Comparison of the Influence of Oxygen Groups Introduced by Graphene Oxide on the Activity of Carbon Felt in Vanadium and Anthraquinone Flow Batteries.

An increasing number of studies focus on organic flow batteries (OFBs) as possible substitutes for the vanadium flow battery (VFB), featuring anthraquinone derivatives, such as anthraquinone-2,7-disulfonic acid (2,7-AQDS). VFBs have been postulated as a promising energy storage technology. However, the fluctuating cost of vanadium minerals and risky supply chains have hampered their implementation, while OFBs could be prepared from renewable raw materials. A critical component of flow batteries is the electrode material, which can determine the power density and energy efficiency. Yet, and in contrast to VFBs, studies on electrodes tailored for OFBs are scarce. Hence, in this work, we propose the modification of commercial carbon felts with reduced graphene oxide (rGO) and poly(ethylene glycol) for the 2,7-AQDS redox couple and to preliminarily assess its effects on the efficiency of a 2,7-AQDS/ferrocyanide flow battery. Results are compared to those of a VFB to evaluate if the benefits of the modification are transferable to OFBs. The modification of carbon felts with surface oxygen groups introduced by the presence of rGO enhanced both its hydrophilicity and surface area, favoring the catalytic activity toward VFB and OFB reactions. The results are promising, given the improved behavior of the modified electrodes. Parallels are established between the electrodes of both FB technologies.

Neutrophil-to-lymphocyte ratio as a predictor of surgical site infection in acute appendicitis.

Background: Surgical site infection (SSI) is one of the most common complications after appendectomy, which carries high associated morbidity. Therefore, it is essential to determine SSI predictive factors in order to prevent its occurrence. The aim of this study is to explore the role of neutrophil-to-lymphocyte ratio (NLR) as a predictor of SSI after appendectomy in children. Methods: A single-center, retrospective cohort study was performed in children who underwent appendectomy between 2017-2020. Demographics, time since symptoms onset, laboratory tests at admission, ultrasound appendiceal diameter, rate of complicated appendicitis, surgical aproach, surgery time and SSI rate were analyzed. Follow-up was performed during hospitalization and at outpatient clinic at 2 weeks and 30 days postoperatively to assess the surgical wound aspect. Diagnostic cut-off values of these markers for SSI prediction were based on the significance in the univariate analysis. Variables with a P value <0.05 in the univariate analysis were then entered into the multivariate analysis. Results: A total of 1,136 patients (710 males; 426 females) were included. SSI was reported in 53 patients (4.7%) during the 30-day follow-up after appendectomy (SSI group), with no demographic differences with the control group. Time since symptoms onset was significantly higher in SSI group (24 vs. 18 hours; P=0.034), as well as ultrasound appendiceal diameter (10.5 vs. 8.5 mm; P=0.010). Complicated appendicitis was observed in about 60% of both groups, without differences in surgical approach between them. Surgery time was statistically higher in the SSI group (62.4 vs. 47.9 min; P<0.001). SSI group presented higher counts of leukocytes, neutrophils and NLR than control group (P<0.001). NLR was the parameter with the highest area under the curve (AUC) (AUC =0.808; P<0.001), with a cut-off point of 9.8 with maximum sensitivity (77.8%) and specificity (72.7%). NLR was an independent predictive factor for SSI in the multivariate analysis [odds ratio (OR) 1.82 (1.13-2.73); P<0.01]. Conclusions: NLR value at admission was the most promising predictive factor for the development of SSI in children undergoing appendectomy. It is an easy, simple, inexpensive, and rapid method to detect patients at high risk for SSI. However, further prospective studies are still needed to confirm these results.

Intussusception Management in Children: A 15-Year Experience in a Referral Center.

OBJECTIVE: To report a 15-y, single-center experience in the management and outcomes of ileocolic intussusception (ICI) episodes. METHODS: A retrospective study was performed in patients with ICI episodes, who were treated at a single quaternary referral center from 2005 to 2019. Data evaluated included patient demographics, clinical presentation, treatment modalities, hospital stay, complications, and outcomes. RESULTS: A total of 546 ICI episodes (66.1% males) were included, with a median age at diagnosis of 15 mo. Enema reduction was performed in 478 patients (87.6%), with an overall success rate of 85.8%. Hydrostatic saline enema was the most effective method (89.3%) when compared to pneumatic (80.6%) or barium enema (79.8%), this difference being statistically significant (p = 0.031). No associated complications were observed during nonoperative reduction. Surgical treatment was performed in 101 patients, in whom 36 bowel resections were performed. Postoperative complications were reported in 6 patients (5.9%). Hospital stay was significantly longer in patients with operative management (median 5 d vs. 1 d; p < 0.001). CONCLUSIONS: Nonoperative management has a high overall success rate and low complication and recurrence rates. Saline enema reduction presents the highest effectiveness, and should be considered the first-line treatment.

The effectiveness of matrix ablation with silver nitrate in the treatment of ingrown toenails. A single-center case-control study.

BACKGROUND: Partial onychectomy with chemical matrixectomy is considered the gold standard treatment for stage II-III ingrown toenails (IT). However, there are scarce reports describing the use of silver nitrate in IT management in adolescents. Our aim is to analyze the effectiveness of matrix ablation with silver nitrate and compare it with partial onychectomy by electrocautery. METHODS: A retrospective study of adolescent patients with stage II-III IT was performed. Those who underwent electrocautery matricectomy in a major outpatient surgical center (Group A) and those who were treated with silver nitrate at an outpatient clinic (Group B) were compared. Efficacy was determined by recurrence and postoperative infection rates. RESULTS: Two hundred and nine patients were included (86 group A; 123 group B), with a total of 382 partial onychectomies (151 group A; 231 group B). Group B patients exhibited a lower recurrence rate (4.7%) when compared to group A (11.2%, p = .02), and had a lower postoperative infection rate (4.0% group A vs. 1.7% group B; p = .18), although not statistically significant. CONCLUSION: Silver nitrate chemical matricectomy after partial onychectomy is an effective treatment for IT in adolescents, with few postoperative complications and low recurrence rate. Therefore, it should be considered as a possible alternative to electrocautery matricectomy.

The role of neutrophil-to-lymphocyte ratio as a predictor of testicular torsion in children.

INTRODUCTION: Doppler ultrasound constitutes the gold standard for the diagnosis of testicular torsion (TT), although sometimes the spermatic cord twisting and absence of testicular flow are difficult to visualize. To date, no laboratory markers have been shown to be useful for preoperative TT diagnosis. OBJECTIVE: Our aim is to analyze the role of the neutrophil-to-lymphocyte ratio (NLR) as a predictor of pediatric TT. STUDY DESIGN: A retrospective single-center case-control study was performed in patients with ultrasound suspicion of TT, in whom surgical testicular examination was performed between 2016 and 2020. Patients were divided into two groups according to the intraoperative findings: TT group (testicular torsion), defined as spermatic cord twisting on itself around its longitudinal axis at least 360°, and non-TT group (no torsion). Demographics, clinical, ultrasound and laboratory features at admission were analyzed. Sensitivity and specificity were determined by the area under the curve (AUC) represented on the receiver operating characteristic (ROC) curves. RESULTS: A total of 159 patients were included (117 TT group; 42 non-TT group), with no demographic or clinical differences. TT group patients presented significantly shorter median time since symptoms onset (4 vs. 8 h; p < 0.012). Laboratory inflammatory test were significantly higher in TT group: Leukocytes (10,900 × 103/µl vs. 7,980 × 103/µl; p < 0.001), neutrophils (8,050 × 103/µl vs. 3,350 × 103/µl; p < 0.001) and NLR (4.6 vs. 1.1; p < 0.001). In ROC curve analysis, NLR presented the highest AUC (0.903), significantly higher than all other laboratory and ultrasound parameters. NLR of 2.3 was the cut-off point with maximum sensitivity (86.9%) and specificity (94.8%). DISCUSSION: This is, to the best of our knowledge, the first study to analyze the usefulness of NLR in predicting the diagnosis of TT in patients with clinical and ultrasound suspicion. The limitations are mainly derived from being a single-center retrospective study. For this reason, multicenter studies with a higher number of patients and prospective design may be useful to minimize these biases. The sample size of our study, although not large, has allowed us to identify significant differences between the distinct parameters analyzed as predictors of TT. However, the absence of other similar studies in pediatric patients has hindered the comparison of our results. CONCLUSION: NLR should be considered as a predictor of pediatric TT in cases with nuclear ultrasound suspicion that may help to anticipate the urgent surgical treatment in these patients.

Complicated Acute Appendicitis during COVID-19 Pandemic: The Hidden Epidemic in Children.

INTRODUCTION: Since home confinement for novel coronavirus disease 2019 (COVID-19) pandemic began, pediatric visits to the emergency department (ED) have decreased, including consultation for abdominal pain. Our aim is to investigate the incidence of complicated acute appendicitis (AA; peritonitis or appendicular mass) during confinement for COVID-19 pandemic and to compare it with the previous 5 years. MATERIALS AND METHODS: A retrospective study was performed in children with AA who underwent surgery between March 9 and April 13 from 2015 to 2020; patients were divided into six groups according to the year of surgery. We analyzed demographic variables, time from onset of symptoms, mean hospital stay, cumulative incidence, and incidence rate of complicated appendicitis. RESULTS: A total of 168 patients were included with no differences in the number of patients, gender, and age between groups. Patients in 2020 (COVID-19 group) presented longer symptom progression time (46.8 hours; p = 0.046), higher rate of complicated appendicitis (48.4%; p = 0.004), longer mean hospital stay (4.9 days; p < 0.001), increased cumulative incidence (8.27 cases per 100,000 children per 0.1 years; p < 0.001), and increased incidence rate of complicated appendicitis (83 cases per 100,000 children; p < 0.001) when compared with other groups. CONCLUSION: Delayed ED visit of children with AA during home confinement lead to an increased rate of complicated appendicitis. It is crucial to make parents aware of the importance of early diagnosis and treatment of abdominal pain.

Percutaneous Cryoanalgesia: A New Strategy for Pain Management in Pectus Excavatum Surgery.

INTRODUCTION: In recent years, pain protocols for pectus excavatum (PE) have incorporated cryoanalgesia through thoracoscopic approach. Since 2019, ultrasound-guided percutaneous cryoanalgesia (PCr) has been applied at our institution, either on the same day as the Nuss procedure or 48 hours before surgery. We carried out a preliminary retrospective review of patients with PE in whom PCr prior to surgery was performed at our institution between 2019 and 2021. MATERIALS AND METHODS: Two groups were evaluated: PCr on the same day (PCrSD) and PCr 48 hours before surgery (PCr48). Despite PCr, patients were treated with "patient-controlled analgesia" (PCA) with opioids for at least 24 hours, switching to conventional intravenous analgesia and oral analgesia in the following days. Demographic, clinical-radiological variables, PCA opioid use, pain grade according to the visual analog scale (VAS), and length of stay (LOS) were compared between the groups. A total of 20 patients were included (12 with PCrSD and 8 with PCr48), without significant differences in demographics or clinical-radiological variables. The overall median time of PCr was 65 minutes (55-127), with no differences between the groups. RESULTS: PCr48 group presented with significantly lower median number of hours of continuous PCA (24 vs. 32 hours; p = 0.031), lower median number of rescue boluses (11 vs. 18; p = 0.042), lower median VAS in the early postoperative hours (2 vs. 5.5; p = 0.043), and lower median LOS (3.5 vs. 5 days). CONCLUSION: PCr performed 48 hours prior to surgery is more effective in terms of PCA requirements, VAS, and LOS when compared with cryoanalgesia on the same day.

Neutropthil-to-Lymphocyte Ratio as a Predictor of Postsurgical Intraabdominal Abscess in Children Operated for Acute Appendicitis.

Aim of the study: Postoperative intra-abdominal abscess (PIAA) is a frequent and severe complication of acute appendicitis (AA) with peritonitis. The neutrophil-to-lymphocyte ratio (NLR) is an inflammatory marker that has been related to the development of peritonitis; however, its diagnostic role in predicting PIAA has not been evaluated. This is the first study that analyzes the usefulness of NLR as a predictor of PIAA in children operated for AA. Material and Methods: Retrospective observational study in children operated for AA in our institution during 2017-2018. Patients aged under 5 years or with incomplete laboratory determinations at hospital admission (blood count, C-reactive protein, and fibrinogen) were excluded. Demographic and laboratory parameters and the development of PIAA were analyzed. NLR was calculated by dividing the absolute number of neutrophils by the absolute number of lymphocytes. By means of ROC curves, we determined the sensitivity and specificity of the different laboratory parameters to predict the development of PIAA. Results: A total of 388 patients aged 10.5 ± 2.9 year were included. Twenty (5.2%) developed PIAA. NLR presented an area under the curve (AUC) of 0.85, significantly higher than the determination of leukocytes (AUC 0.69, p < 0.001), neutrophils (AUC 0.74, p < 0.001), fibrinogen (AUC 0.68, p < 0.001) and C-reactive protein (AUC 0.73, p < 0.001). We estimated the optimal cut-off point of NLR > 10.5, with a sensitivity of 85% and a specificity of 75.2%. Conclusions: NLR is the laboratory parameter with the highest sensitivity and specificity for predicting the development of PIAA in children operated for AA. It can be useful as a predictor of worse postoperative course.

Vibration Monitoring of the Mechanical Harvesting of Citrus to Improve Fruit Detachment Efficiency.

The introduction of a mechanical harvesting process for oranges can contribute to enhancing farm profitability and reducing labour dependency. The objective of this work is to determine the spread of the vibration in citrus tree canopies to establish recommendations to reach high values of fruit detachment efficiency and eliminate the need for subsequent hand-harvesting processes. Field tests were carried out with a lateral tractor-drawn canopy shaker on four commercial plots of sweet oranges. Canopy vibration during the harvesting process was measured with a set of triaxial accelerometer sensors with a datalogger placed on 90 bearing branches. Monitoring of the vibration process, fruit production, and branch properties were analysed. The improvement of fruit detachment efficiency was possible if both the hedge tree and the machinery were mutually adjusted. The hedge should be trained to facilitate access of the rods and to encourage external fructification since the internal canopy branches showed 43% of the acceleration vibration level of the external branches. The machine should be adjusted to vibrate the branches at a vibration time of at least 5.8 s, after the interaction of the rod with the branch, together with a root mean square acceleration value of 23.9 m/s2 to a complete process of fruit detachment.

Application of machine learning techniques to analyse the effects of physical exercise in ventricular fibrillation.

This work presents the application of machine learning techniques to analyse the influence of physical exercise in the physiological properties of the heart, during ventricular fibrillation. To this end, different kinds of classifiers (linear and neural models) are used to classify between trained and sedentary rabbit hearts. The use of those classifiers in combination with a wrapper feature selection algorithm allows to extract knowledge about the most relevant features in the problem. The obtained results show that neural models outperform linear classifiers (better performance indices and a better dimensionality reduction). The most relevant features to describe the benefits of physical exercise are those related to myocardial heterogeneity, mean activation rate and activation complexity.

BELM: Bayesian extreme learning machine.

The theory of extreme learning machine (ELM) has become very popular on the last few years. ELM is a new approach for learning the parameters of the hidden layers of a multilayer neural network (as the multilayer perceptron or the radial basis function neural network). Its main advantage is the lower computational cost, which is especially relevant when dealing with many patterns defined in a high-dimensional space. This brief proposes a bayesian approach to ELM, which presents some advantages over other approaches: it allows the introduction of a priori knowledge; obtains the confidence intervals (CIs) without the need of applying methods that are computationally intensive, e.g., bootstrap; and presents high generalization capabilities. Bayesian ELM is benchmarked against classical ELM in several artificial and real datasets that are widely used for the evaluation of machine learning algorithms. Achieved results show that the proposed approach produces a competitive accuracy with some additional advantages, namely, automatic production of CIs, reduction of probability of model overfitting, and use of a priori knowledge.

The use of neural networks for predicting the result of endoscopic treatment for vesico-ureteric reflux.

OBJECTIVE: To create an artificial neural network (ANN) to aid in predicting the results of endoscopic treatment for vesico-ureteric reflux (VUR). MATERIALS AND METHODS: During 1999-2001 we used endoscopic treatment in 261 ureteric units with VUR of all grades and causes. An ANN based on multilayer perceptron architecture was created using an 11 x 6 x 1 structure, taking the following as variables: the cause and grade of VUR, the patient's age and sex, the type of implanted substance and its volume, the number of treatments, the affected ureter, the endoscopic findings, and the type of cystography used. In all, 174 cases were used as training samples for the ANN and 87 to validate it. We calculated the sensitivity, specificity, positive (PPV) and negative predictive values (NPV), and the success rate (%) of the system. RESULTS: In the training group the ANN gave a sensitivity of 86.4%, a specificity of 89.5%, a PPV of 76% and NPV of 94%, with a success rate of 88.6%. In the same training group logistic regression (LR) gave respective values of 68.2%, 58.8%, 39%, 82.7% and 61.4%. In the validation group the respective values for the ANN were 71.4%, 81.6%, 58.8%, 88.6% and 78.9%, and in the same validation group the LR gave 64.4%, 50%, 32.1%, 79.2% and 53.9%. The Wilcoxon test confirmed the independence of both methods (P < 0.001). CONCLUSION: The ANN is an effective tool for assisting the urologist in indicating and applying endoscopic treatments for VUR.