Custom-Made Zirconium Dioxide Implants for Craniofacial Bone Reconstruction

Reconstruction of the facial skeleton is challenging for surgeons because of difficulties in proper shape restoration and maintenance of the proper long-term effect. ZrO2 implant application can be a solution with many advantages (e.g., osseointegration, stability, and radio-opaqueness) and lacks the disadvantages of other biomaterials (e.g., metalosis, radiotransparency, and no osseointegration) or autologous bone (e.g., morbidity, resorption, and low accuracy). We aimed to evaluate the possibility of using ZrO2 implants as a new application of this material for craniofacial bone defect reconstruction. First, osteoblast (skeleton-related cell) cytotoxicity and genotoxicity were determined in vitro by comparing ZrO2 implants and alumina particle air-abraded ZrO2 implants to the following: 1. a titanium alloy (standard material); 2. ultrahigh-molecular-weight polyethylene (a modern material used in orbital surgery); 3. a negative control (minimally cytotoxic or genotoxic agent action); 4. a positive control (maximally cytotoxic or genotoxic agent action). Next, 14 custom in vivo clinical ZrO2 implants were manufactured for post-traumatologic periorbital region reconstruction. The soft tissue position improvement in photogrammetry was recorded, and clinical follow-up was conducted at least 6 years postoperatively. All the investigated materials revealed no cytotoxicity. Alumina particle air-abraded ZrO2 implants showed genotoxicity compared to those without subjection to air abrasion ZrO2, which were not genotoxic. The 6-month and 6- to 8-year clinical results were aesthetic and stable. Skeleton reconstructions using osseointegrated, radio-opaque, personalized implants comprising ZrO2 material are the next option for craniofacial surgery

Particle size distribution of fly ash from co-incineration of bituminous coal with municipal solid waste

One of the source of air pollutants is emission from local coal-fired boiler-houses and domestic heating boilers. The consequence of incineration of municipal waste is the introduction of additional pollutants into the atmosphere, including fly ash. The aim of this work was to evaluate the particle size distribution of fly ash emitted by coal combustion and co-incineration of coal with municipal waste in a domestic 18 kW central heating boiler equipped with an automatic fuel feeder. Mixtures of bituminous coal with different types of solid waste (5, 10 and 15% of mass fraction) were used. Solid waste types consisted of: printed, colored PE caps, fragmented cable trunking, fragmented car gaskets and shredded tires from trucks. During the incineration of a given mixture of municipal waste with bituminous coal, the velocity of exhaust gas was specified, the concentration and mass flow of fly ash were determined together with the physico-chemical parameters of the exhaust gas, the samples of emitted fly ash were taken as the test material. Particle size analysis of fly ash was performed using laser particle sizer Fritch Analysette 22. The PM10 share from all fly ashes from incineration of mixtures was about 100%. Differences were noted between PM2.5 and PM1

Dust emission from wet, low-emission coke quenching process

Coke plants, which produce various types of coke (metallurgical, foundry or heating), at temperatures between 600 and 1200°C, with limited access to oxygen, are major emitters of particulates and gaseous pollutants to air, water and soils. Primarily, the process of wet quenching should be mentioned, as one of the most cumbersome. Atmospheric pollutants include particulates, tar substances, organic pollutants including B(a)P and many others. Pollutants are also formed from the decomposition of water used to quench coke (CO, phenol, HCN, H2S, NH3, cresol) and decomposition of hot coke in the first phase of quenching (CO, H2S, SO2) [1]. The development of the coke oven technology has resulted in the changes made to different types of technological installations, such as the use of baffles in quench towers, the removal of nitrogen oxides by selective NOx reduction, and the introduction of fabric filters for particulates removal. The BAT conclusions for coke plants [2] provide a methodology for the measurement of particulate emission from a wet, low-emission technology using Mohrhauer probes. The conclusions define the emission level for wet quenching process as 25 g/Mgcoke. The conducted research was aimed at verification of the presented method. For two of three quench towers (A and C) the requirements included in the BAT conclusions are not met and emissions amount to 87.34 and 61.35 g/Mgcoke respectively. The lowest particulates emission was recorded on the quench tower B and amounted to 22.5 g/Mgcoke, therefore not exceeding the requirements

Innowacyjne procesy membranowe w ochronie środowiska : przegląd

The partial solution for the growing contamination of the environment is the implementation of new technologies. The most of the currently operated systems for surface and groundwaters treatment as well as for wastewater treatment characterize with complex technological arrangements based on a number of unit operations. In water-wastewater management membrane processes are more often applied, especially those in which the difference of pressure at both membrane sites is used as a driving force. As an example of such application is the use of nanofiltration for groundwaters treatment at Water Treatment Plant Zawada near Dębica or the treatment of municipal landfill leachate and industrial wastewater at Eko Dolina Waste Utilization Plant in Łężyce near Gdynia (reverse osmosis unit capacity of 120 m3/d). Municipal wastewater treatment based on membrane technologies has already been implemented at domestic wastewater treatment plant. It is especially profitable, when the load of contaminant present in a wastewater varies within a year. In the case of membrane systems use, this issue can be neglected. As an example of membrane based system may serve WWTP in Rowy n/Ustka started up in 2013 and modernized in 2017. The latest trends and developments of selected suppliers of membrane systems are also presented.Częściowym rozwiązaniem wzrastającego zanieczyszczenia środowiska wodnego jest wdrażanie nowych technologii. Większość współczesnych dużych systemów uzdatniania wód powierzchniowych i podziemnych oraz oczyszczania ścieków charakteryzuje się bardzo złożonymi układami technologicznymi zakładającymi sekwencję wielu procesów. W gospodarce wodno-ściekowej w coraz to większym zakresie wykorzystywane są procesy membranowe, przede wszystkim te, których siłą napędową jest różnica ciśnień po obu stronach membrany. Przykładem jest między innymi zastosowanie nanofiltracji do uzdatniania wód głębinowych w SUW Zawada k. Dębicy oraz oczyszczanie odcieków z wysypisk odpadów stałych i ścieków przemysłowych technologią membranową w zakładzie Unieszkodliwiania Odpadów Eko Dolina w Łężycach k/Gdyni (wydajność RO 120 m3/dobę). Oczyszczanie ścieków komunalnych w oparciu o technologie membranowe zostało już wdrożone w krajowych oczyszczalniach ścieków. Jest to szczególnie opłacalne, gdy ładunek zanieczyszczeń obecnych w ściekach waha się w ciągu roku. W przypadku zastosowania systemów membranowych, problem ten można pominąć. Przykładem wdrożenia systemu membranowego może być WWTP w Rowach k/Ustki, którą zbudowano w 2013 r. i zmodernizowano w 2017 r. Ponadto przedstawiono najnowsze rozwiązania oraz trendy rozwoju w niektórych firmach realizujących technologie membranowe u klientów

Dust emission from wet, low-emission coke quenching process

Coke plants, which produce various types of coke (metallurgical, foundry or heating), at temperatures between 600 and 1200°C, with limited access to oxygen, are major emitters of particulates and gaseous pollutants to air, water and soils. Primarily, the process of wet quenching should be mentioned, as one of the most cumbersome. Atmospheric pollutants include particulates, tar substances, organic pollutants including B(a)P and many others. Pollutants are also formed from the decomposition of water used to quench coke (CO, phenol, HCN, H2S, NH3, cresol) and decomposition of hot coke in the first phase of quenching (CO, H2S, SO2) [1]. The development of the coke oven technology has resulted in the changes made to different types of technological installations, such as the use of baffles in quench towers, the removal of nitrogen oxides by selective NOx reduction, and the introduction of fabric filters for particulates removal. The BAT conclusions for coke plants [2] provide a methodology for the measurement of particulate emission from a wet, low-emission technology using Mohrhauer probes. The conclusions define the emission level for wet quenching process as 25 g/Mgcoke. The conducted research was aimed at verification of the presented method. For two of three quench towers (A and C) the requirements included in the BAT conclusions are not met and emissions amount to 87.34 and 61.35 g/Mgcoke respectively. The lowest particulates emission was recorded on the quench tower B and amounted to 22.5 g/Mgcoke, therefore not exceeding the requirements

Challenges of Co–Cr Alloy Additive Manufacturing Methods in Dentistry—The Current State of Knowledge (Systematic Review)

Complex dental components which are individually tailored to the patient can be obtained due to new additive manufacturing technology. This paper reviews the metallic powders used in dental applications, the fabrication process (build orientation, process parameters) and post-processing processes (stress relieving, surface finishing). A review of the literature was performed using PubMed, ScienceDirect, Mendeley and Google Scholar. Over eighty articles were selected based on relevance to this review. This paper attempts to include the latest research from 2010 until 2020, however, older manuscripts (10 articles) were also selected. Over 1200 records were identified through the search; these were screened for title and/or summary. Over eighty articles were selected based on relevance to this review. In order to obtain a product which can be used in clinical applications, the appropriate manufacturing parameters should be selected. A discussion was made on optimal selective laser melting (SLM) parameters in dentistry. In addition, this paper includes a critical review of applied thermal treatment methods for Co–Cr alloys used in dentistry

Mechanical Evaluation of Titanium Plates for Osteoesynthesis High Neck Condylar Fracture of Mandible

Background: In the literature no information about plates for the high-neck mandibular condylar osteosynthesis could be found despite that 30 plate designs have been published. The main course consider the basal condylar or diacapitular fractures. The aim of the study was to test mechanically all available designs (only 4 of 30 was proper) on polyurethane mandibles using an individually designed clamping system. Methods: Forces required for a 1 mm displacement of fixed fracture fragments and incidents of screw loosening were recorded. Results: It has occured that dedicated plates for fixation are much weaker than set of two straight plates (p < 0.0001). General observation is the bigger plate and more screws, the better rigid stable osteosynthesis of mandibular condyle, however, there are limitations in plates design for high-neck fractures resulted in restricted operation field. Conclusion: Double straight plates occured to be the best mechanical fixation for high-neck fractures of the mandibular condyle. Maybe other existing plates could be used but only after prebending or that fracture required novel dedicated plates design

Influence of High Pressure on the Pedal-like Motion and Photoreactivity in the Cocrystals of 1,2-Di(4-pyridyl)ethylene with <i>trans</i>-2-(4-Fluorophenyl)vinylboronic Acid

The photochemical properties of 1,2-di(4-pyridyl)ethylene (bpe) and trans-2-(4-fluorophenyl)vinylboronic acid (fpvb) cocrystals have been investigated using complementary techniques: single-crystal X-ray diffraction, including high-pressure experiments, solid-state and solution nuclear magnetic resonance, and density functional theory calculations. The photochemistry of bpe and fpvb cocrystals strongly depends on the arrangement of bpe molecules. The [2 + 2] photodimerization of bpe occurs in the case of the bpe/fpvb ratio of 1:1, while a ratio of 1:2 is observed in photoinert objects. In the photoreactive cocrystals, a pedal-like motion occurs in bpe molecules. This phenomenon strongly affects photoreactivity because it changes the mutual geometry of two reactant molecules. The intermolecular geometry and the kinetics of the pedal-like motion, and thereby, the kinetics of the [2 + 2] photodimerization of bpe, have been modified by means of high pressure