Nomenclature note: ICTAC Nomenclature of Thermal Analysis (IUPAC Recommendations 2014)

Raširena primjena toplinske analize kao znanstvene laboratorijske tehnike dovela je do razvoja radnih naziva. Nakana je ovog dokumenta pružiti svima koji se bave toplinskom analizom međusobno usklađene definicije koje će omogućiti jasnu i preciznu komunikaciju i sporazumijevanje. Dokument sadrži definicije 13 tehnika, 54 pojma u glosaru te simbole i jedinice.The widespread use of thermal analysis (TA) by scientists as a laboratory technique carries with it a working vocabulary. This document is intended to provide those working in the field with a consistent set of definitions to permit clear and precise communication as well as understanding. Included in the document are the definitions of 13 techniques, 54 terms within the glossary, as well as symbols and units

Sol-gel Process in Preparation of Organic-inorganic Hybrid Materials

Organsko-anorganski hibridni materijali vrsta su nanostrukturnih materijala u kojima su organska i anorganska faza međusobno pomiješane na molekulnoj razini. Anorganska faza u hibridnim materijalima pripravlja se sol-gel postupkom koji obuhvaća reakcije hidrolize i kondenzacije metalnih (većinom silicijevih) alkoksida. Da bi se spriječilo razdvajanje faza tijekom priprave hibrida, poželjno je poboljšati međudjelovanje faza stvaranjem vodikovih ili kovalentnih veza među njima. Kovalentna veza najjednostavnije se uvodi uporabom organski modificiranih alkoksisilana s reaktivnom organskom skupinom koja može reagirati s organskom fazom. Da bi se pripravili hibridni materijali željene strukture, potrebno je podrobno poznavanje mehanizama reakcija hidrolize i kondenzacije. U ovom radu izložit će se utjecaji reakcijskih uvjeta na hidrolizu i kondenzaciju silicijevih alkoksida i organski modificiranih alkoksisilana.Organic-inorganic hybrid materials are a sort of nanostructured material in which the organic and inorganic phases are mixed at molecular level. The inorganic phase in hybrid materials is formed by the sol-gel process, which consists of reactions of hydrolysis and condensation of metal (usually silicon) alkoxides. Flexibility of sol-gel process enables creation of hybrid materials with varying organic and inorganic phases in different ratios, and consequently fine-tuning of their properties. In order to obtain true hybrid materials, contact between the phases should be at molecular level, so phase separation between thermodynamically incompatible organic and inorganic phases has to be prevented. Phase interaction can be improved by formation of hydrogen or covalent bonds between them during preparation of hybrid materials. Covalent bond can be introduced by organically modified silicon alkoxides containing a reactive organic group (substituent) capable of reacting with the organic phase. In order to obtain hybrid materials with desired structures, a detailed knowledge of hydrolysis and condensation mechanism is necessary. The choice of catalyst, whether acid or base, has the most significant influence on the structure of the inorganic phase. Other important parameters are alkoxide concentration, water: alkoxide ratio, type of alkoxide groups, solvent used, temperature, purity of chemicals used, etc. Hydrolysis and condensation of organically modified silicon alkoxides are additionally influenced by nature and size of the organic supstituent

Definitions of Terms Relating to the Structure and Processing of Sols, Gels, Networks, and Inorganic-Organic Hybrid Materials

U ovom dokumentu definirani su pojmovi vezani uz strukturu, pripravu i obradu anorganskih, polimernih i anorgansko-organskih hibridnih materijala, polazeći od polaznih tvari (prekursora) preko gelova do čvrstih proizvoda. Podijeljen je na četiri dijela - polazne tvari, gelovi, čvrste tvari i postupci - a pojmovi su ograničeni na one koji se najčešće upotrebljavaju. Dosljednosti radi preuzeti su pojmovi iz drugih IUPAC-ovih publikacija, ako su im definicije zadovoljavajuće za potrebe ovog dokumenta. Pojmovi i definicije sabrani su uz savjetovanje sa stručnjacima iz odgovarajućih područja. Namjera je da definicije pomognu čitatelju koji nije upoznat sa sol-gel postupkom, keramizacijom te srodnim materijalima i tehnologijama, a da istraživačima u tim područjima posluže kao vodič za ustaljenu terminologiju.This document defines terms related to the structure and processing of inorganic, polymeric, and inorganic-organic hybrid materials from precursors, through gels to solid products. It is divided into four sections – precursors, gels, solids, and processes – and the terms have been restricted to those most commonly encountered. For the sake of completeness and where they are already satisfactorily defined for the scope of this document, terms from other IUPAC publications have been used. Otherwise, the terms and their definitions have been assembled in consultation with experts in the relevant fields. The definitions are intended to assist the reader who is unfamiliar with sol-gel processing, ceramization, and related technologies and materials, and to serve as a guide to the use of standard terminology by those researching in these areas

Cutaneous reactivity to grass pollen and house dust mite in prick test with two types of allergen extracts

Upotrebljivost domaćih nestandardiziranih pripravaka za prick-test htjela se provjeriti usporedbom s internacionalno priznatim standardiziranim pripravcima aktivnosti 100 000 BU. Komparativna su upotrijebljeni alergeni grinje Dermatophagoides pteronyssinus kod 107 ispitanika te pojedinačni poleni trava, i to: Dactylis glomerata, Poa pratensis, Phleum pratense i Secale cereale kod 39 ispitanika. Klinička značajnost kožne reakcije određena je usporedbom veličine urtike izazvane alergenom s onom izazvanom negativnom kontrolom (puferom) te pozitivnom kontrolom (otopinom histamina koncentracije 1 mg/ml). Utvrđeno je da domaći preparat grinje od 3000 PNU/ml ne daje podjednake kožne reakcije kao standardizirani pripravak te ne daje klinički vjerodostojne rezultate, dok su pripravci polena trave, s izuzetkom trave Poa pratensis, vrlo dobri i usporedivi sa standardnim pripravcima, te se mogu pouzdano upotrebljavati u praksi. Na temelju rezultata ovog istraživanja zaključuje se da treba postrožiti kriterije za ocjenu klinički značajno pozitivne kožne reakcije na alergenske pripravke.The reliability of prick testing with allergen preparations produced in Yugoslavia was assessed by comparison to the internationally accepted ones (Pharmacia Diagnostica) of 100 000 BU activity. The following allergens were used: the mite Dermatophagoides pteronyssinus in 107 subjects, and grass pollens: Dactylis glomerata, Poa pratensis, Pbleum pratense and Secale cereale in 39 subjects. The clinical significance of the response was assessed in relation to the skin reaction to the negative control solution and positive histamine control (in concentration of 1 mg/ml). The results indicate that the allergen extract of Dermatophagoides pteronyssinus (3000 PNU/ml) produced in Yugoslavia does not provoke skin reactions comparable to those provoked by the standardized extract of 100 000 BU in contrast to the grass pollen allergens, with the exception of Poa pratensis, which evokes equivalent skin reactions. Thus grass pollen allergens are reliable extracts and can be applied with good confidence in routine work. The need to set more rigorous criteria for assessing skin prick reactions, when domestic, unstandardized products are used, emerged as a result of this study

Implanto-Prosthetic Rehabilitation of the Mandible by Means of Two Implants

Edentulousness is a considerable problem in Croatia. So far prevention has not become the most important part of the dental profession. On the other hand,poor medical knowledge, reduced rights concerning health insurance costs as well as an increasing number of impoverished people in Croatia has resulted in postponed prosthetic rehabilitation. For the above mentioned reasons the Croatian people suffer from premature loss of their teeth. Also lower jaw atrophy occurs, which makes prosthetic rehabilitation even more difficult to achieve. In spite of some disadvantages, the double-implant borne prosthetic suprastructure has proved to be a simple and good solution to the patient\u27s problem, mainly because it is cost-effective. This particularly applies to Croatia patients. Over the last five years we have placed double -implants in 26 patients, in the anterior region of the mandible. The implants were placed in the region of the lower canine or slightly more mesially. Severe atrophy was determined in 13 patients (50%) which impeded their complete denture wearing even before the implant placement started. However, we made up for the loss in two patients by placing the implants again. This time we placed them slightly more mesially. We made one borne implant complete denture for one patient because the examination revealed severe atrophy in one segment of his mandible. In addition since the osseointegration prognosis for this patient was questionable we decided against any additional surgical treatment. Since the belts of the attached gingiva in our patients were wide enough and the diameters of the implants were not very long, no vestibuloplasty was necessary. We installed ITI, IMZ, ASTRA and Ankylos implants. All systems proved to be equally functional

Implanto-Prosthetic Rehabilitation of the Mandible by Means of Two Implants

Edentulousness is a considerable problem in Croatia. So far prevention has not become the most important part of the dental profession. On the other hand,poor medical knowledge, reduced rights concerning health insurance costs as well as an increasing number of impoverished people in Croatia has resulted in postponed prosthetic rehabilitation. For the above mentioned reasons the Croatian people suffer from premature loss of their teeth. Also lower jaw atrophy occurs, which makes prosthetic rehabilitation even more difficult to achieve. In spite of some disadvantages, the double-implant borne prosthetic suprastructure has proved to be a simple and good solution to the patient\u27s problem, mainly because it is cost-effective. This particularly applies to Croatia patients. Over the last five years we have placed double -implants in 26 patients, in the anterior region of the mandible. The implants were placed in the region of the lower canine or slightly more mesially. Severe atrophy was determined in 13 patients (50%) which impeded their complete denture wearing even before the implant placement started. However, we made up for the loss in two patients by placing the implants again. This time we placed them slightly more mesially. We made one borne implant complete denture for one patient because the examination revealed severe atrophy in one segment of his mandible. In addition since the osseointegration prognosis for this patient was questionable we decided against any additional surgical treatment. Since the belts of the attached gingiva in our patients were wide enough and the diameters of the implants were not very long, no vestibuloplasty was necessary. We installed ITI, IMZ, ASTRA and Ankylos implants. All systems proved to be equally functional