BACKGROUND Juvenile polyps(JPs)are non-neoplastic polyps.In adults,JPs present with hematochezia in only approximately half the patients and are often found incidentally during endoscopic screening.JPs have no mucosal...BACKGROUND Juvenile polyps(JPs)are non-neoplastic polyps.In adults,JPs present with hematochezia in only approximately half the patients and are often found incidentally during endoscopic screening.JPs have no mucosal fascia at the tip,and spontaneous shedding and massive gastrointestinal hemorrhage may occur.Thus,the JP bleeding detected in this case by extravascular contrast leakage on computed tomography scans and treated with endoscopic clipping is rare.CASE SUMMARY A previously healthy 31-year-old male patient presented with a 2-day history of bloody stools.Upon hospital arrival,rectal examination revealed fresh blood,and abdominal computed tomography scans showed extravascular contrast leakage from the lower rectum’s left-side wall.His blood pressure was slightly low at 104/62 mmHg.However,his pulse rate(69 bpm)and oxygen level(99%on room air)were within normal limits.Emergency endoscopy revealed a pedunculated lesion in the rectum covered by a non-neoplastic mucosal epithelium.No neoplastic lesions were observed at the tip of the polyp;however,pulsatile bleeding was detected at the distal end.We performed endoscopic hemostasis by clipping the stem and then performed a polypectomy above the stem to examine the lesion tissue.Histopathological evaluation revealed a cystically dilated gland without neoplastic lesions.A subsequent total colonoscopy revealed two JPs with characteristic edematous,smooth,and reddish surfaces close to the hemorrhagic lesion.Subsequent histopathological evaluation indicated findings characteristic of JP,such as severe inflammatory cell infiltration of the stroma and cystic dilatation of the glandular ducts.CONCLUSION There are no reports of adult JPs presenting with contrast extravasation where endoscopic hemostasis was successful,as in this case.展开更多
Peak load and wind energy emission pressure rise more as wind energy penetration keeps growing,which affects the stabilization of the PS(power system).This paper suggests integrated optimal dispatching of thermal powe...Peak load and wind energy emission pressure rise more as wind energy penetration keeps growing,which affects the stabilization of the PS(power system).This paper suggests integrated optimal dispatching of thermal power generators and BESS(battery energy storage system)taking wind energy emission grading punishment and deep peak clipping into consideration.Firstly,in order to minimize wind abandonment,a hierarchical wind abandonment penalty strategy based on fuzzy control is designed and introduced,and the optimal grid-connected power of wind energy is determined as a result of minimizing the peak cutting cost of the system.Secondly,considering BESS and thermal power,the management approach of BESS-assisted virtual peak clipping of thermal power generators is aimed at reducing the degree of deep peak clipping of thermal power generators and optimizing the output of thermal power generators and the charging and discharging power of BESS.Finally,Give an example of how this strategy has been effective in reducing abandonment rates by 0.66% and 7.46% individually for different wind penetration programs,and the daily average can reduce the peak clipping power output of thermal power generators by 42.97 and 72.31 MWh and enhances the effect and economy of system peak clipping.展开更多
Aiming at the problem of high temperature and even demagnetization failure of permanent magnet (PM) due to PM eddy current loss in PM synchronous high-speed motors, this paper proposes a technique to lessen PM eddy cu...Aiming at the problem of high temperature and even demagnetization failure of permanent magnet (PM) due to PM eddy current loss in PM synchronous high-speed motors, this paper proposes a technique to lessen PM eddy current loss by cutting the angle of PM poles to change the shape of PM structure. Firstly, an analysis is conducted on the mechanism of PM synchronous high-speed motor eddy current loss production, the theoretical analytical model of PM eddy current loss is deduced, and it is theoretically proved that the magnetic pole shaving angle can reduce PM eddy current loss. Then, a 25 KW surface-type PM synchronous high-speed motor as an object, using two-dimensional time-step finite element method (FEM) to model and analyze PM eddy current loss. The results show that the smaller the PM pole shaving angle, the less its eddy current loss will be, it is possible to minimize the pole shaving angle of eddy current loss by 9.8% compared to the unshaved angle. Finally, the temperature field of the PM is calculated using a finite element method, and the outcomes demonstrate that the maximum temperature of the PM with a magnetic pole shaving angle can be reduced by about 5% compared with the unshaved angle.展开更多
Improving the efficacy of phytoextraction is critical for its successful application in metal contaminated soils. Mineral nutrition affects plant growth and metal absorption and subsequently the accumulation of heavy ...Improving the efficacy of phytoextraction is critical for its successful application in metal contaminated soils. Mineral nutrition affects plant growth and metal absorption and subsequently the accumulation of heavy metal through hyper-accumulator plants. This study assessed the effects of di-hydrogen phosphates （KH2PO4, Ca（H2PO4）2, NaH2PO4 and NH4H2PO4） application at three levels （22, 88 and 352 mg P/kg soil） on Sedum alfredii growth and metal uptake by three consecutive harvests on aged and Zn/Cd combined contaminated paddy soil. The addition of phosphates （P） significantly increased the amount of Zn taken up by S. alfredii due to increased shoot Zn concentration and dry matter yield （DMY） （P 〈 0.05）. The highest phytoextraction of Zn and Cd was observed in KH2PO4 and NH4H2PO4 treatment at 352 mg P/kg soil. The amount of Zn removed by phytoextraction increased in the order of 1st clipping 〈 2nd clipping 〈 3rd clipping, and for Cd extraction the order was 2nd clipping 〈 1st clipping 〈 3rd clipping. These results indicate that the application of P fertilizers coupled with multiple cuttings can enhance the removal of Zn and Cd from contaminated soils by S. alfredii, thus shortening the time needed for accomplishing remediation goals.展开更多
Predicting how human activity will influence the response of alpine grasslands to future warming has many uncertainties.In this study, a field experiment with controlled warming and clipping was conducted in an alpine...Predicting how human activity will influence the response of alpine grasslands to future warming has many uncertainties.In this study, a field experiment with controlled warming and clipping was conducted in an alpine meadow at three elevations（4313 m, 4513 m and 4693 m） in Northern Tibet to test the hypothesis that clipping would alter warming effect on biomass production.Open top chambers（OTCs） were used to increase temperature since July,2008 and the OTCs increased air temperature by approximately 0.9o C ~ 1.8o C during the growing in2012.Clipping was conducted three times one year during growing season and the aboveground parts of all live plants were clipped to approximately 0.01 m in height using scissors since 2009.Gross primary production（GPP） was calculated from the Moderate-Resolution Imaging Spectroradiometer GPP algorithm and aboveground plant production was estimated using the surface-measured normalized difference vegetation index in 2012.Warming decreased the GPP, aboveground biomass（AGB） and aboveground net primary production（ANPP） at all three elevations when clipping was not applied.In contrast, warming increased AGB at all three elevations, GPP at the two lower elevations and ANPP at the two higher elevations when clipping was applied.These findings show that clipping reduced the negative effect of warming on GPP, AGB and ANPP, suggesting that clipping may reduce the effect of climate warming on GPP, AGB and ANPP in alpine meadows on the Tibetan Plateau, and therefore, may be a viable strategy for mitigating the effects of climate change on grazing and animal husbandry on the Tibetan Plateau.展开更多
Plain reservoirs are shallow, and have low dams and widespread water surfaces.Therefore, wind-wave-induced damage to the dam is one of the important factors affecting the safety of the reservoir.To improve upon unsati...Plain reservoirs are shallow, and have low dams and widespread water surfaces.Therefore, wind-wave-induced damage to the dam is one of the important factors affecting the safety of the reservoir.To improve upon unsatisfactory plain reservoir wave-clipping schemes, a numerical method is proposed to predict and analyze waves in the reservoir in the presence of artificial islands, constructed from dredged sediment.The MIKE21 SW model is applied to a specific plain reservoir for finding the optimal artificial island parameters.The simulated wave height attenuation results are seen to agree well with empirically predicted values.Thus, the validity and reliability of the numerical model are established.Artificial islands at suitable locations in the reservoir can attenuate the wave heights by approximately 10%e30%, which justifies the efficacy of the clipping scheme making use of dredging and island construction.展开更多
Aiming at the problem of the peak to average power ratio(PAPR)in coherent optical orthogonal frequency division multiplexing(CO-OFDM),a hybrid PAPR reduction technique of the CO-OFDM system by combining iterative part...Aiming at the problem of the peak to average power ratio(PAPR)in coherent optical orthogonal frequency division multiplexing(CO-OFDM),a hybrid PAPR reduction technique of the CO-OFDM system by combining iterative partial transmit sequence(IPTS)scheme with modified clipping and filtering(MCF)is proposed.The simulation results show that at the complementary cumulative distribution function(CCDF)of 10^(-4),the PAPR of proposed scheme is optimized by 1.86 d B and 2.13 d B compared with those of IPTS and CF schemes,respectively.Meanwhile,when the bit error rate(BER)is 10^(-3),the optical signal to noise ratio(OSNR)are optimized by 1.57 dB and 0.66 d B compared with those of CF and IPTS-CF schemes,respectively.展开更多
With advances in endoscopic technologies,endoscopic clips have been used widely and successfully in the treatment of various types of oesophageal perforations,anastomosis leakages and fistulas. Our aim was to summariz...With advances in endoscopic technologies,endoscopic clips have been used widely and successfully in the treatment of various types of oesophageal perforations,anastomosis leakages and fistulas. Our aim was to summarize the experience with two types of clips: The through-the-scope(TTS) clip and the over-the-scope clip(OTSC). We summarized the results of oesophageal perforation closure with endoscopic clips. We processed the data from 38 articles and 127 patients using PubM ed search. Based on evidence thus far,it can be stated that both clips can be used in the treatment of early(< 24 h),iatrogenic,spontaneous oesophageal perforations in the case of limited injury or contamination. TTS clips are efficacious in the treatment of 10 mm lesions,while bigger(< 20 mm) lesions can be treated successfully with OTSC clips,whose effectiveness is similar to that of surgical treatment. However,the clinical success rate is significantly lower in the case of fistulas and in the treatment of anastomosis insufficiency. Tough prospective randomized multicentre trials,which produce the largest amount of evidence,are still missing. Based on experience so far,endoscopic clips represent a possible therapeutic alternative to surgery in the treatment of oesophageal perforations under well-defined conditions.展开更多
Visible light communications(VLC)is considered as an effective supplement technology for next-generation(6G)communications due to its abundant spectrum,high power efficiency and easy deployment.Optical orthogonal freq...Visible light communications(VLC)is considered as an effective supplement technology for next-generation(6G)communications due to its abundant spectrum,high power efficiency and easy deployment.Optical orthogonal frequency division multiplexing(O-OFDM)is a common technology to obtain further promotion.In this paper,two typical O-OFDM schemes direct current biased O-OFDM(DCO-OFDM)and asymmetrically clipped O-OFDM(ACO-OFDM)are analyzed in terms of signal clipping at both transmitter and receiver under the constraints of maximum optical power and non-negative optical power.And effective electrical SNR models after signal clipping are proposed and verified by link simulation.Then a noise cancellation scheme is proposed based on received signal clipping and is proved to bring a significant gain for ACO-OFDM.By system simulation,we find that under a certain optical power limitation,most users can achieve above 4 Gbps in indoor scenario when modulation bandwidth of the light emit diode(LED)or laser diode(LD)is 1 GHz.Therefore,it can be expected that the throughput could reach tens Gbps when the LED/LD modulation bandwidth is increased and multiple LEDs/LDs are deployed.展开更多
Prompt diagnosis and therapy of aneurysms are critical for patients with nontraumatic subarachnoid hemorrhage （SAH）.The aim of our study was to assess the clinical usefulness of multislice computed tomography angiog...Prompt diagnosis and therapy of aneurysms are critical for patients with nontraumatic subarachnoid hemorrhage （SAH）.The aim of our study was to assess the clinical usefulness of multislice computed tomography angiography （CTA） in the surgical and endovascular treatment of intracranial aneurysms.A total of 195 cases with 206 intracranial aneurysms underwent CTA.Fifty （24%） aneurysms underwent surgical clipping while 156 （76%） aneurysms underwent endovascular coiling.In the five missed aneurysms at digital substraction angiography and the nine aneurysms with mass intracerebral hematomas,surgical treatment was successfully performed based on 16-slice CTA alone,and the other 36 aneurysms were clipped on the main basis of the CTA.The intraoperative findings correlated well with the CTA findings and all aneurysms were clipped successfully.Sixteen-slice CTA image information has been shown to determine the choice of aneurysm therapy and assist the surgical and endovascular treatment of intracranial aneurysms.展开更多
Early physiotherapy was given to 124 patients with ruptured or unruptured cerebral aneurysms who were treated by surgical clipping or endovascular embolization.Patients were divided into four groups according to their...Early physiotherapy was given to 124 patients with ruptured or unruptured cerebral aneurysms who were treated by surgical clipping or endovascular embolization.Patients were divided into four groups according to their Hunt and Hess grade at admission and aneurysm treatment modality： Group 1,Hunt and Hess grade≤II and surgical clipping;Group 2,Hunt and Hess grade≤II and endovascular embolization;Group 3,Hunt and Hess grade≥III and surgical clipping;Group 4,Hunt and Hess grade≥III and endovascular embolization.Level of consciousness was evaluated using the Glasgow Coma Scale,functional status using the Glasgow Outcome Scale,level of the mobility using the Mobility Scale for acute stroke patients,and independence in activities of daily living using the Barthel Index.After early physiotherapy,the level of consciousness and functional status improved significantly in Groups 1,3,and 4;mobility improved significantly in all groups;and independence in activities of daily living improved significantly in Groups 1 and 3.At discharge, Groups 1 and 2 had better functional status than Groups 3 and 4.Level of consciousness,functional status,mobility and independence in activities of daily living improved after early physiotherapy. These findings suggest that early physiotherapy improved the prognosis of patients with cerebral aneurysms who were treated by surgical clipping or endovascular embolization.Patients with a worse clinical status at presentation had a poorer functional status at discharge.The outcome of physiotherapy was not affected by whether surgical clipping or endovascular embolization was chosen for treatment of the aneurysm.展开更多
In this paper,the supervised Deep Neural Network(DNN)based signal detection is analyzed for combating with nonlinear distortions efficiently and improving error performances in clipping based Orthogonal Frequency Divi...In this paper,the supervised Deep Neural Network(DNN)based signal detection is analyzed for combating with nonlinear distortions efficiently and improving error performances in clipping based Orthogonal Frequency Division Multiplexing(OFDM)ssystem.One of the main disadvantages for the OFDM is the high Peak to Average Power Ratio(PAPR).The clipping is a simple method for the PAPR reduction.However,an effect of the clipping is nonlinear distortion,and estimations for transmitting symbols are difficult despite a Maximum Likelihood(ML)detection at the receiver.The DNN based online signal detection uses the offline learning model where all weights and biases at fully-connected layers are set to overcome nonlinear distortions by using training data sets.Thus,this paper introduces the required processes for the online signal detection and offline learning,and compares error performances with the ML detection in the clipping-based OFDM systems.In simulation results,the DNN based signal detection has better error performance than the conventional ML detection in multi-path fading wireless channel.The performance improvement is large as the complexity of system is increased such as huge Multiple Input Multiple Output(MIMO)system and high clipping rate.展开更多
AIM To determine if prophylactic clipping of post-polypectomy endoscopic mucosal resection(EMR) mucosal defects of large,flat,right sided polyps prevents perforations.METHODS IRB approved review of all colonoscopies,a...AIM To determine if prophylactic clipping of post-polypectomy endoscopic mucosal resection(EMR) mucosal defects of large,flat,right sided polyps prevents perforations.METHODS IRB approved review of all colonoscopies,and prospective data collection of grasp and snare EMR performed by 2 endoscopists between January 1,2010 and March 31,2014 in a community ambulatory endoscopy center.The study consisted of two phases.In the first phase,all right-sided,flat polyps greater than or equal to 1.2 cm in size were removed using the grasp and snare technique.Clipping was done at the discretion of the endoscopist.In the second phase,all mucosal defects were closed using resolution clips.Phase 2 of the study was powered to detect a statistically significant difference in perforation rate with 148 EMRs,if less than or equal to 2 perforations occurred.RESULTS In phase 1 of the study,2121 colonoscopies were performed.Seventy-five patients had 95 large polyps removed.There were 4 perforations in 95 polypectomies(4.2%).The perforations occurred in polyps ranging in size from 1.5 cm to 2.5 cm.In phase 2,there were 2464 colonoscopies performed.One hundred and sixteen patients had 151 large polyps removed,and all mucosal defects were clipped.There were no perforations(P=0.0016).There were no post-polypectomy hemorrhages in either phase.An average of 2.15 clips were required to close the mucosal defects.The median time to perform the polypectomy and clipping was 13 min,and the median procedure duration was 40 min.Five percent of all patients undergoing colonoscopy in our community based,ambulatory endoscopy center had flat,right sided polyps greater than or equal to 1.2 cm in size.CONCLUSION Prophylactic clipping of the mucosal resection defect of large,right-sided,flat polyps reduces the incidence of perforation.展开更多
Orthogonal frequency division multiplex/offset QAM (OFDM/OQAM) has been proven to be a promising multi-carrier modulation (MCM) technique for the transmission of signals over multipath fading channels. However, OFDM/O...Orthogonal frequency division multiplex/offset QAM (OFDM/OQAM) has been proven to be a promising multi-carrier modulation (MCM) technique for the transmission of signals over multipath fading channels. However, OFDM/OQAM has also the intrinsic disadvantage of high peak-to-average-power ratio (PAPR) that should be alleviated. This paper focuses on the reduction of the clipping noise and out-of band radiation caused by the clipping process. The basic principle is to estimate the clipping noise and then eliminate it from the received signal. Analysis and simulation results show that, with one time iteration, the proposed method can effectively improve the bit error ratio (BER) performance.展开更多
BACKGROUND A hybrid operating room(Hybrid-OR)is a surgical theatre that combines a conventional operating room with advanced medical imaging devices.There are still plenty of limitations when endovascular treatment or...BACKGROUND A hybrid operating room(Hybrid-OR)is a surgical theatre that combines a conventional operating room with advanced medical imaging devices.There are still plenty of limitations when endovascular treatment or microsurgical treatment is used individually to treat large or giant carotid-ophthalmic aneurysms.AIM To explore and summarize the technical features and effectiveness of the application of a Hybrid-OR in managing major intracranial carotid-ophthalmic aneurysms.METHODS The Department of Neurosurgery treated 12 cases of large or giant intracranial carotid-ophthalmic aneurysms between March 2013 and December 2019 in a Hybrid-OR.All cases were treated with clipping and parent vessel reconstruction.RESULTS With the assistance of the Hybrid-OR,the rate of incomplete intraoperative aneurysm clipping decreased from 25%(3/12)to 0%,while the rate of vessel stenosis decreased from 16.7%(2/12)to 8.35%(1/12).In terms of thromboembolic events,ischemic infarction complication occurred in only one patient,and none of the patients experienced embolic infarction complications.All 12 patients were followed for an average of 3 years,and no aneurysms recurred.The postoperative recovery was evaluated with the modified Rankin Scale(mRS):11 patients showed no symptoms(mRS=0),1 patient showed slight disability(mRS 1-2),and none of the patients had severe disability(mRS=5)or died(mRS=6).CONCLUSION The Hybrid-OR provides new ideas for the surgical clipping of large or giant intracranial carotid-ophthalmic aneurysms and decreases the rate of intraoperative vessel stenosis and unsuccessful clipping.展开更多
Blood samples have traditionally been used as the main source of DNA for genetic analysis. How-ever, this source can be difficult in terms of collection, transportation, and long-term storage. In this study, we invest...Blood samples have traditionally been used as the main source of DNA for genetic analysis. How-ever, this source can be difficult in terms of collection, transportation, and long-term storage. In this study, we investigated whether human nail clippings could be used as a source of DNA for SNP genotyping, null-allele detection, and whole-genome amplification. From extracted nail DNA, we achieved amplicons up to a length of ~400 bp and >96% concordance for SNP genotyping and 100% concordance for null-allele detection compared to DNA derived from matched blood sam-ples. For whole-genome amplification, OmniPlex performed better than Multiple Displacement Amplification with a success rate of 89.3% and 76.8% for SNP genotyping and null-allele detection, respectively. Concordance was ~98% for both methods. When combined with OmniPlex whole-genome amplification, human nail clippings could potentially be used as an alternative to whole blood as a less invasive and more convenient source of DNA for genotyping studies.展开更多
This study presents a novel approach to computing all intersections between two Bézier curves using cubic hybridclipping. Each intersection is represented by two strip intervals that contain an intersection. In e...This study presents a novel approach to computing all intersections between two Bézier curves using cubic hybridclipping. Each intersection is represented by two strip intervals that contain an intersection. In each step, one curve isbounded by two fat lines, and the other is bounded by two cubic Bézier curves, clipping away the domain that doesnot contain the intersections. By selecting the moving control points of the cubic hybrid curves, better cubic polynomial bounds are obtained to make the proposed method more efficient. It was proved that the two strip intervalshave second- and fourth-order convergence rates for transversal intersections. Experimental results show that thenew algorithm is the most efficient among all existing curve/curve intersection approaches.展开更多
文摘BACKGROUND Juvenile polyps(JPs)are non-neoplastic polyps.In adults,JPs present with hematochezia in only approximately half the patients and are often found incidentally during endoscopic screening.JPs have no mucosal fascia at the tip,and spontaneous shedding and massive gastrointestinal hemorrhage may occur.Thus,the JP bleeding detected in this case by extravascular contrast leakage on computed tomography scans and treated with endoscopic clipping is rare.CASE SUMMARY A previously healthy 31-year-old male patient presented with a 2-day history of bloody stools.Upon hospital arrival,rectal examination revealed fresh blood,and abdominal computed tomography scans showed extravascular contrast leakage from the lower rectum’s left-side wall.His blood pressure was slightly low at 104/62 mmHg.However,his pulse rate(69 bpm)and oxygen level(99%on room air)were within normal limits.Emergency endoscopy revealed a pedunculated lesion in the rectum covered by a non-neoplastic mucosal epithelium.No neoplastic lesions were observed at the tip of the polyp;however,pulsatile bleeding was detected at the distal end.We performed endoscopic hemostasis by clipping the stem and then performed a polypectomy above the stem to examine the lesion tissue.Histopathological evaluation revealed a cystically dilated gland without neoplastic lesions.A subsequent total colonoscopy revealed two JPs with characteristic edematous,smooth,and reddish surfaces close to the hemorrhagic lesion.Subsequent histopathological evaluation indicated findings characteristic of JP,such as severe inflammatory cell infiltration of the stroma and cystic dilatation of the glandular ducts.CONCLUSION There are no reports of adult JPs presenting with contrast extravasation where endoscopic hemostasis was successful,as in this case.
基金supported by Jilin Province Higher Education Teaching Reform Research Project in 2021(JLJY202186163419).
文摘Peak load and wind energy emission pressure rise more as wind energy penetration keeps growing,which affects the stabilization of the PS(power system).This paper suggests integrated optimal dispatching of thermal power generators and BESS(battery energy storage system)taking wind energy emission grading punishment and deep peak clipping into consideration.Firstly,in order to minimize wind abandonment,a hierarchical wind abandonment penalty strategy based on fuzzy control is designed and introduced,and the optimal grid-connected power of wind energy is determined as a result of minimizing the peak cutting cost of the system.Secondly,considering BESS and thermal power,the management approach of BESS-assisted virtual peak clipping of thermal power generators is aimed at reducing the degree of deep peak clipping of thermal power generators and optimizing the output of thermal power generators and the charging and discharging power of BESS.Finally,Give an example of how this strategy has been effective in reducing abandonment rates by 0.66% and 7.46% individually for different wind penetration programs,and the daily average can reduce the peak clipping power output of thermal power generators by 42.97 and 72.31 MWh and enhances the effect and economy of system peak clipping.
文摘Aiming at the problem of high temperature and even demagnetization failure of permanent magnet (PM) due to PM eddy current loss in PM synchronous high-speed motors, this paper proposes a technique to lessen PM eddy current loss by cutting the angle of PM poles to change the shape of PM structure. Firstly, an analysis is conducted on the mechanism of PM synchronous high-speed motor eddy current loss production, the theoretical analytical model of PM eddy current loss is deduced, and it is theoretically proved that the magnetic pole shaving angle can reduce PM eddy current loss. Then, a 25 KW surface-type PM synchronous high-speed motor as an object, using two-dimensional time-step finite element method (FEM) to model and analyze PM eddy current loss. The results show that the smaller the PM pole shaving angle, the less its eddy current loss will be, it is possible to minimize the pole shaving angle of eddy current loss by 9.8% compared to the unshaved angle. Finally, the temperature field of the PM is calculated using a finite element method, and the outcomes demonstrate that the maximum temperature of the PM with a magnetic pole shaving angle can be reduced by about 5% compared with the unshaved angle.
基金supported by the National Natural Science Foundation of China (No. 30630046, 40701074)the National High Technology Research and Development Program of China (No. 2009AA06Z316)+1 种基金the Ministry of Environmental Protection Program of China(No. 2011467057)the Shanghai Tongji Gao Tingyao Environmental Science & Technology Development Foundation (7th Winner, 2010)
文摘Improving the efficacy of phytoextraction is critical for its successful application in metal contaminated soils. Mineral nutrition affects plant growth and metal absorption and subsequently the accumulation of heavy metal through hyper-accumulator plants. This study assessed the effects of di-hydrogen phosphates （KH2PO4, Ca（H2PO4）2, NaH2PO4 and NH4H2PO4） application at three levels （22, 88 and 352 mg P/kg soil） on Sedum alfredii growth and metal uptake by three consecutive harvests on aged and Zn/Cd combined contaminated paddy soil. The addition of phosphates （P） significantly increased the amount of Zn taken up by S. alfredii due to increased shoot Zn concentration and dry matter yield （DMY） （P 〈 0.05）. The highest phytoextraction of Zn and Cd was observed in KH2PO4 and NH4H2PO4 treatment at 352 mg P/kg soil. The amount of Zn removed by phytoextraction increased in the order of 1st clipping 〈 2nd clipping 〈 3rd clipping, and for Cd extraction the order was 2nd clipping 〈 1st clipping 〈 3rd clipping. These results indicate that the application of P fertilizers coupled with multiple cuttings can enhance the removal of Zn and Cd from contaminated soils by S. alfredii, thus shortening the time needed for accomplishing remediation goals.
基金funded by the National Natural Science Foundation of China(Grant No.41171084)the Natural Science Foundation of Tibet Autonomous Region(Response of species richness and aboveground biomass to warming in the alpine meadows of Tibet)
文摘Predicting how human activity will influence the response of alpine grasslands to future warming has many uncertainties.In this study, a field experiment with controlled warming and clipping was conducted in an alpine meadow at three elevations（4313 m, 4513 m and 4693 m） in Northern Tibet to test the hypothesis that clipping would alter warming effect on biomass production.Open top chambers（OTCs） were used to increase temperature since July,2008 and the OTCs increased air temperature by approximately 0.9o C ~ 1.8o C during the growing in2012.Clipping was conducted three times one year during growing season and the aboveground parts of all live plants were clipped to approximately 0.01 m in height using scissors since 2009.Gross primary production（GPP） was calculated from the Moderate-Resolution Imaging Spectroradiometer GPP algorithm and aboveground plant production was estimated using the surface-measured normalized difference vegetation index in 2012.Warming decreased the GPP, aboveground biomass（AGB） and aboveground net primary production（ANPP） at all three elevations when clipping was not applied.In contrast, warming increased AGB at all three elevations, GPP at the two lower elevations and ANPP at the two higher elevations when clipping was applied.These findings show that clipping reduced the negative effect of warming on GPP, AGB and ANPP, suggesting that clipping may reduce the effect of climate warming on GPP, AGB and ANPP in alpine meadows on the Tibetan Plateau, and therefore, may be a viable strategy for mitigating the effects of climate change on grazing and animal husbandry on the Tibetan Plateau.
基金supported by the National Key Research and Development Program of China(Grants No.2016YFC0401603,2016YFC0401605,and 2016YFC0401607)the Central Public-interest Scientific Institution Basal Research Fund(Grants No.Y717012 and Y718007)
文摘Plain reservoirs are shallow, and have low dams and widespread water surfaces.Therefore, wind-wave-induced damage to the dam is one of the important factors affecting the safety of the reservoir.To improve upon unsatisfactory plain reservoir wave-clipping schemes, a numerical method is proposed to predict and analyze waves in the reservoir in the presence of artificial islands, constructed from dredged sediment.The MIKE21 SW model is applied to a specific plain reservoir for finding the optimal artificial island parameters.The simulated wave height attenuation results are seen to agree well with empirically predicted values.Thus, the validity and reliability of the numerical model are established.Artificial islands at suitable locations in the reservoir can attenuate the wave heights by approximately 10%e30%, which justifies the efficacy of the clipping scheme making use of dredging and island construction.
基金supported by the National Natural Science Foundation of China(No.61475118)the State Key Laboratory on Integrated Optoelectronics of China(No.IOSKL2015KF06)the National High-Tech Research and Development Program of China(No.2013AA014201)
文摘Aiming at the problem of the peak to average power ratio(PAPR)in coherent optical orthogonal frequency division multiplexing(CO-OFDM),a hybrid PAPR reduction technique of the CO-OFDM system by combining iterative partial transmit sequence(IPTS)scheme with modified clipping and filtering(MCF)is proposed.The simulation results show that at the complementary cumulative distribution function(CCDF)of 10^(-4),the PAPR of proposed scheme is optimized by 1.86 d B and 2.13 d B compared with those of IPTS and CF schemes,respectively.Meanwhile,when the bit error rate(BER)is 10^(-3),the optical signal to noise ratio(OSNR)are optimized by 1.57 dB and 0.66 d B compared with those of CF and IPTS-CF schemes,respectively.
文摘With advances in endoscopic technologies,endoscopic clips have been used widely and successfully in the treatment of various types of oesophageal perforations,anastomosis leakages and fistulas. Our aim was to summarize the experience with two types of clips: The through-the-scope(TTS) clip and the over-the-scope clip(OTSC). We summarized the results of oesophageal perforation closure with endoscopic clips. We processed the data from 38 articles and 127 patients using PubM ed search. Based on evidence thus far,it can be stated that both clips can be used in the treatment of early(< 24 h),iatrogenic,spontaneous oesophageal perforations in the case of limited injury or contamination. TTS clips are efficacious in the treatment of 10 mm lesions,while bigger(< 20 mm) lesions can be treated successfully with OTSC clips,whose effectiveness is similar to that of surgical treatment. However,the clinical success rate is significantly lower in the case of fistulas and in the treatment of anastomosis insufficiency. Tough prospective randomized multicentre trials,which produce the largest amount of evidence,are still missing. Based on experience so far,endoscopic clips represent a possible therapeutic alternative to surgery in the treatment of oesophageal perforations under well-defined conditions.
文摘Visible light communications(VLC)is considered as an effective supplement technology for next-generation(6G)communications due to its abundant spectrum,high power efficiency and easy deployment.Optical orthogonal frequency division multiplexing(O-OFDM)is a common technology to obtain further promotion.In this paper,two typical O-OFDM schemes direct current biased O-OFDM(DCO-OFDM)and asymmetrically clipped O-OFDM(ACO-OFDM)are analyzed in terms of signal clipping at both transmitter and receiver under the constraints of maximum optical power and non-negative optical power.And effective electrical SNR models after signal clipping are proposed and verified by link simulation.Then a noise cancellation scheme is proposed based on received signal clipping and is proved to bring a significant gain for ACO-OFDM.By system simulation,we find that under a certain optical power limitation,most users can achieve above 4 Gbps in indoor scenario when modulation bandwidth of the light emit diode(LED)or laser diode(LD)is 1 GHz.Therefore,it can be expected that the throughput could reach tens Gbps when the LED/LD modulation bandwidth is increased and multiple LEDs/LDs are deployed.
基金supported by grant of Changzhou science and technology projects of social development (No. CS2007203)
文摘Prompt diagnosis and therapy of aneurysms are critical for patients with nontraumatic subarachnoid hemorrhage （SAH）.The aim of our study was to assess the clinical usefulness of multislice computed tomography angiography （CTA） in the surgical and endovascular treatment of intracranial aneurysms.A total of 195 cases with 206 intracranial aneurysms underwent CTA.Fifty （24%） aneurysms underwent surgical clipping while 156 （76%） aneurysms underwent endovascular coiling.In the five missed aneurysms at digital substraction angiography and the nine aneurysms with mass intracerebral hematomas,surgical treatment was successfully performed based on 16-slice CTA alone,and the other 36 aneurysms were clipped on the main basis of the CTA.The intraoperative findings correlated well with the CTA findings and all aneurysms were clipped successfully.Sixteen-slice CTA image information has been shown to determine the choice of aneurysm therapy and assist the surgical and endovascular treatment of intracranial aneurysms.
文摘Early physiotherapy was given to 124 patients with ruptured or unruptured cerebral aneurysms who were treated by surgical clipping or endovascular embolization.Patients were divided into four groups according to their Hunt and Hess grade at admission and aneurysm treatment modality： Group 1,Hunt and Hess grade≤II and surgical clipping;Group 2,Hunt and Hess grade≤II and endovascular embolization;Group 3,Hunt and Hess grade≥III and surgical clipping;Group 4,Hunt and Hess grade≥III and endovascular embolization.Level of consciousness was evaluated using the Glasgow Coma Scale,functional status using the Glasgow Outcome Scale,level of the mobility using the Mobility Scale for acute stroke patients,and independence in activities of daily living using the Barthel Index.After early physiotherapy,the level of consciousness and functional status improved significantly in Groups 1,3,and 4;mobility improved significantly in all groups;and independence in activities of daily living improved significantly in Groups 1 and 3.At discharge, Groups 1 and 2 had better functional status than Groups 3 and 4.Level of consciousness,functional status,mobility and independence in activities of daily living improved after early physiotherapy. These findings suggest that early physiotherapy improved the prognosis of patients with cerebral aneurysms who were treated by surgical clipping or endovascular embolization.Patients with a worse clinical status at presentation had a poorer functional status at discharge.The outcome of physiotherapy was not affected by whether surgical clipping or endovascular embolization was chosen for treatment of the aneurysm.
基金This work was supported by Institute for Information&communications Technology Promotion(IITP)grant funded by the Korea government(MSIT)(No.2017-0-00217,Development of Immersive Signage Based on Variable Transparency and Multiple Layers)was supported by the MSIT(Ministry of Science and ICT),Korea,under the ITRC(Information Technology Research Center)support program(IITP-2019-2018-0-01423)supervised by the IITP(Institute for Information&communications Technology Promotion).
文摘In this paper,the supervised Deep Neural Network(DNN)based signal detection is analyzed for combating with nonlinear distortions efficiently and improving error performances in clipping based Orthogonal Frequency Division Multiplexing(OFDM)ssystem.One of the main disadvantages for the OFDM is the high Peak to Average Power Ratio(PAPR).The clipping is a simple method for the PAPR reduction.However,an effect of the clipping is nonlinear distortion,and estimations for transmitting symbols are difficult despite a Maximum Likelihood(ML)detection at the receiver.The DNN based online signal detection uses the offline learning model where all weights and biases at fully-connected layers are set to overcome nonlinear distortions by using training data sets.Thus,this paper introduces the required processes for the online signal detection and offline learning,and compares error performances with the ML detection in the clipping-based OFDM systems.In simulation results,the DNN based signal detection has better error performance than the conventional ML detection in multi-path fading wireless channel.The performance improvement is large as the complexity of system is increased such as huge Multiple Input Multiple Output(MIMO)system and high clipping rate.
文摘AIM To determine if prophylactic clipping of post-polypectomy endoscopic mucosal resection(EMR) mucosal defects of large,flat,right sided polyps prevents perforations.METHODS IRB approved review of all colonoscopies,and prospective data collection of grasp and snare EMR performed by 2 endoscopists between January 1,2010 and March 31,2014 in a community ambulatory endoscopy center.The study consisted of two phases.In the first phase,all right-sided,flat polyps greater than or equal to 1.2 cm in size were removed using the grasp and snare technique.Clipping was done at the discretion of the endoscopist.In the second phase,all mucosal defects were closed using resolution clips.Phase 2 of the study was powered to detect a statistically significant difference in perforation rate with 148 EMRs,if less than or equal to 2 perforations occurred.RESULTS In phase 1 of the study,2121 colonoscopies were performed.Seventy-five patients had 95 large polyps removed.There were 4 perforations in 95 polypectomies(4.2%).The perforations occurred in polyps ranging in size from 1.5 cm to 2.5 cm.In phase 2,there were 2464 colonoscopies performed.One hundred and sixteen patients had 151 large polyps removed,and all mucosal defects were clipped.There were no perforations(P=0.0016).There were no post-polypectomy hemorrhages in either phase.An average of 2.15 clips were required to close the mucosal defects.The median time to perform the polypectomy and clipping was 13 min,and the median procedure duration was 40 min.Five percent of all patients undergoing colonoscopy in our community based,ambulatory endoscopy center had flat,right sided polyps greater than or equal to 1.2 cm in size.CONCLUSION Prophylactic clipping of the mucosal resection defect of large,right-sided,flat polyps reduces the incidence of perforation.
文摘Orthogonal frequency division multiplex/offset QAM (OFDM/OQAM) has been proven to be a promising multi-carrier modulation (MCM) technique for the transmission of signals over multipath fading channels. However, OFDM/OQAM has also the intrinsic disadvantage of high peak-to-average-power ratio (PAPR) that should be alleviated. This paper focuses on the reduction of the clipping noise and out-of band radiation caused by the clipping process. The basic principle is to estimate the clipping noise and then eliminate it from the received signal. Analysis and simulation results show that, with one time iteration, the proposed method can effectively improve the bit error ratio (BER) performance.
基金Supported by the Tianjin Science and Technology Projects in Key Areas of Traditional Chinese Medicine,No.2018001.
文摘BACKGROUND A hybrid operating room(Hybrid-OR)is a surgical theatre that combines a conventional operating room with advanced medical imaging devices.There are still plenty of limitations when endovascular treatment or microsurgical treatment is used individually to treat large or giant carotid-ophthalmic aneurysms.AIM To explore and summarize the technical features and effectiveness of the application of a Hybrid-OR in managing major intracranial carotid-ophthalmic aneurysms.METHODS The Department of Neurosurgery treated 12 cases of large or giant intracranial carotid-ophthalmic aneurysms between March 2013 and December 2019 in a Hybrid-OR.All cases were treated with clipping and parent vessel reconstruction.RESULTS With the assistance of the Hybrid-OR,the rate of incomplete intraoperative aneurysm clipping decreased from 25%(3/12)to 0%,while the rate of vessel stenosis decreased from 16.7%(2/12)to 8.35%(1/12).In terms of thromboembolic events,ischemic infarction complication occurred in only one patient,and none of the patients experienced embolic infarction complications.All 12 patients were followed for an average of 3 years,and no aneurysms recurred.The postoperative recovery was evaluated with the modified Rankin Scale(mRS):11 patients showed no symptoms(mRS=0),1 patient showed slight disability(mRS 1-2),and none of the patients had severe disability(mRS=5)or died(mRS=6).CONCLUSION The Hybrid-OR provides new ideas for the surgical clipping of large or giant intracranial carotid-ophthalmic aneurysms and decreases the rate of intraoperative vessel stenosis and unsuccessful clipping.
文摘Blood samples have traditionally been used as the main source of DNA for genetic analysis. How-ever, this source can be difficult in terms of collection, transportation, and long-term storage. In this study, we investigated whether human nail clippings could be used as a source of DNA for SNP genotyping, null-allele detection, and whole-genome amplification. From extracted nail DNA, we achieved amplicons up to a length of ~400 bp and >96% concordance for SNP genotyping and 100% concordance for null-allele detection compared to DNA derived from matched blood sam-ples. For whole-genome amplification, OmniPlex performed better than Multiple Displacement Amplification with a success rate of 89.3% and 76.8% for SNP genotyping and null-allele detection, respectively. Concordance was ~98% for both methods. When combined with OmniPlex whole-genome amplification, human nail clippings could potentially be used as an alternative to whole blood as a less invasive and more convenient source of DNA for genotyping studies.
基金This work was supported by the National Key R&D Program of China,No.2020YFB1708900Natural Science Foundation of China,No.61872328.
文摘This study presents a novel approach to computing all intersections between two Bézier curves using cubic hybridclipping. Each intersection is represented by two strip intervals that contain an intersection. In each step, one curve isbounded by two fat lines, and the other is bounded by two cubic Bézier curves, clipping away the domain that doesnot contain the intersections. By selecting the moving control points of the cubic hybrid curves, better cubic polynomial bounds are obtained to make the proposed method more efficient. It was proved that the two strip intervalshave second- and fourth-order convergence rates for transversal intersections. Experimental results show that thenew algorithm is the most efficient among all existing curve/curve intersection approaches.
