RESUMEN
BACKGROUND AND PURPOSE: Tapering immunosuppressants is desirable in patients with well-controlled myasthenia gravis (MG). However, the association between tapering of calcineurin inhibitor dosage and reduction-associated exacerbation is not known. The aim of this study was to clarify the frequency of reduction-associated exacerbation when tacrolimus is tapered in stable patients with anti-acetylcholine receptor antibody-positive MG, and to determine the factors that predict exacerbations. METHODS: We retrospectively analyzed 115 patients in whom tacrolimus dosage was tapered. The reduction-associated exacerbation was defined as the appearance or worsening of one or more MG symptoms <3 months after the reduction. RESULTS: Tacrolimus dosage was successfully tapered in 110 patients (96%) without any exacerbation. Five patients (4%) experienced an exacerbation, but symptoms were reversed in all patients when the tacrolimus dose was increased to the previous maintenance level. No patient developed an MG crisis. The age at onset was significantly earlier (30 vs. 56 years, P = 0.025) and the reduction in dosage was significantly larger (2.0 vs. 1.0 mg/day, P = 0.002) in patients with reduction-associated exacerbation than in those without exacerbation. The cut-off values determined in a receiver-operating characteristic curve analysis were 52 years (sensitivity, 57%; specificity, 100%) for the age at onset and 1.5 mg (sensitivity, 80%; specificity, 100%) for the dose reduction. CONCLUSION: Tapering of tacrolimus was possible in most patients with well-controlled anti-acetylcholine receptor antibody-positive MG. Early age at onset and a large reduction from maintenance dosage were associated with exacerbation. Reductions ≤1.5 mg/day from the maintenance dosage should be considered for patients with late-onset disease.
Asunto(s)
Inmunosupresores/administración & dosificación , Inmunosupresores/uso terapéutico , Miastenia Gravis/tratamiento farmacológico , Miastenia Gravis/inmunología , Receptores Colinérgicos/inmunología , Tacrolimus/administración & dosificación , Tacrolimus/uso terapéutico , Adulto , Edad de Inicio , Anticuerpos/análisis , Reducción Gradual de Medicamentos , Femenino , Humanos , Inmunosupresores/efectos adversos , Masculino , Persona de Mediana Edad , Curva ROC , Estudios Retrospectivos , Sensibilidad y Especificidad , Tacrolimus/efectos adversosRESUMEN
Pottery was a hunter-gatherer innovation that first emerged in East Asia between 20,000 and 12,000 calibrated years before present (cal bp), towards the end of the Late Pleistocene epoch, a period of time when humans were adjusting to changing climates and new environments. Ceramic container technologies were one of a range of late glacial adaptations that were pivotal to structuring subsequent cultural trajectories in different regions of the world, but the reasons for their emergence and widespread uptake are poorly understood. The first ceramic containers must have provided prehistoric hunter-gatherers with attractive new strategies for processing and consuming foodstuffs, but virtually nothing is known of how early pots were used. Here we report the chemical analysis of food residues associated with Late Pleistocene pottery, focusing on one of the best-studied prehistoric ceramic sequences in the world, the Japanese Jomon. We demonstrate that lipids can be recovered reliably from charred surface deposits adhering to pottery dating from about 15,000 to 11,800 cal bp (the Incipient Jomon period), the oldest pottery so far investigated, and that in most cases these organic compounds are unequivocally derived from processing freshwater and marine organisms. Stable isotope data support the lipid evidence and suggest that most of the 101 charred deposits analysed, from across the major islands of Japan, were derived from high-trophic-level aquatic food. Productive aquatic ecotones were heavily exploited by late glacial foragers, perhaps providing an initial impetus for investment in ceramic container technology, and paving the way for further intensification of pottery use by hunter-gatherers in the early Holocene epoch. Now that we have shown that it is possible to analyse organic residues from some of the world's earliest ceramic vessels, the subsequent development of this critical technology can be clarified through further widespread testing of hunter-gatherer pottery from later periods.
Asunto(s)
Cerámica/historia , Culinaria/historia , Animales , Organismos Acuáticos/química , Organismos Acuáticos/aislamiento & purificación , Arqueología , Grasas de la Dieta/análisis , Cromatografía de Gases y Espectrometría de Masas , Groenlandia , Historia Antigua , Japón , Lípidos/análisis , Lípidos/química , Isótopos de Oxígeno , Alimentos Marinos/análisis , Alimentos Marinos/historiaRESUMEN
BACKGROUND: Giant cell tumor of bone (GCTB) is a rare primary bone tumor, characterized by osteoclast-like giant cells that express receptor activator of nuclear factor-kappa B (RANK), and stromal cells that express RANK ligand (RANKL), a key mediator of osteoclast activation. A RANKL-specific inhibitor, denosumab, was predicted to reduce osteolysis and control disease progression in patients with GCTB. PATIENTS AND METHODS: Seventeen patients with GCTB were enrolled. Patients were treated with denosumab at 120 mg every 4 weeks, with a loading dose of 120 mg on days 8 and 15. To evaluate efficacy, objective tumor response was evaluated prospectively by an independent imaging facility on the basis of prespecified criteria. RESULTS: The proportion of patients with an objective tumor response was 88% based on best response using any tumor response criteria. The proportion of patients with an objective tumor response using individual response criteria was 35% based on the modified Response Evaluation Criteria in Solid Tumors (RECIST) criteria, 82% based on the modified European Organization for Research and Treatment of Cancer (EORTC) criteria, and 71% based on inverse Choi criteria. The median time of study treatment was 13.1 months. CONCLUSION: The findings demonstrate that denosumab has robust clinical efficacy in the treatment of GCTB.
Asunto(s)
Conservadores de la Densidad Ósea/uso terapéutico , Neoplasias Óseas/tratamiento farmacológico , Denosumab/uso terapéutico , Tumor Óseo de Células Gigantes/tratamiento farmacológico , Recurrencia Local de Neoplasia/tratamiento farmacológico , Adolescente , Adulto , Anciano , Neoplasias Óseas/patología , Femenino , Estudios de Seguimiento , Tumor Óseo de Células Gigantes/patología , Humanos , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/patología , Estadificación de Neoplasias , Pronóstico , Estudios Prospectivos , Adulto JovenRESUMEN
BACKGROUND: Recent studies have suggested the potential benefits of habitual coffee and green tea consumption on skeletal muscle health. However, it remains unclear whether these benefits are modified by genetic factors, particularly the alpha-actinin-3 (ACTN3) genotype, which is associated with the skeletal muscle phenotype. This study aimed to investigate the interaction between habitual coffee or green tea consumption and the ACTN3 genotype in association with skeletal muscle mass (SMM) and strength. METHODS: This cross-sectional study was conducted on 1,023 Japanese middle-aged and older adults (619 females, aged 45-74 years) living in the community. SMM was gauged using a bioelectrical impedance spectroscopy device, and handgrip strength (HGS) was used to measure muscle strength. The ACTN3 genotype (RR, RX, and XX) was determined from blood samples. Sex-specific linear regression models were used to analyze the interactions between coffee or green tea consumption and the ACTN3 genotype in association with SMM and HGS. RESULTS: In females, a significant interaction was observed between green tea consumption and the ACTN3 genotype in association with HGS (P interaction < 0.05). Furthermore, stratified analysis revealed a positive association between green tea consumption and HGS, specifically in females with the ACTN3 XX genotype (P trend < 0.05). In males, no significant interactions were observed between coffee or green tea consumption and the ACTN3 genotype in association with SMM or HGS (P interaction > 0.05). CONCLUSION: Our findings suggest that the skeletal muscle strength benefits associated with habitual green tea consumption may be contingent upon sex and the ACTN3 genotype.
Asunto(s)
Actinina , Café , Genotipo , Fuerza de la Mano , Músculo Esquelético , Té , Humanos , Femenino , Masculino , Actinina/genética , Persona de Mediana Edad , Anciano , Estudios Transversales , Músculo Esquelético/fisiología , Fuerza de la Mano/fisiología , Japón , Fuerza MuscularRESUMEN
BACKGROUND: Hyaluronan (HA) plays crucial roles in the tumourigenicity of many types of malignant tumours. 4-Methylumbelliferone (MU) is an inhibitor of HA synthesis. Several studies have shown its inhibitory effects on malignant tumours; however, none have focused on its effects on osteosarcoma. METHODS: We investigated the effects of MU on HA accumulation and tumourigenicity of highly metastatic murine osteosarcoma cells (LM8) that have HA-rich cell-associated matrix, and human osteosarcoma cell lines (MG-63 and HOS). RESULTS: In vitro, MU inhibited HA retention, thereby reducing the formation of functional cell-associated matrices, and also inhibited cell proliferation, migration, and invasion. Akt phosphorylation was suppressed by MU (1.0 mM). In vivo, although MU showed only a mild inhibitory effect on the growth of the primary tumour, it markedly inhibited (75% reduction) the development of lung metastasis. Hyaluronan retention in the periphery of the primary tumour was markedly suppressed by MU. CONCLUSION: These findings suggested that MU suppressed HA retention and cell-associated matrix formation in osteosarcoma cells, resulting in a reduction of tumourigenicity, including lung metastasis. 4-Methylumbelliferone is a promising therapeutic agent targeting both primary tumours and distant metastasis of osteosarcoma, possibly via suppression of HA retention.
Asunto(s)
Ácido Hialurónico/metabolismo , Himecromona/análogos & derivados , Neoplasias Pulmonares/secundario , Osteosarcoma/patología , Apoptosis/efectos de los fármacos , Ciclo Celular , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Humanos , Ácido Hialurónico/antagonistas & inhibidores , Himecromona/farmacología , Inmunohistoquímica , Etiquetado Corte-Fin in Situ , Técnicas In Vitro , Neoplasias Pulmonares/metabolismo , Osteosarcoma/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/metabolismo , Reacción en Cadena en Tiempo Real de la PolimerasaRESUMEN
We experimentally investigate the mix-dimensional scattering occurring when the collisional partners live in different dimensions. We employ a binary mixture of ultracold atoms and exploit a species-selective 1D optical lattice to confine only one atomic species in 2D. By applying an external magnetic field in proximity of a Feshbach resonance, we adjust the free-space scattering length to observe a series of resonances in mixed dimensions. By monitoring 3-body inelastic losses, we measure the magnetic field values corresponding to the mix-dimensional scattering resonances and find a good agreement with the theoretical predictions based on simple energy considerations.
RESUMEN
AIM: To obtain a better understanding of the changes in feeding behaviour from 1 to 6 months of age. By comparing breast- and bottle-feeding, we intended to clarify the difference in longitudinal sucking performance. METHODS: Sucking variables were consecutively measured for 16 breast-fed and eight bottle-fed infants at 1, 3 and 6 months of age. RESULTS: For breast-feeding, number of sucks per burst (17.8 +/- 8.8, 23.8 +/- 8.3 and 32.4 +/- 15.3 times), sucking burst duration (11.2 +/- 6.1, 14.7 +/- 8.0 and 17.9 +/- 8.8 sec) and number of sucking bursts per feed (33.9 +/- 13.9, 28.0 +/- 18.2 and 18.6 +/- 12.8 times) at 1, 3 and 6 months of age respectively showed significant differences between 1 and 6 months of age (p < 0.05). The sucking pressure and total number of sucks per feed did not differ among different ages. Bottle-feeding resulted in longer sucking bursts and more sucks per burst compared with breast-feeding in each month (p < 0.05). CONCLUSION: The increase in the amount of ingested milk with maturation resulted from an increase in bolus volume per minute as well as the higher number of sucks continuously for both breast- and bottle-fed infants.
Asunto(s)
Alimentación con Biberón/métodos , Lactancia Materna , Conducta Alimentaria/fisiología , Conducta del Lactante , Conducta en la Lactancia/fisiología , Factores de Edad , Análisis de Varianza , Peso Corporal , Desarrollo Infantil/fisiología , Femenino , Humanos , Lactante , Estudios Longitudinales , PresiónRESUMEN
Moderate-intensity exercise at the lactate threshold (LT) is considered to be a safe and effective training regimen for improving metabolic syndrome. The aim of the current study was to investigate the effects of moderate exercise performed at the LT on skeletal muscle gene expression. 6 healthy men participated in cycle ergometer training at LT, 60 min/d, 5 d/wk for 12 wks. Muscle samples were collected after 5 d of training, and then 2 d after training at wks 6 and 12. Quantitative real-time PCR analysis revealed that the expression of peroxisome proliferator activated receptor co-activated 1alpha was significantly increased at 1 h after the training session on day 5. Moreover, using serial analysis gene expression, we found that moderate training for 6 and 12 wks simultaneously induced the expression of a number of metabolic genes involved in the TCA cycle, beta-oxidation, and electron transport. Furthermore, several genes encoding antioxidant enzymes and contractile apparatus were induced. The expression levels of 233 novel transcripts were also altered in response to moderate exercise. Thus, moderate training at the LT is a sufficient stimulus to induce the expression of numerous genes implicated in the development of metabolic syndrome, transcripts involved in the contractile apparatus, and novel transcripts.
Asunto(s)
Ciclismo/fisiología , Regulación de la Expresión Génica/fisiología , Músculo Esquelético/fisiología , Adulto , Umbral Anaerobio/fisiología , Ergometría , Ejercicio Físico/fisiología , Humanos , Ácido Láctico/sangre , Masculino , Reacción en Cadena de la Polimerasa , Adulto JovenRESUMEN
Mucin 4 (MUC4) is a high molecular weight transmembrane mucin that is overexpressed in many carcinomas and is a risk factor associated with a poor prognosis. In this study, we show that the DNA methylation pattern is intimately correlated with MUC4 expression in breast, lung, pancreas and colon cancer cell lines. We mapped the DNA methylation status of 94 CpG sites from -3622 to +29 using MassARRAY analysis that utilises base-specific cleavage of nucleic acids. MUC4-negative cancer cell lines and those with low MUC4 expression (eg, A427) were highly methylated near the transcriptional start site, whereas MUC4-positive cell lines (eg, NCI-H292) had low methylation levels. Moreover, 5-aza-2'-deoxycytidine and trichostatin A treatment of MUC4-negative cells or those with low MUC4 expression caused elevation of MUC4 mRNA. Our results suggest that DNA methylation in the 5' flanking region play an important role in MUC4 gene expression in carcinomas of various organs. An understanding of epigenetic changes in MUC4 may contribute to the diagnosis of carcinogenic risk and prediction of outcome in patients with cancer.
Asunto(s)
Islas de CpG , Metilación de ADN , Mucina 4/genética , Neoplasias/genética , Regiones Promotoras Genéticas/genética , Acetilación , Azacitidina/análogos & derivados , Azacitidina/farmacología , Línea Celular Tumoral , Metilasas de Modificación del ADN/antagonistas & inhibidores , ADN de Neoplasias/genética , Decitabina , Inhibidores Enzimáticos/farmacología , Epigénesis Genética , Inhibidores de Histona Desacetilasas , Histona Desacetilasas/metabolismo , Histonas/metabolismo , Humanos , Ácidos Hidroxámicos/farmacología , Neoplasias/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Here we report the first demonstration of entanglement distribution over a record distance of 200 km which is of sufficient fidelity to realize secure communication. In contrast to previous entanglement distribution schemes, we use detection elements based on practical avalanche photodiodes (APDs) operating in a self-differencing mode. These APDs are low-cost, compact and easy to operate requiring only electrical cooling to achieve high single photon detection efficiency. The self-differencing APDs in combination with a reliable parametric down-conversion source demonstrate that entanglement distribution over ultra-long distances has become both possible and practical. Consequently the outlook is extremely promising for real world entanglement-based communication between distantly separated parties.
RESUMEN
Extracellular matrix molecules are generally categorized as collagens, elastin, proteoglycans, or other noncollagenous structural/cell interaction proteins. Many of these extracellular proteins contain distinctive repetitive modules, which can sometimes be found in other proteins. We describe the complete primary structure of an alpha 1 chain of type XII collagen from chick embryonic fibroblasts. This large, structurally chimeric molecule identified by cDNA analysis combines previously unrelated molecular domains into a single large protein 3,124 residues long (approximately 340 kD). The deduced chicken type XII collagen sequence starts at the amino terminus with one unit of the type III motif of fibronectin, which is followed by one unit homologous to the von Willebrand factor A domain, then one more fibronectin type III module, a second A domain from von Willebrand factor, 6 units of type III motif and a third A domain, 10 consecutive units of type III motif and a fourth A domain, a domain homologous to the NC4 domain peptide of type IX collagen, and finally two short collagenous regions previously described as part of the partially sequenced collagen type XII molecule; an Arg-Gly-Asp potential cell adhesive recognition sequence is present in a hydrophilic region at the terminus of one collagenous domain. Antibodies raised to type XII collagen synthesized in a bacterial expression system recognized not only previously reported bands (220 kD et cetera) in tendons, but also bands with apparently different molecular sizes in fibroblasts and 4-d embryos. The antibodies stained a wide variety of extracellular matrices in embryos in patterns distinct from those of fibronectin or interstitial collagens. They prominently stained extracellular matrix associated with certain neuronal tissues, such as axons from dorsal root ganglia and neural tube. These studies identify a novel chimeric type of molecule that contains both adhesion molecule and collagen motifs in one protein. Its structure blurs current classification schemes for extracellular proteins and underscores the potentially large diversity possible in these molecules.
Asunto(s)
Colágeno/química , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Adhesión Celular , Moléculas de Adhesión Celular/química , Moléculas de Adhesión Celular/ultraestructura , Embrión de Pollo , Clonación Molecular , Colágeno/genética , Colágeno/metabolismo , Colágeno/ultraestructura , ADN/genética , Fibronectinas/química , Fibronectinas/ultraestructura , Datos de Secuencia Molecular , Oligonucleótidos/química , Oligopéptidos , Reacción en Cadena de la Polimerasa , Proteínas Recombinantes/inmunología , Alineación de Secuencia , Distribución Tisular , Factor de von Willebrand/química , Factor de von Willebrand/ultraestructuraRESUMEN
In Drosophila, the Jun amino-terminal kinase (JNK) homolog Basket (Bsk) is required for epidermal closure. Mutants for Src42A, a Drosophila c-src protooncogene homolog, are described. Src42A functions in epidermal closure during both embryogenesis and metamorphosis. The severity of the epidermal closure defect in the Src42A mutant depended on the amount of Bsk activity, and the amount of Bsk activity depended on the amount of Src42A. Thus, activation of the Bsk pathway is required downstream of Src42A in epidermal closure. This work confirms mammalian studies that demonstrated a physiological link between Src and JNK.
Asunto(s)
Proteínas de Drosophila , Drosophila/crecimiento & desarrollo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteínas Tirosina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Actinas/metabolismo , Animales , Drosophila/embriología , Drosophila/genética , Drosophila/metabolismo , Activación Enzimática , Epidermis/embriología , Genes de Insecto , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos , Metamorfosis Biológica , Fenotipo , Fosfoproteínas Fosfatasas/genética , Fosfoproteínas Fosfatasas/metabolismo , Fosforilación , Fosfotirosina/metabolismo , Mutación Puntual , Proteínas Tirosina Quinasas/genética , Proteínas Proto-Oncogénicas/genética , Transducción de SeñalRESUMEN
Stellate ganglion blockade (SGB) with a local anesthetic increases muscle sympathetic nerve activity in the tibial nerve in humans. However, whether this sympathetic excitation in the tibial nerve is due to a sympathetic blockade in the neck itself, or due to infiltration of a local anesthetic to adjacent nerves including the vagus nerve remains unknown. To rule out one mechanism, we examined the effects of cervical sympathetic trunk transection on renal sympathetic nerve activity (RSNA) in anesthetized rats. Seven rats were anesthetized with intraperitoneal urethane. RSNA together with arterial blood pressure and heart rate were recorded for 15 min before and 30 min after left cervical sympathetic trunk transection. The baroreceptor unloading RSNA obtained by decreasing arterial blood pressure with administration of sodium nitroprusside was also measured. Left cervical sympathetic trunk transection did not have any significant effects on RSNA, baroreceptor unloading RSNA, arterial blood pressure, and heart rate. These data suggest that there was no compensatory increase in RSNA when cervical sympathetic trunk was transected and that the increase in sympathetic nerve activity in the tibial nerve during SGB in humans may result from infiltration of a local anesthetic to adjacent nerves rather than a sympathetic blockade in the neck itself.
Asunto(s)
Barorreflejo , Ganglios Simpáticos/cirugía , Ganglionectomía , Riñón/inervación , Potenciales de Acción , Adaptación Fisiológica , Animales , Barorreflejo/efectos de los fármacos , Presión Sanguínea , Ganglios Simpáticos/fisiología , Frecuencia Cardíaca , Masculino , Músculo Esquelético/inervación , Nitroprusiato/farmacología , Ratas , Ratas Sprague-Dawley , Nervio Tibial/fisiología , Factores de Tiempo , Vasodilatadores/farmacologíaRESUMEN
Individuals use coping behaviors to deal with unpleasant daily events. Such behaviors can moderate or mediate the pathway between psychosocial stress and health-related outcomes. However, few studies have examined the associations between coping behaviors and genetic variants. We conducted a genome-wide association study (GWAS) on coping behaviors in 14088 participants aged 35 to 69 years as part of the Japan Multi-Institutional Collaborative Cohort Study. Five coping behaviors (emotional expression, emotional support seeking, positive reappraisal, problem solving and disengagement) were measured and analyzed. A GWAS analysis was performed using a mixed linear model adjusted for study area, age and sex. Variants with suggestive significance in the discovery phase (N = 6403) were further examined in the replication phase (N = 7685). We then combined variant-level association evidence into gene-level evidence using a gene-based analysis. The results showed a significant genetic contribution to emotional expression and disengagement, with an estimation that the 19.5% and 6.6% variance in the liability-scale was explained by common variants. In the discovery phase, 12 variants met suggestive significance (P < 1 × 10-6 ) for association with the coping behaviors and perceived stress. However, none of these associations were confirmed in the replication stage. In gene-based analysis, FBXO45, a gene with regulatory roles in synapse maturation, was significantly associated with emotional expression after multiple corrections (P < 3.1 × 10-6 ). In conclusion, our results showed the existence of up to 20% genetic contribution to coping behaviors. Moreover, our gene-based analysis using GWAS data suggests that genetic variations in FBXO45 are associated with emotional expression.
Asunto(s)
Adaptación Psicológica , Emoción Expresada , Proteínas F-Box/genética , Polimorfismo Genético , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
We report the first entanglement-based quantum key distribution (QKD) experiment over a 100-km optical fiber. We used superconducting single photon detectors based on NbN nanowires that provide high-speed single photon detection for the 1.5-mum telecom band, an efficient entangled photon pair source that consists of a fiber coupled periodically poled lithium niobate waveguide and ultra low loss filters, and planar lightwave circuit Mach-Zehnder interferometers (MZIs) with ultra stable operation. These characteristics enabled us to perform an entanglement-based QKD experiment over a 100-km optical fiber. In the experiment, which lasted approximately 8 hours, we successfully generated a 16 kbit sifted key with a quantum bit error rate of 6.9 % at a rate of 0.59 bits per second, from which we were able to distill a 3.9 kbit secure key.
Asunto(s)
Seguridad Computacional/instrumentación , Almacenamiento y Recuperación de la Información/métodos , Fibras Ópticas , Procesamiento de Señales Asistido por Computador/instrumentación , Diseño Asistido por Computadora , Diseño de Equipo , Análisis de Falla de Equipo , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
We report an experimental demonstration of the distribution of time-bin entangled photon pairs over 100 km of optical fiber. In our experiment, 1.5-mum non-degenerated time-bin entangled photon pairs were generated with a periodically poled lithium niobate (PPLN) waveguide by using the parametric down conversion process. Combining this approach with ultra-low-loss filters to eliminate the pump light and separate signal and idler photons, we obtained an efficient entangled photon pair source. To detect the photons, we used single-photon detectors based on frequency up-conversion. These detectors operated in a non-gated mode so that we could use a pulse stream of time correlated entangled photon pairs at a high repetition frequency (1 GHz). Using these elements, we distributed time-bin entangled photon pairs over 100 km of dispersion shifted fiber and performed a two-photon interference experiment. We obtained a coincidence fringe of 81.6% visibility without subtracting any background noise, such as accidental coincidence or dark count, which was good enough to violate Bell's inequality. Thus, we successfully distributed time-bin entangled photon pairs over 100 km.
RESUMEN
We report a field trial of differential phase shift quantum key distribution (QKD) using polarization independent frequency up-conversion detectors. A frequency up-conversion detector is a promising device for achieving a high key generation rate when combined with a high clock rate QKD system. However, its polarization dependence prevents it from being applied to practical QKD systems. In this paper, we employ a modified polarization diversity configuration to eliminate the polarization dependence. Applying this method, we performed a long-term stability test using a 17.6-km installed fiber. We successfully demonstrated stable operation for 6 hours and achieved a sifted key generation rate of 120 kbps and an average quantum bit error rate of 3.14 %. The sifted key generation rate was not the estimated value but the effective value, which means that the sifted key was continuously generated at a rate of 120 kbps for 6 hours.
RESUMEN
A 631-bp fragment containing the 5'-flanking region of the Drosophila melanogaster proliferating-cell nuclear antigen (PCNA) gene was placed upstream of the chloramphenicol acetyltransferase (CAT) gene of a CAT vector. A transient expression assay of CAT activity in Drosophila Kc cells transfected with this plasmid and a set of 5'-deletion derivatives revealed that the promoter function resided within a 192-bp region (-168 to +24 with respect to the transcription initiation site). Cotransfection with a zerknüllt (zen)-expressing plasmid specifically repressed CAT expression. However, cotransfection with expression plasmids for a nonfunctional zen mutation, even-skipped, or bicoid showed no significant effect on CAT expression. RNase protection analysis revealed that the repression by zen was at the transcription step. The target sequence of zen was mapped within the 34-bp region (-119 to -86) of the PCNA gene promoter, even though it lacked zen protein-binding sites. Transgenic flies carrying the PCNA gene regulatory region (-607 to +137 or -168 to +137) fused with lacZ were established. When these flies were crossed with the zen mutant, ectopic expression of lacZ was observed in the dorsal region of gastrulating embryos carrying the transgene with either construct. These results indicate that zen indirectly represses PCNA gene expression, probably by regulating the expression of some transcription factor(s) that binds to the PCNA gene promoter.
Asunto(s)
Drosophila/genética , Regulación de la Expresión Génica/fisiología , Proteínas Nucleares/genética , Regiones Promotoras Genéticas/fisiología , Proteínas/fisiología , Factores de Transcripción/fisiología , Secuencia de Aminoácidos , Animales , Animales Modificados Genéticamente , Secuencia de Bases , Sitios de Unión/genética , Cloranfenicol O-Acetiltransferasa/genética , Drosophila/embriología , Datos de Secuencia Molecular , Mutación/fisiología , Plásmidos/genética , Antígeno Nuclear de Célula en Proliferación , Proteínas/genética , Factores de Transcripción/genética , beta-Galactosidasa/genéticaRESUMEN
In Saccharomyces cerevisiae, adenylyl cyclase forms a complex with the 70-kDa cyclase-associated protein (CAP). By in vitro mutagenesis, we assigned a CAP-binding site of adenylyl cyclase to a small segment near its C terminus and created mutants which lost the ability to bind CAP. CAP binding was assessed first by observing the ability of the overproduced C-terminal 150 residues of adenylyl cyclase to sequester CAP, thereby suppressing the heat shock sensitivity of yeast cells bearing the activated RAS2 gene (RAS2Val-19), and then by immunoprecipitability of adenylyl cyclase activity with anti-CAP antibody and by direct measurement of the amount of CAP bound. Yeast cells whose chromosomal adenylyl cyclase genes were replaced by the CAP-nonbinding mutants possessed adenylyl cyclase activity fully responsive to RAS2 protein in vitro. However, they did not exhibit sensitivity to heat shock in the RAS2Val-19 background. When glucose-induced accumulation of cyclic AMP (cAMP) was measured in these mutants carrying RAS2Val-19, a rapid transient rise indistinguishable from that of wild-type cells was observed and a high peak level and following persistent elevation of the cAMP concentration characteristic of RAS2Val-19 were abolished. In contrast, in the wild-type RAS2 background, similar cyclase gene replacement did not affect the glucose-induced cAMP response. These results suggest that the association with CAP, although not involved in the in vivo response to the wild-type RAS2 protein, is somehow required for the exaggerated response of adenylyl cyclase to activated RAS2.