Shell-supported footbridges

Architects and engineers have been always attracted by concrete shell structures due to their high efficiency and plastic shapes. In this paper the possibility to use concrete shells to support footbridges is explored. Starting from Musmeci's fundamental research andwork in shell bridge design, the use of numerical formfinding methods is analysed. The form-finding of a shellsupported footbridge shaped following Musmeci's work is first introduced. Coupling Musmeci's and Nervi's experiences, an easy construction method using a stay-inplace ferrocement formwork is proposed. Moreover, the advantage of inserting holes in the shell through topology optimization to remove less exploited concrete has been considered. Curved shell-supported footbridges have been also studied, and the possibility of supporting the deck with the shell top edge, that is along a single curve only, has been investigated. The form-finding of curved shell-supported footbridges has been performed using a Particle-Spring System and Thrust Network Analysis. Finally, the form-finding of curved shell-supported footbridges subjected to both vertical and horizontal forces (i.e. earthquake action) has been implemented

Curved footbridges supported by a shell obtained through thrust network analysis

After Maillart's concrete curved arch bridges were built before the Second World War, in the second half of the past century and this century, many curved bridges have been built with both steel and concrete. Conversely, since the construction of Musmeci's shell supported bridge in Potenza, few shell bridges have been constructed. This paper explains how to design a curved footbridge supported by an anticlastic shell by shaping the shell via a thrust network analysis (TNA). By taking advantage of the peculiar properties of anticlastic membranes, the unconventional method of shaping a shell by a TNA is illustrated. The shell top edge that supports the deck has an assigned layout, which is provided by the road curved layout. The form of the bottom edge is obtained by the form-finding procedure as a thrust line, by applying the thrust network analysis (TNA) in a non-standard manner, shaping the shell by applying the boundary conditions and allowing relaxation. The influence of the boundary conditions on the bridge shape obtained as an envelope of thrust lines is investigated. A finite element analysis was performed. The results indicate that the obtained shell form is effective in transferring deck loads to foundations via compressive stresses and taking advantage of concrete mechanical properties

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR): A critical overview on the most promising applications of molecular scissors in oral medicine

The scientific community is continuously working to translate the novel biomedical techniques into effective medical treatments. CRISPR-Cas9 system (Clustered Regularly Interspaced Short Palindromic Repeats-9), commonly known as the “molecular scissor”, represents a recently developed biotechnology able to improve the quality and the efficacy of traditional treatments, related to several human diseases, such as chronic diseases, neurodegenerative pathologies and, interestingly, oral diseases. Of course, dental medicine has notably increased the use of biotechnologies to ensure modern and conservative approaches: in this landscape, the use of CRISPR-Cas9 system may speed and personalize the traditional therapies, ensuring a good predictability of clinical results. The aim of this critical overview is to provide evidence on CRISPR efficacy, taking into specific account its applications in oral medicine

Cystic Dilation of Extrahepatic Bile Ducts in Adulthood: Diagnosis, Surgical Treatment and Long. Term Results

To evaluate the long-term results of surgery for choledohal cyst in adulthood, a series of 13 patients over the age of 16 operated on for choledochal cyst during a period of six years and followed-up for a minimum of 3 years was analyzed. Patients with type I and IVa cysts underwent extrahepatic cyst resection and Roux-en-Y hepatico-jejunostomy. Choledochoceles (type III) were managed endoscopically. No operative mortality or morbidity occurred. Type I and III cysts showed almost ideal follow-up with no sign of stricture on HIDA scan. One type IVa cyst patients developed recurrent cholangitis due to anastomotic stricture, managed percutaneously. Whenever possible, complete cyst resection and Roux-en-Y reconstruction is the treatment of choice for all extrahepatic biliary cysts. Intra- and extrahepatic dilatations are adequately treated by extrahepatic resection and careful endoscopic or radiologic surveillance. Small choledochoceles can be safely managed by endoscopic sphincterotomy

The Emergency Surgery Frailty Index (EmSFI) in Elderly Patients with Acute Appendicitis: An External Validation of Prognostic Score

Background: Identification of reliable risk-stratification tools is critical for surgical decision making, particularly in frail and elderly. The aim of the study is to validate the Emergency Surgery Frailty Index (EmSFI), in over 65 years old patients operated on for acute appendicitis. Methods: An observational study was conducted enrolling elderly patients with diagnosis of acute appendicitis who underwent emergency appendicectomy or right colectomy, between 2016 and 2021. All patients were treated according to the last SIFIPAC/WSES/SICG/SIMEU guidelines. Results: Overall, 61 patients were analyzed. Complication rate was higher for patients in the second EmSFI risk Class. Moreover, ROC analyses identified 3 as the best cutoff value in predicting risk of adverse postoperative events. Complication rate was higher in oldest elderly patients—over 80 years—(42.9 vs 22.5%; p 0.05) and was mainly related to medical complications (42.9 vs 12.5%, p 0.007). However, intestinal obstruction, peri-appendicular abscess on preoperative CT, peritonitis and a longer duration of surgery are related with increased risk of complications in the group of patients under 80 years. Conclusion: The EmSFI score results a valid prognostic marker for frailty status, and it may support the surgeon in emergency setting for acute appendicitis. Patients aged 80 years or older have a higher risk of complications, independent from those factors which relate to increased morbidity in younger elderly patients. Age alone is not a reliable indicator of the real surgical risk, but it must encourage the adoption of multidisciplinary collaborative models of care for this group of patients. © 2023, The Author(s)

Near-Infrared Fluorescence Image-Guided Surgery in Esophageal and Gastric Cancer Operations

Background: Near-infrared fluorescence image-guided surgery helps surgeons to see beyond the classical eye vision. Over the last few years, we have witnessed a revolution which has begun in the field of image-guided surgery. Purpose, and Research design: Fluorescence technology using indocyanine green (ICG) has shown promising results in many organs, and in this review article, we wanted to discuss the 6 main domains where fluorescence image-guided surgery is currently used for esophageal and gastric cancer surgery. Study sample and data collection: Visualization of lymphatic vessels, tumor localization, fluorescence angiography for anastomotic evaluation, thoracic duct visualization, tracheal blood flow analysis, and sentinel node biopsy are discussed. Conclusions: It seems that this technology has already found its place in surgery. However, new possibilities and research avenues in this area will probably make it even more important in the near future

Responsiveness to sensory cues using the Timed Up and Go test in patients with Parkinson's disease: a prospective cohort study.

Objective: To test the effectiveness of the Timed Up and Go (TUG) test to define responsiveness to auditory and visual cues in patients with Parkinson's disease. Methods: Consecutive patients > 50 years old were enrolled if they were classified as stage 1–3 of the Hoehn and Yahr scale; scored ≤ 45 on part III of the Unified Parkinson's Disease Rating Scale; > 23 on the Mini-Mental State Examination; and were able to perform the TUG test without assistance. Within-subject analysis identified positive-responders, negative-responders and non-responders. TUG times with and without sensory cues were studied among all patients, and among responders only using the Friedman Test. Results: Twenty-two patients (16 men, 6 women), mean age 72.4 years (standard deviation (SD) 8.7 years) were included. Basal mean TUG time was 12.3 (SD 4.0). TUG times after visual cues (11.7 (SD 4.8)) were lower than in basal conditions (p = 0.006), whereas TUG times after auditory cues were not (p > 0.05). In the 16 patients who were positive-responders, mean TUG times after visual (11.0 (SD 3.1)) and auditory (11.3 (SD 3.6)) cues were lower than in basal conditions (12.5 (SD 3.8)) (p = 0.0002). Conclusion: The TUG test may be used to tailor the rehabilitation programme in patients with Parkinson's disease, identifying those who respond to visual and auditory cueing

Methylene Blue Near-Infrared Fluorescence Imaging in Breast Cancer Sentinel Node Biopsy

Introduction: Fluorescence-based navigation for breast cancer sentinel node biopsy is a novel method that uses indocyanine green as a fluorophore. However, methylene blue (MB) also has some fluorescent properties. This study is the first in a clinical series presenting the possible use of MB as a fluorescent dye for the identification of sentinel nodes in breast sentinel node biopsy. Material and methods: Forty-nine patients with breast cancer who underwent sentinel node biopsy procedures were enrolled in the study. All patients underwent standard simultaneous injection of nanocolloid and MB. We visualized and assessed the sentinel nodes and the lymphatic channels transcutaneously, with and without fluorescence, and calculated the signal-to-background ratio (SBR). We also analyzed the corresponding fluorescence intensity of various dilutions of MB. Results: In twenty-three patients (46.9%), the location of the sentinel node, or the end of the lymphatic path, was visible transcutaneously. The median SBR for transcutaneous sentinel node location was 1.69 (range 1.66–4.35). Lymphatic channels were visible under fluorescence in 14 patients (28.6%) prior to visualization by the naked eye, with an average SBR of 2.01 (range 1.14–5.6). The sentinel node was visible under fluorescence in 25 patients (51%). The median SBR for sentinel node visualization with MB fluorescence was 2.54 (range 1.34–6.86). Sentinel nodes were visualized faster under fluorescence during sentinel node preparation. Factors associated with the rate of visualization included diabetes (p = 0.001), neoadjuvant chemotherapy (p = 0.003), and multifocality (p = 0.004). The best fluorescence was obtained using 40 µM (0.0128 mg/mL) MB, but we also observed a clinically relevant dilution range between 20 µM (0.0064 mg/mL) and 100 µM (0.032 mg/mL). Conclusions: For the first time, we propose the clinical usage of MB as a fluorophore for fluorescence-guided sentinel node biopsy in breast cancer patients. The quenching effect of the dye may be the reason for its poor detection rate. Our analysis of different concentrations of MB suggests a need for a detailed clinical analysis to highlight the practical usefulness of the dye

How Many Templates for GW Chirp Detection? The Minimal-Match Issue Revisited

In a recent paper dealing with maximum likelihood detection of gravitational wave chirps from coalescing binaries with unknown parameters we introduced an accurate representation of the no-signal cumulative distribution of the supremum of the whole correlator bank. This result can be used to derive a refined estimate of the number of templates yielding the best tradeoff between detector's performance (in terms of lost signals among those potentially detectable) and computational burden.Comment: submitted to Class. Quantum Grav. Typing error in eq. (4.8) fixed; figure replaced in version