Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for...Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for Impulse Radio Ultra-WideBand (IR-UWB) communication systems. This modulation scheme uses pulses with equal amplitude and different widths to carry different information. The receiver employs differences between similarity coefficients among these pulses to distinguish different information. Both theoretical analysis and simulation results verify that this novel scheme has a Signal to Noise Ratio (SNR) gain of about 1.75 dB compared with or- thogonal binary PPM, and has an SNR loss of about 1.4 dB compared with binary PAM. Although both the theoretical analysis and simulations are based on time-hopping multiple access, this modulation scheme can also be applied to other accessing techniques of UWB communication systems.展开更多
Global warming has been the subject of concern in today’s world with elevating temperature causing the melting of polar ice and increasing sea level.The aim of this study was to investigate the physiological and phot...Global warming has been the subject of concern in today’s world with elevating temperature causing the melting of polar ice and increasing sea level.The aim of this study was to investigate the physiological and photosynthetic performance of two polar Chlorella,namely Chlorella UMACC 250 and Chlorella UMACC 234 to elevating temperatures as might be experienced under future warming scenarios.The cultures were exposed to three different temperatures of 4℃,8℃and 12℃.The growth and photosynthetic activity were determined every 2 d for a period of 10 d.At the end of the experiment,the cultures were harvested and analysed for biochemical composition.Both Chlorella strains were able to tolerate higher temperatures than their ambient temperature.The final pigments content showed an increasing trend with increased temperatures for both strains.The photosynthetic activities were measured using pulse-amplitude modulation(PAM)fluorometer.The photosynthetic parameters including maximum quantum efficiency(Fv/Fm),maximum relative electron transport rate(r ETRmax),light harvesting efficiency(a)and photoadaptive index(Ek)were derived from the rapid light curves(RLCs).Both Chlorella strains showed a slight decline in growth and photosynthetic activities at the initial part of the experiment.However,they showed the ability to recuperate with Chlorella UMACC 250 recovers better compared to Chlorella UMACC 234.Both Chlorella strains showed similar trend in their carbohydrate content at 12℃,while the protein content of Chlorella UMACC 234 decreased when exposed to increasing temperatures.The results indicated that polar Chlorella are able to survive at increased temperatures throughout the experiment.展开更多
G-protein coupled receptors(GPCRs)are the largest family of druggable targets.In recent years,GPCR structural biology has made great advances,revealing the three-dimensional structures of many GPCRs and their interact...G-protein coupled receptors(GPCRs)are the largest family of druggable targets.In recent years,GPCR structural biology has made great advances,revealing the three-dimensional structures of many GPCRs and their interactions with ligands,proteins,and membrane components,which also have inspired a surge of structure-based drug discovery campaigns.This article provides a comprehensive summary of the currently available structural insights into the allosteric pockets of GPCRs and their regulatory mechanisms governing GPCR conformational changes.Furthermore,this article also presents several structure-inspired studies that utilize both orthosteric and allosteric modulation to discover small molecular modulators targeting GPCRs.The article emphasizes the promising potential of drug discovery targeting GPCR allosteric sites,while acknowledging the challenges arising from the limited structural information regarding the lipids and cholesterols in the membrane.Finally,the article discusses the future prospects of using large-scale or focused compound libraries to discover novel chemotypes,as well as the application of artificial intelligence(AI)in structure-based virtual screening(SBVS)against GPCRs.展开更多
文摘Since the poor performance of orthogonal binary Pulse Position Modulation (PPM) compared with binary Pulse Amplitude Modulation (PAM), this paper presents a new modulation scheme named Pulse Width Modulation (PWM) for Impulse Radio Ultra-WideBand (IR-UWB) communication systems. This modulation scheme uses pulses with equal amplitude and different widths to carry different information. The receiver employs differences between similarity coefficients among these pulses to distinguish different information. Both theoretical analysis and simulation results verify that this novel scheme has a Signal to Noise Ratio (SNR) gain of about 1.75 dB compared with or- thogonal binary PPM, and has an SNR loss of about 1.4 dB compared with binary PAM. Although both the theoretical analysis and simulations are based on time-hopping multiple access, this modulation scheme can also be applied to other accessing techniques of UWB communication systems.
基金funded by a research grant from the Ministry of Higher Education Malaysia under the Fundamental Research Grant Scheme(Grant no.FRGS/1/2017/STG05/TAYLOR/02/2)。
文摘Global warming has been the subject of concern in today’s world with elevating temperature causing the melting of polar ice and increasing sea level.The aim of this study was to investigate the physiological and photosynthetic performance of two polar Chlorella,namely Chlorella UMACC 250 and Chlorella UMACC 234 to elevating temperatures as might be experienced under future warming scenarios.The cultures were exposed to three different temperatures of 4℃,8℃and 12℃.The growth and photosynthetic activity were determined every 2 d for a period of 10 d.At the end of the experiment,the cultures were harvested and analysed for biochemical composition.Both Chlorella strains were able to tolerate higher temperatures than their ambient temperature.The final pigments content showed an increasing trend with increased temperatures for both strains.The photosynthetic activities were measured using pulse-amplitude modulation(PAM)fluorometer.The photosynthetic parameters including maximum quantum efficiency(Fv/Fm),maximum relative electron transport rate(r ETRmax),light harvesting efficiency(a)and photoadaptive index(Ek)were derived from the rapid light curves(RLCs).Both Chlorella strains showed a slight decline in growth and photosynthetic activities at the initial part of the experiment.However,they showed the ability to recuperate with Chlorella UMACC 250 recovers better compared to Chlorella UMACC 234.Both Chlorella strains showed similar trend in their carbohydrate content at 12℃,while the protein content of Chlorella UMACC 234 decreased when exposed to increasing temperatures.The results indicated that polar Chlorella are able to survive at increased temperatures throughout the experiment.
基金This work is supported by Beijing Municipal Science&Technology Commission(Z201100005320012 to N.H.)and Tsinghua University.
文摘G-protein coupled receptors(GPCRs)are the largest family of druggable targets.In recent years,GPCR structural biology has made great advances,revealing the three-dimensional structures of many GPCRs and their interactions with ligands,proteins,and membrane components,which also have inspired a surge of structure-based drug discovery campaigns.This article provides a comprehensive summary of the currently available structural insights into the allosteric pockets of GPCRs and their regulatory mechanisms governing GPCR conformational changes.Furthermore,this article also presents several structure-inspired studies that utilize both orthosteric and allosteric modulation to discover small molecular modulators targeting GPCRs.The article emphasizes the promising potential of drug discovery targeting GPCR allosteric sites,while acknowledging the challenges arising from the limited structural information regarding the lipids and cholesterols in the membrane.Finally,the article discusses the future prospects of using large-scale or focused compound libraries to discover novel chemotypes,as well as the application of artificial intelligence(AI)in structure-based virtual screening(SBVS)against GPCRs.
