An Enhanced Fuzzy K-means Clustering with Application to Missing Data Imputation

In this paper an adjustment on the Fuzzy K-means (FKM) clustering method was suggested to improve the process of clustering. Also, a novel technique for missing data imputation was proposed and it was implemented twice: (1) using FKM and (2) using the Enhanced Fuzzy K-means (EFKM) clustering. The suggested model for imputing missing data consists of three phases: (1) Input Vectors Partitioning, (2) Enhanced Fuzzy Clustering, and(3) Missing Data Imputation. The implementation and experiments showed a clear improvement in the imputation accuracy in favor of the EFKM according to the value of RMSE

The correlation of blue shift of photoluminescence and morphology of silicon nanoporous

Porous silicon with diameters ranging from 6.41 to 7.12 nm were synthesized via electrochemical etching by varied anodization current density in ethanoic solutions containing aqueous hydrofluoric acid up to 65mA/cm2.The luminescence properties of the nanoporous at room temperature were analyzed via photoluminescence spectroscopy. Photoluminescence PL spectra exhibit a broad emission band in the range of 360-700 nm photon energy. The PL spectrum has a blue shift in varied anodization current density; the blue shift incremented as the existing of anodization although the intensity decreased. The current blue shift is owning to alteration of silicon nanocrystal structure at the superficies. The superficial morphology of the PS layers consists of unified and orderly distribution of nanocrystalline Si structures, have high porosity around (93.75%) and high thickness 39.52 µm

Study the Optical and Spectral Properties of the Acridine Dye As an Effective Medium in Dye Lasers

    تم في هذا البحث دراسة اطياف الامتصاص والفلورة لمحلول صبغة الاكريدين المذابة في الايثانول وبتراكيز مختلفة، اذ تم حساب الخصائص البصرية (معامل الامتصاص ومعامل الانكسار الخطيين) والخصائص الطيفية (العمر الزمني للفلورة والنتاج الكمي للفلورة). اذ لوحظ ان زيادة التركيز يؤدي الى زيادة قيم الامتصاصية ونقصان قيم النفاذية ومن ثم زيادة  قيم معامل الامتصاص ومعامل الانكسار، كذلك تزداد قيم شدة الفلورة وتزاح قمة طيف انبعاث الفلورة نحو الاطوال الموجية الاطول(red shift)  وبالتالي يزداد العمر الزمني للفلورة ويقل النتاج الكمي بزيادة تركيز المحلول.         In this study, the absorption and fluorescence spectra of the dissolved Acridine solution were studied in ethanol and different concentrations. The optical properties (absorption coefficient, linear refraction) and spectral characteristics (Fluorescence time and quantitative fluoridation efficiency) were calculated. It is observed that increasing the concentration increases the absorbance values and decreases the permeability values, thus increasing the values of the absorption coefficient and the refractive index. Also, the values of the fluorine intensity increase. The peak of the emission spectrum is transferred to the longer wavelengths.                                                                                                                   &nbsp

Anti-Biofilm and Anti-Quorum Sensing Properties of Ethanol and Aqueous Extracts of Orthosiphon Stamineus and Andrographis Paniculata Leaves and Stems

Introduction: Quorum sensing controls a wide spectrum of processes and phenotypic behaviours including biofilm formation that helps in the survival and virulence of bacteria in hosts. Thus, anti-quorum sensing is suggested to combat bacterial infections. This study aimed to evaluate the anti-biofilm forming and anti-quorum sensing activities which may contribute to the anti-bacterial effect of ethanol and aqueous extracts of Orthosiphon stamineus and Andrographis paniculata leaves and stems. Materials and method: General biofilm assay protocol with modification was used for the biofilm assay to test the effect of different concentration (2 mg/ml and 3 mg/ml) of extracts on the biofilm formation by Pseudomonas aeruginosa. Optical density of crystal violet/acetic acid solution was measured at 595 nm and the percentage of biofilm inhibition was calculated. In quorum quenching assay, visualization of reporter strain AI1-QQ.1 growth will be used for the detection of bio-molecules interfering with acyl homoserine lactone (AHL). Results: Extracts with the highest ability to inhibit biofilm formation were ethanol extract of O.stamineus stem and A.paniculata leaves with 77.84% at extracts concentration of 3 mg/ml. Aqueous extract of O.stamineus leaves showed the least potential with 13.41% inhibition. However, aqueous extract of A.paniculata showed zero inhibition at 3 mg/ml and two extracts (aqueous extract of O.stamineus and A.paniculata leaves) gave negative value at concentration of 3 mg/ml and 2 mg/ml, respectively. Quorum quenching assay has yet to be done. Conclusion: It could be concluded that most of the extracts possess anti-biofilm property

Impact of ablation time on Cu oxide nanoparticle green synthesis via pulsed laser ablation in liquid media

Large-scale commercial production of nanoparticles via efficient, economical, and environmentally friendly methods is a challenging endeavour. The laser ablation method being a green and potential route of nanoparticles synthesis can be exploited to achieve this end. In this work, we report the ablation of a copper target submerged in distilled water by pulsed Nd:YAG laser. The influence of ablation time on the structure and optical properties of grown copper oxide nanoparticles are studied. Such nanoparticle composition and structure is determined by X-ray diffraction (XRD), Fourier transform infrared, and Raman analyses. Results from transmission electron microscopy images established that synthesised nanoparticles are a spherical shape with average sizes of 24–37 nm. Fluorescence spectra revealed the enhancement of nanoparticle concentration and reduction in the sizes with increasing ablation time, where the optimum ablation time is demonstrated to be 60 min. Photoluminescence spectra exhibited a prominent visible peak (green), which blueshifted from 542 to 537 nm, confirming the shrinkage of copper oxide particle size at higher ablation time. The XRD pattern showed that the prepared nanoparticles possess a single phase of monocline cupric oxide nanostructure

Photo-electrochemically synthesized light emtting nanoporous silicon based UV photodetector: influence of current density

Nanoporous silicon (n-PSi) with diverse morphologies was prepared on silicon (Si) substrate via photo-electrochemical etching technique. The role of changing current density (15, 30 and 45 mA cm−2) on the structure, morphology and optical properties was determined. As-prepared samples were systematically characterized using XRD, FESEM, AFM and photoluminescence measurements. Furthermore, the achieved n-PSi sample was used to make metal–semiconductor–metal (MSM) UV photodetector. The performance of these photodetectors was evaluated upon exposing to visible light of wavelength 530 nm (power density 1.55 mW cm−2), which exhibited very high sensitivity of 150.26 with a low dark current. The achieved internal photoconductive gain was 2.50, the photoresponse peak was 1.23 A W−1 and the response time was 0.49 s and the recovery time was 0.47 s. Excellent attributes of the fabricated photodetectors suggest that the present approach may provide a cost effective and simple way to obtain n-PSi suitable for sundry applications

Pancreatic surgery outcomes: multicentre prospective snapshot study in 67 countries

BACKGROUND: Pancreatic surgery remains associated with high morbidity rates. Although postoperative mortality appears to have improved with specialization, the outcomes reported in the literature reflect the activity of highly specialized centres. The aim of this study was to evaluate the outcomes following pancreatic surgery worldwide. METHODS: This was an international, prospective, multicentre, cross-sectional snapshot study of consecutive patients undergoing pancreatic operations worldwide in a 3-month interval in 2021. The primary outcome was postoperative mortality within 90 days of surgery. Multivariable logistic regression was used to explore relationships with Human Development Index (HDI) and other parameters. RESULTS: A total of 4223 patients from 67 countries were analysed. A complication of any severity was detected in 68.7 per cent of patients (2901 of 4223). Major complication rates (Clavien–Dindo grade at least IIIa) were 24, 18, and 27 per cent, and mortality rates were 10, 5, and 5 per cent in low-to-middle-, high-, and very high-HDI countries respectively. The 90-day postoperative mortality rate was 5.4 per cent (229 of 4223) overall, but was significantly higher in the low-to-middle-HDI group (adjusted OR 2.88, 95 per cent c.i. 1.80 to 4.48). The overall failure-to-rescue rate was 21 per cent; however, it was 41 per cent in low-to-middle- compared with 19 per cent in very high-HDI countries. CONCLUSION: Excess mortality in low-to-middle-HDI countries could be attributable to failure to rescue of patients from severe complications. The authors call for a collaborative response from international and regional associations of pancreatic surgeons to address management related to death from postoperative complications to tackle the global disparities in the outcomes of pancreatic surgery (NCT04652271; ISRCTN95140761

Epidemiology of surgery associated acute kidney injury (EPIS-AKI): a prospective international observational multi-center clinical study

Purpose: The incidence, patient features, risk factors and outcomes of surgery-associated postoperative acute kidney injury (PO-AKI) across different countries and health care systems is unclear. Methods: We conducted an international prospective, observational, multi-center study in 30 countries in patients undergoing major surgery (> 2-h duration and postoperative intensive care unit (ICU) or high dependency unit admission). The primary endpoint was the occurrence of PO-AKI within 72 h of surgery defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Secondary endpoints included PO-AKI severity and duration, use of renal replacement therapy (RRT), mortality, and ICU and hospital length of stay. Results: We studied 10,568 patients and 1945 (18.4%) developed PO-AKI (1236 (63.5%) KDIGO stage 1500 (25.7%) KDIGO stage 2209 (10.7%) KDIGO stage 3). In 33.8% PO-AKI was persistent, and 170/1945 (8.7%) of patients with PO-AKI received RRT in the ICU. Patients with PO-AKI had greater ICU (6.3% vs. 0.7%) and hospital (8.6% vs. 1.4%) mortality, and longer ICU (median 2 (Q1-Q3, 1-3) days vs. 3 (Q1-Q3, 1-6) days) and hospital length of stay (median 14 (Q1-Q3, 9-24) days vs. 10 (Q1-Q3, 7-17) days). Risk factors for PO-AKI included older age, comorbidities (hypertension, diabetes, chronic kidney disease), type, duration and urgency of surgery as well as intraoperative vasopressors, and aminoglycosides administration. Conclusion: In a comprehensive multinational study, approximately one in five patients develop PO-AKI after major surgery. Increasing severity of PO-AKI is associated with a progressive increase in adverse outcomes. Our findings indicate that PO-AKI represents a significant burden for health care worldwide

On the Shortest Pivotal Confidence Intervals: An Entropy Measure Technique

For the important role of confidence intervals in statistical inference, we present in this article the shortest pivotal confidence interval using an entropy measure called the Resistor-Average distance, two examples are used to show the application of the proposed technique which include a simulation study