155 research outputs found
Reconstructing 3D Human Pose from RGB-D Data with Occlusions
We propose a new method to reconstruct the 3D human body from RGB-D images
with occlusions. The foremost challenge is the incompleteness of the RGB-D data
due to occlusions between the body and the environment, leading to implausible
reconstructions that suffer from severe human-scene penetration. To reconstruct
a semantically and physically plausible human body, we propose to reduce the
solution space based on scene information and prior knowledge. Our key idea is
to constrain the solution space of the human body by considering the occluded
body parts and visible body parts separately: modeling all plausible poses
where the occluded body parts do not penetrate the scene, and constraining the
visible body parts using depth data. Specifically, the first component is
realized by a neural network that estimates the candidate region named the
"free zone", a region carved out of the open space within which it is safe to
search for poses of the invisible body parts without concern for penetration.
The second component constrains the visible body parts using the "truncated
shadow volume" of the scanned body point cloud. Furthermore, we propose to use
a volume matching strategy, which yields better performance than surface
matching, to match the human body with the confined region. We conducted
experiments on the PROX dataset, and the results demonstrate that our method
produces more accurate and plausible results compared with other methods
MiR-145 inhibits oral squamous cell carcinoma (OSCC) cell growth by targeting c-Myc and Cdk6
BACKGROUND: MicroRNAs (miRNAs) are a large group of negative gene regulators that potentially play a critical role in tumorigenesis. Increasing evidences indicate that miR-145 acts a tumor suppressor in numerous human cancers. However, its role in oral carcinogenesis remains poorly defined. The aim of this study is to determine expression levels of miR-145 in oral squamous cell carcinomas (OSCCs) and normal mucosa tissues, and explore its biological functions in OSCCs. METHODS: Reverse transcription quantitative real-time PCR (RT-qPCR) assay was used to evaluate expression levels of miR-145. The biological functions of miR-145 were determined by cell proliferation and colony formation, cell cycle and apoptosis, as well as cell invasion assay. RESULTS: MiR-145 was frequently down-regulated in OSCCs compared with normal mucosa tissues. Restoring miR-145 expression in OSCC cells dramatically suppressed cell proliferation and colony formation, and induced G1 phase arrest and cell apoptosis. Importantly, our data showed that miR-145 downregulated the expression of c-Myc and Cdk6, which have previously been identified as two direct targets of miR-145. CONCLUSIONS: Our data suggest that miR-145 exerts its tumor suppressor function by targeting c-Myc and Cdk6, leading to the inhibition of OSCC cell growth. MiR-145 rescue may thus be a rational for diagnostic and therapeutic applications in OSCC
Micro-scale to nano-scale generators for energy harvesting:Self powered piezoelectric, triboelectric and hybrid devices
This comprehensive review focuses on recent advances in energy harvesting of micro-scale and nano-scale generators based on piezoelectric and triboelectric effects. The development of flexible and hybrid devices for a variety of energy harvesting applications are systematically reviewed. A fundamental understanding of the important parameters that determine the performance of piezoelectric, triboelectric and hybrid devices are summarized. Current research directions being explored and the emerging factors to improve harvester functionality and advance progress in achieving high performance and durable energy conversion are provided. Investigations with regard to integrating flexible matrices and optimizing the composition of the piezoelectric and triboelectric materials are examined to enhance device performance and improve cost-effectiveness for the commercial arena. Finally, future research trends, emerging device structures and novel materials in view of imminent developments and harvesting applications are presented.</p
Single charge control of localized excitons in heterostructures with ferroelectric thin films and two-dimensional transition metal dichalcogenides
Single charge control of localized excitons (LXs) in two-dimensional
transition metal dichalcogenides (TMDCs) is crucial for potential applications
in quantum information processing and storage. However, traditional
electrostatic doping method with applying metallic gates onto TMDCs may cause
the inhomogeneous charge distribution, optical quench, and energy loss. Here,
by locally controlling the ferroelectric polarization of the ferroelectric thin
film BiFeO3 (BFO) with a scanning probe, we can deterministically manipulate
the doping type of monolayer WSe2 to achieve the p-type and n-type doping. This
nonvolatile approach can maintain the doping type and hold the localized
excitonic charges for a long time without applied voltage. Our work
demonstrated that ferroelectric polarization of BFO can control the charges of
LXs effectively. Neutral and charged LXs have been observed in different
ferroelectric polarization regions, confirmed by magnetic optical measurement.
Highly circular polarization degree about 90 % of the photon emission from
these quantum emitters have been achieved in high magnetic fields. Controlling
single charge of LXs in a non-volatile way shows a great potential for
deterministic photon emission with desired charge states for photonic long-term
memory.Comment: 13 pages, 5 figure
Asymmetric Chiral Coupling in a Topological Resonator
Chiral light-matter interactions supported by topological edge modes at the
interface of valley photonic crystals provide a robust method to implement the
unidirectional spin transfer. The valley topological photonic crystals possess
a pair of counterpropagating edge modes. The edge modes are robust against the
sharp bend of and , which can form a resonator with
whispering gallery modes. Here, we demonstrate the asymmetric emission of
chiral coupling from single quantum dots in a topological resonator by tuning
the coupling between a quantum emitter and a resonator mode. Under a magnetic
field in Faraday configuration, the exciton state from a single quantum dot
splits into two exciton spin states with opposite circularly polarized
emissions due to Zeeman effect. Two branches of the quantum dot emissions
couple to a resonator mode in different degrees, resulting in an asymmetric
chiral emission. Without the demanding of site-control of quantum emitters for
chiral quantum optics, an extra degree of freedom to tune the chiral contrast
with a topological resonator could be useful for the development of on-chip
integrated photonic circuits.Comment: 13 pages, 4 figure
Controllable Spin-Resolved Photon Emission Enhanced by Slow-Light Mode in Photonic Crystal Waveguides on Chip
We report the slow-light enhanced spin-resolved in-plane emission from a
single quantum dot (QD) in a photonic crystal waveguide (PCW). The slow light
dispersions in PCWs are designed to match the emission wavelengths of single
QDs. The resonance between two spin states emitted from a single QD and a slow
light mode of a waveguide is investigated under a magnetic field with Faraday
configuration. Two spin states of a single QD experience different degrees of
enhancement as their emission wavelengths are shifted by combining diamagnetic
and Zeeman effects with an optical excitation power control. A circular
polarization degree up to 0.81 is achieved by changing the off-resonant
excitation power. Strongly polarized photon emission enhanced by a slow light
mode shows great potential to attain controllable spin-resolved photon sources
for integrated optical quantum networks on chip.Comment: 7 pages,5 figure
Evaluation of branched GDGTs and leaf wax n-alkane δ2H as (paleo) environmental proxies in East Africa
The role of mountain evolution on local climate is poorly understood and potentially underestimated in climate models. One prominent example is East Africa, which underwent major geodynamic changes with the onset of the East African Rift System (EARS) more than 250 Myr ago. This study explores, at the regional East African scale, a molecular approach for terrestrially-based paleo-climatic reconstructions that takes into account both changes in temperature and in altitude, potentially leading to an improved concept in paleo-climatic reconstructions. Using surface soils collected along pronounced altitudinal gradients in Mt. Rungwe (n=40; Southwest Tanzania) and Mt. Kenya (n=20; Central Kenya), we investigate the combination of 2 terrestrial proxies, leaf wax n-alkane δ2H (δ2Hwax) and branched glycerol dialkyl glycerol tetraether (br GDGT) membrane lipids, as (paleo) elevation and (paleo) temperature proxies, respectively. At the mountain scale, a weak link between δ2Hwax and altitude (R2 = 0.33) is observed at Mt. Kenya, but no relationship is observed at Mt. Rungwe. It is likely that additional parameters, such as decreasing relative humidity (RH) or vegetation changes with altitude, are outcompeting the expected 2H-depletion trend along Mt. Rungwe. In contrast, br GDGT-derived absolute mean annual air temperature (MAAT) and temperature lapse rate (0.65 °C/100 m) for both mountains are in good agreement with direct field measurements, further supporting the robustness of this molecular proxy for (paleo) temperature reconstructions. At the regional scale, estimated and observed δ2H data in precipitation along 3 mountains in East Africa (Mts. Rungwe, Kenya and Kilimanjaro) highlight a strong spatial heterogeneity, preventing the establishment of a regional based calibration of δ2Hwax for paeloaltitudinal reconstructions. Different from that, an improved regional soil calibration is developed between br GDGT distribution and MAAT by combining the data from this study (Mts. Rungwe and Kenya) with previous results from East African surface soils along Mts. Kilimanjaro (Tanzania) and Rwenzori (Uganda). This new regional calibration, based on 105 samples, improves both the R2 (0.77) and RMSE (root mean square error; 2.4 °C) of br GDGT-derived MAAT over the global soil calibrations previously established (R2 = 0.56; RMSE = 4.2 °C) and leads to more accurate (paleo) temperature reconstructions in the region
Imprinted antibody responses against SARS-CoV-2 Omicron sublineages
SARS-CoV-2 Omicron sublineages carry distinct spike mutations and represent an antigenic shift resulting in escape from antibodies induced by previous infection or vaccination. We show that hybrid immunity or vaccine boosters result in potent plasma neutralizing activity against Omicron BA.1 and BA.2 and that breakthrough infections, but not vaccination-only, induce neutralizing activity in the nasal mucosa. Consistent with immunological imprinting, most antibodies derived from memory B cells or plasma cells of Omicron breakthrough cases cross-react with the Wuhan-Hu-1, BA.1 and BA.2 receptor-binding domains whereas Omicron primary infections elicit B cells of narrow specificity. While most clinical antibodies have reduced neutralization of Omicron, we identified an ultrapotent pan-variant antibody, that is unaffected by any Omicron lineage spike mutations and is a strong candidate for clinical development
Imprinted antibody responses against SARS-CoV-2 Omicron sublineages
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron sublineages carry distinct spike mutations resulting in escape from antibodies induced by previous infection or vaccination. We show that hybrid immunity or vaccine boosters elicit plasma-neutralizing antibodies against Omicron BA.1, BA.2, BA.2.12.1, and BA.4/5, and that breakthrough infections, but not vaccination alone, induce neutralizing antibodies in the nasal mucosa. Consistent with immunological imprinting, most antibodies derived from memory B cells or plasma cells of Omicron breakthrough cases cross-react with the Wuhan-Hu-1, BA.1, BA.2, and BA.4/5 receptor-binding domains, whereas Omicron primary infections elicit B cells of narrow specificity up to 6 months after infection. Although most clinical antibodies have reduced neutralization of Omicron, we identified an ultrapotent pan-variant–neutralizing antibody that is a strong candidate for clinical development
Qwen Technical Report
Large language models (LLMs) have revolutionized the field of artificial
intelligence, enabling natural language processing tasks that were previously
thought to be exclusive to humans. In this work, we introduce Qwen, the first
installment of our large language model series. Qwen is a comprehensive
language model series that encompasses distinct models with varying parameter
counts. It includes Qwen, the base pretrained language models, and Qwen-Chat,
the chat models finetuned with human alignment techniques. The base language
models consistently demonstrate superior performance across a multitude of
downstream tasks, and the chat models, particularly those trained using
Reinforcement Learning from Human Feedback (RLHF), are highly competitive. The
chat models possess advanced tool-use and planning capabilities for creating
agent applications, showcasing impressive performance even when compared to
bigger models on complex tasks like utilizing a code interpreter. Furthermore,
we have developed coding-specialized models, Code-Qwen and Code-Qwen-Chat, as
well as mathematics-focused models, Math-Qwen-Chat, which are built upon base
language models. These models demonstrate significantly improved performance in
comparison with open-source models, and slightly fall behind the proprietary
models.Comment: 59 pages, 5 figure
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