Heat transfer in steady-periodic flows over heated microwires

Effects of Reynolds number (Re), nondimensional drive frequency (Srp) and amplitude of yoscillations in the flow on the heat transfer coefficient and its frequency response characteristics for oscillatory flows over a micro wire are presented here. Time-averaged Nusselt numbers (Nu) at the stagnation point and averaged over the cylinder are calculated for Re = 10, 30 and 50, .001 < Srp < 1., and oscillation amplitudes, Vp, of 0.1 and 0.2 (for Re = 50). We used a formulation that allows decomposition of the flow into mean and periodic components, and used finite-element simulations to solve for the mean flow over the cylinder. Periodic component of the flow contributes to an artificial body force in the Navier-Stokes equation. According to our simulations, time-averaged Nusselt numbers are not strongly affected by oscillations. Largest increase in the time-averaged average Nu is only 3% larger than its unforced value. Nusselt oscillations have multiple modes and we used Fourier Transform to identify each mode and calculate its corresponding amplitude. The mode for which the frequency is twice as much as the driving frequency is the dominant mode for Srp up to 0.1 for all Reynolds numbers studied here. For larger drive frequencies, the second mode dies off; for Re = 30 and 50 amplitude of the first mode at the drive frequency takes over. For large drive frequencies (Srp~1) all modes tend to diminish

Influence of colonic mesenteric area on the number of lymph node retrieval for colon cancer: a prospective cohort study

Purpose The minimum harvested 12 lymph nodes (LNs) is regarded as the limit for accurate staging of nodal status in colorectal cancer patients. Besides the association of the lengths of resected intestinal segments and vascular pedicles, the mesocolic mesenteric area’s impact on LN count has not been studied. We aimed to evaluate the associations between metric variables, including the mesocolic mesentery area on the nodal harvest. Methods All consecutive patients who underwent elective colectomy with a curative intention for colon adenocarcinoma were prospectively included. The metric variables included the lengths of resected intestinal segments, vascular pedicle, and colonic mesenteric area. The variables influencing the LN count and the correlation between the total LN count and the specimens’ relevant metric measurements were analyzed. Results There were 46 patients with a median age of 64 years. The median count for total LNs was 22, and the LN positivity was 59.2%. There was an inadequate LN yield (0.05). There were significant positive correlations between total LN number and length of vascular pedicle and mesenteric area (r=0.576, P<0.001 and r=0.566, P<0.001). Conclusion The length of the vascular pedicle and mesenteric area were significantly correlated with total LN counts. Although there was no significant impact on the length of resected segments, the colonic mesenteric area can be used alone as a measure for the assessment of the nodal yield in colon cancer

Pediatric trauma and emergency surgery: an international cross-sectional survey among WSES members

Background: In contrast to adults, the situation for pediatric trauma care from an international point of view and the global management of severely injured children remain rather unclear. The current study investigates structural management of pediatric trauma in centers of different trauma levels as well as experiences with pediatric trauma management around the world. Methods: A web-survey had been distributed to the global mailing list of the World Society of Emergency Surgery from 10/2021-03/2022, investigating characteristics of respondents and affiliated hospitals, case-load of pediatric trauma patients, capacities and infrastructure for critical care in children, trauma team composition, clinical work-up and individual experiences with pediatric trauma management in response to patients´ age. The collaboration group was subdivided regarding sizes of affiliated hospitals to allow comparisons concerning hospital volumes. Comparable results were conducted to statistical analysis. Results: A total of 133 participants from 34 countries, i.e. 5 continents responded to the survey. They were most commonly affiliated with larger hospitals (&gt; 500 beds in 72.9%) and with level I or II trauma centers (82.0%), respectively. 74.4% of hospitals offer unrestricted pediatric medical care, but only 63.2% and 42.9% of the participants had sufficient experiences with trauma care in children ≤ 10 and ≤ 5&nbsp;years of age (p = 0.0014). This situation is aggravated in participants from smaller hospitals (p &lt; 0.01). With regard to hospital size (≤ 500 versus &gt; 500 in-hospital beds), larger hospitals were more likely affiliated with advanced trauma centers, more elaborated pediatric intensive care infrastructure (p &lt; 0.0001), treated children at all ages more frequently (p = 0.0938) and have higher case-loads of severely injured children &lt; 12&nbsp;years of age (p = 0.0009). Therefore, the majority of larger hospitals reserve either pediatric surgery departments or board-certified pediatric surgeons (p &lt; 0.0001) and in-hospital trauma management is conducted more multi-disciplinarily. However, the majority of respondents does not feel prepared for treatment of severe pediatric trauma and call for special educational and practical training courses (overall: 80.2% and 64.3%, respectively). Conclusions: Multi-professional management of pediatric trauma and individual experiences with severely injured children depend on volumes, level of trauma centers and infrastructure of the hospital. However, respondents from hospitals at all levels of trauma care complain about an alarming lack of knowledge on pediatric trauma management

Correction to: Two years later: Is the SARS-CoV-2 pandemic still having an impact on emergency surgery? An international cross-sectional survey among WSES members

Background: The SARS-CoV-2 pandemic is still ongoing and a major challenge for health care services worldwide. In the first WSES COVID-19 emergency surgery survey, a strong negative impact on emergency surgery (ES) had been described already early in the pandemic situation. However, the knowledge is limited about current effects of the pandemic on patient flow through emergency rooms, daily routine and decision making in ES as well as their changes over time during the last two pandemic years. This second WSES COVID-19 emergency surgery survey investigates the impact of the SARS-CoV-2 pandemic on ES during the course of the pandemic. Methods: A web survey had been distributed to medical specialists in ES during a four-week period from January 2022, investigating the impact of the pandemic on patients and septic diseases both requiring ES, structural problems due to the pandemic and time-to-intervention in ES routine. Results: 367 collaborators from 59 countries responded to the survey. The majority indicated that the pandemic still significantly impacts on treatment and outcome of surgical emergency patients (83.1% and 78.5%, respectively). As reasons, the collaborators reported decreased case load in ES (44.7%), but patients presenting with more prolonged and severe diseases, especially concerning perforated appendicitis (62.1%) and diverticulitis (57.5%). Otherwise, approximately 50% of the participants still observe a delay in time-to-intervention in ES compared with the situation before the pandemic. Relevant causes leading to enlarged time-to-intervention in ES during the pandemic are persistent problems with in-hospital logistics, lacks in medical staff as well as operating room and intensive care capacities during the pandemic. This leads not only to the need for triage or transferring of ES patients to other hospitals, reported by 64.0% and 48.8% of the collaborators, respectively, but also to paradigm shifts in treatment modalities to non-operative approaches reported by 67.3% of the participants, especially in uncomplicated appendicitis, cholecystitis and multiple-recurrent diverticulitis. Conclusions: The SARS-CoV-2 pandemic still significantly impacts on care and outcome of patients in ES. Well-known problems with in-hospital logistics are not sufficiently resolved by now; however, medical staff shortages and reduced capacities have been dramatically aggravated over last two pandemic years

Goodbye Hartmann trial: a prospective, international, multicenter, observational study on the current use of a surgical procedure developed a century ago

Background: Literature suggests colonic resection and primary anastomosis (RPA) instead of Hartmann's procedure (HP) for the treatment of left-sided colonic emergencies. We aim to evaluate the surgical options globally used to treat patients with acute left-sided colonic emergencies and the factors that leading to the choice of treatment, comparing HP and RPA. Methods: This is a prospective, international, multicenter, observational study registered on ClinicalTrials.gov. A total 1215 patients with left-sided colonic emergencies who required surgery were included from 204 centers during the period of March 1, 2020, to May 31, 2020. with a 1-year follow-up. Results: 564 patients (43.1%) were females. The mean age was 65.9 ± 15.6&nbsp;years. HP was performed in 697 (57.3%) patients and RPA in 384 (31.6%) cases. Complicated acute diverticulitis was the most common cause of left-sided colonic emergencies (40.2%), followed by colorectal malignancy (36.6%). Severe complications (Clavien-Dindo ≥ 3b) were higher in the HP group (P &lt; 0.001). 30-day mortality was higher in HP patients (13.7%), especially in case of bowel perforation and diffused peritonitis. 1-year follow-up showed no differences on ostomy reversal rate between HP and RPA. (P = 0.127). A backward likelihood logistic regression model showed that RPA was preferred in younger patients, having low ASA score (≤ 3), in case of large bowel obstruction, absence of colonic ischemia, longer time from admission to surgery, operating early at the day working hours, by a surgeon who performed more than 50 colorectal resections. Conclusions: After 100&nbsp;years since the first Hartmann's procedure, HP remains the most common treatment for left-sided colorectal emergencies. Treatment's choice depends on patient characteristics, the time of surgery and the experience of the surgeon. RPA should be considered as the gold standard for surgery, with HP being an exception

COVID-19 infection is a significant risk factor for death in patients presenting with acute cholecystitis: a secondary analysis of the ChoCO-W cohort study

Background: During the coronavirus disease (COVID-19) pandemic, there has been a surge in cases of acute cholecystitis. The ChoCO-W global prospective study reported a higher incidence of gangrenous cholecystitis and adverse outcomes in COVID-19 patients. Through this secondary analysis of the ChoCO-W study data, we aim to identify significant risk factors for mortality in patients with acute cholecystitis during the COVID-19 pandemic, emphasizing the role of COVID-19 infection in patient outcomes and treatment efficacy.” Methods: The ChoCO-W global prospective study reported data from 2546 patients collected at 218 centers from 42 countries admitted with acute cholecystitis during the COVID-19 pandemic, from October 1, 2020, to October 31, 2021. Sixty-four of them died. Nonparametric statistical univariate analysis was performed to compare patients who died and patients who survived. Significant factors were then entered into a logistic regression model to define factors predicting mortality. Results: The significant independent factors that predicted death in the logistic regression model with were COVID-19 infection (p &lt; 0.001), postoperative complications (p &lt; 0.001), and type (open/laparoscopic) of surgical intervention (p = 0.003). The odds of death increased 5 times with the COVID-19 infection, 6 times in the presence of complications, and it was reduced by 86% with adequate source control. Survivors predominantly underwent urgent laparoscopic cholecystectomy (52.3% vs. 23.4%). Conclusions: COVID-19 was an independent risk factor for death in patients with acute cholecystitis. Early laparoscopic cholecystectomy has emerged as the cornerstone of treatment for hemodynamically stable patients

Infected pancreatic necrosis: outcomes and clinical predictors of mortality. A post hoc analysis of the MANCTRA-1 international study

: The identification of high-risk patients in the early stages of infected pancreatic necrosis (IPN) is critical, because it could help the clinicians to adopt more effective management strategies. We conducted a post hoc analysis of the MANCTRA-1 international study to assess the association between clinical risk factors and mortality among adult patients with IPN. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality. We identified 247 consecutive patients with IPN hospitalised between January 2019 and December 2020. History of uncontrolled arterial hypertension (p = 0.032; 95% CI 1.135-15.882; aOR 4.245), qSOFA (p = 0.005; 95% CI 1.359-5.879; aOR 2.828), renal failure (p = 0.022; 95% CI 1.138-5.442; aOR 2.489), and haemodynamic failure (p = 0.018; 95% CI 1.184-5.978; aOR 2.661), were identified as independent predictors of mortality in IPN patients. Cholangitis (p = 0.003; 95% CI 1.598-9.930; aOR 3.983), abdominal compartment syndrome (p = 0.032; 95% CI 1.090-6.967; aOR 2.735), and gastrointestinal/intra-abdominal bleeding (p = 0.009; 95% CI 1.286-5.712; aOR 2.710) were independently associated with the risk of mortality. Upfront open surgical necrosectomy was strongly associated with the risk of mortality (p &lt; 0.001; 95% CI 1.912-7.442; aOR 3.772), whereas endoscopic drainage of pancreatic necrosis (p = 0.018; 95% CI 0.138-0.834; aOR 0.339) and enteral nutrition (p = 0.003; 95% CI 0.143-0.716; aOR 0.320) were found as protective factors. Organ failure, acute cholangitis, and upfront open surgical necrosectomy were the most significant predictors of mortality. Our study confirmed that, even in a subgroup of particularly ill patients such as those with IPN, upfront open surgery should be avoided as much as possible. Study protocol registered in ClinicalTrials.Gov (I.D. Number NCT04747990)

Is Mesenteric Ischemia In COVID-19 Patients A Surprise?

Aim. The disease caused by the 2019 novel coronavirus is known predominantly for its respiratory outcomes; a subset of critically ill patients demonstrates clinically remarkable hypercoagulability in which thrombotic events range from acute pulmonary embolism in patients with COVID-19 pneumonia to extremity ischemia. Our observational study aimed to describe the incidence and characteristics, as well as clinical outcomes, of patients presenting and treated for mesenteric ischemia during the COVID-19 pandemic. Material and Methods. Between March 13 and May 13, 2020, 60 patients operated for emergency reasons were analyzed, and it was noticed that 5 of the 6 COVID-positive patients were operated due to mesenteric ischemia. Results. Five of sixty patients (83.3%) applied to our emergency clinic with COVID-19 positive and acute abdomen. Two of them (40%) did not have any comorbidities. All of them (%100) were male. There were no complications and only 1 death (20%). Mean leukocyte, neutrophil, and platelet levels were within the normal range, while the lymphocyte level was near the lower limit. C-Reactive Protein was above the limit in all patients. The mean levels of International Normalized Ratio, Platelet, and Activated Partial Thromboplastin Time were above the limits. While D-dimer levels were close to the upper limit; fibrinogen levels were above the normal limit for each patient. Conclusion. The presence of hypercoagulation status in critical COVID-19 patients should be observed closely, and anticoagulation therapy can be considered in selected patients. More clinical data are needed to examine the role of anticoagulation in COVID-19 treatment. </jats:p

Tooth-Implant Connection: A Review

Connecting teeth to osseointegrated implants presents a biomechanical challenge. This is due to the implant being rigidly fixed to the bone and the tooth being attached to the bone with a periodontal ligament. In order to overcome this problem, various connection types such as rigid and nonrigid have been proposed. However, the mechanism of attachment and the perceived problem of the differential support provided by the implant and the tooth have been discussed by many authors, and the ideal connection type is still controversial. The aim of this study was to carry out a review of all available literature addressing the tooth-implant connection and evidence-based understanding of the management of tooth-implant-retained restorations.</jats:p

Postarthroscopy osteonecrosis of the knee

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