A Josephson radiation threshold detector (JRTD) that is based on the threshold behaviour of a current bias Josephson junction (CBJJ) is designed and fabricated for infrared radiation (IR@1550nm) ...detection at low temperatures. To achieve the optimal performance, we develop a binary hypothesis detection method to calibrate Josephson threshold behaviours (i.e. the switching current distributions of the CBJJ with the Al/AlO
/Al junction) in the absence and presence of radiation. In the absence of IR radiation, the junction transitioned with a measurable voltage drop across the junction, and this signal was treated as the events of hypothesis H
. The events of junction transition observed in the presence of the IR radiation served as hypothesis H
. Considering the usual Gaussian noise and based on statistical decision theory, the accumulated data of the measured switching current distributions are processed, and the threshold sensitivity of the demonstrated JRTD device is estimated. The minimum detectable IR radiation power of the proposed detector is approximately 0.74 pW, which corresponds to the photon rate of 5.692 × 10
photons/second. Further optimisation of JRTDs to implement the desired binary detection of a single photon is still a subject of argument, at least theoretically.
Vegetation plays a key role in maintaining soil quality, but long-term changes in soil quality due to plant species change and successive planting are rarely reported. Using the space-for-time ...substitution method, adjacent plantations of Pinus and first, second, third and fourth generations of Eucalyptus in Guangxi, China were used to study changes in soil quality caused by converting Pinus to Eucalyptus and successive Eucalyptus planting. Soil chemical and biological properties were measured and a soil quality index was calculated using principal component analysis. Soil organic carbon, total nitrogen, alkaline hydrolytic nitrogen, microbial biomass carbon, microbial biomass nitrogen, cellobiosidase, phenol oxidase, peroxidase and acid phosphatase activities were significantly lower in the first and second generations of Eucalyptus plantations compared with Pinus plantation, but they were significantly higher in the third and fourth generations than in the first and second generations and significantly lower than in Pinus plantation. Soil total and available potassium were significantly lower in Eucalyptus plantations (1.8–2.5 g kg−1 and 26–66 mg kg−1) compared to the Pinus plantation (14.3 g kg−1 and 92 mg kg−1), but total phosphorus was significantly higher in Eucalyptus plantations (0.9–1.1 g kg−1) compared to the Pinus plantation (0.4 g kg−1). As an integrated indicator, soil quality index was highest in the Pinus plantation (0.92) and lowest in the first and second generations of Eucalyptus plantations (0.24 and 0.13). Soil quality index in the third and fourth generations (0.36 and 0.38) was between that in Pinus plantation and in first and second generations of Eucalyptus plantations. Changing tree species, reclamation and fertilization may have contributed to the change observed in soil quality during conversion of Pinus to Eucalyptus and successive Eucalyptus planting. Litter retention, keeping understorey coverage, and reducing soil disturbance during logging and subsequent establishment of the next rotation should be considered to help improving soil quality.
Insect defensins, are cationic peptides that play an important role in immunity against microbial infection. In the present study, an anionic defensin from Plutella xylostella, (designated as PxDef) ...was first cloned and characterized. Amino acid sequence analysis showed that the mature peptide owned characteristic six-cysteine motifs with predicted isoelectric point of 5.57, indicating an anionic defensin. Quantitative real-time polymerase chain reaction analysis showed that PxDef was significantly induced in epidermis, fat body, midgut and hemocytes after injection of heat-inactivated Bacillus thuringiensis, while such an induction was delayed by the injection of live B. thuringiensis in the 4th instar larvae of P. xylostella. Knocking down the expression of nuclear transcription factor Dorsal in P. xylostella by RNA interference significantly decreased the mRNA level of PxDef, and increased the sensitivity of P. xylostella larvae to the infection by live B. thuringiensis. The purified recombinant mature peptide (PxDef) showed higher activity against Gram-positive bacteria, with the minimum inhibition concentrations of 1.6 and 2.6 µM against B. thuringiensis and Bacillus subtilis, respectively. To our knowledge, this is the first report about an anionic PxDef, which may play an important role in the immune system of P. xylostella against B. thuringiensis.
Micro/nanotopographical modifications on titanium surfaces constitute a new process to increase osteoblast response to enhance bone formation. In this study, we utilized alkali heat treatment at high ...(SB-AH1) and low temperatures (SB-AH2) to nano-modify sandblasted titanium with microtopographical surfaces. Then, we evaluated the surface properties, biocompatibility and osteogenic capability of SB-AH1 and SB-AH2 in vitro and in vivo, and compared these with conventional sandblast-acid etching (SLA) and Ti control surfaces. SB-AH1 and SB-AH2 surfaces exhibited micro/nanotopographical modifications of nano-needle structures and nano-porous network layers, respectively, compared with the sole microtopographical surface of macro and micro pits on the SLA surface and the relatively smooth surface on the Ti control. SB-AH1 and SB-AH2 showed different roughness and elemental components, but similar wettability. MC3T3-E1 preosteoblasts anchored closely on the nanostructures of SB-AH1 and SB-AH2 surfaces, and these two surfaces more significantly enhanced cell proliferation and alkaline phosphatase (ALP) activity than others, while the SB-AH2 surface exhibited better cell proliferation and higher ALP activity than SB-AH1. All four groups of titanium domes with self-tapping screws were implanted in rabbit calvarial bone models, and these indicated that SB-AH1 and SB-AH2 surfaces achieved better peri-implant bone formation and implant stability, while the SB-AH2 surface achieved the best percentage of bone-implant contact (BIC%). Our study demonstrated that the micro/nanotopographical surface generated by sandblasting and alkali heat treatment significantly enhanced preosteoblast proliferation, ALP activity and bone formation in vitro and in vivo, and nano-porous network topography may further induce better preosteoblast proliferation, ALP activity and BIC%.
Recently, a new kind of distributed element superconducting resonators with granular aluminum (grAl) has been developed for circuit quantum electrodynamics. Given that lumped element resonators ...possess certain advantages over the distributed element ones, in this paper, we use a relatively simple micro-nanotechnology, without the etching process, to fabricate the designed lumped element superconducting grAl resonators. They are deposited on silicon substrates by DC magnetron sputtering of pure Al in an atmosphere of Ar and O2. By cryogenic microwave transmission measurements, at a temperature of 50 mK, we find that, compared with a usual Al resonator of the same size, such a device shows significantly strong nonlinearity and thus higher kinetic inductance. The noise features, quality factors, and temperature-dependence of the resonant frequencies have been investigated experimentally. It is believed that the lumped element superconducting resonators with high kinetic inductance demonstrated here could also be applied to superconducting quantum computation and photon counting in the future.
It is well known that elementary particles in the real 3+1-dimensional world are either bosons or fermions, without exception, and not both. Here, we show that a quantized current-biased Josephson ...junction (CBJJ), as an artificial macroscopic “particle,” can serve as either a boson or a fermion or the combination, depending on the amplitude of the biased dc current. By using high vacuum two-angle electron beam evaporations, we fabricated CBJJ devices and calibrated their physical parameters by applying low-frequency signal drivings. At 50mK temperature environment, the microwave transmission characteristics of the fabricated CBJJ devices were measured at the low power limit. The experimental results verify the relevant theoretical predictions, i.e., when the bias current is significantly lower than the critical ones of the junctions, the device works in a very linear regime and thus behaves as a harmonic oscillator “boson”; while if the biased current is sufficiently large (especially approaching the junctions' critical currents), the device works manifestly in the nonlinear regime and thus behaves as a two-level artificial atom “fermion.” Therefore, by adjusting the biased dc current, the CBJJ device can be effectively switched from a Bose-type macroscopic particle to a Fermi-type one and thus might open an approach for quantum technology applications at a macroscopic scale.
To explore the prognosis factors that influence the postoperative survival rate in patients with malignant solitary pulmonary nodules and to provide a reference for the prognosis risk stratification ...of early lung cancer patients.
In this study, we retrospectively reviewed 172 patients who were admitted to Peking University First Hospital from April 2006 to December 2013. All cases were radiologically defined as solitary pulmonary nodule and were pathologically confirmed to be stage Ia non-small cell lung cancer after surgical procedure. The patients' clinical and follow-up data were summarized and analyzed. The relevance between survival time and factors that may affect patients' prognosis was evaluated, which included gender, age, clinical symptoms, smoking history, comorbidity index, tumor biomarkers, nodule type, type of surgery, nodule location, nodule histopathological type, nodule size, histopathological differentiation grade, proliferating cell nuclear antigen Ki-67 expression level and epidermal growt
MicroRNAs (miRNAs) regulate gene expression. It has been suggested that obtaining miRNA expression profiles can improve classification, diagnostic, and prognostic information in oncology. Here, we ...sought to comprehensively identify the miRNAs that are overexpressed in lung cancer by conducting miRNA microarray expression profiling on normal lung versus adjacent lung cancers from transgenic mice. We found that miR-136, miR-376a, and miR-31 were each prominently overexpressed in murine lung cancers. Real-time RT-PCR and in situ hybridization (ISH) assays confirmed these miRNA expression profiles in paired normal-malignant lung tissues from mice and humans. Engineered knockdown of miR-31, but not other highlighted miRNAs, substantially repressed lung cancer cell growth and tumorigenicity in a dose-dependent manner. Using a bioinformatics approach, we identified miR-31 target mRNAs and independently confirmed them as direct targets in human and mouse lung cancer cell lines. These targets included the tumor-suppressive genes large tumor suppressor 2 (LATS2) and PP2A regulatory subunit B alpha isoform (PPP2R2A), and expression of each was augmented by miR-31 knockdown. Their engineered repression antagonized miR-31-mediated growth inhibition. Notably, miR-31 and these target mRNAs were inversely expressed in mouse and human lung cancers, underscoring their biologic relevance. The clinical relevance of miR-31 expression was further independently and comprehensively validated using an array containing normal and malignant human lung tissues. Together, these findings revealed that miR-31 acts as an oncogenic miRNA (oncomir) in lung cancer by targeting specific tumor suppressors for repression.
Reentrant glass transition is a new glass-transition phenomenon in which a devitrified liquid reenters a second glassy state and is well-known in some colloidal systems. Reentrant glass transition ...has been recently discovered in metallic-liquid systems but its ongoing mechanisms remain mostly unknown. Here, the reentrant glass transition of a series of Pd-Ni-P metallic liquids are investigated using fast-calorimetric analyses and ab-initio molecular dynamics simulation. While the amount of heat release of reentrant glass transition in different Pd-Ni-P liquids are similar, the change of liquid kinetics itself results in different reentrant-glass-transition behaviors: the transition kinetics is governed by the fast hopping of P atoms rather than the cooperative liquid motions related with vitrification. The reentrant glass transition is found to be related to medium-range structural ordering process through vertex-sharing of the P-centered polyhedral clusters. The kinetics map of liquid freezing for Pd-Ni-P glass-forming liquids over broad ranges of heating-rate and composition is presented.
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