Superconducting BSCCO Ceramics as Additive to the Zinc Electrode Mass in the Rechargeable Nickel-Zinc Batteries

The electronic conductivity of the main component of the zinc electrode in the rechargeable zinc-nickel battery – ZnO,  is rather poor and this is the main reason for the electrochemical heterogeneity of the anode mass and the loss of active surface area during charge/discharge cycling with a corresponding negative effect on the electrode characteristics In the present work, the possibility of application of superconductive cuprate Bi-Pb-Sr-Ca-Cu-O (BSCCO) ceramic as a multifunctional conductive additive to the zinc electrode mass is studied. Powder samples of the BSCCO ceramic Bi1,7Pb0,3Sr2Ca2Cu3Ox are produced by two-stage solid-state synthesis and they are physicochemically characterized. The XRD patterns and SEM observation reveal a well crystallized single phase of superconducting 2212 BSCCO system with average crystallite size 5-10 µm. The chemical stability of BSCCO ceramics in highly alkaline medium of the Ni-Zn battery is confirmed by structural and morphological analysis (XRD, SEM and EDX) of the samples before and after prolong exposure (96 h) to 7M KOH. The electrochemical tests are carried out by a specially designed prismatic alkaline Ni-Zn battery cell with conventional sintered type nickel electrodes and pasted zinc electrode with active electrode mass based on ZnO (88 wt.%) and addition of BSCCO powder or acetylene black as conductive additives. The study show that the zinc electrode with BSCCO superconducting ceramic additive exhibits very good cycleability, remarkable capacity stability and much higher discharge capacity at prolong charge/discharge cycling in comparison to the  zinc electrode with the “classic” carbon conductive additive. It is suggested that the addition of BSCCO ceramics improves not only conductivity of the electrode mass and reduces the gas evolution but also stabilizes porosity structure. The results obtained prove the possibility of application of superconducting BSCCO ceramics as a multifunctional additive to the active mass of the zinc electrodes for alkaline battery systems

Multivisceral ‘en-bloc` resections of colorectal tumours - milestones in the surgical techniques

Purpose: Colorectal tumours (CRT) consisting mainly of colorectal cancer (CRC) are diagnosed sometimes at an advanced T4 stage, i. e. local involvement of neighbouring organ/organs and anatomical structure/ structures. Aggressive surgical approach preceded and/or followed by neo-adjuvant/adjuvant therapy is advocated because of proven benefit for the patient. The aim of this study was to carry out a literature survey, on the one hand, and to analyze the cases from the authors` institutional experience, on the other hand, in an attempt to submit for consideration the milestones of the multivisceral en-block resections in cases of locally advanced CRTs, i.e. to describe the specific surgical approaches depending on different tumour location and peritumoural involvement of adjacent structures and organs.Material and methods: A retrospective analysis of 154 cases of CRT was performed, all of them operated in the Clinic of Liver, Biliary, Pancreatic and General Surgery, Tokuda Hospital of Sofia, from January 1, 2007 to March 31, 2013. All the patients were diagnosed in an advanced T4-stage and received multivisceral en-bloc resections. Three main groups of methods that had been used were analyzed: 1) preoperative diagnosis, giving a hint of multivisceral en-bloc resection; 2) intraoperative assessment - gross tumour appearance, frozen sections (?), final histological examinations, and 3) surgical methods.Results: Early morbidity and mortality rates were 22,6% and 5,8%, respectively, without any significant difference when compared with ‘simple` colon and rectum resections and with literature data available.Conclusion: Multivisceral en-bloc resection for CRCs has been performed in more than 10% of the cases. It benefits the long-term prognosis. Tumour location and number of resected organs are essential characteristics of these procedures and they are independently associated with the quantity of intraoperative blood loss, higher early morbidity rates and more frequent local recurrence

Early perioperative res ults in 53 cases of locally rec urrent colorectal cancer

Purpose: The objective of this study was to analyze retrospectively the early perioperative results in a cohort of 53 patients with localy reccurent colorectal cancer (CRC).Material and methods: The study covered 53 patients with CRC 21 males and 32 females at a mean age of 62 years treated in the Clinic of Liver, Biliary, Pancreatic and General Surgery, Tokuda Hospital of Sofia, during the period from January 2007 to March 2013. Any necessary diagnostic and surgical methods were applied.Results: The locally recurrent CRC is a challenge for the surgeon because of the fact that in most cases it engages adjacent anatomical structures and organs, on the one hand, and it is accompanied by complications, on the other hand.Conclusion: Achievement of good late results in patients with recurrent CRC is due to radicality of the interventions. Most often, they should be multivisceral resections. The presence of intestinal obstruction of varying degree and of synchronous peritoneal and liver metastases commonly limit the possibilities for surgical interference with the disease. Particular attention should be paid to possible neoadjuvant treatment capable of reducing the stage of diasease and improving the perioperative outcomes. Therapeutic behaviour should be strictly individual and consider any possible options. The experience of the surgical team is extremely important, too

Locally advanced adenocarcinoma of the supramesocolic part of the colon . Feat ures of surgical treatment and challenges

Purpose: The objective of the present study was to analyze the early results from the surgical treatment of locally advanced carcinoma of the colon in its transverse section and the two flexures.Material and methods: The study covered 36 patients with locally advanced colonic carcinoma, 19 males and 17 females at a mean age of 65,6 years, treated in the Clinic of Liver, Biliary, Pancreatic and General Surgery, Tokuda Hospital of Sofia during the period from January 2007 to March 2013. Any necessary diagnostic and surgical methods were applied.Results: Multivisceral resections were commonly performed in order to achieve a radical surgery in cases of locally advanced disease. Great surgeon`s experience in liver, biliary and pancreatic interventions is obligatorily required. In this paper we share our experience in the treatment of this disease for a period of 6 years.Conclusion: Our application of the multivisceral resections results in surgical radicality along with acceptable levels of perioperative morbidity and mortality rates when compared to other studies in in the foreign literature available

ANTIMICROBIAL ACTIVITY OF LACTOBACILLUS PLANTARUM AGAINST PATHOGENIC AND FOOD SPOILAGE MICROORGANISMS: A REVIEW

One of the most important properties of probiotic bacteria is their antimicrobial activity against many species of microorganisms which could be useful to prevent food spoilage caused by certain sensitive bacteria and fungi as well as to control the speed of propagation of potentially pathogenic bacteria by probiotic application. Lactobacillus plantarum is considered one of the probiotic bacteria with broad-est spectrum of antibacterial activity which makes it useful in veterinary, human medicine and food industry. According to a number of studies Lactobacillus plantarum exerts inhibitory activity against ma¬ny Gram-positive and Gram-negative bacteria – Escherichia coli (including E. coli 0157:H7), Pseudomonas aeruginosa, Helicobacter pylori, Yersinia enterocolitica, Campylobacter jejuni, Lis-teria monocytogenes, Staphylococcus aureus, Klebsiella, Salmonella, Shigella, Bacillus, Clostridium, Enterococcus, Lactobacillus spp., etc. as well as a number of moulds and yeasts – Aspergillus, Fusa-rium, Mucor, Candida spp., etc. The main antibacterial compounds of Lactobacillus plantarum are the bacteriocins and organic acids whereas the antifungal compounds are the organic acids, hydroxy fatty acids and cyclic dipeptides. Because of the high antifungal activity of some L. plantarum strains against food spoilage microorganisms they can be used as effective biopreservatives in food industry. Also, some L. plantarum strains could be applied as supporting therapeutic agents in treatment of infections caused by the corresponding susceptible microorganisms

A novel non-carbon gas diffusion layer for PEM water electrolysis anodes

The work presents a research on the development of novel gas diffusion layer (GDL) suitable for application in PEM water electrolysis. The traditionally used carbon-based GDL is replaced by GDL containing sub-stoichiometry Mаgneli phase titanium oxide. The newly developed GDE is integrated in a membrane electrode assembly (MEA) containing highly active Pt catalyst and proton conductive polymer electrolyte membrane. The MEA performance is characterized in a laboratory PEM electrolyser at standard operative conditions by cyclic voltammetry and steady state polarization techniques. It is found that the new layer ensures excellent electrical conductivity and has very good stability at high anodic potentials. The determined morphology factors of the platinum catalyst however, show that further optimization of the porosity is required in order to improve the water transport to the reactive zone and the catalyst utilization

Comparative study of soil test methods for determination of plant available potassium in Bulgarian arable soils

This comparative study was aimed at estimating analytical behavior of methods for determination of plant available potassium applied to Bulgarian arable soils and to reveal the relationship between the amount of extractable K. Twenty-four samples from two traditional agricultural regions in Bulgaria were studied. Soil potassium was extracted by NH4OAc/HOAc pH 4.5 (AA), diluted double acid (Mehlich 1), CaCl2, BaCl2 and a modified acetate/lactate method (ALM) and determined by Flame AES. The factors influencing the methods accuracy were identified and uncertainty was estimated. The expanded uncertainty was (in mg K2O (100 g dry soil)-1): 0.10 (ALM), 0.64 (Mehlich 1), 0.17 (CaCl2) and 1.1 (AA). The study revealed that the factor which mainly influence the uncertainty of the applied analytical methods for plant available potassium in soil was the calibration of Flame AES determination. The obtained results showed that extractable potassium lowered in the following order K ALM ≥ K AA > K M ehlich 1> K BaCl2> K CaCl2 . Soil potassium extracted by ALM procedure correlated with AA, BaCl2-K, CaCl2 -K and Mehlich 1 - K at 0.05 level of significance. ALM extracted between 1.2 to 5.8 times more soil K than other methods did. The obtained results provided a base for further study on correlation between extractable K and soil fertility indices for particular soil types and climatic regions in Bulgaria.The authors of this study were thankful to prof. Margarita Nikolova for the idea and discussions; to Mr. Vencislav Nekov (Sembodja, Ltd., Sofia, Bulgaria) for providing soil samples. Lyudmila Angelova acknowledged the financial support of the National Program for Support of Young Researchers 2018–2020 funded by the Bulgarian Ministry of Education and Science. The authors are thankful to Ms. Yulia Ivanova for making some of the laboratory experiments

‘Down with communism – Power to the people’: The legacies of 1989 and beyond

This special issue brings together reflections on the thirtieth anniversary of the revolutions of 1989 and considers their consequences for our understandings of European and global society. What seemed for some at least the surprising and rapid collapse of Eastern European state socialism prompted rethinking in social theory about the potential for emancipatory politics and new modes of social and political organization. At the same time, there was increased reflection on the nature of varieties of capitalism and the meaning of socialism beyond the failure of at least its etatist and autarkic mode. The five articles here and the editors’ introduction address themes such as utopian hopes, civil society, the transformation of Europe, the world beyond 1989, and new configurations of power and conflict

Relative luminosity measurement of the LHC with the ATLAS forward calorimeter

In this paper it is shown that a measurement of the relative luminosity changes at the LHC may be obtained by analysing the currents drawn from the high voltage power supplies of the electromagnetic section of the forward calorimeter of the ATLAS detector. The method was verified with a reproduction of a small section of the ATLAS forward calorimeter using proton beams of known beam energies and variable intensities at the U-70 accelerator at IHEP in Protvino, Russia. The experimental setup and the data taking during a test beam run in April 2008 are described in detail. A comparison of the measured high voltage currents with reference measurements from beam intensity monitors shows a linear dependence on the beam intensity. The non-linearities are measured to be less than 0.5 % combining statistical and systematic uncertainties.Comment: 16 page