220 research outputs found
Response of Stomatal Density and Bound Gas Exchange in Leaves of Maize to Soil Water Deficit
Stomatal behavior in response to drought has been the focus of intensive research, but less attention has been paid to stomatal density. In this study, 5-week-old maize seedlings were exposed to different soil water contents. Stomatal density and size as well as leaf gas exchange were investigated after 2-, 4- and 6-weeks of treatment, which corresponded to the jointing, trumpeting, and filling stages of maize development. Results showed that new stomata were generated continually during leaf growth. Reduced soil water content significantly stimulated stomatal generation, resulting in a significant increase in stomatal density but a decrease in stomatal size and aperture. Independent of soil water conditions, stomatal density and length in the trumpeting and filling stages were greater than in the jointing stage. Irrespective of growth stage, severe water deficit significantly reduced stomatal conductance (Gs), decreasing the leaf transpiration rate (Tr) and net photosynthetic rate (Pn). Stomatal density was significantly negatively correlated with both Pn and Tr but more strongly with Tr, so the leaf instantaneous water use efficiency (WUEi) correlated positively with stomatal density. In conclusion, drought led to a significant increase in stomatal density and a reduction in stomatal size and aperture, resulting in decreased Pn and Tr. Because the negative correlation of stomatal density to Tr was stronger than that to Pn, leaf WUEi tended to increase
The Development and Validation of an EFL Learner Attitude Scale for Phonetic Symbol Learning in A Chinese University Context
Research has established that learner attitude significantly impacts the outcomes of learning English as a foreign language (EFL). However, previous studies have rarely considered a validated attitude scale for English phonetic symbol learning (EPSL). This study aims to develop and validate a scale to measure students\u27 attitudes toward EPSL by integrating findings from learning attitude research in education and psychology. The results demonstrate that the attitude scale can predict attitudes towards EPSL in the context of a Chinese university and has good reliability and validity (KMO=0.892, α=0.749). Pedagogical suggestions are made to help students develop a more positive attitude toward EPSL
Early selection of \u3cem\u3ebZIP73\u3c/em\u3e facilitated adaptation of \u3cem\u3ejaponica\u3c/em\u3e rice to cold climates
Cold stress is a major factor limiting production and geographic distribution of rice (Oryza sativa). Although the growth range of japonica subspecies has expanded northward compared to modern wild rice (O. rufipogon), the molecular basis of the adaptation remains unclear. Here we report bZIP73, a bZIP transcription factor-coding gene with only one functional polymorphism (+511 G\u3eA) between the two subspecies japonica and indica, may have facilitated japonica adaptation to cold climates. We show the japonica version of bZIP73 (bZIP73Jap) interacts with bZIP71 and modulates ABA levels and ROS homeostasis. Evolutionary and population genetic analyses suggest bZIP73 has undergone balancing selection; the bZIP73Jap allele has firstly selected from standing variations in wild rice and likely facilitated cold climate adaptation during initial japonica domestication, while the indica allele bZIP73Ind was subsequently selected for reasons that remain unclear. Our findings reveal early selection of bZIP73Jap may have facilitated climate adaptation of primitive rice germplasms
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Green cell planning and deployment for small cell networks in smart cities
In smart cities, cellular network plays a crucial role to support wireless access for numerous devices anywhere and anytime. The future 5G network aims to build the infrastructure from mobile internet to connected world. Small Cell is one of the most promising technologies of 5G to provide more connections and high data rate. In order to make the best use of small cell technology, smart cell planning should be implemented to guarantee connectivity and performance for all end nodes. It is particularly a challenging task to deploy dense small cells in the presence of dynamic traffic demands and severe co-channel interference. In this paper, we model various traffic patterns using stochastic geometry approach and propose an energy-efficient scheme to deploy and plan small cells according to the prevailing traffic pattern. The simulation results indicate that our scheme can meet dynamic traffic demands with optimized deployment of small cells and enhance the energy efficiency of the system without compromising on quality-of-service (QoS) requirements. In addition, our scheme can achieve very close performance compared with the leading optimization solver CPLEX and find solutions in much less computational times than CPLEX
Interaction of serum vitamin B12 and folate with MTHFR genotypes on risk of ischemic stroke
ObjectiveWe evaluated the interaction of serum folate and vitamin B12 with methylenetetrahydrofolate reductase (MTHFR) C677T genotypes on the risk of first ischemic stroke and on the efficacy of folic acid treatment in prevention of first ischemic stroke.MethodsA total of 20,702 hypertensive adults were randomized to a double-blind treatment of daily enalapril 10 mg and folic acid 0.8 mg or enalapril 10 mg alone. Participants were followed up every 3 months.ResultsMedian values of folate and B12 concentrations at baseline were 8.1 ng/mL and 280.2 pmol/L, respectively. Over a median of 4.5 years, among those not receiving folic acid, participants with baseline serum B12 or serum folate above the median had a significantly lower risk of first ischemic stroke (hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.57-0.96), especially in those with MTHFR 677 CC genotype (wild-type) (HR, 0.49; 95% CI, 0.31-0.78). Folic acid treatment significantly reduced the risk of first ischemic stroke in participants with both folate and B12 below the median (2.3% in enalapril-folic acid group vs 3.6% in enalapril-only group; HR, 0.62; 95% CI, 0.46-0.86), particularly in MTHFR 677 CC carriers (1.6% vs 4.9%; HR, 0.24; 95% CI, 0.11-0.55). However, TT homozygotes responded better with both folate and B12 levels above the median (HR, 0.28; 95% CI, 0.10-0.75).ConclusionsThe risk of first ischemic stroke was significantly higher in hypertensive patients with low levels of both folate and B12. Effect of folic acid treatment was greatest in patients with low folate and B12 with the CC genotype, and with high folate and B12 with the TT genotype
A multi-task learning model for super resolution of wireless channel characteristics
Channel modeling has always been the core part in communication system design and development, especially in 5G and 6G era. Traditional approaches like stochastic channel modeling and ray-tracing (RT) based channel modeling depend heavily on measurement data or simulation, which are usually expensive and time consuming. In this paper, we propose a novel super resolution (SR) model for generating channel character-istics data. The model is based on multi-task learning (MTL) convolutional neural networks (CNN) with residual connection. Experiments demonstrate that the proposed SR model could achieve excellent performances in mean absolute error and standard deviation of error. Advantages of the proposed model are demonstrated in comparisons with other state-of-the-art deep learning models. Ablation study also proved the necessity of multi-task learning and techniques in model design. The contribution in this paper could be helpful in channel modeling, network optimization, positioning and other wireless channel characteristics related work by largely reducing workload of simulation or measurement
Acupuncture Improved Neurological Recovery after Traumatic Brain Injury by Activating BDNF/TrkB Pathway
How to promote neural repair following traumatic brain injury (TBI) has long been an intractable problem. Although acupuncture has been demonstrated to facilitate the neurological recovery, the underlying mechanism is elusive. Brain-derived neurotrophic factor (BDNF) exerts substantial protective effects for neurological disorders. In this study, we found that the level of BDNF and tropomyosin receptor kinase B (TrkB) was elevated spontaneously after TBI and reached up to the peak at 12 h. Nevertheless, this enhancement is quickly declined to the normal at 48 h. After combined stimulation at the acupoints of Baihui, Renzhong, Hegu, and Zusanli, we found that BDNF and TrkB were still significantly elevated at 168 h. We also observed that the downstream molecular p-Akt and p-Erk1/2 were significantly increased, suggesting that acupuncture could persistently activate the BDNF/TrkB pathway. To further verify that acupuncture improved recovery through activating BDNF/TrkB pathway, K252a (specific inhibitor of TrkB) was treated by injection stereotaxically into lateral ventricle. We observed that K252a could significantly prevent the acupuncture-induced amelioration of motor, sensation, cognition, and synaptic plasticity. These data indicated that acupuncture promoted the recovery of neurological impairment after TBI by activating BDNF/TrkB signaling pathway, providing new molecular mechanism for understanding traditional therapy of acupuncture
EFFECTS OF SALVIA MILTIORRHIZAE ON THE KIDNEY OF RATS WITH SEVERE ACUTE PANCREATITIS AND OBSTRUTIVE JAUNDICE
Background: Severe acute pancreatitis (SAP) and obstructive jaundice (OJ) are frequent recurring diseases that bring
about huge threat to human health. Some reports have demonstrated that Salviae miltiorrhizae can protect multiple
organs of SAP and OJ model animals or patients, but their related mechanisms were not clear. In this study, we
observed the effects of Salvia miltiorrhizae injection on apoptosis and NF-κB expression in kidney and explored the
protective effect and mechanism of Salvia miltiorrhizae on the kidney of SAP or OJ rats. The results obtained will
provide a theoretical basis for clinical application of Salvia miltiorrhizae.
Material and Methods: A total of 288 rats were used for SAP - and OJ-associated experiments. The mortality rates of
rats, the contents of serum BUN and CREA, the expression levels of Bax, NF-κB proteins and the apoptosis index were
observed, respectively.
Results: The pathological changes in the kidney of SAP or OJ rats in treated group were mitigated to varying degrees.
At 6 and 12 hours after operation in SAP rats or on 21 and 28 days after operation in OJ rats, the contents of serum
CREA in treated group were significantly lower than those in model control group; At 3 and 6 hours after operation,
the staining intensity of Bax protein of kidney in treated group was significantly lower than that in model control group;
on 14 days after operation, the apoptosis index in the kidney of OJ rats in treated group was significantly lower than
that in model control group.
Conclusion: Salvia miltiorrhizae can exert protective effects on the kidney of SAP and OJ rats
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