107 research outputs found
Microtube's Tapers Affect its Subwavelength Focusing Effect
AbstractA tapered microtube fabricated from a glass capillary tube can achieve subwavelength focusing at optical frequencies. This focusing effect is influenced by many factures. The role of taper ratios is invested in this paper with theoretical analysis and numerical simulation. It revealed that when the taper ratio is larger, the focusing spot has higher intensity and smaller FWHM
Experimental demonstrations of high-Q superconducting coplanar waveguide resonators
We designed and successfully fabricated an absorption-type of superconducting
coplanar waveguide (CPW) resonators. The resonators are made from a Niobium
film (about 160 nm thick) on a high-resistance Si substrate, and each resonator
is fabricated as a meandered quarter-wavelength transmission line (one end
shorts to the ground and another end is capacitively coupled to a through
feedline). With a vector network analyzer we measured the transmissions of the
applied microwave through the resonators at ultra-low temperature (e.g., at 20
mK), and found that their loaded quality factors are significantly high, i.e.,
up to 10^6. With the temperature increases slowly from the base temperature
(i.e., 20 mK), we observed the resonance frequencies of the resonators are blue
shifted and the quality factors are lowered slightly. In principle, this type
of CPW-device can integrate a series of resonators with a common feedline,
making it a promising candidate of either the data bus for coupling the distant
solid-state qubits or the sensitive detector of single photons.Comment: Accepted by Chinese Science Bulleti
Mechanistic insight into how multidrug resistant Acinetobacter baumannii response regulator AdeR recognizes an intercistronic region
AdeR-AdeS is a two-component regulatory system, which controls expression of the adeABC efflux pump involved in Acinetobacter baumannii multidrug resistance. AdeR is a response regulator consisting of an N-terminal receiver domain and a C-terminal DNA-binding-domain. AdeR binds to a direct-repeat DNA in the intercistronic region between adeR and adeABC. We demonstrate a markedly high affinity binding between unphosphorylated AdeR and DNA with a dissociation constant of 20 nM. In addition, we provide a 2.75 angstrom crystal structure of AdeR DNA-binding-domain complexed with the intercistronic DNA. This structure shows that the alpha 3 and beta hairpin formed by beta 5-beta 6 interacts with the major and minor groove of the DNA, which in turn leads to the introduction of a bend. The AdeR receiver domain structure revealed a dimerization motif mediated by a gearwheel-like structure involving the D108F109-R122 motif through cation pi stack interaction. The structure of AdeR receiver domain bound with magnesium indicated a conserved Glu19Asp20-Asp63 magnesium-binding motif, and revealed that the potential phosphorylation site Asp63(OD1) forms a hydrogen bond with Lys112. We thus dissected the mechanism of how AdeR recognizes the intercistronic DNA, which leads to a diverse mode of response regulation. Unlocking the AdeRS mechanism provides ways to circumvent A. baumannii antibiotic resistance
High-performance non-Fermi-liquid metallic thermoelectric materials
Searching for high-performance thermoelectric (TE) materials in the paradigm
of narrow-bandgap semiconductors has lasted for nearly 70 years and is
obviously hampered by a bottleneck of research now. Here we report on the
discovery of a few metallic compounds, TiFexCu2x-1Sb and TiFe1.33Sb, showing
the thermopower exceeding many TE semiconductors and the dimensionless figure
of merits comparable with the state-of-the-art TE materials. A quasi-linear
temperature (T) dependence of electrical resistivity in 2 K - 700 K and the
logarithmic T-dependent electronic specific heat at low temperature are also
observed to coexist with the high thermopower, highlighting the strong
intercoupling of the non-Fermi-liquid (NFL) quantum critical behavior of
electrons with TE transports. Electronic structure analysis reveals the
existence of fluctuating Fe-eg-related local magnetic moments, Fe-Fe
antiferromagnetic (AFM) interaction at the nearest 4c-4d sites, and two-fold
degenerate eg orbitals antiferromagnetically coupled with the dual-type
itinerant electrons close to the Fermi level, all of which infer to a
competition between the AFM ordering and Kondo-like spin compensation as well
as a parallel two-channel Kondo effect. These effects are both strongly
meditated by the structural disorder due to the random filling of Fe/Cu at the
equivalent 4c/4d sites of the Heusler crystal lattice. The magnetic
susceptibility deviates from ideal antiferromagnetism but can be fitted well by
x(T) = 1/({\theta} + BT{\alpha}), seemingly being consistent with the quantum
critical scenario of strong local correlation as discussed before. Our work not
only breaks the dilemma that the promising TE materials should be heavily-doped
semiconductors, but also demonstrates the correlation among high TE
performance, NFL quantum criticality, and magnetic fluctuation, which opens up
new directions for future research.Comment: 19 pages with 6 figure
Progress and perspectives of perioperative immunotherapy in non-small cell lung cancer
Lung cancer is one of the leading causes of cancer-related death. Lung cancer mortality has decreased over the past decade, which is partly attributed to improved treatments. Curative surgery for patients with early-stage lung cancer is the standard of care, but not all surgical treatments have a good prognosis. Adjuvant and neoadjuvant chemotherapy are used to improve the prognosis of patients with resectable lung cancer. Immunotherapy, an epoch-defining treatment, has improved curative effects, prognosis, and tolerability compared with traditional and ordinary cytotoxic chemotherapy, providing new hope for patients with non-small cell lung cancer (NSCLC). Immunotherapy-related clinical trials have reported encouraging clinical outcomes in their exploration of different types of perioperative immunotherapy, from neoadjuvant immune checkpoint inhibitor (ICI) monotherapy, neoadjuvant immune-combination therapy (chemoimmunotherapy, immunotherapy plus antiangiogenic therapy, immunotherapy plus radiotherapy, or concurrent chemoradiotherapy), adjuvant immunotherapy, and neoadjuvant combined adjuvant immunotherapy. Phase 3 studies such as IMpower 010 and CheckMate 816 reported survival benefits of perioperative immunotherapy for operable patients. This review summarizes up-to-date clinical studies and analyzes the efficiency and feasibility of different neoadjuvant therapies and biomarkers to identify optimal types of perioperative immunotherapy for NSCLC
The molecular mechanisms of peptidyl-prolyl cis/trans isomerase Pin1 and its relevance to kidney disease
Pin1 is a member of the peptidyl-prolyl cis/trans isomerase subfamily and is widely expressed in various cell types and tissues. Alterations in Pin1 expression levels play pivotal roles in both physiological processes and multiple pathological conditions, especially in the onset and progression of kidney diseases. Herein, we present an overview of the role of Pin1 in the regulation of fibrosis, oxidative stress, and autophagy. It plays a significant role in various kidney diseases including Renal I/R injury, chronic kidney disease with secondary hyperparathyroidism, diabetic nephropathy, renal fibrosis, and renal cell carcinoma. The representative therapeutic agent Juglone has emerged as a potential treatment for inhibiting Pin1 activity and mitigating kidney disease. Understanding the role of Pin1 in kidney diseases is expected to provide new insights into innovative therapeutic interventions and strategies. Consequently, this review delves into the molecular mechanisms of Pin1 and its relevance in kidney disease, paving the way for novel therapeutic approaches
Microbial Community and Functional Gene Changes in Arctic Tundra Soils in a Microcosm Warming Experiment
Microbial decomposition of soil organic carbon (SOC) in thawing Arctic permafrost is important in determining greenhouse gas feedbacks of tundra ecosystems to climate. However, the changes in microbial community structure during SOC decomposition are poorly known. Here we examine these changes using frozen soils from Barrow, Alaska, USA, in anoxic microcosm incubation at −2 and 8°C for 122 days. The functional gene array GeoChip was used to determine microbial community structure and the functional genes associated with SOC degradation, methanogenesis, and Fe(III) reduction. Results show that soil incubation after 122 days at 8°C significantly decreased functional gene abundance (P < 0.05) associated with SOC degradation, fermentation, methanogenesis, and iron cycling, particularly in organic-rich soil. These observations correspond well with decreases in labile SOC content (e.g., reducing sugar and ethanol), methane and CO2 production, and Fe(III) reduction. In contrast, the community functional structure was largely unchanged in the −2°C incubation. Soil type (i.e., organic vs. mineral) and the availability of labile SOC were among the most significant factors impacting microbial community structure. These results demonstrate the important roles of microbial community in SOC degradation and support previous findings that SOC in organic-rich Arctic tundra is highly vulnerable to microbial degradation under warming
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