<p>U okviru doktorske disertacije izvedena su eksperimentalna istraživanja osnovnih hidrodinamičkih i maseno-prenosnih karakteristika airlift reaktora sa spoljnom recirkulacijom sa ugrađenom vi&scaron;ekanalnom cevnom membranom u silaznu cev (ALSRM). ALSRM je radio na dva načina rada: bez mehurova u silaznoj cevi (način rada A) i sa mehurovima u silaznoj cevi (način rada B) u zavisnosti od nivoa tečnosti u gasnom separatoru. Ispitivani su uticaji prividne brzine gasa, povr&scaron;inskih osobina tečne faze, tipa distributora gasa i prisustva mehurova gasa u silaznoj cevi na sadržaj gasa, brzinu tečnosti u silaznoj cevi i zapreminski koeficijent prenosa mase u tečnoj fazi u ALSRM. Rezultati su poređeni sa vrednostima dobijenim u istom reaktoru ali bez membrane (ALSR). Sadržaj gasa u uzlaznoj i silaznoj cevi određivan je pomoću piezometarskih cevi merenjem hidrostatičkog pritiska na dnu i vrhu uzlazne i silazne cevi. Brzina tečnosti merena je pomoću konduktometrijskih elektroda dok je zapreminski koeficijent prenosa mase dobijen primenom dinamičke metode merenjem promene koncentracije kiseonika u vremenu optičkom elektrodom. Eksperimentalni rezultati pokazuju da sadržaj gasa, brzina tečnosti i zapreminski koeficijent prenosa mase zavise od prividne brzine gasa, vrste alkohola i tipa distributora gasa kod oba reaktora. Vi&scaron;ekanalna cevna membrana u silaznoj cevi uzrokovala je povećanje ukupnog koeficijenta trenja za 90% i time dovela do smanjenja brzine tečnosti u silaznoj cevi do 50%. Smanjena brzina tečnosti u silaznoj cevi povećala je sadržaj gasa do 16%. Predložene neuronske mreže i empirijske korelacije odlično predviđaju vrednosti za sadržaj gasa, brzinu tečnosti i zapreminski koeficijent prenosa mase.</p> / <p>An objective of this study was to investigate the hydrodynamics and the gas-liquid mass transfer coefficient of an external-loop airlift membrane reactor (ELAMR). The ELAMR was operated in two modes: without (mode A), and with bubbles in the downcomer (mode B), depending on the liquid level in the gas separator. The influence of superficial gas velocity, gas distributor&rsquo;s geometry and various diluted alcohol solutions on hydrodynamics and gas-liquid mass transfer coefficient of the ELAMR was studied. Results are commented with respect to the external loop airlift reactor of the same geometry but without membrane in the downcomer (ELAR). The gas holdup values in the riser and the downcomer were obtained by measuring the pressures at the bottom and the top of the riser and downcomer using piezometric tubes. The liquid velocity in the downcomer was determined by the tracer response method by two conductivity probes in the downcomer. The volumetric mass transfer coefficient was obtained by using the dynamic oxygenation method by dissolved oxygen probe. According to experimental results gas holdup, liquid velocity and gas-liquid mass transfer coefficient depend on superficial gas velocity, type of alcohol solution and gas distributor for both reactors. Due to the presence of the multichannel membrane in the downcomer, the overall hydrodynamic resistance increased up to 90%, the liquid velocity in the downcomer decreased up to 50%, while the gas holdup in the riser of the ELAMR increased maximally by 16%. The values of the gas holdup, the liquid velocity and the gas-liquid mass transfer coefficient predicted by the application of empirical power law correlations and feed forward back propagation neural network (ANN) are in very good agreement with experimental values.</p>

<p>Određivanje koncentracije etanola u telesnim tečnostima, pre svega u krvi, neophodan je uslov da bi se ustanovio uticaj alkoholemije na psihomotorne sposobnosti. Poznavanje stabilnosti lekova, droga i metabolita u biolo&scaron;kim uzorcima je od ključne važnosti kada se ukaže potreba za ponovljenom analizom i evaluacijom rezultata u sudskom postupku. Osnovni ciljevi ovog rada su da se uz pomoć HS-GC metode (hedspejs gasna hromatografija) ustanovi da li postoji statistički značajna promena koncentracije etanola u uzorcima krvi dobijenih od živih osoba i u biolo&scaron;kim uzorcima uzorcima sa autopsijskog materijala. Na osnovu rezultata potrebno je bilo utvrditi u kojem tipu uzorka uzetog sa le&scaron;nog materijala postoji najmanja promena koncentracije tokom perioda čuvanja uzorka. Istraživanje je bilo otvoreno, randomizirano i prospektivnog tipa. Biolo&scaron;ki uzorci krvi krvi živih osoba i le&scaron;nog materijala (krv, mokraća i staklasto telo) uzimani su metodom slučajnog izbora, u rasponu alkoholemije od 0,1 mg/ml do 5 mg/ml. Nakon inicijalne dvostruke analize, jedan biolo&scaron;ki uzorak čuvan je u trajanju od 180 dana, dok je drugi otvaran i analiziran nakon 60, 120 i 180 dana. Ukupan broj analiza alkoholemije u krvi živih osoba iznosio je 500. Ukupan broj analiza koncentracije etanola u krvi, mokraći i staklastom telu sa le&scaron;eva iznosio je 360. Etanol je u uzorcima krvi živih osoba, kao i u biolo&scaron;kim uzorcima sa autopsijskog materijala određivan metodom HS GC. Tokom čuvanja biolo&scaron;kih uzoraka u periodu od &scaron;est meseci ustanovljeno je da je do&scaron;lo do značajnog smanjenja koncentracije etanola u svim analiziranim uzorcima, nezavisno od njegovog porekla. Promena koncentracije etanola tokom čuvanja u zavisnosti je od tkivne vrste uzorka, inicijalne alkoholemije, dužine čuvanja, integriteta vijala i čepova, temperature, odnosa tečne i gasne faze, prisustva konzervansa i potencijalnog intermitentnog otvaranja radi analiza.</p> / <p>Determination of ethanol concentration in body fluids, especially blood, is a necessary objective to establish the influence of alcohol on psychomotor skills. Knowing the stability of medicines, drugs and metabolites in biological samples is of crucial importance when there is a need for repeated analysis and result evaluation in court. The main objectives of this work were to determine whether there was a statistically significant change in ethanol concentration in blood samples obtained from living subjects and from autopsy material, by using HS-GC method (headspace gas chromatography). Based on the results it was necessary to determine which type of sample collected from autopsy showed the lowest change in concentration during the storage period. The study was open, randomized and prospective. Biological samples of living person&#39;s blood and autopsy biological samples (blood, urine and the vitreous humor) were taken at random, in the level range between 0.1 mg/ml and 5 mg/ml. After an initial duplicate analysis, one biological sample was stored for a period of 180 days, while the other was opened and analyzed after 60, 120 and 180 days. Total number of analysis of living person&#39;s blood samples was 500. The total number of analysis of autopsy biological samples was 360. All concentrations were determined by HS-GC method. During the storage, results showed that there has been a significant decrease in the concentration of ethanol in all of the analyzed samples, regardless of its origin. The level of this change was dependent on the type of tissue sample, initial alcohol concentration, duration of storage, integrity of the vials and stoppers, temperature, ratio of liquid and gas phases, presence of preservatives and intermittent opening for analysis.</p>

<p>Oralni karcinom je po učestalosti &scaron;esta najče&scaron;ća maligna bolest u svetu čija incidenca varira u različitim geografskim područjima. Predstavlja 5% svih novootkrivenih malignih tumora godi&scaron;nje i čini 14% svih malignih tumora glave i vrata. Pod oralnim karcinom podrazumevamo planocelularni karcinom obzirom na činjenicu da on čini preko 90% malignih tumora oralne lokalizacije, dok se u manjem procentu javljaju drugi tumori (maligni tumori malih pljuvačnih žlezda, limfomi, mezenhimni tumori). Oralni karcinom podrazumeva karcinome koji se javljaju u sledećim anatomskim regijama: sluznici prednje 2/3 jezika, poda usta, obraza, gingivi gornje i donje vilice, retromolarnom trouglu, kao i sluznici mekog i tvrdog nepca. Najče&scaron;ća lokalizacija oralnog planocelularnog karcinoma je sluznica pokretnog dela jezika i poda usta. Oralni karcinom se če&scaron;će javlja kod mu&scaron;karaca (odnos mu&scaron;karci:žene je 3:1) verovatno zbog većeg procenta rizičnog pona&scaron;anja kod mu&scaron;karaca. Najče&scaron;će se javlja u &scaron;estoj i sedmoj deceniji života (medijana je 62 godine) iako se poslednjih godina sve če&scaron;će javlja kod mlađih od 45 godina. Faktori rizika za oboljevanje su dobro poznati. Na prvom mestu se izdvaja pu&scaron;enje duvana (značajna je dužina pu&scaron;enja, da li pacijent pu&scaron;i lulu ili cigaretu, da li žvaće duvan, kao i dužina trajanja apstinencije). Smatra se da je smrtnost kod oralnog karcinoma direktno povezana sa brojem popu&scaron;enih cigareta na dan. Preko 75% pacijenata sa oralnim karcinomom anamnestički daje podatak o prekomernoj upotrebi alkohola. Postoji sinergističko dejstvo alkohola i cigareta, dugotrajna ekspozicija ovim faktorima rizika dovodi do pojave &ldquo;polja kancerizacije&ldquo;, pojave genetske nestabilnosti i razvoja tumora. Kod oralnog planocelulranog karcinoma primećene su hromozomske abnormalnosti koje su rezultat o&scaron;tećenja DNK i uključuju promene genetskog materijala na hromozomima.Jedna od najče&scaron;ćih genetskih abnormalnosti kod oralnog planocelularnog karcinoma je mutacija r53 gena koji se nalazi na kratkom kraku hromozoma 17 i predstavlja tumor supresor gen. Planocelularni karcinom nije te&scaron;ko dijagnostikovati kada postane simptomatski. Pacijent se žali na bol, krvavljenje, otalgiju, otežano gutanje, smanjenje pokretljivosti jezika. Neretko je prvi simptom metastatski uvećan limfni čvor na vratu jer bolesnici ne primećuju ili ignori&scaron;u oralnu patologiju. Dijagnoza oralnog karcinoma se postavlja na osnovu detaljno uzete anamneze, kliničkog pregleda i patohistolo&scaron;ke verifikacije. Oralni planocelularni karcinom se javlja u tri klinike forme: egzofitična, endofitična i infiltrativna. Zlatni standard za dijagnozu oralnog karcinoma je biopsija i patohistolo&scaron;ka verifikacija, pri čemu se može primeniti &bdquo;punch&ldquo; biopsija, inciziona biopsija ili eksciziona biopsija kod manjih promena. TNM &bdquo;staging&ldquo; sistem AJCC (American Joint Committee on Cancer) se danas standardno koristi za klinički &bdquo;staging&ldquo; oralnog karcinoma i bazira se na podacima dobijenim kliničkim pregledom i &bdquo;imaging&ldquo; metodama. Sam &bdquo;staging&ldquo; je bitan kako zbog komunikacije među lekarima koji učestvuju u lečenju bolesnika tako i zbog standardizacije prognoze. T stadijum označava veličinu primarnog tumora, N stadijum označava regionalnu nodalnu zahvaćenost dok M stadijum prikazuje prisustvo udaljenih metastaza. Terapija patohistolo&scaron;ki dokazanog oralnog karcinoma zahteva multidisciplinarni pristup. Osnova terapije oralnog planocelularnog karcinoma je hirur&scaron;ko lečenje koje podrazumeva ablativno i rekonstruktivno hirur&scaron;ko lečenje. Osnovni princip ablativne hirurgije kod oralnog karcinoma je resekcija primarnog tumora sa najmanje 1cm negativnim hirur&scaron;kim marginama. Pored ablacije tumora hirur&scaron;ko lečenje podrazumeva i uklanjanje regionalnih limfnih čvorova vrata. Cilj disekcije vrata je da se kod klinički evidentnih metastaza iste uklone (terapijska disekcija) ili da se uklone okultne metastaze koje su klinički neevidentne (elektivna disekcija). Oralni planocelularni karcinom spada u tumore sa visokom stopom smrtnosti, većom nego &scaron;to je kod limfoma, laringealnog karcinoma, karcinoma testisa i endokrinih karcinoma. Stopa petogodi&scaron;njeg preživljavanja je direktno povezana sa veličinom tumora, prisustvom metastaza u regionalnim limfnim čvorovima i prisutvom udaljenih metastaza. Prosečno trogodi&scaron;nje preživljavanje bolesnika sa oralnim karcinomom je 52% dok je prosečno petogodi&scaron;nje preživljavanje oko 39% i ove stope se nisu mnogo menjale tokom godina bez obzira na nova saznanja i nove pristupe lečenju oralnog planocelulanog karcinoma. Ciljevi istraživanja su da se utvrdi da li postoji korelacija debljine OPK izmerene kompjuterizovanom tomografijom i svetlosnim mikroskopom, da li dubina invazije OPK i volume tumora mogu biti prediktivni faktor za razvoj regionalnih cervikalnih metastaza kod oralnog planocelularnog karcinoma. Istraživanje je uključilo 65 konsekutivnih bolesnika oba pola lečenih od oralnog karcinoma na Klinici za maksilofacijalnu hirurgiju Kliničkog centra Vojvodine. Dijagnoza oralnog karcinoma je postavljena na osnovu anamneze, kliničkog pregleda i biopsije. U sklopu TNM &bdquo;staging&ldquo;-a bolesnika načinjen je pregled glave i vrata i grudnog ko&scaron;a kompjuterizovanom tomografijom (CT) na osnovu kog smo dobili podatak o dimenzijama tumora. Na osnovu kliničkog nalaza i analize CT nalaza planiralo se operativno lečenje u skladu sa bolesnikovim TNM statusom. Postoperatativni patohisto&scaron;ki preparati je pregledan od strane istog patologa. Parametri koji će su određivani su sledeći: 1. Veličina tumora (2 dimenzije) izmerene na osnovu CT pregleda izražene u cm 2. Debljina tumora izmerena na osnovu CT pregleda izražena u cm 3. Veličina tumora (2 dijametra) na makroskopskom preparatu izražena u cm 4. Debljina tumora na mikroskopskom preparatu izmerena svetlosnim mikroskopom izražena u cm 5. Dubina invazije tumora na mikroskopskom preparatu izmerena svetlosnim mikroskopom izražena u mm 6. Volumen tumora koji se izračunavao prema formuli: VT=&pi;/6 x maksimalni dijametar tumora A x minimalni dijametar tumora B x dubina invazije tumora i izražava se u cm&sup3; 7. Broj metastatski izmenjenih limfnih čvorova u disekatu vrata 8. Ukupan broj patohistolo&scaron;ki ispitanih limfnih čvorova u disekatu vrata Nakon prikupljanja planiranog materijala urađena je statistička obrada podataka. Statistička analiza podataka je uključila metode deskriptivne statistike (srednja vrednost, standardna devijacija, učestalost), kao i standardne parametrijske i neparametrijske testove za komparacije dve grupe (Studentov T test, Mann&ndash;Whitney U test, hikvadrat test). U fazi statističke analize međusobnih uticaja i povezanosti prikupljenih podataka kori&scaron;ćen je Pearsonov test korelacije. Sva testiranja sprovedena su na nivou statističke značajnosti p&lt;0,05. REZULTATI: Istraživanje je obuhvatilo 65 bolesnika, od kojih je 82% bilo mu&scaron;kog pola prosečne starosti 59 godina. 83% bolesnika su se izja&scaron;njavali kao pu&scaron;ači, dok je 69% bolesnika navelo da redovno koristi alkohol. Svim pacijentima je tokom hirur&scaron;kog lečenja OPK rađena disekcija vrata i to najče&scaron;čće selektivna disekcija vrata (91%). Kod 30 bolesnika je utvrđeno postojanje cervikalnih regionalnih metastaza na operativnom preparatu te su bolesnici podeljeni u dve grupe: sa prisustvom i bez prisustva metastaza u limfnim čvorovima vrata. Utvrđeno je da se ove dve grupe statistički značajno razlikuju u dubini invazije tumora i volumenu tumora. Utvrđeno je takođe da postoji statistički značajna korelacija između debljine tumora izmerene CT pregledom i debljine tumora izmerene svetlosnim mikroskopom. Dokazano je da dubina invazije tumora veća od 7mm i zapremina tumora veća od 4cm&sup3; predstavljaju prediktivni faktor za pojavu regionalnih cervikalnih metastaza. ZAKLjUČAK: Na osnovu istraživanja izvedeni su zaključci koji ukazuju na to da postoji statistički značajna korelacija između debljine tumora OPK izmerene CTpregledom i svetlosnim mikroskopom te se debljina tumora izmerena CT pregledom može koristiti za planiranje operativnog zahvata prilikom lečenja OPK. Dubina invazije tumora veća od 7mm i volumen tumora veći od 4 cm&sup3; predstavljaju prediktivni faktor za pojavu nodalnih cervikalnih metastaza te su značajni za određivanje stadijuma bolesti.</p> / <p>Oral cancer is the sixth most common malignant disease in the world which incidence varies based on geographic area. It represents 5% of all newly discovered malignant tumors annually and constitutes 14 % of all malignant tumors of head and neck. Squamous cell carcinoma is considered to be a type of oral cancer because more than 90 % of malignant tumors that occur in oral cavity are squamous cell carcinomas while other tumors (malignant tumor of minor salivary gland, lymphoma, sarcoma) rarely occur. Oral cancer is the cancer found in the following anatomic regions: mucosa of front two-thirds of the tongue, the floor of the mouth, cheeks, upper and lower gingiva, retromolar trigone as well as&nbsp; mucosa of soft and hard palates. Oral squamous cell carcinoma is most commonly localized in mucous membrane of the movable part of the tongue and floor of the mouth. Men are more affected than women (male to female ratio is 3:1) probably because of men&rsquo;s riskier behavior. It is most commonly diagnosed in the sixth and seventh decade of life (the median is 62 years old) although it has been diagnosed in patents younger than 45 in recent years. Risk factors of oral squamous cell carcinoma are well known. The major factor is tobacco smoking (the period of smoking is significant, it is also important to consider whether a patient smokes a pipe or cigarette, whether he/she chews tobacco as well as the period of abstinence). The mortality rate is believed to be directly related to the number of cigarettes smoked a day. An excessive use of alcohol has been reported in over 75% of patients with oral cancer. There is a synergistic effect of alcohol and cigarette consumption and long-term exposure to these risk factors results in &lsquo;field of cancerization&rsquo;, genetic instability and tumor development. Chromosome abnormalities, which are caused by DNA damage and include the change in genetic material of chromosomes, have been reported in patients with oral squamous cell carcinoma. One of the most common genetic abnormalities in patients with oral squamous cell carcinoma is a mutation of р53 gene which is located on a short arm of chromosome 17 and represents a tumor suppressor gene. Oral squamous cell carcinoma is not difficult to diagnose when it becomes symptomatic. The patient complains of pain, bleeding, otalgia, swallowing difficulties, decreased tongue mobility. The first symptom is rarely metastatic lymph node on the neck because patients either do not notice or ignore oral pathology. The oral cancer is diagnosed based on the detailed anamnesis, physical examination and pathohistological verification. The oral squamous cell carcinoma occurs in three clinical forms: exophytic, endophytic and infiltrative form. The gold standard for diagnosis of oral cancer is biopsy and pathohistological verification. However, in case of smaller changes, punch biopsy, incisional and excisional biopsies can also be applied. ТNМ staging system of AJCC (American Joint Committee on Cancer) is nowadays used for clinical staging of oral cancer and it is based on the data acquired by clinical examination and imaging methods. Not only is the staging itself important for communication between the doctors involved in treatment, but it is also important for standardization of prognosis. Т describes the size of primary tumor, N describes regional nodal spread and М describes distant metastasis. The treatment of histopathologically proven oral cancer requires multidisciplinary approach. The main treatment of oral squamous cell carcinoma is surgical treatment which involves ablative and reconstructive surgical treatment. The basic principle of ablative surgery for oral cancer is the resection of primary tumor with at least 1 cm negative surgical margins. Apart from tumor ablation surgical treatment also involves removal of regional lymph nodes on the neck. The aim of neck dissection is to remove clinically evident metastasis (therapeutic dissection) or to remove occult metastasis that are not clinically evident (elective dissection). The oral squamous cell carcinoma is the cancer with high mortality rate. The mortality rate is higher than the mortality rate for lymphoma, laryngeal cancer, testicular cancer and endocrine cancer. The five-year survival rate is directly related to the size of the tumor, presence of metastasis in regional lymph nodes and distant metastasis. The average three-year survival rate of the patients with oral cancer is 52% and the average five-year survival rate is 39%. These rates have not changed a lot over the years regardless of new knowledge and approaches in treatment of oral squamous cell carcinoma. The aims of the study are to determine whether there is a correlation between the depth of invasion of oral squamous cell carcinoma determined by computed tomography and light microscope and whether the invasion depth of OSCC and tumor volume can be predictive factors of development of regional cervical metastases in case of oral squamous cell carcinoma. The study covered 65 consecutive patients of both sexes who received treatment for oral cancer at the Clinic for Maxillofacial Surgery of the Clinical Center of Vojvodina. The diagnosis of oral cancer was established based on the anamnesis, physical examination and biopsies. The TNM &lsquo;staging&rsquo; of the cancer involved the examination of the patient&rsquo;s head and thorax by computed tomography (CT) which enabled us to obtain reliable data about the tumor size. After obtaining clinical findings and CT results, the patients&rsquo; treatment was planned based on their TNM status. A postoperative histopathological examination was performed by the same pathologist and the following parameters were determined: 1. Tumor size (2 dimensions) measured by CT and expressed in cm 2. Tumor thickness measured by CT and expressed in cm 3. Tumor size (2 diameters) on microscopic device and expressed in cm 4. Tumor thickness on microscopic device measured by light microscope and expressed in cm 5. Depth of tumor invasion on microscopic device measured by light microscope and expressed in cm 6. Tumor volume calculated based on the following formula: VT=&pi;/6 x maximum tumor diameter А x minimum tumor diameter B x depth of tumor invasion and expressed in cm&sup3; 7. The number of metastatic lymph nodes in the neck dissection 8. Total number of pathohistologically tested lymph nodes in the neck dissection. Upon collecting the planned material, statistical analysis of all data was carried out. The statistical analysis included the methods of descriptive statistics (mean value, standard deviation, frequency) and standard parametric and nonparametric tests for comparison of two groups (Student&rsquo;s T test, Whitney U test, chi-square test). The Pearson&rsquo;s Test of Correlation was used in the phase of statistical analysis of interaction effects and correlation of obtained data. All tests were performed at the level of statistical significance of p&lt;0.05. RESULTS: The study covered 65 patients, out of which 82% were male patients aged 59. 83% of patients said they smoked and 69% of patients stated that they consumed alcohol regularly. A neck dissection was performed in all patients during surgical treatment of OSCC and it was selective neck dissection (91%). Cervical regional metastasis was found in 30 patients so they were divided into two groups: the group of patients who had metastasis in the lymph nodes and the group of patients with no metastasis in lymph nodes of the neck. It was determined that there was a statistically significant difference in depth of invasion and tumor volume between these two groups. The statistically significant difference was also determined between the thickness of tumor measured by CT and thickness of tumor measured by light microscope. Moreover, the depth of invasion of tumor greater than 7mm and volume of tumor greater than 4cm&sup3; were proven to represent a predictive factor of development of regional cervical metastasis. The study results show that there is a statistically significant correlation between the thickness of OSCC tumor measured by CT and the thickness measured by light microscope, so the thickness of tumor measured by CT can be used for planning the surgery during the treatment of OSCC. The depth of tumor invasion greater than 7 mm and tumor volume greater than 4 cm&sup3; represent a predictive factor of development of cervical metastasis, which means that they are significant for determining the stage of disease.</p>