Effects of Wood Particles from Deadwood on the Properties and Formaldehyde Emission of Particleboards

The volume of deadwood increases annually because of changes in environmental, climatic, and hydrological conditions. On the other hand, during the last decade, manufacturers of wood-based boards have been facing an acute problem of a shortage of conventional raw materials. The purpose of this study was to evaluate the possibility of using wood particles from deadwood in the production of particleboards. Three-layer particleboards with different content of deadwood particles (0%, 25%, 50%, 75%, 100%) were produced. Conventional urea-formaldehyde (UF) resin was used for gluing the particles. The physical and mechanical properties of the boards, as well as the formaldehyde content in the boards, were determined. In addition, the effect of adding melamine-urea-formaldehyde (MUF) resin to UF adhesive on the properties of the boards was investigated. Replacing conventional sound wood particles with deadwood particles leads to deterioration of the physical and mechanical properties of the boards. The boards from deadwood particles absorb more water and swell more. The bending strength (MOR), modulus of elasticity in bending (MOE), and internal bonding (IB) values for boards with 100% deadwood particles are reduced by 26.5%, 23.1%, and 72.4%, respectively, compared to reference boards from sound wood particles. Despite this, a significant advantage is that boards made from 100% deadwood particles are characterized by 34.5% less formaldehyde content than reference boards made from conventional sound wood. Moreover, adding 3% of MUF resin to UF adhesive increases MOR, MOE, and IB by 44.1%, 43.3%, and 294.4%, respectively.O

Water jet technology used in medicine

Tehnologija abrazivnog vodenog mlaza od nedavno se koristi uglavnom u industrijskim područjima. Ova tehnologija pruža nekoliko prednosti u usporedbi s konvencionalnim metodama. Trenutačno, to je uporaba u medicini. U radu se razmatra mogućnost korištenja tehnologije mlaza vode u medicini. U radu su opisane prednosti i uporaba u ortopedskoj kirurgiji, plastičnoj kirurgiji, neurokirurgiji, dermatologiji, urologiji te u oralnoj kirurgiji.Abrasive water jet technology has been recently used mainly in industrial areas. This technology provides several advantages in comparison with conventional methods. At present, it is used in medicine. This paper discusses the possibility of using water jet technology in medicine. The paper describes the benefits and usage in orthopedic surgery, plastic surgery, neurosurgery, dermatology, urology, and in dental surgery

Preliminary results of experimental cutting of porcine bones by abrasive waterjet

Rezanje abrazivnim mlazom vode danas se primjenjuje za širok spektar materijala, stoga se ova tehnologija implementira u različitim granama tehnike. Prioritetna korist ove tehnologije je odsutnost toplinskih utjecaja pri rezanju radnog komada. To je razlog zašto se ova tehnologija počinje primjenjivati ne samo u industriji, nego i u medicini. No, mogućnosti daljnje primjene rezanja abrazivnim vodenim mlazom još uvijek nisu završene. Jedno od područja gdje je primjena te tehnologije još uvijek na početku, jest ortopedska kirurgija. U cilju implementiranja ove tehnike rezanja, provedeno je eksperimentalno rezanje svinjske kosti "ex vivo". Dobivene površine su mjerene kontaktnim profilometrom, kako bi se odredile vrijednosti parametara hrapavosti Ra, Rq i Rz. Ovaj eksperiment predstavlja prvi korak autora u mogućoj primjeni tehnike rezanja vodenim abrazivnim mlazom u ortopedskoj kirurgiji.The abrasive waterjet (AWJ) cutting is currently applied to a wide range of materials; thus, this technology is implemented in different kinds of techniques. A priority benefit of this technology includes the absence of thermal effect on the workpiece. This is the reason why the AWJ is being extensively applied not only in many types of industry, but also in medicine. Possibilities of its further use however have not yet finished. One of the areas in which this technology is in the beginning is orthopaedic surgery. In order to implement this cutting technique, the experimental cutting of porcine bones "ex vivo" were performed. The surfaces created by waterjet were measured by a contact profilometer in order to quantify the surface profile parameters Ra, Rq and Rz. These experiments represent the first step of the authors in implementing the abrasive waterjet cutting technology into the orthopaedic surgery

Translation initiation from the ribosomal A site or the P site, dependent on the conformation of RNA pseudoknot I in dicistrovirus RNAs

available in PMC 2010 July 31.Translation initiation of the second ORF of insect dicistrovirus RNA depends on an internal ribosomal entry site (IRES) in its intergenic region (IGR) and is exceptional in using a codon other than AUG and in not using the canonical initiator methionine tRNA. Studies in vitro suggest that pseudoknot I (PKI) immediately preceding the initiation codon occupies the ribosomal P site and that an elongator tRNA initiates translation from the ribosomal A site. Using dicistronic reporters carrying mutations in the initiation codon of the second ORF and mutant elongator or initiator tRNAs capable of reading these codons, we provide direct evidence for initiation from the A site in mammalian cells and, under certain conditions, also from the P site. Initiation from the A but not the P site requires PKI. Thus, PKI structure may be dynamic, and optimal IGR IRES-mediated translation of dicistroviral RNAs may require trans-acting factors to stabilize PKI.National Institutes of Health (U.S.) (grant GM17151)Japan. Ministry of Education, Culture, Sports, Science and Technology (Grants-In-Aid for Scientific Research on Priority Areas

Thermal manifestations and nanoindentation of bone cements for orthopaedic surgery

Improving of bone cements properties is possible by research of variables influencing exothermal behaviour and mechanical properties. Paper deals with exothermal behaviour experimental evaluation of bone cements used for medical purposes. Specimens were prepared by a conventional manual mixing technique. The work addresses primary risk factor associated with application of bone cement to femoral canal. Different size samples of bone cement has been created with diameter d = 2; 5;12,5 mm fixed in dentacryl. As an experimental material, Palacos R+G high viscosity, radiopaque bone cement containing Gentamicin and Radiopaque bone cement Antibiotic Simplex with Tobramycin, was used. Thermal effect during exothermic polymerisation was measured with period I minute. Evaluated factors were mass and thickness of bone cement. Significant influence of bone cement mass on temperature has been found

Case report of a woman with monoclonal gammapathy and papillary thyroid carcinoma, diagnosed because of detection of CHEK2 (I157T) mutation in genetic examinations

The CHEK2 gene encodes the CHK2 protein, which is kinase involved in DNA repair processes. By activating a lot of cell substrates, it can regulate the cell cycle, demonstrates suppressive effects, and participates in the senescence and apoptosis processes. Mutations in the CHEK2 gene are associated with increased risk of numerous cancers. The case described herein is that of a woman with a missense mutation that results in the substitution of isoleucine for threonine at position 157. This variant of the mutation doubles the risk of papillary thyroid carcinoma two times and causes up to 9% of these cancer. It is also associated with a two-fold increased risk of cancers of the kidney (10%), colon (10%), and ovary (10% - G1), a 1.6-fold increased risk of prostate cancer (8% of all of them and 12% of familiar ones), and a 1.5-fold increased risk of breast cancer (7%). The screening procedures were initiated in a carrier who revealed papillary thyroid carcinoma. Genetic screening of the family diagnosed her daughter as the carrier of this mutation. Until now no active cancer disease has been recognized in the daughter. On the example of the presented case we discuss indications for screening in cases of positive family history. The group especially predisposed seem to be patients with at least two coexisting carcinomas. Having diagnosed the mutation, it is necessary to do genetic screening of family members. Continuous oncological observation of the carriers of CHEK 2 mutation is essential. (Pol J Endocrinol 2010; 61 (5): 502-506)Ludzki gen CHEK2 koduje białko CHK2, będące kinazą efektorową zaangażowaną w naprawę DNA. Aktywując wiele substratów komórkowych, bierze udział w regulacji cyklu komórkowego, wykazuje działanie supresyjnie, wpływa również na proces apoptozy i starzenia się komórek. Mutacje genu CHEK2 są związane z ryzykiem licznych nowotworów. Opisywany przypadek chorej dotyczy mutacji typu missens, gdzie dochodzi do zamiany izoleucyny na treoninę w pozycji 157. Mutacja ta zwiększa 2-krotnie ryzyko raka brodawkowatego tarczycy. Predysponuje do występowania 2-krotnie częściej raka nerki (10%), jelita grubego (10%), jajnika (10% - G1), 1,6-krotnie częściej raka prostaty (8% wszystkich i 12%występujących rodzinnie) oraz 1,5-krotnie częściej raka piersi (7%). Na podstawie diagnostyki w kierunku predysponowanych nowotworów wykryto u chorej raka brodawkowatego tarczycy. Skrining genetyczny rodziny pozwolił na wykazanie nosicielstwa tej mutacji u córki pacjentki - dotychczas nie stwierdzono u niej czynnej choroby nowotworowej. Opisywany przypadek chorej wskazuje na celowość przeprowadzania badań genetycznych w przypadku dodatniego wywiadu rodzinnego w kierunku chorób nowotworowych. Szczególnie predysponowaną grupą wydają się być chorzy z co najmniej dwoma współistniejącymi nowotworami. Wykazanie mutacji nakłada obowiązek badań genetycznych u pozostałych członków rodziny, jak również bezterminowy nadzór onkologiczny u nosicieli mutacji. (Endokrynol Pol 2010; 61 (5): 502-506

Thermal manifestations and nanoindentation of bone cements for orthopaedic surgery

Improving of bone cements properties is possible by research of variables influencing exothermal behaviour and mechanical properties. Paper deals with exothermal behaviour experimental evaluation of bone cements used for medical purposes. Specimens were prepared by a conventional manual mixing technique. The work addresses primary risk factor associated with application of bone cement to femoral canal. Different size samples of bone cement has been created with diameter d = 2; 5;12,5 mm fixed in dentacryl. As an experimental material, Palacos R+G high viscosity, radiopaque bone cement containing Gentamicin and Radiopaque bone cement Antibiotic Simplex with Tobramycin, was used. Thermal effect during exothermic polymerisation was measured with period I minute. Evaluated factors were mass and thickness of bone cement. Significant influence of bone cement mass on temperature has been found

Spectral analysis of metallic surfaces topography generated by abrasive waterjet

Osnovna studija topografije površina nastalih rezanjem abrazivnim vodenim mlazom izrađena je uz pomoć spektralne analize tih površina. Početni podatci su prikupljeni primjenom optičkog profilometra MicroProf FRT u obliku 2D karata visina površina. U radu se predstavljeni osnovni pojmovi spektralne analize primijenjeni na topografiju površine. Razmotrena su ograničenja postupka mjerenja. Raspravljena su iskrivljavanja površinske gustoće spektra snage. Procjena površinske gustoće spektra snage je obavljena pomoću metode periodograma u kombinaciji s Welchovom metodom. Uspoređene su površine dobivene rezanjem pomoću abrazivnog vodenog mlaza uz različite vrijednosti tehnoloških parametara rezanja. Pokazano je da se spektralnom analizom navedenih površina nude nove mogućnosti karakterizacije njihove topografije.Abasic study of a surface topography generated by an abrasive waterjet cutting is performed by means of the spectral analysis of these surfaces. The initial data were acquired by using an optical profilometer MicroProf FRTin the form of 2D maps of the surfaces\u27 heights. The basic notions of the spectral analysis applied to the surface topography are presented. Limitations of the measurement procedure are considered. Distortions of the areal power spectral density are discussed. An estimation of the areal power spectral density is carried out using a periodogram method combined with the Welch´s method. A comparison of surfaces prepared by the abrasive waterjet cutting with different values of the cutting technological parameters is performed. It has been demonstrated that the areal spectral analysis of the aforementioned surfaces offers new possibilities of their topography characterization