BACKGROUND The management of gallbladder perforation(GBP)with fistulous communication(Neimeier type I)is controversial.AIM To recommend management options for GBP with fistulous communication.METHODS A systematic revi...BACKGROUND The management of gallbladder perforation(GBP)with fistulous communication(Neimeier type I)is controversial.AIM To recommend management options for GBP with fistulous communication.METHODS A systematic review of studies describing the management of Neimeier type I GBP was performed according to the PRISMA guidelines.The search strategy was conducted in Scopus,Web of Science,MEDLINE,and EMBASE(May 2022).Data extraction was obtained for patient characteristics,type of intervention,days of hospitalization(DoH),complications,and site of fistulous communication.RESULTS A total of 54 patients(61%female)from case reports,series,and cohorts were included.The most frequent fistulous communication occurred in the abdominal wall.Patients from case reports/series had a similar proportion of complications between open cholecystectomy(OC)and laparoscopic cholecystectomy(LC)(28.6 vs 12.5;P=0.569).Mortality was higher in OC(14.3 vs 0.0;P=0.467)but this proportion was given by only one patient.DoH were higher in OC(mean 26.3 d vs 6.6 d).There was no clear association between higher rates of complications of a given intervention in cohorts,and no mortality was observed.CONCLUSION Surgeons must evaluate the advantages and disadvantages of the therapeutic options.OC and LC are adequate options for the surgical management of GBP,with no significant differences.展开更多
Cardiovascular diseases(CVDs) remain the leading cause of death in the world and in most developed countries. Patients with type 2 diabetes mellitus(T2DM)suffer from both microvascular and macrovascular diseases and t...Cardiovascular diseases(CVDs) remain the leading cause of death in the world and in most developed countries. Patients with type 2 diabetes mellitus(T2DM)suffer from both microvascular and macrovascular diseases and therefore have higher rates of morbidity and mortality compared to those without T2DM. If current trends continue, the Center for Disease Control and Prevention estimates that 1 in 3 Americans will have T2DM by year 2050. As a consequence of the controversy surrounding rosiglitazone and the increasing prevalence of diabetes and CVDs, in 2008 the Food and Drug Administration(FDA) established new expectations for the evaluation of new antidiabetic agents, advising for pre and,in some cases, post-marketing data on major cardiovascular events. As a direct consequence, there has been a paradigm shift in new antidiabetic agents that has given birth to the recently published American Diabetes Association/European Association for the Study of Diabetes consensus statement recommending sodium-glucose cotransporter-2 inhibitors(SGLT2i) and glucagon like peptide-1 receptor agonists(GLP-1RA) in patients with T2DM and established CVD. As a result of over a decade of randomized placebo controlled cardiovascular outcome trials, the aforementioned drugs have received FDA approval for risk reduction of cardiovascular(CV) events in patients with T2DM and established CV disease.SGLT2i have been shown to have a stronger benefit in patients with congestiveheart failure and diabetic kidney disease when compared to their GLP-1RA counterparts. These benefits are not withstanding additional considerations such as cost and the multiple FDA Black Box warnings. This topic is currently an emerging research area and this mini-review paper examines the role of these two novel classes of drugs in patients with T2DM with both confirmed, and at risk for, CVD.展开更多
A sample of 76 older adults (27 with diabetes and 49 without diabetes) were selected to judge three information factors, metamemory related to—drug organization—stress and physical activity in relation to their perc...A sample of 76 older adults (27 with diabetes and 49 without diabetes) were selected to judge three information factors, metamemory related to—drug organization—stress and physical activity in relation to their perception of self-care. In order to do so, an Integration Information Theory was considered to determine systematic cognitive algebra rules underlying judgment about 24 different health self-care scenarios. Results indicate that older adults without diabetes use a summative cognitive rule to integrate relevant health information but older adults with diabetes do not. Both groups agreed that metamemory was the most relevant factor to their self-care followed by stress and physical activity. However, valuation of these factors does depend on the type of group. Implications of these results to healthcare a behavioral nursing intervention are discussed in this paper.展开更多
To the Editor:We sincerely applaud the work done by Gupta et al.,in which they analyzed a single-center experience regarding gallbladder per-foration(GBP)management[1].Currently,there is a lack of cohort studies to ad...To the Editor:We sincerely applaud the work done by Gupta et al.,in which they analyzed a single-center experience regarding gallbladder per-foration(GBP)management[1].Currently,there is a lack of cohort studies to adequately describe the approach strategies and man-agement for this pathology,with international guidelines making ambiguous recommendations[2,3].Their study stratified GBP types and provided details regarding clinical presentation,comorbidities,preoperative diagnosis,etiology,imaging techniques,and surgical approach.The study reported a high conversion rate when a la-paroscopic approach was attempted for cholecystectomy.展开更多
Dear Editor,Persistent hematuria could trigger urinary retention,leading the patient to the emergency department for abdominal pain,decreased urinary output,anemia,and azotemia[1,2].Conventional bladder clot evacuatio...Dear Editor,Persistent hematuria could trigger urinary retention,leading the patient to the emergency department for abdominal pain,decreased urinary output,anemia,and azotemia[1,2].Conventional bladder clot evacuation requires a three-way catheter with continuous irrigation and aspiration with a syringe or Ellik evacuator[3].Sometimes a large and well-organized hematoma requires an open cystostomy[1,4].We want to introduce a combined method using hydrogen peroxide as well as suction technique with an endotracheal catheter to evacuate intravesical clots.展开更多
A sample of 65 older adults (with and without diabetes) as well as a sample of 84 healthy young people were required to take affective priming studies to compare recognition latencies of stress related word pairs agai...A sample of 65 older adults (with and without diabetes) as well as a sample of 84 healthy young people were required to take affective priming studies to compare recognition latencies of stress related word pairs against recognition latencies of positive, negative and neutral word pairs. Moreover, older adults took a stress questionnaire related to relevant disturbing events in the third age. The goal was to test any automatic emotional processing bias to these events. Results suggested that even when people with diabetes obtained low stress test scores, they showed automatic cognitive bias to process stressful events differently than older adults without diabetes and young people. This suggested that people with diabetes patients’ controlled strategies to cope with stress might not be aware of such an automatic cognitive bias. It is argued that this information processing style to stressful events makes patients prone to cognitive emotional vulnerability.展开更多
Hepatitis C virus(HCV) replication is associated with the endoplasmic reticulum, where the virus can induce cellular stress. Oxidative cell damage plays an important role in HCV physiopathology. Oxidative stress is tr...Hepatitis C virus(HCV) replication is associated with the endoplasmic reticulum, where the virus can induce cellular stress. Oxidative cell damage plays an important role in HCV physiopathology. Oxidative stress is triggered when the concentration of oxygen species in the extracellular or intracellular environment exceeds antioxidant defenses. Cells are protected and modulate oxidative stress through the interplay of intracellular antioxidant agents, mainly glutathione system(GSH) and thioredoxin; and antioxidant enzyme systems such as superoxide dismutase, catalase, GSH peroxidase, and heme oxygenase-1. Also, the use of natural and synthetic antioxidants(vitamin C and E, N-acetylcysteine, glycyrrhizin, polyenylphosphatidyl choline, mitoquinone, quercetin, S-adenosylmethionine and silymarin) has already shown promising results as co-adjuvants in HCV therapy. Despite all the available information, it is not known how different agents with antiviral activity can interfere with the modulation of the cell redox state induced by HCV and decrease viral replication. This review describes an evidence-based consensus on molecular mechanisms involved in HCV replication and their relationship with cell damage induced by oxidative stress generated by the virus itself and cell antiviral machinery. It also describes some molecules that modify the levels of oxidative stress in HCV-infected cells.展开更多
AIM: To investigate the effects of ketamine anesthesia on the motility alterations and tissue injury caused by ischemia/reperfusion in rats. METHODS: Thirty male Wistar rats weighing 200-250 g were used. Ischemia was ...AIM: To investigate the effects of ketamine anesthesia on the motility alterations and tissue injury caused by ischemia/reperfusion in rats. METHODS: Thirty male Wistar rats weighing 200-250 g were used. Ischemia was induced by ob-structing blood flow in 25% of the total small intesti-nal length (ileum) with a vascular clamp for 45 min, after which either 60 min or 24 h of reperfusion was allowed. Rats were either anesthetized with pento-barbital sodium (50 mg/kg) or ketamine (100 mg/kg). Control groups received sham surgery. After 60 min of reperfusion, the intestine was examined for mor-phological alterations, and after 24 h intestinal basic electrical rhythm (BER) frequency was calculated, and intestinal transit determined in all groups. RESULTS: The intestinal mucosa in rats that were anesthetized with ketamine showed moderate altera-tions such as epithelial lifting, while ulceration and hemorrhage was observed in rats that received pento-barbital sodium after 60 min of reperfusion. Quantita-tive analysis of structural damage using the Chiu scaleshowed significantly less injury in rats that received ketamine than in rats that did not (2.35 ± 1.14 vs 4.58 ± 0.50, P < 0.0001). The distance traveled by a mark-er, expressed as percentage of total intestinal length, in rats that received pentobarbital sodium was 20% ± 2% in comparison with 25.9% ± 1.64% in rats that re-ceived ketamine (P = 0.017). BER was not statistically different between groups. CONCLUSION: Our results show that ketamine anesthesia is associated with diminished intestinal injury and abolishes the intestinal transit delay induced by ischemia/reperfusion.展开更多
Treatment of petroleum spills and organic solvent pollution in general is an important issue; several techniques are under development to remove oil from water. The use of absorbents is one of the most common techniqu...Treatment of petroleum spills and organic solvent pollution in general is an important issue; several techniques are under development to remove oil from water. The use of absorbents is one of the most common techniques to tackle this problem. These absorbents can be classified based on their characteristics of recyclability into irreversible and reversible ones. In this review, we discuss the application of several materials as oil absorbents, according to their classification and characteristics such as hydrophobicity, surface area and oil absorption capacity. Also, the fabrication methods for some materials are presented and analyzed.展开更多
Mg–Xwt.%Ni(X=5 and 20)alloys have been prepared by mechanical alloying using milling times of 15 and 30 h in a planetary ball milling to know the effects of magnesium with the addition of Ni as catalyst,dispersion on...Mg–Xwt.%Ni(X=5 and 20)alloys have been prepared by mechanical alloying using milling times of 15 and 30 h in a planetary ball milling to know the effects of magnesium with the addition of Ni as catalyst,dispersion on the microstructure,area surface and the efficiency of hydrogen storage.SEM-EDS,XRD and ImageJ^(■)software have been used to characterize the microstructure and chemical composition of the alloys.Hydriding experiments were performed as batch-type tests at 200,250 and 300℃ under 2 MPa H2 pressure during 30 min.These experiments resulted in varying amounts of MgH2 in the hydrided powders depending on composition and hydriding conditions.The best results point to an optimum Ni dispersion,which in turn depends on Ni content and milling time.展开更多
BACKGROUND Few cases of avulsion fractures of the tibial tuberosity with simultaneous rupture of the patellar tendon have been reported in the literature.Therefore,its mechanism and incidence have not been determined ...BACKGROUND Few cases of avulsion fractures of the tibial tuberosity with simultaneous rupture of the patellar tendon have been reported in the literature.Therefore,its mechanism and incidence have not been determined conclusively.This type of fracture is considered a serious injury that requires prompt diagnosis and early surgical repair.There is no therapeutic algorithm or standard method of treatment due to the infrequency of the injury.In this case report,we conducted an exhaustive review and synthesis of the existing literature including all previously reported cases.CASE SUMMARY We present a 16-year-old male soccer player with a case of a tibial tuberosity fracture with distal avulsion of the patellar tendon 5 d prior to surgical treatment.The patient presented with a loss of the extensor mechanism of the knee,edema,the inability to walk,and pain.X-rays showed a high patella and a 180-degree avulsion of the tibial tuberosity.The diagnosis was confirmed by magnetic resonance imaging and computed tomography.The patient underwent open reduction and internal fixation of the fracture with a cannulated screw and washer as well as patellar tendon repair with two metallic anchors.The rehabilitation protocol consisted of initial immobilization in extension followed by passive mobility and muscle strengthening exercises.The patient demonstrated excellent postoperative outcomes and returned to regular activity without complications.CONCLUSION This case presentation and literature review comprise the most relevant clinical,radiographic,and treatment details described in the international literature to date,providing the reader with an overview of this rare condition.展开更多
The present study was undertaken to determine the variability in fiber cell morphology and its length among wood species of the Tamaulipan Thorn Scrub, Northeastern Mexico, used for various uses such as timber for fur...The present study was undertaken to determine the variability in fiber cell morphology and its length among wood species of the Tamaulipan Thorn Scrub, Northeastern Mexico, used for various uses such as timber for furniture, fence, post, firewood and sources of forage. The results reveal large variability in fiber cell morphology and fiber cell dimensions. The species are classified on the basis of its fiber cell morphology and fiber cell length and recommended for their possible utilization for different purposes. Wood having fibre cells with broad lumen and thin wall could be suitable for the manufacture of paper documented in the literature viz. Acacia farnesciana, Caesalpinia mexicana, Cordia boisiieri, Diospyros palmeri, Forestieria angustifolia, Morus celtifolia, Prosopis laevigata. This technique can be used in preliminary screening of woody species for its utilization for different purposes. Further studies are needed to confirm.展开更多
The aim of this study was to detect and analyze the conceptions of teaching, learning activities and assessment of learning in classroom, and blended courses for university professor's face-to-face courses. The study...The aim of this study was to detect and analyze the conceptions of teaching, learning activities and assessment of learning in classroom, and blended courses for university professor's face-to-face courses. The study design was non-experimental, descriptive, and mixed cut. The sample was not random with participation of 129 university professors' face-to-face courses. As was applied, the open questions questionnaire on teaching and learning conceptions of teachers and data reported six questions related to the conception of teaching, didactic activities and assessment of learning of courses in classroom and blended courses. The data were worked through content analysis and percentages. The findings showed a conception of classroom teaching with a focus on learning and a conception blended teaching with a strong focus on teaching. The most reported didactic activities in classroom courses at a decreasing hierarchy were: exposition and presentation, se, discussion forums, chat and Wikis. In classroom assessment participation, and research and blended courses the research, Wikis, teachers did not specify evaluation resources case study and mixed courses, technology per courses predominated, in the abstract tests, forums and blog,展开更多
文摘BACKGROUND The management of gallbladder perforation(GBP)with fistulous communication(Neimeier type I)is controversial.AIM To recommend management options for GBP with fistulous communication.METHODS A systematic review of studies describing the management of Neimeier type I GBP was performed according to the PRISMA guidelines.The search strategy was conducted in Scopus,Web of Science,MEDLINE,and EMBASE(May 2022).Data extraction was obtained for patient characteristics,type of intervention,days of hospitalization(DoH),complications,and site of fistulous communication.RESULTS A total of 54 patients(61%female)from case reports,series,and cohorts were included.The most frequent fistulous communication occurred in the abdominal wall.Patients from case reports/series had a similar proportion of complications between open cholecystectomy(OC)and laparoscopic cholecystectomy(LC)(28.6 vs 12.5;P=0.569).Mortality was higher in OC(14.3 vs 0.0;P=0.467)but this proportion was given by only one patient.DoH were higher in OC(mean 26.3 d vs 6.6 d).There was no clear association between higher rates of complications of a given intervention in cohorts,and no mortality was observed.CONCLUSION Surgeons must evaluate the advantages and disadvantages of the therapeutic options.OC and LC are adequate options for the surgical management of GBP,with no significant differences.
文摘Cardiovascular diseases(CVDs) remain the leading cause of death in the world and in most developed countries. Patients with type 2 diabetes mellitus(T2DM)suffer from both microvascular and macrovascular diseases and therefore have higher rates of morbidity and mortality compared to those without T2DM. If current trends continue, the Center for Disease Control and Prevention estimates that 1 in 3 Americans will have T2DM by year 2050. As a consequence of the controversy surrounding rosiglitazone and the increasing prevalence of diabetes and CVDs, in 2008 the Food and Drug Administration(FDA) established new expectations for the evaluation of new antidiabetic agents, advising for pre and,in some cases, post-marketing data on major cardiovascular events. As a direct consequence, there has been a paradigm shift in new antidiabetic agents that has given birth to the recently published American Diabetes Association/European Association for the Study of Diabetes consensus statement recommending sodium-glucose cotransporter-2 inhibitors(SGLT2i) and glucagon like peptide-1 receptor agonists(GLP-1RA) in patients with T2DM and established CVD. As a result of over a decade of randomized placebo controlled cardiovascular outcome trials, the aforementioned drugs have received FDA approval for risk reduction of cardiovascular(CV) events in patients with T2DM and established CV disease.SGLT2i have been shown to have a stronger benefit in patients with congestiveheart failure and diabetic kidney disease when compared to their GLP-1RA counterparts. These benefits are not withstanding additional considerations such as cost and the multiple FDA Black Box warnings. This topic is currently an emerging research area and this mini-review paper examines the role of these two novel classes of drugs in patients with T2DM with both confirmed, and at risk for, CVD.
文摘A sample of 76 older adults (27 with diabetes and 49 without diabetes) were selected to judge three information factors, metamemory related to—drug organization—stress and physical activity in relation to their perception of self-care. In order to do so, an Integration Information Theory was considered to determine systematic cognitive algebra rules underlying judgment about 24 different health self-care scenarios. Results indicate that older adults without diabetes use a summative cognitive rule to integrate relevant health information but older adults with diabetes do not. Both groups agreed that metamemory was the most relevant factor to their self-care followed by stress and physical activity. However, valuation of these factors does depend on the type of group. Implications of these results to healthcare a behavioral nursing intervention are discussed in this paper.
文摘To the Editor:We sincerely applaud the work done by Gupta et al.,in which they analyzed a single-center experience regarding gallbladder per-foration(GBP)management[1].Currently,there is a lack of cohort studies to adequately describe the approach strategies and man-agement for this pathology,with international guidelines making ambiguous recommendations[2,3].Their study stratified GBP types and provided details regarding clinical presentation,comorbidities,preoperative diagnosis,etiology,imaging techniques,and surgical approach.The study reported a high conversion rate when a la-paroscopic approach was attempted for cholecystectomy.
文摘Dear Editor,Persistent hematuria could trigger urinary retention,leading the patient to the emergency department for abdominal pain,decreased urinary output,anemia,and azotemia[1,2].Conventional bladder clot evacuation requires a three-way catheter with continuous irrigation and aspiration with a syringe or Ellik evacuator[3].Sometimes a large and well-organized hematoma requires an open cystostomy[1,4].We want to introduce a combined method using hydrogen peroxide as well as suction technique with an endotracheal catheter to evacuate intravesical clots.
文摘A sample of 65 older adults (with and without diabetes) as well as a sample of 84 healthy young people were required to take affective priming studies to compare recognition latencies of stress related word pairs against recognition latencies of positive, negative and neutral word pairs. Moreover, older adults took a stress questionnaire related to relevant disturbing events in the third age. The goal was to test any automatic emotional processing bias to these events. Results suggested that even when people with diabetes obtained low stress test scores, they showed automatic cognitive bias to process stressful events differently than older adults without diabetes and young people. This suggested that people with diabetes patients’ controlled strategies to cope with stress might not be aware of such an automatic cognitive bias. It is argued that this information processing style to stressful events makes patients prone to cognitive emotional vulnerability.
基金Supported by The CONACYTNo.CB-2011-1-58781 to Ana M Rivas-Estilla(partially)Red CA Fisiopatología de Enfermedades Hepáticas 2015
文摘Hepatitis C virus(HCV) replication is associated with the endoplasmic reticulum, where the virus can induce cellular stress. Oxidative cell damage plays an important role in HCV physiopathology. Oxidative stress is triggered when the concentration of oxygen species in the extracellular or intracellular environment exceeds antioxidant defenses. Cells are protected and modulate oxidative stress through the interplay of intracellular antioxidant agents, mainly glutathione system(GSH) and thioredoxin; and antioxidant enzyme systems such as superoxide dismutase, catalase, GSH peroxidase, and heme oxygenase-1. Also, the use of natural and synthetic antioxidants(vitamin C and E, N-acetylcysteine, glycyrrhizin, polyenylphosphatidyl choline, mitoquinone, quercetin, S-adenosylmethionine and silymarin) has already shown promising results as co-adjuvants in HCV therapy. Despite all the available information, it is not known how different agents with antiviral activity can interfere with the modulation of the cell redox state induced by HCV and decrease viral replication. This review describes an evidence-based consensus on molecular mechanisms involved in HCV replication and their relationship with cell damage induced by oxidative stress generated by the virus itself and cell antiviral machinery. It also describes some molecules that modify the levels of oxidative stress in HCV-infected cells.
文摘AIM: To investigate the effects of ketamine anesthesia on the motility alterations and tissue injury caused by ischemia/reperfusion in rats. METHODS: Thirty male Wistar rats weighing 200-250 g were used. Ischemia was induced by ob-structing blood flow in 25% of the total small intesti-nal length (ileum) with a vascular clamp for 45 min, after which either 60 min or 24 h of reperfusion was allowed. Rats were either anesthetized with pento-barbital sodium (50 mg/kg) or ketamine (100 mg/kg). Control groups received sham surgery. After 60 min of reperfusion, the intestine was examined for mor-phological alterations, and after 24 h intestinal basic electrical rhythm (BER) frequency was calculated, and intestinal transit determined in all groups. RESULTS: The intestinal mucosa in rats that were anesthetized with ketamine showed moderate altera-tions such as epithelial lifting, while ulceration and hemorrhage was observed in rats that received pento-barbital sodium after 60 min of reperfusion. Quantita-tive analysis of structural damage using the Chiu scaleshowed significantly less injury in rats that received ketamine than in rats that did not (2.35 ± 1.14 vs 4.58 ± 0.50, P < 0.0001). The distance traveled by a mark-er, expressed as percentage of total intestinal length, in rats that received pentobarbital sodium was 20% ± 2% in comparison with 25.9% ± 1.64% in rats that re-ceived ketamine (P = 0.017). BER was not statistically different between groups. CONCLUSION: Our results show that ketamine anesthesia is associated with diminished intestinal injury and abolishes the intestinal transit delay induced by ischemia/reperfusion.
基金the Universidad Autónoma de Nuevo León (Monterrey city, Mexico) for financial support (Project Paicyt-2015)
文摘Treatment of petroleum spills and organic solvent pollution in general is an important issue; several techniques are under development to remove oil from water. The use of absorbents is one of the most common techniques to tackle this problem. These absorbents can be classified based on their characteristics of recyclability into irreversible and reversible ones. In this review, we discuss the application of several materials as oil absorbents, according to their classification and characteristics such as hydrophobicity, surface area and oil absorption capacity. Also, the fabrication methods for some materials are presented and analyzed.
基金Authors acknowledge to PAICYT-UANL 2011-2012the National Council of Science and Technology of Mexico(CONACYT)for the economical support provided by means of project 107063.
文摘Mg–Xwt.%Ni(X=5 and 20)alloys have been prepared by mechanical alloying using milling times of 15 and 30 h in a planetary ball milling to know the effects of magnesium with the addition of Ni as catalyst,dispersion on the microstructure,area surface and the efficiency of hydrogen storage.SEM-EDS,XRD and ImageJ^(■)software have been used to characterize the microstructure and chemical composition of the alloys.Hydriding experiments were performed as batch-type tests at 200,250 and 300℃ under 2 MPa H2 pressure during 30 min.These experiments resulted in varying amounts of MgH2 in the hydrided powders depending on composition and hydriding conditions.The best results point to an optimum Ni dispersion,which in turn depends on Ni content and milling time.
文摘BACKGROUND Few cases of avulsion fractures of the tibial tuberosity with simultaneous rupture of the patellar tendon have been reported in the literature.Therefore,its mechanism and incidence have not been determined conclusively.This type of fracture is considered a serious injury that requires prompt diagnosis and early surgical repair.There is no therapeutic algorithm or standard method of treatment due to the infrequency of the injury.In this case report,we conducted an exhaustive review and synthesis of the existing literature including all previously reported cases.CASE SUMMARY We present a 16-year-old male soccer player with a case of a tibial tuberosity fracture with distal avulsion of the patellar tendon 5 d prior to surgical treatment.The patient presented with a loss of the extensor mechanism of the knee,edema,the inability to walk,and pain.X-rays showed a high patella and a 180-degree avulsion of the tibial tuberosity.The diagnosis was confirmed by magnetic resonance imaging and computed tomography.The patient underwent open reduction and internal fixation of the fracture with a cannulated screw and washer as well as patellar tendon repair with two metallic anchors.The rehabilitation protocol consisted of initial immobilization in extension followed by passive mobility and muscle strengthening exercises.The patient demonstrated excellent postoperative outcomes and returned to regular activity without complications.CONCLUSION This case presentation and literature review comprise the most relevant clinical,radiographic,and treatment details described in the international literature to date,providing the reader with an overview of this rare condition.
文摘The present study was undertaken to determine the variability in fiber cell morphology and its length among wood species of the Tamaulipan Thorn Scrub, Northeastern Mexico, used for various uses such as timber for furniture, fence, post, firewood and sources of forage. The results reveal large variability in fiber cell morphology and fiber cell dimensions. The species are classified on the basis of its fiber cell morphology and fiber cell length and recommended for their possible utilization for different purposes. Wood having fibre cells with broad lumen and thin wall could be suitable for the manufacture of paper documented in the literature viz. Acacia farnesciana, Caesalpinia mexicana, Cordia boisiieri, Diospyros palmeri, Forestieria angustifolia, Morus celtifolia, Prosopis laevigata. This technique can be used in preliminary screening of woody species for its utilization for different purposes. Further studies are needed to confirm.
文摘The aim of this study was to detect and analyze the conceptions of teaching, learning activities and assessment of learning in classroom, and blended courses for university professor's face-to-face courses. The study design was non-experimental, descriptive, and mixed cut. The sample was not random with participation of 129 university professors' face-to-face courses. As was applied, the open questions questionnaire on teaching and learning conceptions of teachers and data reported six questions related to the conception of teaching, didactic activities and assessment of learning of courses in classroom and blended courses. The data were worked through content analysis and percentages. The findings showed a conception of classroom teaching with a focus on learning and a conception blended teaching with a strong focus on teaching. The most reported didactic activities in classroom courses at a decreasing hierarchy were: exposition and presentation, se, discussion forums, chat and Wikis. In classroom assessment participation, and research and blended courses the research, Wikis, teachers did not specify evaluation resources case study and mixed courses, technology per courses predominated, in the abstract tests, forums and blog,