Systematic literature review of cold-formed steel at elevated temperature scenario.

Cold-formed steels (CFS) or light gauge steels (LGS) are steel sections created through processes without heat application, such as roll forming or press-braking. In the past few decades, the utilization of CFS as a structural material has expanded due to its advantages over the other materials used in the construction industry, consequently increasing the number of studies conducted by many researchers. CFS studies have focused on many research areas, including designing, and analyzing members and systems, connections, sustainability, residual stresses, and post-fire data. As a result, several authors have also conducted a literature review involving these areas. However, a literature review for more recent studies involving elevated temperature exposure of CFS has not been conducted. This paper seeks to compile and review the recent publications regarding CFS behavior and performance at high temperatures events. Sixty-nine (69) journal articles published from 2017 to 2023 were retrieved from the Scopus database and systematically reviewed through text mining with the aid of VOS Viewer. Prior studies utilizing finite element analysis and experimental methods to investigate the performance at elevated temperature events of varying CFS sections, systems, and steel grades have been summarized. In addition, this paper also briefly discussed the findings of the recent research works involving member connections of CFS. Key points from the literature review have been emphasized such as the outcome of experimental and numerical validation of existing design rules from different codes such as American Iron and Steel Institute (AISI), Eurocodes, and Australian codes which could vary depending on the CFS section and steel grades. Important points of previous studies regarding the CFS walls, insulations, and screwed connections have also been noted in this paper. Based on the review, research gaps in the prior studies involving elevated temperature exposure of CFS have been identified, such as lack of CFS investigation under fatigue and cyclic loading. These were then recommended as future direction and concentration of CFS at elevated temperatures research works.

Enhancing the Mechanical Properties of Historical Masonry Using Fiber-Reinforced Geopolymers.

Current research into the production of sustainable construction materials for retrofitting and strengthening historic structures has been rising, with geopolymer technology being seen as an advantageous alternative to traditional concrete. Fiber reinforcement using this novel cementitious material involves a low embodied carbon footprint while ensuring cohesiveness with local materials. This study aims to develop fly ash-based geopolymers reinforced with six different types of fibers: polyvinyl alcohol, polypropylene, chopped basalt, carbon fiber, and copper-coated stainless steel. The samples are produced by mixing the geopolymer mortar in random distribution and content. Twenty-eight geopolymer mixes are evaluated through compressive strength, split-tensile strength, and modulus of elasticity to determine the fiber mix with the best performance compared with pure geopolymer mortar as a control. Polyvinyl alcohol and copper-coated stainless-steel fiber samples had considerably high mechanical properties and fracture toughness under applied tensile loads. However, the polypropylene fiber source did not perform well and had lower mechanical properties. One-way ANOVA verifies these results. Based on these findings, polyvinyl alcohol and stainless-steel fibers are viable options for fiber reinforcement in historical structures, and further optimization and testing are recommended before application as a reinforcement material in historic structures.

Gonadal characterization of the Amazonian fish Serrapinnus kriegi (Characidae: Cheirodontinae) / Caracterização gonadal do peixe Amazônico Serrapinnus kriegi (Characidae: Cheirodontinae)

The knowledge of the testicular and ovarian morphology of a particular fish species is of paramount importance. Such analyze enables the development of studies and techniques aiming the improvement of their reproduction, management, commercialization and even their conservation. This study performed the ovarian and testicular characterization of the ornamental Amazon fish Serrapinnus kriegi. A total of three males and three females had their gonads analyzed by optical microscopy. Females present ovaries filled with oocytes in asynchronous development, indicating partial spawning in the species. Moreover, the micropyle and micropilar cell formation was observed in primary growing oocytes, representing a precocious oocyte development; and the zona radiata in the final vitellogenic oocytes is thicker than other related species, evidencing the development of a better protection to the embryos in function of the waters’ turbulence that characterize it spawning sites in the Amazonian streams. The male specimens’ present anastomosed tubular testes with unrestricted spermatogonia spread along the entire seminiferous tubules. The present data elucidate the dynamic of spermatogenesis and oogenesis of an ornamental Amazonian species, through the description of the male and female germ cells development.

O conhecimento da morfologia testicular e ovariana de uma determinada espécie de peixe é de suma importância, pois através destas análises é possível o desenvolvimento de estudos e técnicas visando o melhoramento de sua reprodução, manejo e comercialização e até mesmo auxiliar em sua conservação. Este estudo realizou a caracterização ovariana e testicular do peixe Amazônico ornamental Serrapinnus kriegi. Um total de três machos e três fêmeas tiveram suas gônadas analisadas através de microscopia óptica. As fêmeas apresentam ovários preenchidos por oócitos em desenvolvimento assincrônico, indicando desova parcelada da espécie. Além disso, observou-se a formação de micrópila e célula micropilar em oócitos em crescimento primário, representando o desenvolvimento precoce do oócito; a zona radiata nos oócitos vitelogênicos finais é mais espessa em comparação a outras espécies relacionadas, evidenciando o desenvolvimento de uma melhor proteção aos embriões, em função das águas turbulentas que caracterizam seu local de desova nos córregos amazônicos. Os machos apresentam testículos do tipo tubular anastomosado com espermatogônias irrestritas, espalhadas por todo o túbulo seminífero. Os dados apresentados elucidam a dinâmica da espermatogênese e oogênese de uma espécie de peixe ornamental amazônica, por meio da descrição das células germinativas masculinas e femininas.

Gonadal characterization of the Amazonian fish Serrapinnus kriegi (Characidae: Cheirodontinae)

Abstract The knowledge of the testicular and ovarian morphology of a particular fish species is of paramount importance. Such analyze enables the development of studies and techniques aiming the improvement of their reproduction, management, commercialization and even their conservation. This study performed the ovarian and testicular characterization of the ornamental Amazon fish Serrapinnus kriegi. A total of three males and three females had their gonads analyzed by optical microscopy. Females present ovaries filled with oocytes in asynchronous development, indicating partial spawning in the species. Moreover, the micropyle and micropilar cell formation was observed in primary growing oocytes, representing a precocious oocyte development; and the zona radiata in the final vitellogenic oocytes is thicker than other related species, evidencing the development of a better protection to the embryos in function of the waters turbulence that characterize it spawning sites in the Amazonian streams. The male specimens present anastomosed tubular testes with unrestricted spermatogonia spread along the entire seminiferous tubules. The present data elucidate the dynamic of spermatogenesis and oogenesis of an ornamental Amazonian species, through the description of the male and female germ cells development.

Resumo O conhecimento da morfologia testicular e ovariana de uma determinada espécie de peixe é de suma importância, pois através destas análises é possível o desenvolvimento de estudos e técnicas visando o melhoramento de sua reprodução, manejo e comercialização e até mesmo auxiliar em sua conservação. Este estudo realizou a caracterização ovariana e testicular do peixe Amazônico ornamental Serrapinnus kriegi. Um total de três machos e três fêmeas tiveram suas gônadas analisadas através de microscopia óptica. As fêmeas apresentam ovários preenchidos por oócitos em desenvolvimento assincrônico, indicando desova parcelada da espécie. Além disso, observou-se a formação de micrópila e célula micropilar em oócitos em crescimento primário, representando o desenvolvimento precoce do oócito; a zona radiata nos oócitos vitelogênicos finais é mais espessa em comparação a outras espécies relacionadas, evidenciando o desenvolvimento de uma melhor proteção aos embriões, em função das águas turbulentas que caracterizam seu local de desova nos córregos amazônicos. Os machos apresentam testículos do tipo tubular anastomosado com espermatogônias irrestritas, espalhadas por todo o túbulo seminífero. Os dados apresentados elucidam a dinâmica da espermatogênese e oogênese de uma espécie de peixe ornamental amazônica, por meio da descrição das células germinativas masculinas e femininas.

Gonadal characterization of the Amazonian fish Serrapinnus kriegi (Characidae: Cheirodontinae) / Caracterização gonadal do peixe Amazônico Serrapinnus kriegi (Characidae: Cheirodontinae)

Abstract The knowledge of the testicular and ovarian morphology of a particular fish species is of paramount importance. Such analyze enables the development of studies and techniques aiming the improvement of their reproduction, management, commercialization and even their conservation. This study performed the ovarian and testicular characterization of the ornamental Amazon fish Serrapinnus kriegi. A total of three males and three females had their gonads analyzed by optical microscopy. Females present ovaries filled with oocytes in asynchronous development, indicating partial spawning in the species. Moreover, the micropyle and micropilar cell formation was observed in primary growing oocytes, representing a precocious oocyte development; and the zona radiata in the final vitellogenic oocytes is thicker than other related species, evidencing the development of a better protection to the embryos in function of the waters' turbulence that characterize it spawning sites in the Amazonian streams. The male specimens' present anastomosed tubular testes with unrestricted spermatogonia spread along the entire seminiferous tubules. The present data elucidate the dynamic of spermatogenesis and oogenesis of an ornamental Amazonian species, through the description of the male and female germ cells development.

Resumo O conhecimento da morfologia testicular e ovariana de uma determinada espécie de peixe é de suma importância, pois através destas análises é possível o desenvolvimento de estudos e técnicas visando o melhoramento de sua reprodução, manejo e comercialização e até mesmo auxiliar em sua conservação. Este estudo realizou a caracterização ovariana e testicular do peixe Amazônico ornamental Serrapinnus kriegi. Um total de três machos e três fêmeas tiveram suas gônadas analisadas através de microscopia óptica. As fêmeas apresentam ovários preenchidos por oócitos em desenvolvimento assincrônico, indicando desova parcelada da espécie. Além disso, observou-se a formação de micrópila e célula micropilar em oócitos em crescimento primário, representando o desenvolvimento precoce do oócito; a zona radiata nos oócitos vitelogênicos finais é mais espessa em comparação a outras espécies relacionadas, evidenciando o desenvolvimento de uma melhor proteção aos embriões, em função das águas turbulentas que caracterizam seu local de desova nos córregos amazônicos. Os machos apresentam testículos do tipo tubular anastomosado com espermatogônias irrestritas, espalhadas por todo o túbulo seminífero. Os dados apresentados elucidam a dinâmica da espermatogênese e oogênese de uma espécie de peixe ornamental amazônica, por meio da descrição das células germinativas masculinas e femininas.

Urgent capsule endoscopy is useful in severe obscure-overt gastrointestinal bleeding.

AIM: With capsule endoscopy (CE) it is possible to examine the entire small bowel. The present study assessed the diagnostic yield of CE in severe obscure-overt gastrointestinal bleeding (OOGIB). METHODS: During a 3-year period, 15 capsule examinations (4.5% of all CE in a single institution) were carried out in 15 patients (11 men; mean age 69.9 +/- 20.1 years) with severe ongoing bleeding, defined as persistent melena and/or hematochezia, with hemodynamic instability and the need for significant red blood cell transfusion. CE was carried out after non-diagnostic standard upper and lower endoscopy. The mean time from admission until CE was 4.1 +/- 4.4 days (0-15 days). RESULTS: CE revealed active bleeding in seven patients and signs of recent bleeding in four. Etiology of bleeding was correctly diagnosed in 11 patients (73.3%) (portal hypertension enteropathy, three patients; subepithelial ulcerated lesion, two patients; angiodysplasia, two patients; jejunal ulcer with visible vessel, one patient; multiple small bowel ulcers, one patient; jejunal tumor, one patient; jejunal mucosa irregularity with adherent clot, one patient). One patient (6.7%) had active bleeding but no visible lesion. As a consequence of the capsule findings, specific therapeutic measures were undertaken in 11 patients (73.3%) with five managed conservatively, four endoscopically and two surgically. Two patients experienced bleeding recurrence. One of them, with a probable small bowel tumor, refused any other interventions. CONCLUSIONS: CE is useful in patients with severe OOGIB by providing positive findings in the majority of patients, with subsequent impact on therapeutic procedures.

Small bowel pseudomelanosis and oral iron therapy.

Small bowel pseudomelanosis is a rarely reported clinical entity characterized by brown pigmentation of small bowel mucosa. The authors describe two cases, both with iron deficiency anemia, one of an 81-year-old female patient submitted for capsule endoscopy that revealed a brown pigmentation of all small bowel mucosa and another of an 81-year-old male whose retrograde double-balloon enteroscopy revealed a diffuse brown pattern of small bowel mucosa. Ileal biopsies confirmed intense iron deposition in the macrophages of the lamina propria. Both patients were on oral iron therapy and the second one had a previous double-balloon enteroscopy, 2 years earlier, which revealed only ileal angiodysplasias. These two cases demonstrate the importance of two new endoscopic methods for diagnosis of small bowel pseudomelanosis, the rarity of such an entity and its close relation with oral iron therapy.

Double-balloon enteroscopy and small bowel tumors: a South-European single-center experience.

Small bowel tumors are rare, accounting for 1-2% of all gastrointestinal neoplasms. We sought to determine the diagnostic and therapeutic impact of double-balloon enteroscopy (DBE) in patients with small bowel tumors. Between January 2005 and March 2008, 78 patients underwent 96 DBE. All nine patients (seven males; mean age 68 +/- 11.3 years) with small bowel tumors were retrospectively reviewed. Clinical presentation was: mid-gastrointestinal bleeding or iron-deficient anemia (55.6%); abdominal pain (22.2%); nausea/vomiting and abdominal distension (22.2%). Five patients had abnormal findings in previous capsule endoscopy and four in previous radiologic examinations. Route of insertion was exclusively oral and abnormal lesions were detected in all patients (jejunum 8; ileum 1). Biopsies were taken in seven patients and provided definitive histological diagnosis in all except one. There were no complications of DBE. Surgical resection took place in eight patients. Final histologic diagnosis were: primary carcinoma (33.3%), gastrointestinal stromal tumor (GIST) (33.3%), malignant lymphoma (22.2%), and carcinoid tumor (11.1%). Mean follow-up time was 15.4 +/- 12.7 months (range 2-34 months). Six patients were submitted to chemotherapy. Two patients died. Small bowel tumors are common in patients submitted to DBE. Given its safety and diagnostic capabilities, DBE should be considered the gold-standard method in the study of these neoplasms.

Primary leiomyoma of the liver: accurate preoperative diagnosis on liver biopsy.

Primary leiomyoma of the liver is an exceptionally rare tumour in non-immunocompromised patients. Preoperative diagnosis of the lesion is difficult as complete imaging of this type of lesion is scarcely defined and preoperative biopsy was not the practice in previously reported cases. We report a voluminous primary leiomyoma of the liver occurring in a healthy middle-aged woman where a preoperative diagnosis was accurately achieved on biopsy. Because of its size, surgery was undertaken for exclusion of malignancy. A 16-month uneventful follow-up has been completed. We discuss the advantage of a preoperative diagnosis and propose that an imaging-guided liver biopsy should be undertaken, provided malignancy features are absent. This could prevent liver surgery merely for diagnostic purposes. Finally, we report imaging features that have not been previously described, namely on magnetic resonance imaging, which may provide an insight about the nature of this particular lesion and, advantageously, contribute toward a non-invasive diagnosis.

Effect of portal hypertension in the small bowel: an endoscopic approach.

BACKGROUND AND AIM: The effects of portal hypertension in the small bowel are largely unknown. The aim of the study was to prospectively assess portal hypertension manifestations in the small bowel. METHODS: We compared, by performing enteroscopy with capsule endoscopy, the endoscopic findings of 36 patients with portal hypertension, 25 cirrhotic and 11 non-cirrhotic, with 30 controls. RESULTS: Varices, defined as distended, tortuous, or saccular veins, and areas of mucosa with a reticulate pattern were significantly more frequent in patients with PTH. These two findings were detected in 26 of the 66 patients (39%), 25 from the group with PTH (69%) and one from the control group (3%) (P < 0.0001). Among the 25 patients with PTH exhibiting these patterns, 17 were cirrhotic and 8 were non-cirrhotic (P = 0.551). The presence of these endoscopic changes was not related to age, gender, presence of cirrhosis, esophageal or gastric varices, portal hypertensive gastropathy, portal hypertensive colopathy, prior esophageal endoscopic treatment, current administration of beta-blockers, or Child-Pugh Class C. More patients with these endoscopic patterns had a previous history of acute digestive bleeding (72% vs. 36%) (P = 0.05). Active bleeding was found in two patients (5.5%). CONCLUSIONS: The presence of varices or areas of mucosa with a reticulate pattern are manifestations of portal hypertension in the small bowel, found in both cirrhotic and non-cirrhotic patients. The clinical implications of these findings, as regards digestive bleeding, are uncertain, although we documented acute bleeding from the small bowel in two patients (5.5%).