneedles or SC administration with a 27-G stainless needle of graded vaccine doses. RESULTS: The unit used a tandem array of six microneedles, each with a side delivery hole, and a conduit inside for solution. Microneedles installed in the injector punctured the skin with the aid of a spring. Injection of solution formed a wheal due to ID distribution. Histologically, a wedge-shaped skin defect in the upper skin corresponded to each puncture site. Antibody titers following vaccinations on days 1 and 8 were significantly higher with ID injection than with SC delivery on day 15 and every 7 days thereafter until day 36 with mumps vaccination, and until day 36 with varicella vaccination. CONCLUSIONS: The microneedle unit presented here delivered solution intradermally without any difficulty and evoked antibody responses against viruses even with the reduced vaccine volume. Our findings confirm promising results of ID delivery as an immunogenic option to enhance vaccination efficacy.


Asunto(s)
Vacuna contra la Varicela/inmunología , Inyecciones Intradérmicas/instrumentación , Vacuna contra la Parotiditis/inmunología , Agujas , Vacunación/instrumentación , Animales , Anticuerpos Antivirales/sangre , Vacuna contra la Varicela/administración & dosificación , Diseño de Equipo , Inmunoglobulina G/sangre , Inyecciones Subcutáneas , Masculino , Modelos Animales , Vacuna contra la Parotiditis/administración & dosificación , Ácido Poliglicólico , Ratas , Ratas Sprague-Dawley
7.
Nat Commun ; 6: 6958, 2015 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-25891310

RESUMEN

A 'pseudogap' was introduced by Mott to describe a state of matter that has a minimum in the density of states at the Fermi level, deep enough for states to become localized. It can arise either from Coulomb repulsion between electrons, and/or incipient charge or spin order. Here we employ ultrafast spectroscopy to study dynamical properties of the normal to pseudogap state transition in the prototype high-temperature superconductor Bi2Sr2CaCu2O8+δ. We perform a systematic temperature and doping dependence study of the pseudogap photodestruction and recovery in coherent quench experiments, revealing marked absence of critical behaviour of the elementary excitations, which implies an absence of collective electronic ordering beyond a few coherence lengths on short timescales. The data imply ultrafast carrier localization into a textured polaronic state arising from a competing Coulomb interaction and lattice strain, enhanced by a Fermi surface instability.

8.
Sci Rep ; 4: 5656, 2014 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-25014162

RESUMEN

In classical superconductors an energy gap and phase coherence appear simultaneously with pairing at the transition to the superconducting state. In high-temperature superconductors, the possibility that pairing and phase coherence are distinct and independent processes has led to intense experimental search of their separate manifestations. Using femtosecond spectroscopy methods we now show that it is possible to clearly separate fluctuation dynamics of the superconducting pairing amplitude from the phase relaxation above the critical transition temperature. Empirically establishing a close correspondence between the superfluid density measured by THz spectroscopy and superconducting optical pump-probe response over a wide region of temperature, we find that in differently doped Bi(2)Sr(2)CaCu(2)O(8+δ) crystals the pairing gap amplitude monotonically extends well beyond Tc, while the phase coherence shows a pronounced power-law divergence as T → T(c), thus showing that phase coherence and gap formation are distinct processes which occur on different timescales.

9.
Oncogene ; 32(7): 894-902, 2013 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-22450745

RESUMEN

The small GTPase Ral is known to be highly activated in several human cancers, such as bladder, colon and pancreas cancers. It is reported that activated Ral is involved in cell proliferation, migration and metastasis of bladder cancer. This protein is activated by Ral guanine nucleotide exchange factors (RalGEFs) and inactivated by Ral GTPase-activating proteins (RalGAPs), the latter of which consist of heterodimers containing a catalytic α1 or α2 subunit and a common ß subunit. In Ras-driven cancers, such as pancreas and colon cancers, constitutively active Ras mutant activates Ral through interaction with RalGEFs, which contain the Ras association domain. However, little is known with regard to the mechanism that governs aberrant activation of Ral in bladder cancer, in which Ras mutations are relatively infrequent. Here, we show that Ral was highly activated in invasive bladder cancer cells due to reduced expression of RalGAPα2, the dominant catalytic subunit in bladder, rather than increased expression of RalGEFs. Exogenous expression of wild-type RalGAPα2 in KU7 bladder cancer cells with invasive phenotype, but not mutant RalGAPα2-N1742K lacking RalGAP activity, resulted in attenuated cell migration in vitro and lung metastasis in vivo. Furthermore, genetic ablation of Ralgapa2 promoted tumor invasion in a chemically-induced murine bladder cancer model. Importantly, immunohistochemical analysis of human bladder cancer specimens revealed that lower expression of RalGAPα2 was associated with advanced clinical stage and poor survival of patients. Collectively, these results are highly indicative that attenuated expression of RalGAPα2 leads to disease progression of bladder cancer through enhancement of Ral activity.


Asunto(s)
Carcinoma/genética , Carcinoma/patología , Proteínas Activadoras de GTPasa/genética , Neoplasias de la Vejiga Urinaria/genética , Neoplasias de la Vejiga Urinaria/patología , Adulto , Anciano , Anciano de 80 o más Años , Animales , Línea Celular Tumoral , Progresión de la Enfermedad , Regulación hacia Abajo/efectos de los fármacos , Femenino , Proteínas Activadoras de GTPasa/antagonistas & inhibidores , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/fisiología , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Persona de Mediana Edad , Invasividad Neoplásica , Metástasis de la Neoplasia , Ensayos Antitumor por Modelo de Xenoinjerto
10.
Oncogene ; 31(25): 3098-110, 2012 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-22020339

RESUMEN

Inactivation of the von Hippel-Lindau (VHL) tumor-suppressor gene causes both hereditary and sporadic clear-cell renal-cell carcinoma (ccRCC). Although the best-characterized function of the VHL protein (pVHL) is regulation of hypoxia-inducible factor-α (HIFα), pVHL also controls the development of pheochromocytoma through HIF-independent pathways by regulating JunB. However, it is largely unknown how these pathways contribute to the development and progression of ccRCC. In the present study, we confirmed that JunB was upregulated in VHL-defective ccRCC specimens by immunostaining. Short-hairpin RNA (shRNA)-mediated knockdown of JunB in 786-O and A498 VHL null ccRCC cells suppressed their invasiveness. In addition, JunB knockdown significantly repressed tumor growth and microvessel density in xenograft tumor assays. Conversely, forced expression of wild-type, but not dimerization-defective, JunB in a VHL-restored 786-O subclone promoted invasion in vitro and tumor growth and vessel formation in vivo. Quantitative PCR array analysis revealed that JunB regulated multiple genes relating to tumor invasion and angiogenesis such as matrix metalloproteinase-2 (MMP-2), MMP-9 and chemokine (C-C motif) ligand-2 (CCL2) in 786-O cells. JunB knockdown in these cells reduced the proteolytic activity of both MMPs in gelatin zymography and the amount of CCL2 in the culture supernatant. Moreover, shRNA-mediated knockdown of MMP-2 or inhibition of CCL2 activity with a neutralizing antibody repressed xenograft tumor growth and angiogenesis. Collectively, these results suggest that JunB promotes tumor invasiveness and enhances angiogenesis in VHL-defective ccRCCs.


Asunto(s)
Carcinoma de Células Renales/metabolismo , Neoplasias Renales/metabolismo , Neovascularización Patológica/metabolismo , Proteínas Proto-Oncogénicas c-jun/metabolismo , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/metabolismo , Animales , Carcinoma de Células Renales/irrigación sanguínea , Carcinoma de Células Renales/patología , Humanos , Neoplasias Renales/irrigación sanguínea , Neoplasias Renales/patología , Ratones , Invasividad Neoplásica , Trasplante de Neoplasias , Proteínas Proto-Oncogénicas c-jun/genética , Trasplante Heterólogo
11.
Phys Rev Lett ; 107(22): 227002, 2011 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-22182038

RESUMEN

We investigate the relaxation dynamics of nonequilibrium carriers in organic conductors κ-(BEDT-TTF)(2)Cu[N(CN)(2)]X (X=Br and Cl) using ultrafast time-resolved optical spectroscopy. The dynamics for both salts show similar temperature dependences, which is well characterized by the carrier relaxation across the pseudogap (PG) of the magnitude Δ(PG) ≈ 16 meV for Br salt and 7.0 meV for Cl salt. On the other hand, only the Br salt shows an abrupt increase of the decay time at low temperature, indicating an additional decay component associated with the superconducting (SC) gap below T(c). The fluence dependent dynamics at low temperature evidences the superposition of the SC component onto the PG component. These results indicate a metallic-insulating phase separation in the Br salt triggered by photoexcited nonequilibrium carriers.

12.
Neuropediatrics ; 42(6): 215-21, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22131192

RESUMEN

Since the neuroradiological features of patients with 22q11.2 deletion syndrome are not well-understood, examinations using functional imaging were performed in this study. Brain magnetic resonance imaging (MRI) and 1H-magnetic resonance spectroscopy (MRS) were performed using a clinical 3-Tesla MR imager in 4 patients with 22q11.2 deletion syndrome (2 boys and 2 girls; aged 2-6 years.) and 20 age- and sex-matched healthy control subjects. Furthermore, interictal 123I-iomazenil (IMZ) single photon emission computed tomography (SPECT) was examined in 2 of the 4 patients. Among the 4 patients with 22q11.2 deletion syndrome, 2 patients showed polymicrogyria and 1 patient showed agyria. Those patients with brain malformations also showed abnormal brain artery patterns and decreased accumulation of IMZ in 123I-IMZ SPECT. Although all 4 patients showed epileptic discharges in their electroencephalograms (EEG), one patient with polymicrogyria had no seizure episodes. Decreases in γ-aminobutyric acid (GABA) corresponding to the areas of polymicrogyria and/or epileptic discharges in EEG were shown in all patients except for the patient with agyria. Although consistent evidence was not seen in patients with 22q11.2 deletion syndrome in this study, brain malformations and disturbances of the GABAergic nervous system would be underlying mechanisms of the neurodevelopmental abnormalities in this syndrome.


Asunto(s)
Síndrome de DiGeorge/patología , Síndrome de DiGeorge/fisiopatología , Epilepsia/complicaciones , Estudios de Casos y Controles , Niño , Preescolar , Síndrome de DiGeorge/complicaciones , Síndrome de DiGeorge/diagnóstico por imagen , Electroencefalografía , Femenino , Flumazenil/análogos & derivados , Humanos , Hidrógeno , Imagen por Resonancia Magnética , Espectroscopía de Resonancia Magnética , Masculino , Malformaciones del Desarrollo Cortical/diagnóstico por imagen , Radiografía , Tomografía Computarizada de Emisión de Fotón Único , Ácido gamma-Aminobutírico/metabolismo
13.
Opt Express ; 18(17): 17796-804, 2010 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-20721167

RESUMEN

We study the dynamics of a paired optical vortex (OV) generated by second-harmonic generation (SHG) using sub-picosecond pulses. By changing the position of a thin nonlinear crystal along the propagation direction, we observe a rotation of two vortices with changing separation distance. The dynamics is well explained by SHG with a beam walk-off, which introduces a contamination of zero-order Laguerre-Gaussian beam (LG(0)) together with topological charge doubling. The quantitative analysis indicates that the rotation angle of the OVs manifests the Gouy phase while the splitting provides the walk-off angle of the crystal. We also show that the subtraction of LG(0) is realized by the superposition of LG(0) with an anti-balanced phase in the pump.


Asunto(s)
Bario/química , Boratos/química , Cristalografía/métodos , Óptica y Fotónica/métodos , Modelos Teóricos , Dinámicas no Lineales
14.
J Phys Condens Matter ; 22(18): 185701, 2010 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-21393688

RESUMEN

In order to compare the carrier dynamics and reveal the origin of differences in their electrical behaviour, time-resolved reflectivity changes were measured on single crystals of the title compounds. The observed relaxation behaviour explained well their electrical behaviour, and indicated that different conduction mechanisms dominated κ- and λ-type BETS salts, irrespective of local spins, at about 8-100 K; the electrical behaviour of the κ-type salts is governed by relaxation times of carriers and/or density of states at the Fermi levels, while that of the λ-type salts is dominated by the latter.

15.
Phys Rev Lett ; 105(17): 176401, 2010 Oct 22.
Artículo en Inglés | MEDLINE | ID: mdl-21231061

RESUMEN

We discovered the chirality of charge-density waves (CDW) in 1T-TiSe2 by using STM and time-domain optical polarimetry. We found that the CDW intensity becomes Ia1∶Ia2∶Ia3 = 1∶0.7 ± 0.1∶0.5 ± 0.1, where Ia(i) (i=1,2,3) is the amplitude of the tunneling current contributed by the CDWs. There were two states, in which the three intensity peaks of the CDW decrease clockwise and anticlockwise. The chirality in CDW results in the threefold symmetry breaking. Macroscopically, twofold symmetry was indeed observed in optical measurement. We propose the new generalized CDW chirality H(CDW) ≡ q1·(q2×q3), where q(i) are the CDW q vectors, which is independent of the symmetry of components. The nonzero H(CDW)-the triple-q vectors do not exist in an identical plane in the reciprocal space-should induce a real-space chirality in CDW system.

16.
Opt Express ; 17(22): 20567-74, 2009 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-19997285

RESUMEN

We demonstrate the coherent transfer of optical orbital angular momentum (OAM) to the center of mass momentum of excitons in semiconductor GaN using a four-wave mixing (FWM) process. When we apply the optical vortex (OV) as an excitation pulse, the diffracted FWM signal exhibits phase singularities that satisfy the OAM conservation law, which remain clear within the exciton dephasing time (approximately 1ps). We also demonstrate the arbitrary control of the topological charge in the output signal by changing the OAM of the input pulse. The results provide a way of controlling the optical OAM through carriers in solids. Moreover, the time evolution of the FWM with OAM leads to the study of the closed-loop carrier coherence in materials.


Asunto(s)
Galio/química , Modelos Químicos , Simulación por Computador , Luz , Dispersión de Radiación
17.
Acta Biomater ; 5(8): 3157-64, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19435618

RESUMEN

Ag(+) and Zn(2+) or Cu(2+) ions were co-doped with beta-tricalcium phosphate (AgZn-TCP and AgCu-TCP), and their substitution models, antimicrobial activities, mechanisms and cytotoxicities were investigated. The lattice constants (a-axis and c-axis) of AgZn-TCP and AgCu-TCP decreased linearly with the amount of Zn(2+) or Cu(2+) ions up to 9.09 mol.%, which indicated that Ag(+) ions were doped at the Ca(4) site and a vacancy in the beta-TCP structure, and Zn(2+) or Cu(2+) ions were doped at the Ca(5) site. Antibacterial activities of AgZn-TCP and AgCu-TCP on Escherichia coli and Staphylococcus aureus were higher than those of Ag(+) ions-doped beta-TCP (Ag-TCP) and pure beta-TCP. These antimicrobial activities suggested that an interaction occurred between bacteria and Ag(+), Zn(2+) and Cu(2+) ions eluted from AgZn-TCP and AgCu-TCP and between bacteria and the free radicals generated by antibacterial agents or in bacterial cells. AgZn-TCP and AgCu-TCP can be used over long periods of time with high antimicrobial activity, because the rate at which Ag(+) ions are released from AgZn-TCP and AgCu-TCP is slower than that at which Ag(+) ions are released from Ag-TCP. However, it is necessary to determine the suitable amounts of Ag(+), Zn(2+) and Cu(2+) ions in AgZn-TCP and AgCu-TCP by considering both their antimicrobial activities and cytotoxicities, because beta-TCP doped with a large amount of these metal ions exhibits cytotoxicity. Furthermore, AgZn-TCP and AgCu-TCP are considered to be promising materials for use in various fields.


Asunto(s)
Antibacterianos/farmacología , Fenómenos Fisiológicos Bacterianos/efectos de los fármacos , Sustitutos de Huesos/química , Sustitutos de Huesos/farmacología , Fosfatos de Calcio/química , Metales/química , Metales/farmacología , Antibacterianos/química , Fosfatos de Calcio/farmacología , Supervivencia Celular/efectos de los fármacos , Iones , Ensayo de Materiales , Propiedades de Superficie
18.
J Phys Condens Matter ; 21(15): 156001, 2009 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-21825376

RESUMEN

We report magnetization, heat capacity and electrical resistivity measurements on CePtZn, which crystallizes in the orthorhombic TiNiSi type structure. Magnetization and electrical resistivity on the iso-structural series of compounds Ce(1-x)La(x)PtZn (x = 0.1, 0.2 0.5 and 1) were also carried out. The electrical resistivity of CePtZn was also measured in external magnetic fields up to 12 T and under pressures up to 2.66 GPa. We find that CePtZn is a dense Kondo lattice, ordering antiferromagnetically at T(N) = 1.7 K, with a comparable Kondo temperature. The magnetic transition temperature, T(N), is continuously suppressed both by the magnetic field and pressure and [Formula: see text] around 5-6 T and at 1.2 GPa, respectively. Non-Fermi liquid behavior of resistivity at 4 T and 1.2 GPa and logarithmic divergence of the heat capacity, C(4f)/T, at 6 T in a limited temperature region strongly suggest the emergence of a quantum critical point as [Formula: see text].

19.
Phys Rev Lett ; 101(13): 137003, 2008 Sep 26.
Artículo en Inglés | MEDLINE | ID: mdl-18851484

RESUMEN

We report the ultrafast optical response of quasiparticles (QPs) in both the pseudogap (PG) and superconducting (SC) states of an underdoped Bi2Sr2CaCu2O8 + y (Bi2212) single crystal measured with the time-resolved pump-probe technique. At a probe energy variant planck's over omegapr = 1.55 eV, it is found that the reflectivity change DeltaR/R changes its sign at exactly Tc, which allows the direct separation of the charge dynamics of PG and SC QPs. Further systematic investigations indicate that the transient signals associated with PG and SC QPs depend on the probe beam energy and polarization. By tuning them below Tc, two distinct components can be detected simultaneously, providing evidence for the coexistence of PG and SC QPs.

20.
Int J Artif Organs ; 31(4): 309-16, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18432586

RESUMEN

OBJECTIVE: To study the nature of the association between glycemia and ICU mortality in pediatric cardiac surgery patients treated with peritoneal dialysis (PD). MATERIALS AND METHODS: Retrospective observational study in the ICU of a tertiary hospital involving forty pediatric cardiac surgery patients treated with PD. We selected patients requiring PD, extracted glucose measurements and nutritional intake data during ICU stay and calculated mean and maximum blood glucose values i) during ICU stay; ii) during dependence on PD; and iii) during independence from PD. We statistically assessed the relationship between glycemia-related variables and ICU mortality. MEASUREMENTS AND RESULTS: Twenty-two patients treated with PD died (mortality 55%). In the PD cohort, 9725 blood glucose measurements were performed (every 3.3 hours on average). The mean glycemia during dependence on PD was significantly higher in non-survivors than survivors (p<0.0001), but not during independence from PD (p=0.49). The area under the receiver operator characteristic curve for the mean glycemia during dependence on PD was significantly greater than that obtained during independence from PD. Even after adjustment for severity of illness using multivariate logistic analysis, the mean glycemia and calorie intake during PD were significant and independent predictors of ICU mortality. CONCLUSIONS: A higher mean blood glucose concentration during PD, but not during PD-free periods was associated with greater ICU mortality. Mean glycemia and calorie intake during PD were significant and independent predictors of ICU mortality.


Asunto(s)
Glucemia/metabolismo , Procedimientos Quirúrgicos Cardíacos/mortalidad , Ingestión de Energía , Hiperglucemia/mortalidad , Diálisis Peritoneal/mortalidad , Procedimientos Quirúrgicos Cardíacos/efectos adversos , Femenino , Mortalidad Hospitalaria , Humanos , Hiperglucemia/etiología , Hiperglucemia/metabolismo , Lactante , Recién Nacido , Unidades de Cuidado Intensivo Pediátrico/estadística & datos numéricos , Modelos Logísticos , Masculino , Diálisis Peritoneal/efectos adversos , Curva ROC , Estudios Retrospectivos , Medición de Riesgo , Resultado del Tratamiento
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