Fire-induced structural failure: the World Trade Center, New York

Fire investigation has generally concentrated on determination of the cause and origin of a fire. Methodologies developed for this purpose have thus focused on the dynamics of fire growth and investigation of its effect on different objects within the structure affected by the fire. It is unusual to see a fire investigation emphasising structural damage as a way to obtain information for fire reconstruction. The series of dramatic fire events that occurred on 11 September 2001 within the World Trade Center, New York complex have emphasised the need to introduce structural analysis as a companion to evaluation of a fire timeline. Only a combined analysis is capable of providing a complete reconstruction of the event and therefore a solid determination of causality. This paper presents a methodology to establish, by means of modern structural and fire analysis tools, the sequence of events leading to a structural failure. This analysis will be compared with classic cause and origin techniques, emphasising the importance of a comprehensive study. Specific structural features and fire conditions that lead to unique forms of failure will be discussed, establishing the complexity of linking fire, structure characteristics and failure mode. The collapse of buildings 1 and 2 of the World Trade Center will be used to illustrate different forms of failure and the fires that cause them

Ablation of the renal stroma defines its critical role in nephron progenitor and vasculature patterning

The renal stroma is an embryonic cell population located in the cortex that provides a structural framework as well as a source of endothelial progenitors for the developing kidney. The exact role of the renal stroma in normal kidney development hasn't been clearly defined. However, previous studies have shown that the genetic deletion of Foxd1, a renal stroma specific gene, leads to severe kidney malformations confirming the importance of stroma in normal kidney development. This study further investigates the role of renal stroma by ablating Foxd1-derived stroma cells themselves and observing the response of the remaining cell populations. A Foxd1cre (renal stroma specific) mouse was crossed with a diphtheria toxin mouse (DTA) to specifically induce apoptosis in stromal cells. Histological examination of kidneys at embryonic day 13.5-18.5 showed a lack of stromal tissue, mispatterning of renal structures, and dysplastic and/or fused horseshoe kidneys. Immunofluorescence staining of nephron progenitors, vasculature, ureteric epithelium, differentiated nephron progenitors, and vascular supportive cells revealed that mutants had thickened nephron progenitor caps, cortical regions devoid of nephron progenitors, aberrant vessel patterning and thickening, ureteric branching defects and migration of differentiated nephron structures into the medulla. The similarities between the renal deformities caused by Foxd1 genetic knockout and Foxd1DTA mouse models reveal the importance of Foxd1 in mediating and maintaining the functional integrity of the renal stroma. © 2014 Hum et al

The world trade center 9/11 disaster and progressive collapse of tall buildings

The collapse of the World Trade Center buildings on September 11, 2001 posed questions on the stability of tall buildings in fire. Understanding the collapse of the WTC Towers offers the opportunity to learn useful engineering lessons in order to improve the design of future tall buildings against fire induced collapse. This paper extends previous research on the modelling of the collapse of the WTC Towers on September 11, 2001 using a newly developed ‘‘structures in fire’’ simulation capability in the open source software framework OpenSees. The simulations carried out are validated by comparisons with previous work and against the findings from the NIST investigation, albeit not in the forensic sense. The column ‘‘pull in’’ that triggers the instability of the structure and leads to collapse is explained. The collapse mechanisms of generic composite tall buildings are also examined. This is achieved through carrying out a detailed parametric study varying the relative stiffness of the column and the floors. The two main mechanisms identified in previous research (weak and strong floor) are reproduced and criteria are established on their occurrence. The analyses performed revealed that the collapse mechanism type depended on the bending stiffness ratio and the number of floors subjected to fire and that the most probable type of failure is the strong floor collapse. The knowledge of these mechanisms is of practical use if stakeholders wish to extend the tenability of a tall building structure in a major fire.Professor Jose Torero and the Open-Sees team at PEER, UC Berkele

Postoperative airway management after nasal endoscopic sinus surgery: A comparison of traditional nasal packing with nasal airway

BACKGROUND: Nasal packing after the nasal surgery can be extremely hazardous and can lead to airway complications such as dyspnea and respiratory obstruction. OBJECTIVE: The present study aimed at comparing the traditional nasal packing with nasal airway during the immediate postoperative period in patients undergoing fibreoptic endoscopic sinus surgery (FESS) under general anaesthesia (GA) with regards to airway management. MATERIALS AND METHODS: The study groups consisted of 90 ASA grade I and II patients aged 16 to 58 years who underwent FESS under GA. Patients were randomly assigned into three groups: Group NP, UA and Group BA of 30 patients each. At the end of surgery, Group NP patients were managed with traditional bilateral nasal packing while a presterilized 5 mm ID uncuffed ETT was cut to an appropriate size and inserted into one of the nostrils in UA and bilaterally in BA group patients. During postoperative period following parameters and variables were observed over the next 24 hours: Any respiratory distress or obstruction, pain and discomfort, oxygen saturation, heart rate, blood pressure, bleeding episode, ease of suctioning through nasal airway, anaesthesiologists and surgeons satisfaction during postoperative period, discomfort during removal of nasal airway and any fresh bleeding episode during removal of nasal airway. The data was compiled and analyzed using Chi-square test and ANOVA with post-hoc significance. Value of P < 0.05 was considered significant and P < 0.0001 as highly significant. RESULTS: The post-op mean cardio-respiratory parameters showed significant variations among NP group (P < 0.05) and the patient of UA and BA groups while intergroup comparison between UA and BA was non-significant (P > 0.05). Pain and discomfort, bleeding episode, ease of suctioning through nasal airway, pain and bleeding during removal of nasal airway (P < 0.0001) as well as surgeons and anaesthesiologists satisfaction criteria showed significant results among the NP group as compared to UA and BA groups (P < 0.05). CONCLUSION: The present intervention to maintain airway patency can be termed as excellent with additional benefits like ease of suctioning; oxygen supplementation and a possible haemostatic effect due to pressure on the operated site. The low cost of the modified nasal airway and easily replicable design were the standout observations of the present study

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Not AvailableInfectious Bovine Rhinotracheitis (IBR) is caused by Bovine herpesvirus-1 (BoHV-1), an infectious diseasecausing huge economic loss in dairy cattle. To keep dairy farming healthy and highly productive, there should be an IBR surveillance programme in dairy cattle, hence a study on the seroprevalence of IBR was undertaken in the Andaman and Nicobar Islands where the density of livestock population was more. A total of 418 cattle serum samples during 2019-20 from 11 villages of two districts of Andaman and Nicobar Islands were screened for IBR antibodies using ICAR-NIVEDI Avidin Biotin ELISA, of which 107 were found positive revealing 25.60% of seropositivity. HF crossbred and Jersey breed showed seropositivity of 24.06% and 33.33% respectively. Cattle of 5-6 years of age showed high seropositivity of 27.65-38.98%. Hence, it is recommended to test raw fresh semen/frozen semen straws, dairy animals regularly for IBR antigen/antibodies to avoid the spread of infectionNot Availabl