419 research outputs found
The Noninvasive Measurement of Central Aortic Blood Pressure Waveform
Central aortic pressure (CAP) is a potential surrogate of brachial blood pressure in both clinical practice and routine health screening. It directly reflects the status of the central aorta. Noninvasive measurement of CAP becomes a crucial technique of great interest. There have been advances in recent years, including the proposal of novel methods and commercialization of several instruments. This chapter briefly introduces the clinical importance of CAP and the theoretical basis for the generation of CAP in the first and second sections. The third section describes and discusses the measurement of peripheral blood pressure waveforms, which is employed to estimate CAP. We then review the proposed methods for the measurement of CAP. The calibration of blood pressure waveforms is discussed in the fourth section. After a brief discussion of the technical limitations, we give suggestions for perspectives and future challenges
Evolution of H9N2 influenza viruses from domestic poultry in Mainland China
AbstractH9N2 viruses have circulated in domestic poultry in Mainland China since 1994, and an inactivated vaccine has been used in chickens to control the disease since 1998. The present study analyzed 27 H9N2 avian influenza viruses that were isolated from chickens and ducks from 1996 to 2002. Infection studies indicated that most of the viruses replicate efficiently but none of them is lethal for SPF chickens. However, these viruses exhibit different phenotypes of replication in a mouse model. Five viruses, including 4 early isolates and one 2000 isolate, are not able to replicate in mice; 14 viruses replicate to moderate titers in mouse lungs and cause less than 5% weight loss, while other 8 viruses could replicate to high titers in the lungs and 7 of them induce 10–20% weight loss of the mice on day 5 after inoculation. Most of the viruses isolated after 1996 are antigenically different from the vaccine strain that is currently used in China. Three viruses isolated in central China in 1998 are resistant to adamantanes. Phylogenetic analysis revealed that all of the viruses originated from CK/BJ/1/94-like virus and formed multiple genotypes through complicated reassortment with QA/HK/G1/97-, CK/HK/G9/97-, CK/SH/F/98-, and TY/WI/66-like viruses. This study is a description of the previously uncharacterized H9N2 avian influenza viruses recently circulating in chickens and ducks in Mainland China. Our findings suggest that urgent attention should be paid to the control of H9N2 influenza viruses in animals and to the human's influenza pandemic preparedness
Afforestation in Karst Area
In order to study the afforestation technology in rocky desertification area and provide guidance for the cultivation and management of artificial forest in the later stage, an experimental study was carried out on the artificial forest in National long term scientific research base for comprehensive control of rocky desertification in Wuling Mountain, Western Hunan Province. The experiences of afforestation, land preparation and forest management in this area were summarized. The result show that: 1. Through appropriate afforestation land preparation and forest management measures, the forest in rocky desertification area can be successfully restored. 2. Vegetation restoration in rocky desertification area has formed relatively healthy and stable multi tree species and multi-level forest communities. 3. The biological yield of each afforestation tree species was significantly different with different tree species. 4. The diversity index and evenness index of undergrowth plants in different stands were significantly different. 5. Young trees of dominant species dominated the undergrowth vegetation of different stands, and the natural regeneration of each stand has been stabilized. 6. There are some differences in soil chemical properties under different stands. There were significant differences in SOM, TN, NO3-N, NH4-N and AP contents in the soil of the eight stands
Correlation between intercalated magnetic layers and superconductivity in pressurized EuFe2(As0.81P0.19)2
We report comprehensive high pressure studies on correlation between
intercalated magnetic layers and superconductivity in EuFe2(As0.81P0.19)2
single crystal through in-situ high pressure resistance, specific heat, X-ray
diffraction and X-ray absorption measurements. We find that an unconfirmed
magnetic order of the intercalated layers coexists with superconductivity in a
narrow pressure range 0-0.5GPa, and then it converts to a ferromagnetic (FM)
order at pressure above 0.5 GPa, where its superconductivity is absent. The
obtained temperature-pressure phase diagram clearly demonstrates that the
unconfirmed magnetic order can emerge from the superconducting state. In stark
contrast, the superconductivity cannot develop from the FM state that is
evolved from the unconfirmed magnetic state. High pressure X-ray absorption
(XAS) measurements reveal that the pressure-induced enhancement of Eu's mean
valence plays an important role in suppressing the superconductivity and tuning
the transition from the unconfirmed magnetic state to a FM state. The unusual
interplay among valence state of Eu ions, magnetism and superconductivity under
pressure may shed new light on understanding the role of the intercalated
magnetic layers in Fe-based superconductors
Insulin Attenuates Beta-Amyloid-Associated Insulin/Akt/EAAT Signaling Perturbations in Human Astrocytes
The excitatory amino acid transporters 1 and 2 (EAAT1 and EAAT2), mostly located on astrocytes, are the main mediators for glutamate clearance in humans. Malfunctions of these transporters may lead to excessive glutamate accumulation and subsequent excitotoxicity to neurons, which has been implicated in many kinds of neurodegenerative disorders including Alzheimer’s disease (AD). Yet, the specific mechanism of the glutamate system dysregulation remains vague. To explore whether the insulin/protein kinase B (Akt)/EAAT signaling in human astrocytes could be disturbed by beta-amyloid protein (Aβ) and be protected by insulin, we incubated HA-1800 cells with varying concentrations of Aβ1–42 oligomers and insulin. Then the alterations of several key substrates in this signal transduction pathway were determined. Our results showed that expressions of insulin receptor, phospho-insulin receptor, phospho-protein kinase B, phospho-mammalian target of rapamycin, and EAAT1 and EAAT2 were decreased by the Aβ1–42 oligomers in a dose-dependent manner (p 0.05), and the mRNA levels of EAAT1 and EAAT2 were also unchanged (p > 0.05). Taken together, this study indicates that Aβ1–42 oligomers could cause disturbances in insulin/Akt/EAAT signaling in astrocytes, which might be responsible for AD onset and progression. Additionally, insulin can exert protective functions to the brain by modulating protein modifications or expressions
The vital role of hole-carriers for superconductivity in pressurized black phosphorus
The influence of carrier type on superconductivity has been an important
issue for understanding both conventional and unconventional superconductors
[1-7]. For elements that superconduct, it is known that hole-carriers govern
the superconductivity for transition and main group metals [8-10]. The role of
hole-carriers in elements that are not normally conducting but can be converted
to superconductors, however, remains unclear due to the lack of experimental
data. Here we report the first in-situ high pressure Hall effect measurements
on single crystal black phosphorus, measured up to ~ 50 GPa, and find a
correlation between the Hall coefficient and the superconducting transition
temperature (TC). Our results reveal that hole-carriers play a vital role in
developing superconductivity and enhancing TC. Importantly, we also find a
Lifshitz transition in the high-pressure cubic phase at ~17.2GPa, which
uncovers the origin of a puzzling valley in the superconducting TC-pressure
phase diagram. These results offer insight into the role of hole-carriers in
developing superconductivity in simple semiconducting solids under pressure.Comment: 9 pages anf 3 figure
Patterns of Convergence and Divergence Between Bipolar Disorder Type I and Type II: Evidence From Integrative Genomic Analyses
Aim: Genome-wide association studies (GWAS) analyses have revealed genetic evidence of bipolar disorder (BD), but little is known about the genetic structure of BD subtypes. We aimed to investigate the genetic overlap and distinction of bipolar type I (BD I) & type II (BD II) by conducting integrative post-GWAS analyses.
Methods: We utilized single nucleotide polymorphism (SNP)-level approaches to uncover correlated and distinct genetic loci. Transcriptome-wide association analyses (TWAS) were then approached to pinpoint functional genes expressed in specific brain tissues and blood. Next, we performed cross-phenotype analysis, including exploring the potential causal associations between two BD subtypes and lithium responses and comparing the difference in genetic structures among four different psychiatric traits.
Results: SNP-level evidence revealed three genomic loci, SLC25A17, ZNF184, and RPL10AP3, shared by BD I and II, and one locus (MAD1L1) and significant gene sets involved in calcium channel activity, neural and synapsed signals that distinguished two subtypes. TWAS data implicated different genes affecting BD I and II through expression in specific brain regions (nucleus accumbens for BD I). Cross-phenotype analyses indicated that BD I and II share continuous genetic structures with schizophrenia and major depressive disorder, which help fill the gaps left by the dichotomy of mental disorders.
Conclusion: These combined evidences illustrate genetic convergence and divergence between BD I and II and provide an underlying biological and trans-diagnostic insight into major psychiatric disorders
Can LLMs like GPT-4 outperform traditional AI tools in dementia diagnosis? Maybe, but not today
Recent investigations show that large language models (LLMs), specifically
GPT-4, not only have remarkable capabilities in common Natural Language
Processing (NLP) tasks but also exhibit human-level performance on various
professional and academic benchmarks. However, whether GPT-4 can be directly
used in practical applications and replace traditional artificial intelligence
(AI) tools in specialized domains requires further experimental validation. In
this paper, we explore the potential of LLMs such as GPT-4 to outperform
traditional AI tools in dementia diagnosis. Comprehensive comparisons between
GPT-4 and traditional AI tools are conducted to examine their diagnostic
accuracy in a clinical setting. Experimental results on two real clinical
datasets show that, although LLMs like GPT-4 demonstrate potential for future
advancements in dementia diagnosis, they currently do not surpass the
performance of traditional AI tools. The interpretability and faithfulness of
GPT-4 are also evaluated by comparison with real doctors. We discuss the
limitations of GPT-4 in its current state and propose future research
directions to enhance GPT-4 in dementia diagnosis.Comment: 16 pages, 6 figure
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