812 research outputs found
Feasibility Of OneâDedicatedâLane Bus Rapid Transit âLightâRail Systems And Their Expansion To TwoâDedicatedâLane Systems: A Focus On Geometric Configuration And Performance Planning, MTI Report 08-01
This report consists primarily of two parts, the first on feasibility and the next on space minimization. In the section on feasibility, we propose the concept of a Bus Rapid Transit (BRT) or lightârail system that effectively requires only one dedicated but reversible lane throughout the system to support two-way traffic in the median of a busy commute corridor with regular provision of leftâturn lanes. Based on key ideas proposed in that section, the section on space minimization first addresses how to implement a twoâdedicatedâlane BRT or lightârail system with minimum rightâofâway width and then proposes ways to expand a oneâdedicatedâlane system to two dedicated lanes. In a oneâdedicatedâlane system, traffic crossing is accommodated on the otherwise unused or underused median space resulting from provision of the leftâturn lanes. Although not necessary, some leftâturn lanes can be sacrificed for bus stops. Conceptual design options and geometric configuration sketches for the bus stop and crossing space are provided in the section on feasibility, which also discusses system performance in terms of travel speed, headway of operations, distance between two neighboring crossing spaces, and number of crossing spaces. To ensure practicality, we study implementation of such a system on an existing corridor. Such a system is also useful as an intermediate step toward a twoâdedicatedâlane system because of its potential for facilitating transitâoriented development. In typical existing or planned BRT or lightârail systems implemented with two dedicated traffic lanes, a space equivalent to four traffic lanes is dedicated for a bus stop. In the section on space minimization, we propose implementations requiring only three lanes at a bus stop, based on two key ideas proposed for a oneâdedicatedâlane system. That section also discusses ways to expand a oneâdedicatedâlane system to its corresponding twoâdedicatedâlane system
Life-Long Physical Activity Involvement and the Risk of Ischemic Stroke in Southern China
A case-control study was conducted in southern China to investigate the relationship between life-long physical activity involvement and the risk of ischemic stroke. Information on life-long physical activity exposure and other lifestyle characteristics was obtained from 374 incident stroke patients and 464 hospital-based controls using a validated and reliable questionnaire. Logistic regression analyses were performed to assess the association between life-long physical activity involvement and the ischemic stroke risk. The control subjects reported more involvement in physical activity over the life course than the stroke patients (P < .001). The risk of ischemic stroke was inversely associated with life-long physical activity exposure, with adjusted odds ratio 0.39 (95% confidence interval 0.25 to 0.59) for participants who had always been involved relative to those who have never been much involved. The dose-response relationship was also significant (P < .001). Therefore, being active life long should be encouraged to prevent this major chronic disease
Does the Consumption of Green Tea Reduce the Risk of Lung Cancer Among Smokers?
Experimental and epidemiological studies were reviewed to assess whether the consumption of green tea could reduce the risk of lung cancer in smokers. Articles published since 1990 were located by searching electronic databases PubMed, Ovid and Science Direct, using keywords âlung cancerâ, âteaâ and âsmokingâ without any restriction on language. After relevant articles had been located, further papers were obtained from their reference lists. Evidence from experimental studies (in vitro animal and human trials) suggested that regular intake of green tea may be protective against tobacco carcinogens. However, the mechanism behind the protective effect is only partly understood. In most of the epidemiological studies reviewed, the green tea exposure was within 5 years of the interview or follow-up, which would coincide with the induction period and latent period of lung cancer. Longer term studies are thus needed to further quantify the cancer risk. There is some evidence suggesting regular intake of green tea at high level (>3 cups per day) may reduce the risk of smokers developing lung cancer. Improvement in measuring green tea intake is required in order to confirm the evidence from epidemiological studies
Harvested area gaps in China between 1981 and 2010:Effects of climatic and land management factors
Previous analyses have shown that cropland in China is intensifying, leading to an increase in crop production. However, these output measures leave the potential for further intensification largely unassessed. This study uses the harvested area gap (HAG), which expresses the amount of harvested area that can be gained if all existing cropland is harvested as frequently as possible, according to their potential limit for multi-cropping. Specifically, we calculate the HAG and changes in the HAG in China between 1981 and 2010. We further assess how climatic and land management factors affect these changes. We find that in China the HAG decreases between the 1980s and the 1990s, and subsequently increases between the 1990s and the 2000s, resulting in a small net increase for the entire study period. The initial decrease in the HAG is the result of an increase in the average multi-cropping index throughout the country, which is larger than the increase in the potential multi-cropping index as a result of the changed climatic factors. The subsequent increase in the HAG is the result of a decrease in average multi-cropping index throughout the country, in combination with a stagnant potential. Despite the overall increase in harvested area in China, many regions, e.g. Northeast and Lower Yangtze, are characterized by an increased HAG, indicating their potential for further increasing the multi-cropping index. The study demonstrates the application of the HAG as a method to identify areas where the harvested area can increase to increase crop production, which is currently underexplored in scientific literature
CD40L membrane retention enhances the immunostimulatory effects of CD40 ligation
In carcinomas, the nature of CD40 ligand shapes the outcome of CD40 ligation. To date, the consequences of membrane-bound CD40L (mCD40L) on its immune-stimulatory function are unknown. Here, we examined the impact of mCD40L versus soluble CD40L (sCD40L) on T24 bladder carcinoma gene expression profiling. Of 410 differentially expressed genes, 286 were upregulated and 124 downregulated by mCD40L versus sCD40L. Gene ontology enrichment analysis revealed immune-stimulatory function as the most significant enriched biological process affected by upregulated transcripts, while those downregulated were critical for cell growth and division. Furthermore, immature dendritic cells (iDC) responded to mCD40L with enhanced maturation and activation over sCD40L evidenced by higher expression levels of CD83, CD86, HLA-DR and CD54, increased secretion of IL12 and IL10 and higher tumour-antigen (TA) uptake capacity. Furthermore, autologus CD3+ T cells responded to TA-loaded mCD40L-activated DC with increased proliferation and cytotoxic response (CD107a and IFN-Îł-producing CD3+ CD8+ T cells) to the tumour-loaded autologous PBMCs compared to sCD40L. Thus, these data indicate that mCD40L enhances the immunostimulatory capacity over sCD40L. Furthermore, the ability of mCD40L to also directly induce cell death in CD40-expressing carcinomas, subsequently releasing tumour-specific antigens into the tumour microenvironment highlights the potential for mCD40L as a multi-faceted anti-cancer immunotherapeutic
Highly Efficient and Selective Photocatalytic Nonoxidative Coupling of Methane to Ethylene over Pd-Zn Synergistic Catalytic Sites
Photocatalytic nonoxidative coupling of CH4 to multicarbon (C2+) hydrocarbons (e.g., C2H4) and H2 under ambient conditions provides a promising energy-conserving approach for utilization of carbon resource. However, as the methyl intermediates prefer to undergo self-coupling to produce ethane, it is a challenging task to control the selective conversion of CH4 to higher value-added C2H4. Herein, we adopt a synergistic catalysis strategy by integrating Pd-Zn active sites on visible light-responsive defective WO3 nanosheets for synergizing the adsorption, activation, and dehydrogenation processes in CH4 to C2H4 conversion. Benefiting from the synergy, our model catalyst achieves a remarkable C2+ compounds yield of 31.85 mu mol center dot g-1 center dot h-1 with an exceptionally high C2H4 selectivity of 75.3% and a stoichiometric H2 evolution. In situ spectroscopic studies reveal that the Zn sites promote the adsorption and activation of CH4 molecules to generate methyl and methoxy intermediates with the assistance of lattice oxygen, while the Pd sites facilitate the dehydrogenation of methoxy to methylene radicals for producing C2H4 and suppress overoxidation. This work demonstrates a strategy for designing efficient photocatalysts toward selective coupling of CH4 to higher value-added chemicals and highlights the importance of synergistic active sites to the synergy of key steps in catalytic reactions.Peer reviewe
Dynamics of An Underdamped Josephson Junction Ladder
We show analytically that the dynamical equations for an underdamped ladder
of coupled small Josephson junctions can be approximately reduced to the
discrete sine-Gordon equation. As numerical confirmation, we solve the coupled
Josephson equations for such a ladder in a magnetic field. We obtain
discrete-sine-Gordon-like IV characteristics, including a flux flow and a
``whirling'' regime at low and high currents, and voltage steps which represent
a lock-in between the vortex motion and linear ``phasons'', and which are
quantitatively predicted by a simple formula. At sufficiently high anisotropy,
the fluxons on the steps propagate ballistically.Comment: 11pages, latex, no figure
The chemistrode: A droplet-based microfluidic device for stimulation and recording with high temporal, spatial, and chemical resolution
Microelectrodes enable localized electrical stimulation and recording, and they have revolutionized our understanding of the spatiotemporal dynamics of systems that generate or respond to
electrical signals. However, such comprehensive understanding of
systems that rely on molecular signalsâe.g., chemical communication in multicellular neural, developmental, or immune systemsâremains elusive because of the inability to deliver, capture,
and interpret complex chemical information. To overcome this
challenge, we developed the ââchemistrode,ââ a plug-based microïŹuidic device that enables stimulation, recording, and analysis
of molecular signals with high spatial and temporal resolution.
Stimulation with and recording of pulses as short as 50 ms was
demonstrated. A pair of chemistrodes fabricated by multilayer soft
lithography recorded independent signals from 2 locations separated by 15 ÎŒm. Like an electrode, the chemistrode does not need
to be built into an experimental systemâit is simply brought into
contact with a chemical or biological substrate, and, instead of
electrical signals, molecular signals are exchanged. Recorded molecular signals can be injected with additional reagents and analyzed off-line by multiple, independent techniques in parallel (e.g.,
ïŹuorescence correlation spectroscopy, MALDI-MS, and ïŹuorescence microscopy). When recombined, these analyses provide a
time-resolved chemical record of a systemâs response to stimulation. Insulin secretion from a single murine islet of Langerhans was
measured at a frequency of 0.67 Hz by using the chemistrode. This
article characterizes and tests the physical principles that govern
the operation of the chemistrode to enable its application to
probing local dynamics of chemically responsive matter in chemistry and biology
The receptor like kinase at Rhg1-a/Rfs2 caused pleiotropic resistance to sudden death syndrome and soybean cyst nematode as a transgene by altering signaling responses
Background: Soybean (Glycine max (L. Merr.)) resistance to any population of Heterodera glycines (I.), or Fusarium virguliforme (Akoi, OâDonnell, Homma & Lattanzi) required a functional allele at Rhg1/Rfs2. H. glycines, the soybean cyst nematode (SCN) was an ancient, endemic, pest of soybean whereas F. virguliforme causal agent of sudden death syndrome (SDS), was a recent, regional, pest. This study examined the role of a receptor like kinase (RLK) GmRLK18-1 (gene model Glyma_18_02680 at 1,071 kbp on chromosome 18 of the genome sequence) within the Rhg1/Rfs2 locus in causing resistance to SCN and SDS.
Results: A BAC (B73p06) encompassing the Rhg1/Rfs2 locus was sequenced from a resistant cultivar and compared to the sequences of two susceptible cultivars from which 800 SNPs were found. Sequence alignments inferred that the resistance allele was an introgressed region of about 59 kbp at the center of which the GmRLK18-1 was the most polymorphic gene and encoded protein. Analyses were made of plants that were either heterozygous at, or transgenic (and so hemizygous at a new location) with, the resistance allele of GmRLK18-1. Those plants infested with either H. glycines or F. virguliforme showed that the allele for resistance was dominant. In the absence of Rhg4 the GmRLK18-1 was sufficient to confer nearly complete resistance to both root and leaf symptoms of SDS caused by F. virguliforme and provided partial resistance to three different populations of nematodes (mature female cysts were reduced by 30â50%). In the presence of Rhg4 the plants with the transgene were nearly classed as fully resistant to SCN (females reduced to 11% of the susceptible control) as well as SDS. A reduction in the rate of early seedling root development was also shown to be caused by the resistance allele of the GmRLK18-1. Field trials of transgenic plants showed an increase in foliar susceptibility to insect herbivory.
Conclusions: The inference that soybean has adapted part of an existing pathogen recognition and defense cascade (H.glycines; SCN and insect herbivory) to a new pathogen (F. virguliforme; SDS) has broad implications for crop improvement. Stable resistance to many pathogens might be achieved by manipulation the genes encoding a small number of pathogen recognition proteins
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