用Boosting方法组合增强Stumps进行文本分类(英文)

为提高文本分类的精度,Schapire和Singer尝试了一个用Boosting来组合仅有一个划分的简单决策树(Stumps)的方法.其基学习器的划分是由某个特定词项是否在待分类文档中出现决定的.这样的基学习器明显太弱,造成最后组合成的Boosting分类器精度不够理想,而且需要的迭代次数很大,因而效率很低.针对这个问题,提出由文档中所有词项来决定基学习器划分以增强基学习器分类能力的方法.它把以VSM表示的文档与类代表向量之间的相似度和某特定阈值的大小关系作为基学习器划分的标准.同时,为提高算法的收敛速度,在类代表向量的计算过程中动态引入Boosting分配给各学习样本的权重.实验结果表明,这种方法提高了用Boosting组合Stump分类器进行文本分类的性能(精度和效率),而且问题规模越大,效果越明显.

Bioinformatic analysis of cytokine expression in the proximal and distal nerve stumps after peripheral nerve injury

In our previous study,we investigated the dynamic expression of cytokines in the distal nerve stumps after peripheral nerve injury using microarray analysis,which can characterize the dynamic expression of proteins.In the present study,we used a rat model of right sciatic nerve transection to examine changes in the expression of cytokines at 1,7,14 and 28 days after injury using protein microarray analysis.Interleukins were increased in the distal nerve stumps at 1–14 days post nerve transection.However,growth factors and growth factor-related proteins were mainly upregulated in the proximal nerve stumps.The P-values of the inflammatory response,apoptotic response and cell-cell adhesion in the distal stumps were higher than those in the proximal nerve stumps,but the opposite was observed for angiogenesis.The number of cytokines related to axons in the distal stumps was greater than that in the proximal stumps,while the percentage of cytokines related to axons in the distal stumps was lower than that in the proximal nerve stumps.Visualization of the results revealed the specific expression patterns and differences in cytokines in and between the proximal and distal nerve stumps.Our findings offer potential therapeutic targets and should help advance the development of clinical treatments for peripheral nerve injury.Approval for animal use in this study was obtained from the Animal Ethics Committee of the Chinese PLA General Hospital on September 7,2016(approval No.2016-x9-07).

Characteristics of cytokines in the sciatic nerve stumps and DRG after rat sciatic nerve crush injury

Background: Cytokines are essential cellular modulators of various physiological and pathological activities, including peripheral nerve repair and regeneration. However, the molecular changes of these cellular mediators after peripheral nerve injury are still unclear. This study aimed to identify cytokines critical for the regenerative process of injured peripheral nerves.Methods: The sequencing data of the injured nerve stumps and the dorsal root ganglia(DRG) of Sprague-Dawley(SD) rats subjected to sciatic nerve(SN) crush injury were analyzed to determine the expression patterns of genes coding for cytokines. PCR was used to validate the accuracy of the sequencing data.Results: A total of 46, 52, and 54 upstream cytokines were differentially expressed in the SN at 1 day, 4 days, and 7 days after nerve injury. A total of 25, 28, and 34 upstream cytokines were differentially expressed in the DRG at these time points. The expression patterns of some essential upstream cytokines are displayed in a heatmap and were validated by PCR. Bioinformatic analysis of these differentially expressed upstream cytokines after nerve injury demonstrated that inflammatory and immune responses were significantly involved.Conclusions: In summary, these findings provide an overview of the dynamic changes in cytokines in the SN and DRG at different time points after nerve crush injury in rats, elucidate the biological processes of differentially expressed cytokines, especially the important roles in inflammatory and immune responses after peripheral nerve injury, and thus might contribute to the identification of potential treatments for peripheral nerve repair and regeneration.

Protein microarray analysis of cytokine expression changes in distal stumps after sciatic nerve transection

A large number of chemokines,cytokines,other trophic factors and the extracellular matrix molecules form a favorable microenvironment for peripheral nerve regeneration.This microenvironment is one of the major factors for regenerative success.Therefore,it is important to investigate the key molecules and regulators affecting nerve regeneration after peripheral nerve injury.However,the identities of specific cytokines at various time points after sciatic nerve injury have not been determined.The study was performed by transecting the sciatic nerve to establish a model of peripheral nerve injury and to analyze,by protein microarray,the expression of different cytokines in the distal nerve after injury.Results showed a large number of cytokines were up-regulated at different time points post injury and several cytokines,e.g.,ciliary neurotrophic factor,were downregulated.The construction of a protein-protein interaction network was used to screen how the proteins interacted with differentially expressed cytokines.Kyoto Encyclopedia of Genes and Genomes pathway and Gene ontology analyses indicated that the differentially expressed cytokines were significantly associated with chemokine signaling pathways,Janus kinase/signal transducers and activators of transcription,phosphoinositide 3-kinase/protein kinase B,and notch signaling pathway.The cytokines involved in inflammation,immune response and cell chemotaxis were up-regulated initially and the cytokines involved in neuronal apoptotic processes,cell-cell adhesion,and cell proliferation were up-regulated at 28 days after injury.Western blot analysis showed that the expression and changes of hepatocyte growth factor,glial cell line-derived neurotrophic factor and ciliary neurotrophic factor were consistent with the results of protein microarray analysis.The results provide a comprehensive understanding of changes in cytokine expression and changes in these cytokines and classical signaling pathways and biological functions during Wallerian degeneration,as well as a basis for potential treatments of peripheral nerve injury.The study was approved by the Institutional Animal Care and Use Committee of the Chinese PLA General Hospital,China(approval number:2016-x9-07)in September 2016.

Characterization of Two Different Stumps of <i>Spirulina platensis</i>Drying: Assessment of Water Transport Coefficient

The sorption behaviour and water transport mechanisms inside Spirulina platensis samples were experimentally analysed during isothermal drying at 25℃ and 50℃. Two different products grown in semi-industrial farms from Burkina Faso and France with initial water contents respectively of the range from 2.73 kg w /kg dm to 3.12 kg w /kg dm were characterized. A novel procedure has been developed to determine the water content profiles inside samples during isothermal drying. At both temperatures, experimental results underlined that the physical properties of Spirulina are not sensitive to the geographical origin, Burkina-Faso or France. To keep Spirulina at an water activity below 0.6 in order to preserve it from micro-organisms development, sorption isotherm curves show that a sufficient requirement is to lower the water content until an upper limit of w = 0.075 db. The evolution of water transport coefficient as a function of water content highlights a monotonous exponential dependence with a transport coefficient ranging from 1.70 × 10–10 to 94 × 10–10 m2/s. The contribution of solid phase shrinkage to the transport of water is negligible for the last drying steps.

Bamboo stumps as mosquito larval habitats in Darjeeling Himalayas, India： A spatial scale analysis

Bamboo stumps can be a congenial breeding habitat of the mosquitoes. In view of this, a preliminary assessment of the dipteran immatures inhabiting the stumps of bamboo groves in the Darjeeling Himalayas was carded out at a spatial scale. Of the 104 stumps of Dendrocalamus hamiltoni surveyed, 70 were found to host immatures of three dipteran species, the mosquitoes Aedes aegypti and Culex quinquefasciatus and the midges Chironomus sp. in varying densities. Though the stumps varied in diameter, in each stump on average 12. 1 immatures were found. The abundance of the immatures was positively correlated with the diameter of the stumps （r = ＋0.382; P 〈 0.001） but negatively with the pH of the water present in the stumps （r = -0.336; P 〈 0.01）. The coefficient of association was found to be ＋8.4 for the Ae. aegypti and Chironomus immatures, while in the rest of the species pair the association seemed to be independent. Thus it can be concluded that the stumps in the bamboo groves of Darjeeling Himalayas provides a favourable habitat for the mosquito and chironomid immatures.

Laparoscopic management of remnant gall bladder with stones: Lessons from a tertiary care centre's experience

Objective:Laparoscopic cholecystectomy is currently the gold standard for treating symptomatic gallstone disease.Despite its success,approximately 10%of patients may experience persistent biliary symptoms,leading to the post-cholecystectomy syndrome.A remnant gallbladder with cystic duct or bile duct stones is one of the causes of this syndrome.The objective of this study was to shed light on the clinical manifestations,evaluation,therapeutic strategies,and outcomes associated with laparoscopic management of symptomatic remnant gallbladders.Methods:This was a retrospective study,conducted over a five-year period(January 2017 to December 2022)at Apollo Hospitals in South India.All patients who underwent laparoscopic completion cholecystectomy for a remnant gall bladder were included.The following data were collected:patient demographics,symptoms,preoperative investigations,intraoperative details and post operative outcomes.Results:In total,36 patients were included and analysed.The majority of patients were male(25,69.4%),with a mean age of 50.7±12.1 years.The most common presentation was pain in the upper abdomen or right upper quadrant region(24,66.7%).The laparoscopic approach was attempted in all patients,with a success rate of 94.4%.Two patients required conversion to open surgery.Cholecystoenteric fistula to the colon was observed in one patient.Choledocholithiasis was observed in 7 patients(19.4%),and stone clearance was successfully achieved using endoscopic retrograde cholangiopancreatography in all patients preoperatively.Conclusion:Incomplete gall bladder removal either intentionally or unintentionally leaves a remnant gall bladder that is at risk for stone formation and infection.Patients who have this clinical entity with symptoms require a redo or complete cholecystectomy,a complex procedure associated with certain risks.This study highlights the feasibility and safety of laparoscopic completion cholecystectomy for the management of remnant gallbladder with cystic duct or bile duct stones.

Quality assessment of surgery for colorectal cancer:Where do we stand?

Quality assurance in surgery has been one of the most important topics of debate among colorectal surgeons in the past decade.It has produced new surgical standards that led in part to the impressive oncological outcomes we see in many units today.Total mesorectal excision,complete mesocolic excision(CME),and the Japanese D3 lymphadenectomy are now benchmark techniques embraced by many surgeons and widely recommended by surgical societies.However,there are still ongoing discrepancies in outcomes largely based on surgeon performance.This is one of the main reasons why many countries have shifted colorectal cancer surgery only to high volume centers.Defining markers of surgical quality is thus a perquisite to ensure that standards and oncological outcomes are met at an institutional level.With the evolution of CME surgery,various quality markers have been described,mostly based on measurements on the surgical specimen and lymph node yield,while others have proposed radiological markers(i.e.arterial stumps)measured on postoperative scans as part of the routine cancer follow-up.There is no ideal marker;however,taken together and assembled into a new score or set of criteria may become a future point of reference for reporting outcomes of colorectal cancer surgery in research studies and defining subspecialization requirements both at an individual and hospital level.

Appraisal of gastric stump carcinoma and current state of affairs

Gastric stump carcinoma,also known as remnant gastric carcinoma,is a malignancy arising in the remnant stomach following gastrectomy for a benign or malignant condition.Enterogastric reflux and preexisting risk factors in a patient with gastric cancer are the major contributors to the development of gastric stump carcinoma.The occurrence of gastric stump carcinoma is time-dependent and seen earlier in patients operated on for malignant rather than benign diseases.The tumor location is predominantly at the anastomotic site towards the stomach.However,it can occur anywhere in the remnant stomach.The pattern of lymph node involvement and the type of surgery required is distinctly different compared to primary gastric cancer.Gastric stump carcinoma is traditionally considered a malignancy with a dismal outcome.However,recent advances in diagnostic and therapeutic strategies have improved outcomes.Recent advances in molecular profiling of gastric stump carcinoma have identified distinct molecular subtypes,thereby providing novel therapeutic targets.Also,reports of gastric stump carcinoma following pancreatoduodenectomy and bariatric surgery highlight the need for more research to standardize the diagnosis,staging,and treatment of these tumors.The present review aims to provide an overview of gastric stump carcinoma highlighting the differences in clinicopathological profile and management compared to primary gastric carcinoma.

Comprehensive classifications for the endovascular recanalization of vertebral artery stump syndrome

Background:and purpose:To share our single-center vertebral artery stump syndrome(VASS)treatment experience and assess the role of comprehensive classification based on anatomic development,proximal conditions,and distal conditions(PAD).Materials and methods:Data were retrospectively collected from patients who underwent endovascular thrombectomy(EVT)at the Stroke Center of the First Hospital of Jilin University between January 2016 and December2021.Among patients with acute ischemic stroke in the posterior circulation,those with acute occlusion of the intracranial arteries and occlusion at the origin of the vertebral artery confirmed by digital subtraction angiography were selected.The clinical data were summarized and analyzed.Results:Fifteen patients with VASS were enrolled in the study.The overall success rate of surgical recanalization was 80%.The successful proximal recanalization rate was 70.6%,and the recanalization rates for P1,P2,P3,and P4 were 100%,71.4%,50%,and 66.67%,respectively.The mean operation times for the A1 and A2 types were124 and 120 min,respectively.The successful distal recanalization rate was 91.7%,and the recanalization rates for types D1,D2,D3,and D4 were 100%,83.3%,100%,and 100%,respectively.Five patients experienced perioperative complications(incidence rate:33.3%).Distal embolism occurred in three patients(incidence rate:20%).No dissection or subarachnoid hemorrhage occurred in any patient.Conclusion:EVT is a technically feasible treatment for VASS,and comprehensive PAD classification can,to a certain extent,help initially estimate the difficulty of surgery and provide guidance for interventional procedures.

Does gastric stump cancer really differ from primary proximal gastric cancer? A multicentre, propensity score matching-used, retrospective cohort study

BACKGROUND Although the location of proximal cancer of the remnant stomach is the same as that of primary proximal cancer of the stomach,its clinical characteristics and prognosis are still controversial.AIM To evaluate the clinicopathological features and prognosis factors of gastric stump cancer(GSC)and primary proximal gastric cancer(PGC).METHODS From January,2005 to December,2016,178 patients with GSC and 957 cases with PGC who received surgical treatment were enrolled.Patients in both groups underwent 1:1 propensity score matching analysis,and both clinical and pathological data were systematically collected for statistical purposes.Quality of RESULTS One hundred and fifty-two pairs were successfully matched after propensity score matching analysis.Of the 15 demographic and pathological variables collected,the analysis further revealed that the number of lymph nodes and positive lymph nodes were different prognostic and clinicopathological factors between PGC and GSC.Univariate and multivariate analyses showed that gender,differentiation degree and tumor-node-metastasis stage were independent risk factors for patients with GSC.Gender,vascular invasion,differentiation degree,depth of infiltration,positive lymph nodes,and tumor-node-metastasis stage were independent risk factors for patients with PGC.The 5-year overall survival and cancer-specific survival of patients with GSC were significantly lower than those in the PGC group,the scores for overall quality of life in the GSC-malignant group were lower than the GSC-benign,and the differences were statistically significant.CONCLUSION The differences in clinicopathological characteristics between GSC and PGC were clarified,and PGC had a better prognosis than GSC.

p16、p53和Ki-67在子宫平滑肌肿瘤中的诊断价值

目的研究p16、p53和Ki-67在子宫平滑肌肿瘤中的表达情况并探讨其在子宫平滑肌肿瘤鉴别诊断中的意义。方法收集35例子宫平滑肌瘤,13例恶性潜能不确定的子宫平滑肌肿瘤(STUMP)和16例子宫平滑肌肉瘤(LMS),采用免疫组化法检测p16、p53和Ki-67在这64例子宫平滑肌肿瘤中表达的情况。11例STUMP得到随访。结果 p16在100%的平滑肌肉瘤、7.7%的STUMP和0%的子宫平滑肌瘤中弥漫强(+)。p53在25%的平滑肌肉瘤、7.7%的STUMP和0%的子宫平滑肌瘤中弥漫强(+)。LMS的Ki-67阳性率15%～70%。1例(7.7%)STUMP的Ki-67阳性率达到20%,其余92.3%的STUMP和100%的子宫平滑肌瘤均<5%。1例STUMP发生多发肝转移,转移的肿瘤形态符合平滑肌肉瘤,ER、PR、p16和p53弥漫强(+),Ki-67阳性率20%,免疫组化与原子宫内STUMP一致。结论 p53和p16可用于子宫平滑肌肉瘤与良性子宫平滑肌肿瘤的鉴别。弥漫强阳的阳性方式才有诊断意义,提示肿瘤恶性。在STUMP中,较高的细胞增殖指数Ki-67(>15%)提示恶性可能,但需要结合组织形态及p16和p53的表达情况综合考虑。

Assistive technologies for pain management in people with amputation: a literature review

The prevalence of limb amputation is increasing globally as a devastating experience that can physically and psychologically affect the lifestyle of a person. The residual limb pain and phantom limb pain are common disabling sequelae after amputation surgery. Assistive devices/technologies can be used to relieve pain in people with amputation. The existing assistive devices/technologies for pain management in people with amputation include electrical nerve block devices/technologies, TENS units, elastomeric pumps and catheters, residual limb covers, laser systems, myoelectric prostheses and virtual reality systems, etc. There is a great potential to design, fabricate, and manufacture some portable, wireless, smart, and thin devices/technologies to stimulate the spinal cord or peripheral nerves by electrical, thermal, mechanical, and pharmaceutical stimulus. Although some preliminary efforts have been done, more attention must be paid by researchers, clinicians, designers, engineers, and manufacturers to the post amputation pain and its treatment methods.

AdaBoost算法中的数据类别不平衡现象

分析了AdaBoost算法可能面临的数据类别不平衡现象，指出通过限制重抽样比例来防止不平衡的不良影响的方式是不可取的，本文提出了基于分类错误率最小化准则与GMA最大化准则相配合的方法，有效地防止了不平衡现象对集成分类器性能的不良影响，并得到实验验证。

Management of duodenal stump fistula after gastrectomy for gastric cancer: Systematic review

AIM: To identify the most effective treatment of duodenalstump fistula(DSF) after gastrectomy for gastric cancer.METHODS: A systematic review of the literature was performed. Pub Med, EMBASE, Cochrane Library, CILEA Archive, BMJ Clinical Evidence and Up To Date databases were analyzed. Three hundred eighty-eight manuscripts were retrieved and analyzed and thirteen studies published between 1988 and 2014 were finally selected according to the inclusion criteria, for a total of 145 cases of DSF, which represented our group of study. Only patients with DSF after gastrectomy for malignancy were selected. Data about patients' characteristics, type of treatment, short and long-term outcomes were extracted and analyzed. RESULTS: In the 13 studies different types of treatment were proposed: conservative approach, surgical approach, percutaneous approach and endoscopic approach(3 cases). The overall mortality rate was 11.7% for the entire cohort. The more frequent complications were sepsis, abscesses, peritonitis, bleeding, pneumonia and multi-organ failure. Conservative approach was performed in 6 studies for a total of 79 patients, in patients with stable general condition, often associated with percutaneous approach. A complete resolution of the leakage was achieved in 92.3% of these patients, with a healing time ranging from 17 to 71 d. Surgical approach included duodenostomy, duodenojejunostomy, pancreatoduodenectomy and the use of rectus muscle flap. In-hospital stay of patients who underwent relaparotomy ranged from 1 to 1035 d. The percutaneous approach included drainage of abscesses or duodenostomy(32 cases) and percutaneous biliary diversion(13 cases). The median healing time in this group was 43 d. CONCLUSION: Conservative approach is the treatment of choice, eventually associated with percutaneus drainage. Surgical approach should be reserved for severe cases or when conservative approaches fail.

Prognostic factors and survival in patients with gastric stump cancer

AIM:To elucidate the clinicopathological characteristics and prognostic factors of gastric stump cancer(GSC).METHODS:The clinical data for 92 patients with GSC were collected at Fudan University Shanghai Cancer Center.The prognostic factors were analyzed with Cox proportional hazard models.RESULTS:GSC tended to occur within 25 years following the primary surgery,when the initial disease is benign,whereas it primarily occurred within the first15 years post-operation for gastric cancer.Patients with regular follow-up after primary surgery had a better survival rate.The multivariate Cox regression analysis revealed that Borrmann type?Ⅰ/Ⅱ(HR=3.165,95%CI:1.055-9.500,P=0.040)and radical resection(HR=1.780,95%CI:1.061-2.987,P=0.029)were independent prognostic factors for GSC.The overall 1-,3-,and 5-year survival rates of the 92 patients were78.3%,45.6%and 27.6%,respectively.The 1-,3-,and 5-year survival rates of those undergoing radical resection were 79.3%,52.2%,and 37.8%,respectively.The 5-year survival rates for stages?Ⅰ,Ⅱ,Ⅲ,andⅣwere 85.7%,47.4%,16.0%,and 13.3%,respectively(P=0.005).CONCLUSION:The appearance of GSC occurs sooner in patients with primary malignant cancer than in patients with a primary benign disease.Therefore,close follow-up is necessary.The overall survival of patients with GSC is poor,and curative resection can improve their prognosis.

Carcinogenic potential of duodenal reflux juice from patients with long-standing postgastrectomy

AIM To determine, whether study on thecarcinogenic potential of reflux juice frompatients with remote gastrectomy could clarifythe inherent relationship between duodenalreflux and gastric stump cancer.METHODS A total of 37 reflux juice samples(13 Billroth T, 24 Billroth Ⅱ ) were employed inthe present study. A two- stage transformationassay using BALB/c 3T3 cells was carried out totest the initiating or promoting activity of thesesamples.RESULTS Two of 18 (11.1%) reflux samplesexerted initiating activities, whereas 9/19(47.4%) samples enhanced the MNNG-initiafingcell transformation, suggesting the duodenalreflux juice might more frequently possess thetumor-promoter activity (P = 0. 029). In addition,there was no difference in initiating activities ofthe samples irrespective of surgical procedures(P=0.488), while Billroth Ⅱ samples exhibitedstronger tumor-promoter activity than Billroth Ⅰsamples (P = 0.027). Furthermore, the promoteractivities were well correlated with thehistological changes of the stomas (rs = 0.625,P = 0.004), but neither their cytotoxicities norinitiating activities had this correlation( Probabilities were 0.523 and 0.085,respectively).CONCLUSION The duodenal reflux juice frompatients with remote postgastrectomy did havecarcinogenic potential, and suggested thattumor-promoting activity should principallyaccount for the high incidence of gastric cancerin gastrectomy patients. In contrast, it isdifficult to explain the high stump-cancerincidence with the 'N-nitroso compounds'theory-a popular theory for the intact stomachcarcinogenesis, and it seemed to be justified tofocus chemoprevention of this cancer on thetumor-promoting potential of reflux juice.

Balloon-occluded transcatheter arterial chemoembolization for hepatocellular carcinoma

Transcatheter arterial chemoembolization(TACE) is widely accepted as a treatment for patients with hepatocellular carcinoma(HCC) in the intermediate stage according to the Barcelona Clinic Liver Cancer(BCLC) guidelines. Recently, balloon-occluded TACE(B-TACE) was developed in Japan. Despite the lack of a clear definition, B-TACE is generally defined as the infusion of emulsion of chemotherapeutic agents with lipiodol followed by gelatin particles under the occlusion of feeding arteries by a microballoon catheter, which leads to the dense lipiodol emulsion(LE) accumulation in HCC nodules. This phenomenon cannot be explained only by the prevention of proximal migration and leakage of embolization materials; it further involves causing local changes in the hemodynamics of the surrounding occlusion artery and targeted HCC nodules. Balloon-occluded arterial stump pressure plays an important role in the dense LE accumulation in targeted HCC nodules. Although randomized controlled trials comparing the therapeutic effect and the prognosis of B-TACE to those of the other TACE procedures, such as conventional-TACE and drug-eluting beads TACE, are still lacking, B-TACE is thought to be a promising treatment. The purpose of this review is to summarize the mechanism, therapeutic effect, indication, prognosis and complications of BTACE.

Management of Helicobacter pylori infection after gastric surgery

The Maastricht IV/Florence Consensus Report and the Second Asia-Pacific Consensus Guidelines strongly recommend eradication of Helicobacter pylori(H.pylori)in patients with previous gastric neoplasia who have undergone gastric surgery.However,the guidelines do not mention optimal timing,eradication regimens,diagnostic tools,and follow-up strategies for patients undergoing gastrectomy and do not indicate if eradication of H.pylori reduces the risk of marginal ulcer or stump cancer in the residual stomach after gastrectomy.The purpose of this review is to provide an update which may help physicians to properly manage H.pylori infection in patients who have undergone gastric surgery.This review focuses on(1)the microenvironment change in the stomach after gastrectomy;(2)the phenomenon of spontaneous clearance of H.pylori after gastrectomy;(3)the effects of H.pylori on gastric atrophy and intestinal metaplasia after gastrectomy;(4)incidence and clinical features of ulcers developing after gastrectomy;(5)does eradication of H.pylori reduce the risk of gastric stump cancer in the residual stomach?(6)does eradication of H.pylori reduce the risk of secondary metachronous gastric cancer in the residual stomach?and(7)optimal timing and regimens for H.pylori eradication,diagnostic tools and follow-up strategies for patients undergoing gastrectomy.