Temperature Evolution of Composition, Thermal, Electrical and Magnetic Properties of Ti3C2Tx-MXene.

MXenes are a family of two-dimensional nanomaterials. Titanium carbide MXene (Ti3C2Tx-MXene), reported in 2011, is the first inorganic compound reported among the MXene family. In the present work, we report on the study of the composition and various physical properties of Ti3C2Tx-MXene nanomaterial, as well as their temperature evolution, to consider MXenes for space applications. X-ray diffraction, thermal analysis and mass spectroscopy measurements confirmed the structure and terminating groups of the MXene surface, revealing a predominant single OH layer character. The temperature dependence of the specific heat shows a Debye-like character in the measured range of 2 K-300 K with a linear part below 10 K, characteristic of conduction electrons of metallic materials. The electron density of states (DOS) calculations for Ti3C2OH-MXene reveal a significant DOS value at the Fermi level, with a large slope, confirming its metallic character, which is consistent with the experimental findings. The temperature dependence of electrical resistivity of the MXene samples was tested for a wide temperature range (3 K-350 K) and shows a decrease on lowering temperature with an upturn at low temperatures, where negative magnetoresistance is observed. The magnetoresistance versus field is approximately linear and increases its magnitude with decreasing temperature. The magnetization curves are straight lines with temperature-independent positive slopes, indicating Pauli paramagnetism due to conduction electrons.

Predicting complications following bariatric surgery: the diagnostic accuracy of available tools.

BACKGROUND: Bariatric surgery is effective and safe obesity treatment. Obesity-related co-morbidities contribute to higher postoperative morbidity. Assessment of possible outcomes seems to be crucial in the qualification process and perioperative care. Recently, various tools predicting complications after bariatric surgery have been proposed. OBJECTIVES: The objective of the study was to validate the performance of available diagnostic algorithms as the predictors of 30-day complications after bariatric procedures. SETTING: Department of General Surgery, University Hospital, Poland. METHODS: The literature review was done to identify available risk prediction models. The analysis included patients after Roux-en-Y gastric bypass or sleeve gastrectomy (SG). The probability of postoperative complications was calculated for each patient. The assessed endpoints were general and severe morbidity stratified with Clavien-Dindo classification. The relationship between predicted and observed outcomes was assessed by logistic regression. Diagnostic accuracy was evaluated by the area under the receiver operating characteristic curves and Hosmer-Lemeshow test. RESULTS: Out of 1329 patients, 65.31% were women with a mean body mass index of 45 kg/m2. The majority of patients underwent SG (75.02%). The most common co-morbidities were as follows: dyslipidemia, hypertension, and diabetes. General morbidity reached 8.43%, whereas severe morbidity was 2.78%. We identified 10 eligible models. Only Gupta and Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) calculators presented a significant association with any and severe complications and reached acceptable accuracy in predicting severe complications. None of the models achieved sufficient discrimination in predicting general morbidity. All models remained well-fitted. CONCLUSIONS: MBSAQIP and Gupta's calculators seem to be helpful in the assessment of severe complications after bariatric surgery. Further studies should focus on improving the predictive accuracy of existing models.

Sintering, Microstructure, and Dielectric Properties of Copper Borates for High Frequency LTCC Applications.

New ceramic materials based on two copper borates, CuB2O4 and Cu3B2O6, were prepared via solid state synthesis and sintering, and characterized as promising candidates for low dielectric permittivity substrates for very high frequency circuits. The sintering behavior, composition, microstructure, and dielectric properties of the ceramics were investigated using a heating microscope, X-ray diffractometry, scanning electron microscopy, energy dispersive spectroscopy, and terahertz time domain spectroscopy. The studies revealed a low dielectric permittivity of 5.1-6.7 and low dielectric loss in the frequency range 0.14-0.7 THz. The copper borate-based materials, owing to a low sintering temperature of 900-960 °C, are suitable for LTCC (low temperature cofired ceramics) applications.

Structural, Thermal and Dielectric Properties of Low Dielectric Permittivity Cordierite-Mullite-Glass Substrates at Terahertz Frequencies.

Glass-ceramic composites containing cordierite, mullite, SiO2 glass and SiO2-B2O3-Al2O3-BaO-ZrO2 glass were fabricated in a process comprising solid state synthesis, milling, pressing and sintering. Thermal behavior, microstructure, composition and dielectric properties in the Hz-MHz, GHz and THz ranges were examined using a heating microscope, differential thermal analysis, thermogravimetry, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction analysis, impedance spectroscopy, transmission method and time domain spectroscopy (TDS). The obtained substrates exhibited a low dielectric permittivity of 4.0-4.8. Spontaneously formed closed porosity dependent on the sintering conditions was considered as a factor that decreased the effective dielectric permittivity.

Is It Possible to Predict Weight Loss After Bariatric Surgery?-External Validation of Predictive Models.

BACKGROUND: Bariatric surgery is the most effective obesity treatment. Weight loss varies among patients, and not everyone achieves desired outcome. Identification of predictive factors for weight loss after bariatric surgery resulted in several prediction tools proposed. We aimed to validate the performance of available prediction models for weight reduction 1 year after surgical treatment. MATERIALS AND METHODS: The retrospective analysis included patients after Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) who completed 1-year follow-up. Postoperative body mass index (BMI) predicted by 12 models was calculated for each patient. The correlation between predicted and observed BMI was assessed using linear regression. Accuracy was evaluated by squared Pearson's correlation coefficient (R2). Goodness-of-fit was assessed by standard error of estimate (SE) and paired sample t test between estimated and observed BMI. RESULTS: Out of 760 patients enrolled, 509 (67.00%) were women with median age 42 years. Of patients, 65.92% underwent SG and 34.08% had RYGB. Median BMI decreased from 45.19 to 32.53kg/m2 after 1 year. EWL amounted to 62.97%. All models presented significant relationship between predicted and observed BMI in linear regression (correlation coefficient between 0.29 and 1.22). The best predictive model explained 24% variation of weight reduction (adjusted R2=0.24). Majority of models overestimated outcome with SE 5.03 to 5.13kg/m2. CONCLUSION: Although predicted BMI had reasonable correlation with observed values, none of evaluated models presented acceptable accuracy. All models tend to overestimate the outcome. Accurate tool for weight loss prediction should be developed to enhance patient's assessment.

LTCC and Bulk Zn4B6O13-Zn2SiO4 Composites for Submillimeter Wave Applications.

New zinc metaborate Zn4B6O13-willemite Zn2SiO4 composites were investigated as promising materials for LTCC (low temperature cofired ceramics) substrates of microelectronic circuits for submillimeter wave applications. Composites were prepared as bulk ceramics and LTCC multilayer structures with cofired conductive thick films. The phase composition, crystal structure, microstructure, sintering behavior, and dielectric properties were studied as a function of willemite content (0, 10, 13, 15, 20, 40, 50, 60, 100 wt %). The dielectric properties characterization performed by THz time domain spectroscopy proved the applicability of the composites at very high frequencies. For the 87% Zn4B6O13-13% Zn2SiO4 composite, the best characteristics were obtained, which are suitable for LTCC submillimeter wave applications. These were a low sintering temperature of 930 °C, compatibility with Ag-based conductors, a low dielectric constant (5.8 at 0.15-1.1 THz), a low dissipation factor (0.006 at 1 THz), and weak frequency and temperature dependences of dielectric constant.

Laparoscopic Sleeve Gastrectomy with Omentopexy: Is It Really a Promising Method?-A Systematic Review with Meta-analysis.

PURPOSE: Laparoscopic sleeve gastrectomy (LSG) is one of the most commonly performed bariatric procedure worldwide. Omentopexy during LSG is a novel variation of this well-established technique. There are no clear conclusions on indications for this procedure, safeness, and effects of such a method. We aimed to compare the outcomes of laparoscopic sleeve gastrectomy (LSG) with omentopexy (OP) and without omentopexy. MATERIALS AND METHODS: We searched the Medline, EMBASE, and Scopus databases up-to June 2020. Full-text articles and conference abstracts were included for further analysis. This review follows the PRISMA guidelines. RESULTS: Of initial 66 records, only 4 studies (N = 1396 patients) were included in the meta-analysis. Our findings showed that LSG with omentopexy had significantly lowered overall morbidity compared to LSG without omentopexy (RR = 0.38; 95% CI [0.15, 0.94]; p=0.04). Gastric leakage rate (RR = 0.17; 95% CI [0.04, 0.76]; p = 0.02) was also significantly lower in LSG with omentopexy. There were no significant differences between groups in length of hospital stay. CONCLUSIONS: Our meta-analysis showed that LSG with omentopexy may be a feasible procedure for decreasing morbidity and gastric leak rate. However, despite promising results, the procedure needs to be researched more in randomized controlled studies to draw solid conclusions.

Prognostic Factors for Immune Thrombocytopenic Purpura Remission after Laparoscopic Splenectomy: A Cohort Study.

BACKGROUND AND OBJECTIVES: Laparoscopic splenectomy (LS) has become the gold standard for patients with immune thrombocytopenic purpura (ITP). The total remission rate after splenectomy is 70%-90%, of which 66% is long-term. Despite this high response rate, some patients do not benefit from surgery. It is therefore important to try to identify risk factors for an unsatisfactory clinical response. The aim of this study was to assess long-term outcomes of LS for ITP and identify factors associated with increased disease remission rates. MATERIALS AND METHODS: We retrospectively studied consecutive patients with ITP undergoing LS in a tertiary referral surgical center prospectively recorded in a database. Inclusion criteria were: Elective, laparoscopic splenectomy for diagnosed ITP, and complete follow-up. The cohort was divided into two groups-Group 1 (G1) patients with ITP remission after splenectomy and Group 2 (G2) patients without remission. There were 113 G1 patients and 52 G2 patients. Median follow-up was 9.5 (IQR: 5-15) years. RESULTS: In univariate analysis, patient's age, body mass index (BMI), preoperative platelet count, the need for platelet transfusions, and presence of hemorrhagic diathesis were shown to be statistically significant factors. Next, we built a multivariate logistic regression model using factors significant in univariate analysis. Age <41 years (odds ratio (OR) 4.49; 95% CI: 1.66-12.09), BMI <24.3 kg/m2 (OR: 4.67; 95% CI: 1.44-15.16), and preoperative platelet count ≥97 × 103/mm3 (OR: 3.50; 95% CI: 1.30-9.47) were shown to be independent prognostic factors for ITP remission after LS. CONCLUSION: The independent prognostic factors for ITP remission after LS revealed in our study are: age <41 years, BMI <24.3 kg/m2, and preoperative platelet count ≥97 × 103/mm3. Duration of the ITP and the time of treatment are not related to remission after LS.

Patients' opinions on enhanced recovery after surgery perioperative care principles: a questionnaire study.

INTRODUCTION: The enhanced recovery after surgery (ERAS) protocol relies on patients' compliance and their awareness of its principles. Patients' views on ERAS implementation have never been evaluated in Poland before. AIM: To analyse patients' opinions about this protocol. MATERIAL AND METHODS: One hundred forty consecutive patients undergoing elective laparoscopic procedures in which ERAS was implemented were asked to join the study. Out of them, 120 fulfilled the trial criteria and were surveyed once before and twice after surgery. A 22-question survey about the patient's perception of ERAS principles was presented upon admission and on the day of discharge. A telephone follow-up was performed 2 weeks after discharge. RESULTS: Patients reported the need for being counselled by the anaesthetist/surgeon as the most important element of the protocol. Items such as being free of pain, being free of gastrointestinal symptoms, and being free of catheter were rated more highly preoperatively than on the day of discharge, whereas telephone check-up call, being able to drink and eat early after surgery, avoiding bowel preparation, avoiding preoperative fasting and reducing postoperative intravenous fluids were rated more highly on the day of discharge. Pain was still present in over half of patients two weeks after discharge. Only 4.76% of patients admitted in the telephone survey that they were afraid of early discharge. Shortening of the length of hospital stay thanks to ERAS was widely appreciated among all patients who did not find it necessary to spend a longer time in the hospital. CONCLUSIONS: Polish patients approve the ERAS protocol as modern perioperative care. Patients emphasize the need for preoperative counselling and painless recovery.

Prediction of Technical Difficulties in Laparoscopic Splenectomy and Analysis of Risk Factors for Postoperative Complications in 468 Cases.

Prediction of intraoperative difficulties may be helpful in planning surgery; however, few studies explored this issue in laparoscopic splenectomy (LS). We performed retrospective analysis of consecutive 468 patients undergoing LS from 1998 to 2017 (295 women; median age 47 years). The patients were divided into difficult LS and control groups. The inclusion criteria for difficult LS were operative time ≥mean + 2SD; intraoperative blood loss ≥500 mL, intraoperative adverse events (IAE), conversion. Primary outcomes were risk factors for difficult splenectomy and secondary outcomes for perioperative morbidity. Fifty-six patients were included in the difficult LS group (12%). Spleens ≥19 cm and higher participation of younger surgeons in consecutive years were predictive for difficult splenectomy. Age ≥53 years and diagnosis other than idiopathic thrombocytopenic purpura (ITP) were independent risk factors of spleen ≥19 cm. The perioperative morbidity was 8.33%; its OR was increased only by blood loss and IAEs. Only blood loss significantly increased serious morbidity. Male sex, spleens ≥19 cm, and IAEs were independent risk factors for intraoperative hemorrhage. Spleen length ≥19 cm was a risk factor for difficult LS and intraoperative hemorrhage. Diagnoses other than ITP in patients aged ≥53 years with ≥19 cm spleens are predictive for intraoperative difficulties and perioperative complications.

Pancreatoduodenectomy for pancreatic head tumors in the elderly - Systematic review and meta-analysis.

The age at which patients are undergoing pancreatoduodenectomy is increasing worldwide. The data on the outcome of this surgical procedure in the elderly is constantly expanding. This meta-analysis aims to assess the safety of pancreatoduodenectomy in elderly population, primarily focusing on morbidity and mortality. We searched the Medline, Embase and Cochrane databases to identify eligible studies. The most recent search was performed on 10th April 2017. Inclusion criteria were: (1) comparison of the characteristics and perioperative outcomes of older patients versus younger patients undergoing pancreatoduodenectomy; (2) objective evaluation of mortality or overall morbidity; and (3), publication in English. Exclusion criteria were: (1) a lack of comparative data; (2) a lack of primary outcomes or insufficient data to analyze; (3) a focus on procedures other than pancreatoduodenectomy; or (4), the impossibility of extraction of data specifically concerning pancreatoduodenectomy. Primary outcomes were overall morbidity and mortality. Secondary outcomes analyzed postoperative complications, R0 rate and length of hospital stay. 45 eligible studies were chosen, with a combined total of 21,295 patients. Older patients compared to younger patients had a higher risk of death (2.26% vs. 4.54%; RR: 2.23; 95% CI 1.74-2.87) and a higher complication rate (47.23% vs. 39.35%; RR: 1.17; 95% CI 1.12-1.24). There were no differences in pancreatic fistula occurrence (p = 0.27), bile leakage (p = 0.81), postoperative hemorrhage (p = 0.08), or R0 rate (p = 0.92). Our review confirms, that in the case of pancreatoduodenectomy, advanced age is a risk factor for increased non-surgical morbidity and, by extension, higher mortality.

Laparoscopic splenectomy for immune thrombocytopenia in patients with a very low platelet count.

INTRODUCTION: Laparoscopic splenectomy (LS) is the gold standard in treating immune thrombocytopenia (ITP). However, there are still some problems in decision-making when considering LS in patients with a very low platelet count (PLT). AIM: To evaluate safety outcomes of LS in patients with severe ITP and very low PLT in comparison to those with higher PLT. MATERIAL AND METHODS: We retrospectively analyzed consecutive patients who underwent LS in a single institution between April 1998 and December 2017. Perioperative care was based on an algorithm developed at our department which takes into consideration the patient's PLT level. Patients were divided into 2 groups depending on the PLT level (cut-off point 50,000/mm3). RESULTS: The mean operative time in the low PLT group and high PLT group was 90 ±42.1 min and 95 ±45 min, respectively (p = 0.59). Intraoperative blood loss was 144 ±226.1 ml in the low PLT group and 83 ±161.24 ml in the high PLT group (p = 0.23). Complications occurred in 5 (9.09%) patients in the low PLT group and 16 (11.51%) in the high PLT group (p = 0.67). There were no conversions in the group with lower PLT, while 2 patients in the group with higher PLT had to be converted to open surgery (p = 0.38). Patients with low PLT preoperatively more often required perioperative platelet transfusions (13 vs. 1, p < 0.001). CONCLUSIONS: Laparoscopic splenectomy is safe and feasible treatment in patients with ITP regardless of the PLT level. Still, patients with critical ITP and marginally low PLT require special awareness.

20 years' experience with laparoscopic splenectomy. Single center outcomes of a cohort study of 500 cases.

BACKGROUND: Laparoscopic splenectomy (LS) has become the gold standard in elective spleen surgery. Although it is considered relatively safe, treatment results vary depending on a hospital's profile and the experience of the surgeon and center. We would like to present experience of a high-volume referral center with minimally invasive operations of the spleen. MATERIAL AND METHODS: The retrospective cohort study included consecutive patients undergoing laparoscopic splenectomy in tertiary referral surgical center in 1998-2017. The entire study population (500 patients) was grouped into 5 cohorts of 100 consecutively operated patients. The primary endpoints were short-term outcomes of LS and secondary - analysis of indications and operative technique. The study group consisted of 316 women and 184 men, 46 (28-59) years old on average. RESULTS: The most common indications for splenectomy were ITP (53%), lymphoma (21%) and spherocytosis (7%). Ratio of ITP versus other indications decreased significantly over time in favor of more difficult cases (<0.001). Average operative time of 100 (75-132.5) min and blood loss of 50 (20-150) ml were changing during study. Forty two patients required a blood transfusion with no difference among groups (p = 0.765). The use of postoperative drainage diminished from 100% to 7% (p < 0.001). The overall conversion rate (3%) and intraoperative complications (5%) did not differ among groups (p = 0.863 and 0.888). Perioperative morbidity was 8.6% and decreased significantly over time (OR: 0.78, 95%CI: 0.62-0.98). We noted mortality of 0.4% (1 patient in 1st and 1 in 5th group). Median LOS was 4 (1-16) days. A significant change in the operative technique from vessels first to hilar transection was noted. CONCLUSION: Laparoscopic splenectomy seems to be a safe method associated with a low risk of perioperative complications and mortality. A careful reproducible operative technique, along with a well-trained team and standardized modern postoperative care is critical to improving outcomes.

Postoperative Care and Functional Recovery After Laparoscopic Sleeve Gastrectomy vs. Laparoscopic Roux-en-Y Gastric Bypass Among Patients Under ERAS Protocol.

BACKGROUND: The most commonly performed bariatric procedures are laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB). There are major differences between LSG and LRYGB during postoperative period. Optimization of the postoperative care may be achieved by using enhanced recovery after surgery (ERAS) protocol, which allows earlier functional recovery. PURPOSE: The aim was to assess differences in the course of postoperative care conducted in accordance with ERAS protocol among patients after LSG and LRYGB. MATERIAL AND METHODS: Data concerning patients treated for morbid obesity were prospectively gathered in one academic center. Patients were divided into two groups: LSG (n = 364, 63.41%) and LRYGB (n = 210, 36.59%). Multiple factors were used as endpoints to determine the influence of the type of bariatric procedure on postoperative course. RESULTS: The rate of postoperative nausea and vomiting and incidence of intravenous fluid administration during the operation was higher in LSG group. LRYGB patients were able to tolerate higher oral fluid intake volumes during the first and the second postoperative day. Mean diuresis during the second and the third postoperative day was significantly higher in LRYGB group. Administration of diuretics and painkillers was comparable between groups, while the risk of fever after the operation was higher in LRYGB group. Mean length of stay was higher in LSG group (LRYGB vs. LSG, 3.46 days ± 1.58 vs. 3.64 days ± 4.41, p = 0.039). CONCLUSIONS: In our opinion, postoperative treatment after LSG requires more supervision and longer time until functional recovery is achieved.

Laparoscopic uncinate process first pancreatoduodenectomy-feasibility study of a modified 'artery first' approach to pancreatic head cancer.

PURPOSE: The aim of this study was to discuss the feasibility of laparoscopic 'uncinate first' pancreatoduodenectomy. METHODS: The analysis included prospectively collected data from 12 consecutive patients undergoing elective pure laparoscopic 'uncinate process first' pancreatoduodenectomy (Group 1). They were compared with patients previously operated on with a classical laparoscopic approach (Group 2). The primary outcome was the quality of the resected specimen (lymph node (LN) yield, R0 rate, involved resection margins). Secondary outcomes were perioperative parameters. RESULTS: The LN yield in Group 1 was 19.3 and in Group 2 it was 13.9 (p = 0.03). R0 resection rates did not vary (66.7 vs. 63.2%, p = 0.84). Although the involvement of the superior mesenteric artery margin and uncinate process margin seemed lower in Group 1, the difference was not significant. Total operative time (467 vs. 425 min, p = 0.13) and resection time (221 vs. 232 min, p = 0.34) were similar in both groups. The estimated blood loss in Group 1 was 408 ml, whereas in Group 2 it was 392 ml (p = 0.33). Complication rates were 66.7% in Group 1 and 63.2% in Group 2 (p = 0.84). Median length of stay was 9 days in both groups (p = 0.36). Postoperative complication rates did not differ between groups. CONCLUSIONS: Laparoscopic uncinate first approach is a feasible method for pancreatic head neoplasms. Achieved quality of the specimen is comparable with the traditional laparoscopic approach, whereas intra- and postoperative course is not inferior. However, further studies on larger cohorts are required to fully establish whether the novel approach has potential advantages over classical access in pancreatic head cancer.

Do we really need the full compliance with ERAS protocol in laparoscopic colorectal surgery? A prospective cohort study.

BACKGROUND: Although the relation between adherence to the ERAS protocol and clinical outcomes was extensively studied, there is still ongoing discussion on the need and feasibility of full compliance in laparoscopic colorectal surgery. In this study, we aimed to verify whether a strict adherence to the protocol (>90%) leads to further improvement in clinical outcomes compared to high (70-90%) and low (<70%) compliance groups. MATERIALS AND METHODS: The analysis included consecutive prospectively registered patients operated laparoscopically for colorectal cancer between January 2012 and December 2015. Patients were divided into three groups depending on the compliance with the ERAS protocol: <70% (Group 1), 70-90% (Group 2), >90% (Group 3). The measured outcomes were: complication rate, readmission rate, recovery parameters (tolerance of early oral diet on 1st postoperative day and mobilization of a patient on the day of surgery), length of stay (LOS). RESULTS: Group 1 consisted of 70, Group 2 of 65 and Group 3 of 116 patients. There were no statistical differences between the groups based on demographic parameters, stage of cancer and operative parameters (operative time, blood loss, conversion rate). The overall compliance with the protocol in the study group was 85.6 ± 11.9%. There was a significant decrease in complication rate with increasing compliance (35.7% vs. 36.4% vs. 16.4%, p = 0.0024) and severity of complications according to the Clavien-Dindo classification (p = 0.0198). Moreover, we observed differences in recovery parameters between the groups: tolerance of oral diet on the 1st postoperative day (52.8% vs. 79.5% vs. 87.9%, p < 0.0001), mobilization of a patient on the day of surgery (68.6% vs. 92.3% vs. 99.1%, p < 0.0001), respectively. We also observed that with compliance increase, the median LOS decreased (6 vs. 4 vs. 3 days, p < 0.0001). CONCLUSION: Full implementation of the ERAS protocol significantly improves short term outcomes both in comparison to the high- and low-compliant groups.

X-ray photoelectron spectroscopic and electrochemical impedance spectroscopic analysis of RuO2-Ta2O5 thick film pH sensors.

The paper reports on investigation of the pH sensing mechanism of thick film RuO2-Ta2O5 sensors by using X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). Interdigitated conductimetric pH sensors were screen printed on alumina substrates. The microstructure and elemental composition of the films were examined by scanning electron microscopy and energy dispersive spectroscopy. The XPS studies revealed the presence of Ru ions at different oxidation states and the surface hydroxylation of the sensing layer increasing with increasing pH. The EIS analysis carried out in the frequency range 10 Hz-2 MHz showed that the electrical parameters of the sensitive electrodes in the low frequency range were distinctly dependent on pH. The charge transfer and ionic exchange occurring at metal oxide-solution interface were indicated as processes responsible for the sensing mechanism of thick film RuO2-Ta2O5 pH sensors.

Potentiometric RuO2-Ta2O5 pH sensors fabricated using thick film and LTCC technologies.

The paper reports on the preparation, properties and application of potentiometric pH sensors with thick film RuO2-Ta2O5 sensing electrode and Ag/AgCl/KCl reference electrode screen printed on an alumina substrate. Furthermore, it presents fabrication procedure and characterization of a new miniaturized pH sensor on LTCC (low temperature cofired ceramics) substrate, destined for wireless monitoring. The crystal structure, phase and elemental composition, and microstructure of the films were investigated by X-ray diffractometry, Raman spectroscopy, scanning electron microscopy and energy dispersive spectroscopy. Potentiometric characterization was performed in a wide pH range of 2-12 for different storage conditions and pH loops. The advantages of the proposed thick film pH sensors are: (a) low cost and easy fabrication, (b) excellent sensitivity close to the Nernstian response (56mV/pH) in the wide pH range, (c) fast response, (d) long lifetime, (e) good reproducibility, (f) low hysteresis and drift effects, and (g) low cross-sensitivity towards Li(+), Na(+) and K(+) as interfering ions. The applicability of the sensors for pH measurement of river, tap and distilled water, and some drinks was also tested.

Laparoscopic adrenalectomy by the lateral transperitoneal approach in patients with a history of previous abdominal surgery.

INTRODUCTION: Even the half of patients undergoing laparoscopic adrenalectomy has history of previous abdominal surgeries. However, it is still uncertain if this fact has an impact on the operation itself as well as the postoperative course. AIM: To analyze the effects of previous abdominal surgery on surgical outcomes in adrenal tumor patients subjected to laparoscopic adrenalectomy. MATERIAL AND METHODS: This study included 268 patients with adrenal gland tumors operated on by means of laparoscopic lateral transperitoneal adrenalectomy: 1) previously subjected to at least one abdominal surgery (group A, n = 101), or 2) with no history of previous abdominal operations (group B, n = 167). RESULTS: Groups A and B did not differ in terms of tumor size (p = 0.132), mean operation time (p = 0.456), mean intraoperative blood loss (p = 0.754), or perioperative complication rate (p = 0.833). Dissection of intraperitoneal adhesions was considered difficult in 32 patients from group A (31.6%) and 8 subjects from group B (4.7%, p < 0.001). Conversion was required in three subjects from group A (2.9%) and 3 patients from group B (1.8%, p = 0.529). CONCLUSIONS: Previous abdominal surgery does not constitute a contraindication to laparoscopic transperitoneal adrenalectomy.

Changes in the localization of perforated peptic ulcer and its relation to gender and age of the patients throughout the last 45 years.

BACKGROUND: Throughout recent decades there has been noticeable change in the incidence of peptic ulcer disease and its complications. The aim of the present study was to determine the character of changes over the last 45 years in the localization of perforation, in patient age, and in patient gender. METHODS: A group of 881 patients admitted to the Second Department of General Surgery in Krakow, Poland, from 1962 to 2006 were included in the study and constituted the material for the analysis. The study was divided into three time periods (1962-1976, 1977-1991, and 1992-2006) to allow statistical analysis of trends. RESULTS: The general incidence of perforations of peptic ulcer did not show changes; however, the percentage of women with perforated duodenal ulcer markedly increased. Patients with perforated stomach ulcer--regardless of gender--and females suffering from perforated duodenal ulcer were, on the average, about 10 years older than males with perforated duodenal ulcers. The mean age of male and female patients with perforated duodenal ulcer over the last 45 years showed an insignificant upward trend. CONCLUSIONS: (1) The percentage of women with perforated duodenal ulcer continuously and statistically significantly rose. (2) Men with perforated duodenal ulcer were significantly younger than other patients. (3) The mean ages of male and female patients with perforated duodenal ulcer over the last 45 years showed an insignificant upward trend.