Flicker Noise in Resistive Gas Sensors-Measurement Setups and Applications for Enhanced Gas Sensing.

We discuss the implementation challenges of gas sensing systems based on low-frequency noise measurements on chemoresistive sensors. Resistance fluctuations in various gas sensing materials, in a frequency range typically up to a few kHz, can enhance gas sensing by considering its intensity and the slope of power spectral density. The issues of low-frequency noise measurements in resistive gas sensors, specifically in two-dimensional materials exhibiting gas-sensing properties, are considered. We present measurement setups and noise-processing methods for gas detection. The chemoresistive sensors show various DC resistances requiring different flicker noise measurement approaches. Separate noise measurement setups are used for resistances up to a few hundred kΩ and for resistances with much higher values. Noise measurements in highly resistive materials (e.g., MoS2, WS2, and ZrS3) are prone to external interferences but can be modulated using temperature or light irradiation for enhanced sensing. Therefore, such materials are of considerable interest for gas sensing.

Bariatric Surgery in Asthma: A Narrative Review.

Nearly 60% of asthmatics in the USA suffer from obesity. Asthma is a comorbid condition alongside obesity, commonly accompanied by conditions such as hypertension and type 2 diabetes. The positive effect of bariatric surgery on patients suffering from hypertension and type 2 diabetes, which leads to either a reduction in the dose of medication taken for the aforementioned diseases or the withdrawal of the disease, is quite well proven in the literature. Currently, the impact of bariatric operations on the control and course of bronchial asthma and pharmacological treatment has not been fully recognized and described, requiring further research; therefore, the following review of the literature was conducted.

Obesity as a Risk Factor for Breast Cancer-The Role of miRNA.

Breast cancer (BC) is the most common cancer diagnosed among women in the world, with an ever-increasing incidence rate. Due to the dynamic increase in the occurrence of risk factors, including obesity and related metabolic disorders, the search for new regulatory mechanisms is necessary. This will help a complete understanding of the pathogenesis of breast cancer. The review presents the mechanisms of obesity as a factor that increases the risk of developing breast cancer and that even initiates the cancer process in the female population. The mechanisms presented in the paper relate to the inflammatory process resulting from current or progressive obesity leading to cell metabolism disorders and disturbed hormonal metabolism. All these processes are widely regulated by the action of microRNAs (miRNAs), which may constitute potential biomarkers influencing the pathogenesis of breast cancer and may be a promising target of anti-cancer therapies.

Influence of COVID-19 Pandemic Lockdown on Patients from the Bariatric Surgery Waiting List.

Background and Objectives: Social isolation and lockdown due to the COVID-19 pandemic have influenced dietary habits and physical activity of all the population, but the obese population is the most vulnerable to weight gain. Material and Methods: A group of 189 patients (166 female and 23 male) from the bariatric surgery waiting list filled in a survey about the influence of COVID-19 pandemic lockdown on their dietary habits, physical activity, and the possibility of contact with their bariatric care center. Results: The majority of patients with weight gain declared a decrease in physical activity, compared to half of the patients without weight gain (50.5% vs. 74.5%, p < 0.05). The continuation of bariatric care and the possibility of contact with a bariatric surgeon, dietician, and psychologist had each significant influence on reducing the risk of patients' weight gain (p < 0.05). Conclusions: Maintaining physical activity and contact with bariatric care specialists are important factors in allowing to avoid weight gain in patients waiting for bariatric surgery.

Impact of the COVID-19 Pandemic on the Patient's Decision about Bariatric Surgery: Results of a National Survey.

Background: the COVID-19 pandemic and the implemented restrictions have changed the functioning of healthcare systems worldwide. The purpose of the study was to evaluate the impact of the present epidemiological situation on patients' decisions about undergoing weight loss surgery. Methods: data were collected from 906 bariatric patients by the means of a national online survey, the majority of whom were women (87.9%). The survey started on 9 April 2020 and was open until 28 April 2020. The questionnaire included multiple choice and open questions, divided into three chapters: general information about the patient, life during the COVID-19 pandemic, and bariatric care during the COVID-19 pandemic. Results: despite the pandemic and the associated risk of COVID-19 infection, 443 responders (48.9%) would have decided to undergo bariatric surgery. Awareness of the negative impact of obesity on the course of COVID-19 illness had only marginable impact on patients' decision-making (76.6% vs. 75.3%; p < 0.80). Contact with COVID-19 prior to the survey had a negative impact on the willingness to undergo bariatric surgery (3.0% vs. 4.4%; p < 0.55). There was a positive correlation between the BMI and preference for bariatric surgery in the time of the pandemic (37.4 ± 9.0 vs. 34.9 ± 8.7; p < 0.001). Conclusions: the level of awareness about the advantages of operative treatment of obesity is high among bariatric patients. The majority of patients awaiting bariatric surgery at the moment of the survey were positive about undergoing bariatric surgery despite the increased risk of a serious course of COVID-19 infection. Therefore, a large proportion of patients was determined to have bariatric treatment even during the pandemic, being aware of the increased risk of worse pace of COVID-19 disease in case of obesity and related diseases.

An Investigation of the Stability of Patients' Treatment Preferences Over the Course of a Clinical Trial.

OBJECTIVES: The usefulness of discrete choice experiments (DCEs) to inform clinical guidelines rests on the assumption that patients facing the same treatment choice at different points in time will express the same preferences. This study provides the first investigation, to our knowledge, to specifically focus on the stability of patients' treatment preferences over the course of a clinical trial. METHODS: The same DCE was completed by participants at baseline and final post-treatment assessment in a trial of the efficacy of alternative topical treatments for actinic keratosis as a means for the prevention of skin cancer. The study assesses both the consistency of stated treatment choices and the stability of population-level preference parameter estimates and analyzes how the former is influenced by design aspects of the DCE. RESULTS: No evidence was found of population-level preference parameter instability over the course of the trial despite only a moderate strength of choice consistency. Choice consistency is negatively related to task difficulty with weak evidence of the existence of ordering effects over the sequence of choice tasks. CONCLUSIONS: The results provide no evidence that the timing of a DCE within a clinical trial significantly influences population-level treatment preference estimates.

Assessment of Electronic Sensing Techniques for the Rapid Identification of Alveolar Echinococcosis through Exhaled Breath Analysis.

Here we present a proof-of-concept study showing the potential of a chemical gas sensors system to identify the patients with alveolar echinococcosis disease through exhaled breath analysis. The sensors system employed comprised an array of three commercial gas sensors and a custom gas sensor based on WO3 nanowires doped with gold nanoparticles, optimized for the measurement of common breath volatile organic compounds. The measurement setup was designed for the concomitant measurement of both sensors DC resistance and AC fluctuations during breath samples exposure. Discriminant Function Analysis classification models were built with features extracted from sensors responses, and the discrimination of alveolar echinococcosis was estimated through bootstrap validation. The commercial sensor that detects gases such as alkane derivatives and ethanol, associated with lipid peroxidation and intestinal gut flora, provided the best classification (63.4% success rate, 66.3% sensitivity and 54.6% specificity) when sensors' responses were individually analyzed, while the model built with the AC features extracted from the responses of the cross-reactive sensors array yielded 90.2% classification success rate, 93.6% sensitivity and 79.4% specificity. This result paves the way for the development of a noninvasive, easy to use, fast and inexpensive diagnostic test for alveolar echinococcosis diagnosis at an early stage, when curative treatment can be applied to the patients.

Cardiac status of persons qualified for living kidney donation--single-center experience.

UNLABELLED: Some of living kidney donors have medical conditions associated with future risk of cardiovascular diseases. It seems justified to identify risk factors and cardiological disorders prior to the donation. AIM: To determine the cardiological status of persons qualified as a living kidney donor. MATERIAL AND METHODS: We analyzed the data of 109 potential living kidney donors, aged 25-70 (mean 45.7 ± 10.9) years. They underwent clinical and biochemical examination. In some of them extended diagnostics was performed. The presence of risk factors of coronary artery disease were registered. RESULTS: Only 46 (42%) persons were qualified for kidney donation. As many as 40 of them had 21 risk factor. In 75 (68.8%) patients without hypertension, 24-hours ambulatory blood pressure monitoring was done. The masked hypertension was found in 6 persons. In 22 candidates aged > 50 years the exercise test was performed (positive or inconclusive in 3 persons). Coronarography was done in 5 individuals (in no any significant atherosclerotic lesions were found). 63 (58%) person were disqualified. In 15 (23.8%) person the reasons were cardiological. In 2 patient the abdominal aneurysms were found. Both men smoked and had severe dyslipidaemias. In 3rd patient we observed persistent atrial fibrillation. The next 2 men had the peripheral occlusive arterial disease. In 9 patients ≥ 2 risk factors and in the last one morbid obesity were present. CONCLUSION: In Poland candidates for living kidney donation have very often risk factors of cardiovascular disease. Among the persons proceeded for kidney donation cardiovascular problems are an important cause of disqualification.

Potentially Lethal But Rarely Considered. Risk of Developing Refeeding Syndrome in Primary Oral Squamous Cell Carcinoma.

Presurgical preparation and postoperative care are cornerstones of all surgical procedures. Surgeons should be especially vigilant with malnourished cancer patients. Refeeding syn-drome (RFS) is a serious, potentially fatal complication of initiating appropriate nutrition in malnourished patients or after a period of starvation, although no standard precise definition has been proposed. The rarity of its une-quivocally life-threatening course means that its risk may be underestimated in clinical practice. The study's main goal was to assess the degree of malnutrition and the risk of RFS in the presurgical status of patients with oral cavity cancer and to identify risk factors for the occurrence of RFS. This single-center prospective observational study included patients diagnosed with oral squamous cell carcinoma. We investigated the relationship of RFS with age, BMI, features of the malignant tumor process selected internal medicine comorbidities, inflam-matory markers, renal and hepatic parameters, plasma levels of diverse electrolytes, and microelements were assessed. In the work, we utilized the National Institute for Health and Clinical Excellence (NICE) criteria. The study included 90 patients: 35 women and 55 men, aged 64.2±10.5. A robust statistical correlation at a significance level of p < 0.05 was demonstrated between advanced age, lower BMI, lymph node metastases, and a relatively low LDH as positive predictors of the onset of RFS and confirmed the high predictive value of the NRS-2002 scale. This paper seeks to call attention to RFS and identify critical issues that may be useful for its prevention.

Effect of Significant Postoperative Complications on Decision Regret After Laparoscopic Sleeve Gastrectomy: a Case-Control Study.

BACKGROUND: Thus far, no data are available on decision regret about sleeve gastrectomy (SG), particularly in patients who experienced perioperative complications. This study aimed to assess whether patients with postoperative complications regret their decision to undergo laparoscopic SG more than patients with an uneventful postoperative course. METHODS: The study group comprised patients with complications after laparoscopic SG (cases). The control group comprised patients who did not experience any postoperative complications (controls). A telephone survey was conducted on all patients. Patients' satisfaction regarding their decision to undergo surgery was assessed using the Decision Regret Scale. RESULTS: In total, 21 patients who experienced postoperative complications and 69 controls were included. The patients in the study and control groups achieved similar percentages of total weight loss (32.9 ± 11.9 vs. 33.8 ± 15.0, p = 0.717) and excessive body mass index loss (74.9 ± 30.7 vs. 73.1 ± 36.7, p = 0.398) at 1 year postoperatively. The difference in weight change at 12 months postoperatively was not significant in both groups. The mean regret scores in the study and control groups were 13.2 ± 1.2 (range, 28-63) and 13.3 ± 1.1 (range, 12-66) (p = 0.818), respectively. Moreover, no significant difference was found among patients who expressed regret between the study and control groups (regret score > 50; 4.76% vs. 4.35%) (p = 1.000). CONCLUSION: This study suggests that patients with postoperative complications do not regret their decision to undergo SG more than patients with an uneventful postoperative course.

Clinical studies of detecting COVID-19 from exhaled breath with electronic nose.

The COVID-19 pandemic has attracted numerous research studies because of its impact on society and the economy. The pandemic has led to progress in the development of diagnostic methods, utilizing the polymerase chain reaction (PCR) as the gold standard for coronavirus SARS-CoV-2 detection. Numerous tests can be used at home within 15 min or so but of with lower accuracy than PCR. There is still a need for point-of-care tests available for mass daily screening of large crowds in airports, schools, and stadiums. The same problem exists with fast and continuous monitoring of patients during their medical treatment. The rapid methods can use exhaled breath analysis which is non-invasive and delivers the result quite fast. Electronic nose can detect a cocktail of volatile organic com-pounds (VOCs) induced by virus infection and disturbed metabolism in the human body. In our exploratory studies, we present the results of COVID-19 detection in a local hospital by applying the developed electronic setup utilising commercial VOC gas sensors. We consider the technical problems noticed during the reported studies and affecting the detection results. We believe that our studies help to advance the proposed technique to limit the spread of COVID-19 and similar viral infections.

Organic Vapor Sensing Mechanisms by Large-Area Graphene Back-Gated Field-Effect Transistors under UV Irradiation.

The gas sensing properties of graphene back-gated field-effect transistor (GFET) sensors toward acetonitrile, tetrahydrofuran, and chloroform vapors were investigated with the focus on unfolding possible gas detection mechanisms. The FET configuration of the sensor device enabled gate voltage tuning for enhanced measurements of changes in DC electrical characteristics. Electrical measurements were combined with a fluctuation-enhanced sensing methodology and intermittent UV irradiation. Distinctly different features in 1/f noise spectra for the organic gases measured under UV irradiation and in the dark were observed. The most intense response observed for tetrahydrofuran prompted the decomposition of the DC characteristic, revealing the photoconductive and photogating effect occurring in the graphene channel with the dominance of the latter. Our observations shed light on understanding surface processes at the interface between graphene and volatile organic compounds for graphene-based sensors in ambient conditions that yield enhanced sensitivity and selectivity.

Embedded gas sensing setup for air samples analysis.

This paper describes a measurement setup (eNose) designed to analyze air samples containing various volatile organic compounds (VOCs). The setup utilizes a set of resistive gas sensors of divergent gas selectivity and sensitivity. Some of the applied sensors are commercially available and were proposed recently to reduce their consumed energy. The sensors detect various VOCs at sensitivities determined by metal oxide sensors' technology and operating conditions. The setup can utilize prototype gas sensors, made of resistive layers of different compositions, as well. Their properties can be modulated by selecting operating temperature or using UV light irradiation. The unit is controlled by an embedded system M5Stack Core2 ESP32 IoT. We used this development kit to program the measurement procedure and data recording fastly. The setup utilizes an aluminum gas chamber of a volume of 220 ml, a set of electrical valves to introduce there an air sample with the help of an electrical micropump. The handling of the setup was simplified to a selection of a few operations by touch screen only without a necessity of extra training. The recorded data are saved in a memory card for further processing. The evolved setup can be upgraded to apply more advanced data processing by utilizing WiFi or Bluetooth connection. The control program was prepared using the Arduino IDE software environment and can be further advanced with ease. The applied materials and the established measurement procedure can use various air samples, including exhaled breath samples for patients' screening check-ups. We applied the same time of 10 min for response and recovery, acceptable for practical use.

Decision Regret after Laparoscopic Sleeve Gastrectomy-5 Years' Perspective.

INTRODUCTION: Patient's satisfaction after weight loss surgery is in the research spotlight. However, there are still no quantitative data regarding whether patients regret their decision to undergo laparoscopic sleeve gastrectomy (SG). OBJECTIVES: The present study aimed to evaluate whether patients regret their decision to undergo SG 5 years after surgery. The secondary objective was to identify whether weight loss and a higher quality of life (QoL) score correlate with the regret expressed by patients. SETTING: Military Hospital, Poland METHODS: A telephone survey was carried out among patients 5 years after surgery. Patient satisfaction regarding their decision to undergo SG was assessed using the Decision Regret Scale. QoL scores were determined using the 36-Item Short Form Survey (SF-36). RESULTS: One hundred and four patients who answered a full telephone survey were enrolled in the study. Change in body mass index (ΔBMI) was 12.31±6.2, excess body mass index loss (%EBMIL) was 55.45%±25.52%, and percent total weight loss (%TWL) was 25.20%±11.7%. At the 5-year postoperative telephone survey, the mean general health score was 50.96±14.0 and the mean regret score was 32.33±13.24 (range, 25-85). A statistically significant negative correlation was observed between %EBMIL and regret score (r=-0.435; p<0.001). There was a significant negative association between regret score and energy/fatigue QoL (r=-0.205; p=0.040). Only eight patients (7.69%) scored >50 on the Decision Regret Scale, which was considered to represent overall regret for their decision. CONCLUSION: Our study suggests that, in general, patients did not regret their decision to undergo SG. KEY POINTS: The majority of patients did not regret their decision to undergo SG. There was a statistically significant negative correlation between weight loss and patients' feelings of regret. Energy/fatigue QoL was the strongest correlate of whether patients regretted their decision to undergo SG.

The impact of the last ten minutes of surgery on hemorrhagic complications after laparoscopic sleeve gastrectomy. Case-control study.

INTRODUCTION: Hemorrhagic complications after laparoscopic sleeve gastrectomy (LSG) are among the most common adverse events. The last 10 min of LSG are essential in terms of hemostasis. AIM: To assess the blood pressure profile in the last 10 min of LSG in patients who experienced hemorrhagic complications after laparoscopic sleeve gastrectomy. MATERIAL AND METHODS: We performed a retrospective case-control study. The medical records of 867 patients who underwent primary LSG were analyzed. Cases were defined as patients who required surgical revision due to hemorrhagic complications within 72 h. Controls were matched (1 : 1) with cases by age, body mass index, gender, staple line reinforcement, comorbidities and surgeon's experience. Comparison of the last three intraoperative blood pressure measurements at the end of surgery was made. RESULTS: The bleeding rate was 3.0%. A total of 24 subjects (12 matched pairs) were included in the study. Cases had statistically significant increased mean arterial blood pressure (mm Hg) 5 min before the end of surgery (87.8 ±11.9 vs. 79.4 ±8.8 mm Hg, p = 0.049) and at the end of surgery (89.2 ±11.7 vs. 77.5 ±11.8 mm Hg, p = 0.011). Higher diastolic blood pressure measurements were observed 5 min before the end (72.1 ±10.7 vs. 62.8 ±8.1 mm Hg, p = 0.023) and at the end of surgery (74.2 ±10.0 vs. 60.8 ±11.2 mm Hg, p = 0.004). CONCLUSIONS: Compared with closely matched control subjects, patients with HC after LSG have increased mean arterial pressure in the last 5 min of surgery. This phenomenon has not been reported in the literature before.

The influence of gestational weight gain after bariatric procedures on selected pregnancy outcomes: a single center study.

Pregnancy after bariatric surgery is known to be associated with a higher risk of small for gestational age infants (SGA) and maternal anemia. 71 patients with a history of bariatric surgery, who had at least one pregnancy ended with a delivery of a single live-born neonate after the bariatric surgery were included in the study. The main endpoints were gestational weight gain (GWG), GWG as % of the maternal weight at the beginning of pregnancy (GWG%), maternal anemia, SGA and large for gestational age infants (LGA), neonatal intensive care unit admission (NICU). GWG% was 23.8% ± 14.1 in the LGA group vs 13.9% ± 11.0 in the normal weight neonates group; p < 0.03. Patients diagnosed with anemia before pregnancy had higher GWG% than patients without pre-pregnancy anemia (20.1% ± 11.1 vs 13.4% ± 11.6); p < 0.05. GWG% was higher in patients, whose infants were admitted to NICU (25.3% ± 17.6 vs 14.1% ± 11.0; p < 0.04). GWG% can be considered a risk predictor of the LGA and NICU admissions in bariatric patients. Anemia diagnosed before pregnancy is associated with higher GWG%.

Pregnancy after bariatric surgery - a narrative literature review.

The purpose of this review was to analyze the literature about pregnancy after bariatric surgery. We searched for available articles on the subject from the last decade (2010 to 2020). The positive impact of bariatric surgery on the level of comorbidities and pregnancy and neonatal outcomes cannot be overrated. Weight loss after bariatric surgery reduces the incidence of obesity-related conditions in pregnancy. A pregnancy in a woman after bariatric surgery should be considered a high-risk pregnancy and taken care of by a multidisciplinary team with appropriate micronutrient and vitamin supplementation provided. Optimum time to conception should be chosen following the international recommendations. Every woman after bariatric surgery should be aware of symptoms of surgical complications and immediately contact their surgeon in case of abdominal pain.

Intrauterine growth retardation after laparoscopic Roux-en-Y gastric bypass - clinical presentation and literature review.

Bariatric surgery is associated with a higher risk of intrauterine growth retardation (IUGR) and small for gestational age neonates. We present two examples of IUGR after laparoscopic Roux-en-Y gastric bypass, both associated with excessive restriction in patients caloric intake, one due to obstetrician's indications and the other resulting from patient's anxiety of weight gain in pregnancy. IUGR was observed accordingly in the 35th and 28th week of pregnancy. The first patient had an urgent cesarean section due to pathological cardiotocography tracings in the 35th week of pregnancy, with the newborn's weight of 1690 g (< 1st percentile). The second patient, admitted in the 28th week with suspected IUGR, had an elective cesarean section in the 36th week, with the newborn's weight of 2095 g (5th percentile). Although malabsorptive mechanisms are known to be involved in the impaired fetal growth after bariatric surgery, patients' and obstetricians' adherence to nutrition and supplementation regimen are of utmost importance. The problem of optimum daily caloric intake, vitamin and micronutrients supplementation in pregnancies after bariatric surgery is presently discussed in the literature. Optimum care and advice for bariatric patients have to be diversified as malabsorptive and restrictive operations lead to changes in metabolism, nutrition and hormonal balance.

Bariatric tourists. Foreign bariatric patients treated in Poland - a survey based study.

<b>Introduction:</b> Bariatric procedures are becoming more popular worldwide. We present a current situation of foreign patients treated by high-volume bariatric surgeons in Poland in 2016. <br><b>Material and Methods:</b> We sent an online survey to twenty high-volume bariatric surgeons. The questionnaire regarded the year 2016. We asked for number and types of bariatric procedures performed or supervised, number of foreign bariatric patients, their qualification process, country of origin, types of procedure, and post-op recommendations. <br><b>Results:</b> We received 9 surveys (45%). Five surgeons performed or supervised from 100 to 300 bariatric procedures, 2 performed or supervised over 300 procedures, 2 performed or supervised from 50 to 100 procedures. All of the respondents performed laparoscopic sleeve gastrectomy (LSG) and laparoscopic gastric bypass (LRYGB), four carried out mini gastric bypass, two - gastric banding (LAGB), one - SADI-S and duodenal switch (DS). Six surgeons operated on the total of 64 foreign patients, mainly performing LSG, LRYGB and mini gastric bypass. Most of the patients were qualified based on international criteria [body mass index (BMI) over 40 kg/m² or BMI over 35 kg/m² with comorbidities]. United Kingdom was the most popular country of origin, followed by Germany, USA, Ireland and Sweden. Qualification for surgery was based on a personal visit. After surgery, 83.3% (n = 5) of the respondents gave out discharge documents in English, recommending long-term bariatric follow-up in the country of origin. Every respondent carried out 3-month personal follow-up of every foreign patient. <br><b>Conclusions:</b> Foreign bariatric patients travelling to Poland are qualified for surgery according to known international standards. Most of the patients receive post-op discharge documents in English, with a 3-month follow-up performed by their surgeon. Further bariatric supervision in the country of origin is routinely recommended.

Is every patient eligible to have an office hysteroscopy? A retrospective analysis of 1301 procedures.

INTRODUCTION: Hysteroscopy is the gold standard for diagnosis and treatment of uterine pathologies. The office setting seems to be safe, reducing the anesthesia risks and also decreasing the overall costs of the procedure. Recent literature suggests that hysteroscopy performed without anesthesia may not be as painless as it was previously considered. Moreover, not every patient can be referred for a hysteroscopy in an office setting. AIM: To analyze the factors correlated with a successful hysteroscopy in an office setting. MATERIAL AND METHODS: We analyzed the documentation of 1301 patients who underwent hysteroscopy at our department in the period 2013-2016. The impact of the type of the procedure and the various demographic factors on the need for general anesthesia was assessed. RESULTS: Almost 80% of all hysteroscopies were performed without analgesia in an office setting. The remaining patients underwent a hysteroscopy in general anesthesia. The key aspect for successful office hysteroscopy is the scope of the performed surgery. Over 91% of diagnostic hysteroscopies have been done without analgesia, but only about 30% of extensive endometrial scratching procedures were performed in an office setting. A previous vaginal delivery increases the chances for a successful office hysteroscopy by about 21%, and in the case of diagnostic procedures, multiparous patients were at an about 79% lower risk of analgesia necessity. CONCLUSIONS: It is possible to perform nearly all diagnostic hysteroscopies in an office setting. In the case of operative hysteroscopy, the most crucial factor is the scope of the procedure.