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Unveiling the secrets of diatom-mediated calcification:Implications for the biological pump

Science china Earth Sciences 2024年第9期67卷 2895-2909页

作者： Yiwen PAN Yifan LI chen-Tung arthur cHEN Zong-Pei JIANG Wei-Jun cAI Yunwen SHEN Zesheng DING Qixian cHEN Yanan DI Wei FAN chenba ZHU Ying cHEN Ocean college Zhejiang UniversityZhoushan 316021China Hainan Institute of Zhejiang University Sanya 570203China Department of Oceanography Sun Yat-Sen UniversityGaoxiong 80424China School of Marine Science and Policy University of DelawareNewark DE 19716USA carbon Neutral Innovation Research center Xiamen UniversityXiamen 361005China

Siliceous diatoms are one of the most prominent actors in the oceans,and they account for approximately 40%of the primary production and particulate organic carbon export *** is believed that changes in carbon flux caused by variations in diatom distribution can lead to significant climate *** the fundamental pathways of diatom-driven carbon sequestration have long been established,there are no reports of cacO_(3) precipitation induced by marine diatom *** manuscript introduces novel details regarding the enhancement of aragonite precipitation during photosynthesis in Skeletonema costatum in both artificial and natural *** direct measurements of cell surfaces via a pH microelectrode and zeta potential analyzer,it was determined that the diatom-mediated promotion of cacO_(3) precipitation is achieved through the creation of specific microenvironments with concentrated[cO_(3)^(2-)]and[ca^(2+)]and/or the dehydrating effect of adsorbed ca^(2+).Based on this mechanism,it is highly plausible that diatom-mediated calcification could occur in the oceans,an assertion that was supported by the significant deviation of total alkalinity(TA)from the conservative TA-salinity mixing line during a Skeletonema costatum bloom in the East china Sea and other similar *** newly discovered calcification pathway establishes a link between particulate inorganic and organic carbon flux and thus helps in the reassessment of marine carbon export fluxes and cO_(2) sequestration *** discovery may have important ramifications for assessing marine carbon cycling and predicting the potential effects of future ocean acidification.

关键词： Diatom bloom Skeletonema costatum calcification Biological carbon pump counter carbonate pump

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Broad Hormonal Responses Induced by Aluminum in Roots of Dwarf Transgenics of Solanum lycopersicum L. cv “Micro-Tom”

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American Journal of Plant Sciences 2024年第5期15卷 349-358页

作者： arthur B. Rates Daniela Boanares Daniele S. G. Pianetti Felipe Della-Torre Joni E. Lima Marcel G. c. França Department of Botany and Plant Physiology Laboratory Federal University of Minas Gerais Belo Horizonte Brazil

The spatial pattern distribution of plant hormones in response to aluminum (Al) toxicity in roots remains to be shown. This study was performed to assess the root hormonal accumulation and gene expression in response to Al toxicity in five transgenic miniature dwarf tomatoes cv. Micro-Tom (MT). MT and MT transgenics to acid indole acetic, cytokinin, gibberellin, abscisic acid and ethylene were cultivated in nutrient solutions containing different Al concentrations. Root growth elongation was measured and cellular damage was visualized by staining Evans’s blue. The GUS reporter gene staining technique was used to visualize hormonal changes in MT apex root tissues. Data indicated that the MT is sensitive to Al that induced significant growth inhibition and cellular damage. Al concentration of 27 μM was significantly toxic, inducing root apex darkening and inhibition of root development. The qualitative evaluation of GUS reporter gene expression showed intense crosstalk among all hormones studied, underscoring the complexity of signaling induced by Al in apex roots. Results point out to a major understanding of the hormonal signaling in response to Al toxicity, which may induce a change of root growth and architecture with growth inhibition and cell constraints modulated by all different hormones evaluated.

关键词： Gene Reporter Metal Plant Hormones Root Staining

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Results of Surgical Management of Malignant Obstruction of the common Bile Duct in Yaoundé

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Surgical Science 2024年第4期15卷 265-277页

作者： Eric Patrick Savom Gaël Tsanga Nomo Richard II Mbele Mahamat Yannick Ekani Boukar cédric Paterson Atangana Fred Dikongue Dikongue Guy Aristide Bang arthur Essomba Yaoundé General Hospital Yaound&#233 Cameroon Faculty of Medicine and Biomedical Sciences of the Universityof Yaoundé I Yaound&#233 Cameroon Faculty of Health Sciences University of Buea Buea Cameroon Faculty of Medicine and Biomedical Sciences of the University of Dschang Dschang Cameroon Yaoundé Teaching Hospital Yaound&#233 Cameroon

Introduction: In cameroon, surgery remains the only approach in malignant obstructions of the common bile duct (MOcBD) even in palliative situations. The aim of this work was to describe the modalities of surgical treatment of MOcBD, evaluate the results and detect the factors associated with postoperative morbidity and mortality. Patients and Methods: We conducted an analytical observational study, with retrospective data collection from the files of patients operated upon for MOcBD. This was done in four referral hospitals in the city of Yaoundé for a 42-month period spanning from January 1, 2020 to June 30, 2023. Demographic data, clinical presentation, surgical data, and 30-day postoperative outcomes were collected. Results: We collected 71 files. The sex ratio was 1.4 and the mean age was 56 ± 11 years. Fifty-three (53) patients (74.6%) were overweight or obese and 10 patients (14.1%) were hypertensive. A clinical cholestasis syndrome was present in 69 patients (97.2%). Fifty-five (55) patients (77.5%) had a cancer of the head of the pancreas, 8 patients (11.3%) had an extra-hepatic cholangiocarcinoma and 8 patients (11.3%) had an ampullary adenocarcinoma. Eight (8) resections (11.3%) with curative intent had been carried out and in 63 cases (88.7%), surgery was palliative. Postoperative morbidity was 55.7%, influenced by advanced WHO stage (p = 0.02). Postoperative mortality was 25.7%, associated with a high ASA score (p = 0.01). conclusion: Pancreatic head cancer is the main etiology of malignant obstructions of the common bile duct in cameroon. Surgical treatment is most often palliative. Postoperative morbidity and mortality are high, influenced by high WHO and ASA scores.

关键词： Malignant Obstruction common Bile Duct Palliative Treatment Morbidity Mortality

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Surgical Management of Perforated colon Tumours in Yaoundé: A Multicentre Retrospective Review of 30-Day Postoperative Outcome

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Surgical Science 2024年第5期15卷 330-341页

作者： Eric Patrick Savom Richard II Mbele colman Tamboh Tankou Mahamat Yannick Ekani Boukar cédric Paterson Atangana Fred Dikongue Dikongue Daniel Biwole Biwole Guy Aristide Bang arthur Essomba Yaoundé General Hospital Yaound&#233 Cameroon Faculty of Medicine and Biomedical Sciences University of Yaound&#233 I Yaound&#233 Cameroon Faculty of Health Sciences University of Buea Buea Cameroon Faculty of Medicine and Biomedical Sciences University of Dschang Dschang Cameroon Yaoundé Central Hospital Yaound&#233 Cameroon Yaoundé University Teaching Hospital Yaound&#233 Cameroon

Introduction: colon cancer is often diagnosed late in our context and there is a high prevalence of complicated forms, this including perforation. The optimal surgical treatment remains controversial. The aim of this study was to improve the short-term postoperative outcomes of patients operated upon for perforated colon cancer, by identifying factors associated with complications occurring within 30 days after surgery. Patients and methods: We carried out an analytical observational study, with a retrospective collection of data from the files of patients operated upon for an in situ tumoral colon perforation. This was done in four referral hospitals in the city of Yaoundé. The period was from the 1st of January, 2012 to the 31st of December, 2021. cox regression identified the factors associated with postoperative morbidity and mortality. Results: We collected files of 46 patients. The mean age was 54.7 ± 19.9 years with a sex ratio of 1.4. The clinical presentation on admission was dominated by the presence of signs of peritoneal irritation (91.3%) and bowel obstruction (28.3%). The diagnosis was made preoperatively in 16 cases (34.8%). The surgical procedures consisted of colectomy with anastomosis in 28 cases (60.9%) and without anastomosis in 14 cases (30.4%). Postoperative morbidity was 60.9% dominated by surgical site infection (37%). Postoperative mortality was 39.1%. The existence of generalized peritonitis was associated with the occurrence of postoperative complications (p = 0.019). The main factors associated with postoperative mortality were resection with primary anastomosis (p = 0.027), enterocutaneous fistula (p = 0.005). conclusion: colic resection with primary anastomosis or ideal colectomy is associated with an increased risk of mortality and should therefore not be performed in this setting.

关键词： Perforated colon cancer Postoperative Morbidity and Mortality colectomy Acute Generalized Peritonitis

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Laparoscopic Surgery of Incisional Hernia: Technique and Short-Term Results in Three Surgical Units in cameroon

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Surgical Science 2024年第4期15卷 232-243页

作者： Guy Aristide Bang Eric Patrick Savom Achille Aimé Bekolo Otiti Fred Dikongue Dikongue Mahamat Yannick Ekani Boukar Richard II Mbele cédric Paterson Atangana Daniel Biwole Biwole arthur Essomba Yaoundé Teaching Hospital Yaound&#233 Cameroon Faculty of Medicine and Biomedical Sciences of the University of Yaoundé I Yaound&#233 Cameroon Yaoundé General Hospital Yaound&#233 Cameroon Faculty of Medicine and Biomedical Sciences of the University of Dschang Dschang Cameroon Faculty of Health Sciences University of Buea Buea Cameroon Yaoundé Central Hospital Yaound&#233 Cameroon

Introduction: Incisional hernia is a common medical situation and its treatment has always been a challenge for general surgeons. If laparoscopic repair has become a gold standard elsewhere, it is increasingly done in our milieu, but no data has been found. The aim of this study was to review this surgery done in our country so far, to describe the operative technique and to evaluate the postoperative outcomes. Patients and Methods: We conducted an observational descriptive study with retrospective collection of data from the 1st of July 2018 to 30th of June 2022, in three hospitals in cameroon. Data on socio-demographic and clinical characteristics, surgical technique and postoperative outcomes of patients who had a laparoscopic repair of their incisional hernia were collected. Results: We reviewed 20 files. There were 14 women with an average age of 54.6 years. The average BMI was 32.8 kg/m2. Thirteen patients had a moderate size hernia and the hernia was localized at the midline in 18 cases. Only composite biface meshes were used with dimensions chosen to obtain at least 5 cm overlap. Spiral tacks were the only fixation means used. We registered 3 complications. One case of generalized peritonitis secondary to missed digestive perforation, one case of seroma and one case of postoperative ileus. We registered no death. conclusion: Laparoscopic repair of incisional hernias is feasible in a resource-limited setting like ours. compliance with the operative technique and recommendations is important to obtain short-term results closed to that put forward by literature.

关键词： Incisional Hernia Laparoscopy Repair composite Biface Mesh Postoperative Outcomes

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Description of Post-Stroke cognitive Disorders at Abidjan University Hospitals, côte d’Ivoire

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Neuroscience & Medicine 2024年第2期15卷 92-105页

作者： N’guessan N’cho arthur Kouassi Kouamé Léonard Ouattara Niemtiah Tako Neme Antoine Biology and Health Laboratory Felix Houphout-Boigny University Abidjan Cte dIvoire Department of Neurology cHU Yopougon Felix Houphout-Boigny University Abidjan Cte dIvoire

Stroke patients often experience motor deficits and cognitive problems after a stroke. Objective: To improve our understanding of the cognitive consequences of stroke. Method: a descriptive and analytical cross-sectional study was conducted over 12-month period in the neurology departments of the cocody and Treichville Hospitals in côte d’Ivoire. Results: Out of 724 patients admitted to the neurology department, 415 (57.32%) were stroke patients, of which 145 (34.94%) were screened. The frequency of global cognitive functioning impairment was 86.21%, significantly higher than the frequency of patients without impairment, which was 13.79%. The study focused on detailing the cognitive status of stroke patients in neurology departments, assessing several cognitive functions during the subacute phase of stroke. These functions included global cognitive functioning, executive functions, language and memory. The frequency of post-stroke cognitive impairment is high among stroke patients in Abidjan. This frequency is comparable to figures found in Subsaharian stroke populations. Demographic and clinical characteristics studied included age, gender, education level, employment status, vascular diseases and cerebral affected area. Among these characteristics, only the education level and the cerebral affected area have been found significant. conclusion: The incidence of cognitive impairment after a stroke is significantly high among stroke patients in Abidjan.

关键词： cognitive Disorders Subacute Stroke Related Risk Factors

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The effects of human-generated sound on fish

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Integrative Zoology 2009年第1期4卷 43-52页

作者： arthur N.POPPER Mardi c.HASTINGS Department of Biology University of MarylandCollege ParkUSA Applied Research Laboratory The Pennsylvania State UniversityState CollegeUSA

There is growing international concern about the effects of human-generated sound on fish and other aquatic ***,because of a striking paucity of well-designed and controlled experimental data,very little is actually known about the effects of these sounds on *** suggest that human-generated sounds,even from very high intensity sources,might have no effect in some cases or might result in effects that range from small and temporary shifts in behavior all the way to immediate *** this point,however,it is nearly impossible to ex-trapolate from results with one sound source,one fish species,or even fish of one size to other sources,species,or fish *** present paper briefly discusses the potential effects of sound on fish,describes some of the more recent well-controlled experimental studies,and points out areas for future study that will be needed before a real understanding of the effects of sound on fish can be developed.

关键词： anthropogenic sound behavior hearing noise sound.

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co_(6)Se_(8)(PEt_(3))_(6) superatoms as tunable chemical dopants for two-dimensional semiconductors

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npj computational Materials 2018年第1期4卷 373-378页

作者： arthur c.Reber Shiv N.Khanna Department of Physics Virginia Commonwealth UniversityRichmondVA 23284USA

Electronic,optoelectronic,and other functionalities of semiconductors are controlled by the nature and density of carriers,and the location of the Fermi *** strategies to tune these parameters holds the key to precise control over semiconductors *** propose that ligand exchange on superatoms can offer a systematic strategy to vary these *** demonstrate this by considering a WSe_(2) surface doped with ligated metal chalcogenide co_(6)Se_(8)(PEt_(3))_(6) *** superatoms are characterized by valence quantum states that can readily donate multiple *** find that the WSe_(2) support binds more strongly to the co_(6)Se_(8) cluster than the PEt3 ligand,so ligand exchange between the phosphine ligand and the WSe_(2) support is energetically *** metal chalcogenide superatoms serves as a donor that may transform the WSe_(2) p-type film into an ntype *** theoretical findings complement recent experiments where WSe_(2) films with supported co_(6)Se_(8)(PEt_(3))_(6) are indeed found to undergo a change in behavior from p-to *** further show that by replacing the PEt3 ligands by cO ligands,one can control the electronic character of the surface and deposited species.

关键词： properties. semiconductors holds

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Angiographic evaluation and management of acute gastrointestinal hemorrhage

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World Journal of Gastroenterology 2012年第11期18卷 1191-1201页

作者： T Gregory Walker Gloria M Salazar arthur c Waltman Division of Vascular Imaging and Intervention Massachusetts General HospitalHarvard Medical SchoolBostonMA 02114United States

Although most cases of acute nonvariceal gastrointestinal hemorrhage either spontaneously resolve or respond to medical management or endoscopic treatment,there are still a significant number of patients who require emergency angiography and transcatheter *** with noninvasive imaging such as nuclear scintigraphy or computed tomography may localize the bleeding source and/or confirm active hemorrhage prior to *** angiographic evaluation should begin with selective catheterization of the artery supplying the most likely site of bleeding,as determined by the available clinical,endoscopic and imaging *** a hemorrhage source is identified,superselective catheterization followed by transcatheter microcoil embolization is usually the most effective means of successfully controlling hemorrhage while minimizing potential *** is now wellrecognized as a viable and safe alternative to emergency *** selected situations transcatheter intra-arterial infusion of vasopressin may also be useful in controlling acute gastrointestinal *** must be aware of the various side effects and potential complications associated with this treatment,however,and recognize the high re-bleeding *** this article we review the current role of angiography,transcatheter arterial embolization and infusion therapy in the evaluation and management of nonvariceal gastrointestinal hemorrhage.

关键词： Angiodysplasia Aneurysm Digital subtrac-tion angiography contrast media Hemorrhage Radio-nuclide angiography Therapeutic embolization

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correcting for non-compliance when determining colonic transit time with radio-opaque markers

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World Journal of Gastroenterology 2017年第4期23卷 740-742页

作者： Alvin Ibarra Kaisa Olli arthur c Ouwehand DuPont Nutrition and Health 02460 KantvikFinland

The use of radio-opaque markers and abdominal X-ray is the standard method for determining colonic transit time(cTT). However, when there are deviations in the intake of these markers by participants in clinical trials it is desirable to improve observations by introducingcorrections, where possible. To date, there is no standard procedure to adjust for such deviations. This report proposes a series of alternatives based on possible scenarios for deviations from the intended intake of radio-opaque markers. The proposed method to correct for missed or delayed consumption of radioopaque markers can help to increase the accuracy of the cTT measurements in clinical trials.

关键词： colonic transit time Gastroenterology Gut transit time Radio-opaque marker X-ray

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