Electrode Kinetics of Fe(III)/Fe(II) Redox Couple on an Electrodeposited Ruthenium Electrode

The heterogeneous electron transfer in Fe(CN)g /3" and aquo complexes of Fe3+/2+ redox couples have been investigated on a ruthenized platinum electrode in 0.5 mol dm-3 sulphuric acid solution. Qualitative voltammetric data measured on a rotating disc electrode showed that a ruthenized platinum layer was a good electronic conductor, which did not block electron transfer in either direction of Fe(CN)g_/3_ redox couple. Quantitative electrode kinetic data were obtained using aquo complexes of Fe3+/2+ redox couple on a freshly deposited ruthenium electrode and on an electrode activated to the state of enhanced oxygen evolution from acid solution. The heterogeneous electron transfer rate constant of 3.9 x 10~5 cm s_1 on the unactivated electrode increased by 30% in the case of the activated electrode

Surface Modification of Stainless Steel-304 Electrode. 2. An Experimental Comparative Study of Electrochemically, Hydrothermally and Chemically Modified Oxide Films

Stainless steel-304 was modified electrochemically by potentiostatic and potentiodynamic methods (triangular and square-wave potential-time programs) in 1 mol dm–3 NaOH solution, hydrothermally in 1 mol dm–3 NaOH at 200 °C, and chemically in 0.5 mol dm–3 K2Cr2O7 solution. Oxide films were characterized voltammetrically by the charge of Fe(OH)2/FeOOH surface electrochemical reaction. The stability of the oxide films was measured in 0.5 mol dm–3 H2SO4 by anodic potentiodynamic polarization and by opencircuit potential-time measurements. The hydrothermally grown oxide film was most stable. The most efficient oxide growth was achieved by the use of square-wave type of modification. The oxide modified by this procedure exhibited lower stability than the oxide grown by triangular potential-time program, which was much more stable due to the uncompleted reduction of chromium oxide. The importance of careful control of experimental conditions, where a small change in surface treatment could lead to a significant change in corrosion behaviour, is pointed out

Surface Modification of Stainless Steel-304 Electrode. 1. Voltammetric, Rotating Ring-Disc Electrode and XPS Studies

Hydrous oxide film was grown on stainless steel-304 under conditions of cycling voltammetry in 1 mol dm–3 NaOH solution. The anodic voltammetric peak of Fe(OH)2 oxidation was used as a measure of the oxide growth as a function of potential limits, sweep rates and the number of potential cycles. The oxide film stability was monitored by the use of rotating ring-disc electrode. During potential cycling in alkaline solution, it was found that after 30 cycles, 1.4% of the anodic charge was due to iron dissolution from the oxide film. The selective dissolution of iron and nickel from the oxide film, previously grown in alkaline solution, was monitored at the potential of open circuit in an acid solution of pH 2.7. A model for enhanced stability of hydrous oxide film in acid solution is proposed. The model, based on voltammetric, rotating ring-disc electrode and X-ray photoelectron spectroscopy measurements, implies that after hydrous oxide growth by potential cycling in an alkaline solution, the oxide placed in an acid solution remains enriched in chromium due to selective dissolution of nickel and iron. The Cr- O-Cr chains stabilize the modified layer and contribute to the enhanced stability against corrosion. This model unifies several previously proposed models: the model for a hydrous oxide growth by potential cycling, the polymeric hydrated oxide model for the passivity of iron and stainless steels and the percolation model for the passivity of stainless steels

The nonspecific lymph node uptake of 18F-choline in patients with prostate cancer — a prospective observational study

BACKGROUND: The aim of this study was to observe and characterize the nonspecific 18F-choline lymph node uptake in patients with prostate cancer. MATERIAL AND METHODS: In this single center, prospective observational study which was done in University Hospital Center Zagreb between December 2012 and October 2014, 69 patients (median age 71 years; range 50–92) with prostate cancer were included. Patients underwent 18F-choline PET/CT for staging or restaging of prostate cancer. The mean follow-up period was 11.5 months. Kruskal-Wallis test was used to find out if the differences between SUV values of specific and nonspecific accumulation of the tracer are statistically significant. RESULTS: Nonspecific accumulation of 18F-choline in lymph nodes was found in 36 patients (52.7%). Most of these findings (n = 24) were nonspecific accumulation of the tracer in mediastinal lymph nodes. Other sites of nonspecific tracer uptake were pulmonary hila (n = 20), inguinal lymph nodes (n = 15), and axillary lymph nodes (n = 10). Mean SUV values for mediastinal lymph nodes, pulmonary hila, axillary and inguinal lymph nodes were 4.8, 4.3, 3.1 and 4.1, respectively. Mean SUV value of nonspecific sites of tracer accumulation was lower (not significantly; (p = 0.2) than tracer uptake values measured in metastases sites (bone metastases mean SUVmax value — 13.2, metastatic lymph nodes mean SUVmax value — 9.2). CONCLUSIONS: 18F-choline PET/CT is a valuable and an established functional diagnostic imaging method for staging and restaging prostate cancer. However, nonspecific uptake of the tracer can often be seen in lymph nodes not related to primary disease. Patient history, clinical examination, laboratory tests and correlation with other imaging methods, must be taken into consideration when interpreting 18F-choline PET/CT findings

Jetreni apsces kao terapijski i dijagnostički problem

Liver abscess still represents a significant clinical entity with mortality rates of up to 10%. Traditional treatment of liver abscesses is open surgical treatment. Recently, percutaneous and laparoscopic drainage has been increasingly used. Still, in spite of these relatively novel techniques and improved imaging, liver abscess can sometimes be difficult to diagnose or treat. Here we present two cases of chronic liver abscess treated at our department. First patient was twice hospitalized in other hospitals without reaching definitive diagnosis. He was admitted at our department because of clinical presentation of sepsis, and definitive diagnosis of liver abscess was established only during open surgery. Second patient was admitted after laparoscopic drainage and repeated percutaneous drainage had failed to resolve his symptoms. In both cases, liver segment resection led to complete healing. These cases indicate that chronic liver abscess can still present a diagnostic and therapeutic challenge.Jetreni apscesi i dalje predstavljaju ozbiljan klinički entitet sa stopom smrtnosti i do 10%. Tradicionalno liječenje apscesa jetre je putem otvorenog kirurškog zahvata, iako se u posljednje vrijeme sve češće rabi perkutana ili laparoskopska drenaža. Usprkos tim načinima liječenja i sve boljim dijagnostičkim metodama apsces jetre ponekad nije jednostavno niti dokazati ni liječiti. Ovdje prikazujemo dva slučaja kroničnog apscesa jetre liječena na našem odjelu. U prvom slučaju bolesnik je bio u dva navrata hospitaliziran u drugim ustanovama pod dijagnozom jetrene ehinokokoze. Kod nas je bio primljen zbog kliničke slike sepse. Cistična tvorba u jetri je dijagnosticirana kao apsces tek tijekom operacije. Učinjena je resekcija VII . segmenta jetre gdje se apsces nalazio. Drugi bolesnik je primljen nakon pokušaja laparoskopske drenaže i više pokušaja perkutane drenaže apscesa. U oba slučaja je učinjena segmentektomija jetre, što je dovelo do izliječenja bolesnika. Ova dva slučaja pokazuju kako kronični jetreni apscesi još uvijek ponekad predstavljaju dijagnostički i terapijski izazov

Population Ageing as the Limitation Factor of the Demographic Development of Žumberak Region, Croatia

Suvremeni demografski razvoj Žumberka reflektira duboko ukorijenjene utjecaje dosadašnjeg vrlo specifičnog demografskog, društvenog i gospodarskog razvoja. Reljefna raščlanjenost prostora s dominantnim brdsko-planinskim morfostrukturnim obilježjima, granični položaj, nedovoljna prometna povezanost i gospodarska nerazvijenost kroz prošlost sve do danas znatno su otežavali društveno-gospodarski i s njim neraskidivo povezani demografski razvoj Žumberka. Dugotrajni proces ukupne depopulacije u obliku kontinuirane emigracije stanovništva u bioreproduktivnoj dobi te s tim povezani negativni biodinamički populacijski procesi utjecali su izrazito negativno na strukturna obilježja stanovništva Žumberka. Smanjeni priljev stanovništva u fertilnu dob postupno je doveo do smanjenja nataliteta, a sve veći udio staroga stanovništva podizao razinu mortaliteta. Stoga je Žumberak u pogledu demografske biodinamike postao prostor snažne biološke depopulacije stanovništva. Starenje stanovništva Žumberka kao dominantan demografski proces inducira daljnje negativne dinamičke i strukturne populacijske procese. Zbog dominantnog utjecaja na formiranje fertilnog i radnog kontingenta stanovništva demografsko je starenje značajna prepreka budućim demografskim i društveno-gospodarskim zbivanjima. Sve nepovoljniji odnos mladog i starog stanovništva Žumberka implicira povećanu potrebu za mirovinskim, socijalnim i zdravstvenim izdvajanjima što dodatno opterećuje gospodarstvo toga slabo razvijenoga prostora. Nedostatak temeljne infrastrukture, nedovoljna ponuda radnih mjesta te nedostatak radno aktivnog stanovništva ne pružaju mogućnosti za revitalizaciju i razvoj promatranog prostora.Contemporary demographic development of Žumberak reflects the deeply rooted influences of very specific historical and socio-economic development. The relief dynamics with the predominant mountainous morphostructural characteristics, together with the peripheral border location and bad traffic infrastructure have had a key role in the forming of existing negative demographic situation. The long lasting processes of total depopulation, emigration of the reproductive age population, as well as decrease of natality, have very negatively affected the forming of the structures of the population. The reduced influx of the population into fertile age, caused by emigration and reduced natality contributed the further drop of natality. The increase of the percentage of old population resulted in increased mortality. Therefore, Žumberak became the area of strong biological depopulation. The population ageing, as the main demographic process induces the further negative processes in the population dynamics and structures. The population ageing is the major obstacle in the forming of future working and fertile population contingent, which has negative effect to the entire socio-economic development. Due to the population ageing more funds are needed for the social and health care which additionally burdens the weak economy of Žumberak an Croatia in general. The lack of basic infrastructure, insufficient employment potentials, and old population are bad starting point for revitalisation and development of the researched region

Antibiotic prophylaxis in patients undergoing colorectal cancer resection

Infekcija rane je i dalje jedna od najčešćih postoperacijskih komplikacija, s posljedičnom produženom hospitalizacijom, dužim oporavkom bolesnika i povećanim troškovima liječenja. Smanjenje incidencije infekcije rane obavlja se na razne načine, uključujući optimalnu preoperativnu pripremu operacijskoga polja, kiruršku tehniku, antibiotsku profilaksu i postoperativno liječenje bolesnika. Iako postoje razni protokoli, optimalna antibiotska profilaksa kod bolesnika s kolorektalnim karcinomom još nije utvrđena. U ovoj studiji smo retrospektivno analizirali bolesnike koji su na našem odjelu operirani radi kolorektalnog karcinoma. Bolesnike smo svrstali ovisno o protokolu antibiotske profilakse u dvije skupine. Skupina A dobivala je gentamicin i metronidazol, a skupina B cefazolin i metronidazol. U obje skupine antibiotska profilaksa započeta je neposredno prije operacije i trajala je 24 sata. Uključeno je 57 bolesnika koji su primali gentamicin i metronidazol te 35 bolesnika koji su primali cefazolin i metronidazol. Učestalost infekcije rane u skupini B bila je 6%, dok je u skupini A, koja je primala gentamicin i metronidazol, bila 24% (p<0,05). Navedeni rezultati upućuju daje kombinacija cefazolina i metronidazola u trajanju od 24 sata učinkovita kao antibiotska profilaksa kod bolesnika s kolorektalnim karcinomom.Surgical site infection remains one of the most frequent postoperative complications, leading to prolonged hospital stay and morbidity as well as increased treatment costs. Efforts to decrease incidence of surgical site infections are various, including improving preoperative skin preparation, surgical technique, antibiotic prophylaxis and postoperative patient management. Optimal antibiotic prophylaxis in colorectal surgery is yet to be determined, although there are various recommended regimes. Patients operated for colorectal cancer at our department were retrospectively analyzed. The patients were grouped according to the antibiotic prophylaxis they received. Earlier group of patients received gentamicin and metronidazole and later group received cefazolin and metronidazole. In both groups antibiotic prophylaxis was initiated immediately before surgery and maintained for 24 hours. 57 patients who received gentamicin and metronidazole and 35 patients who received cefazolin and metronidazole were analyzed. Incidence of surgical site infection in the latter group was 6%, compared with 24% (p<0,05) in the group of patients who received gentamicin and metronidazole. This study indicates that a combination of cefazolin and metronidazole administered for 24 hours is effective as antibiotic prophylaxis in patients undergoing colorectal surgery

Isolated Splenic Metastasis from Colon Cancer – Case Report and Literature Review

Solitary splenic metastases are very rare and sporadic. There are several explanations for this low incidence of splenic metastasis including anatomical, histological and immunological features of the spleen. In this paper we present a case of 70-year-old man with no history of previous diseases who was first operated under the diagnosis of acute abdomen revealing perforated colon tumor of splenic flexure with no metastases at that time. Left hemicolectomy was performed followed by postoperative complications demanding a subtotal colectomy and ileostomy. Primary tumor was classified as Dukes (Astler-Coller)-C2, T4N1M0. Patient was referred to oncologist and received chemotherapy (5FU, Leucovorin). 5 months later continuity of the gut was performed by ileosygmoanastomosis. 2 years after first surgical procedure, a CT scan and abdominal ultrasound, followed by needle biopsy, showed isolated metastasis in spleen, so splenectomy was performed. Pathological findings revealed sharply bordered, partially necrotic tumor inside of spleen tissue, spreading to, but not reaching splenic hilum. Histology showed low to medium differentiated adenocarcinoma tissue with desmoplastic stromal reaction. There were no protrusions of tumor cells through spleen surface. In splenic hilum 4 tumor free lymph nodes were harvested. No additional chemotherapy was conducted. The latest follow up, a year after diagnosis of metastasis showed no signs of cancer disease. Review of the literature showed that long term survival and prognosis of isolated splenic colorectal metastasis after splenectomy are rather optimistic, although these are the cases of distant metastasis. Due to small number of cases reported in literature, definitive conclusions and/or guidelines for the treatment of isolated splenic metastasis cannot be given, but splenectomy and chemotherapy are preferable in the treatment, promising long term survival at least for metachronous metastasis