Influence of pH Galvanic Baths on the Nickel Deposits

The influence of pH on cathodic and anodic current efficiency, surface quality and morphology of nickel deposit in the electrolyte solutions of the Watts bath type was investigated. Cathodic current efficiency of nickel deposit is maximum for electrolytic bath whose pH value is about 4 and decreases for an electrolytic bath with a higher pH. The deposited thickness is a significant parameter because the thickness determining may establish if the deposition corresponds to the destination application deposition or not; and the measurements were made by non-destructive physical methods. The properties of nickel deposits, brightness and hardness are influenced by the pH of the bath electrolyte. The surface morphology of nickel deposit was analyzed by scanning electronic microscopy (SEM). The results showed that the structure of nickel deposits is influenced by pH of the bath. The pH increasing causes structural changes on the deposits in fine to coarse, while the electrodeposited nickel at pH 6.21 has a compact morphology with many cracks

Influence of Technological Parameters on the Evolution of Nickel Films Deposited by Electrolysis

The influence of technological parameters on the structure of nickel layers electrodeposited on a copper substrate in a Watts bath has been studied. The complex influence of current densities, temperature and pH values on the formation of the deposition layers are compared. The surface morphology of the nickel films was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). X-ray diffraction (XRD) was used to investigate the crystallinity of the prepared samples. The increase in the current density leads to fine crystallized films, while layers obtained at even higher current density have dendritic structures. The temperature increasing results in a structure change from fine to coarse

Obtaining and Utilizing Cellulose Fibers with in-Situ Loading as an Additive for Printing Paper

The goal of this study was to analyze the effects of cellulose fibers loading by precipitation in-situ of calcium carbonate over the properties of printing paper obtained from mixtures of the softwood and hardwood fibers. The effects of fibers with in-situ loading were analyzed comparatively with conventional paper loading respectively, by adding precipitated calcium carbonate into fiber stock. The effectiveness of the methods was evaluated by various analyses and investigations: calcium carbonate content, Scanning electron microscope (SEM) images, X-ray diffraction, optical and mechanical properties of the paper sheets. The evaluation of the effects on paper properties led to the conclusion that, at the same filler content, the in-situ loading method gives higher opacity and brightness than conventional methods. The utilization of cellulose fibers with in-situ loading as additive, shown as a modification of the ratio between fibers with in-situ loading and fibers without loading, regardless of whether they are softwood or hardwood fibers, allowed us to optimize printing paper properties, especially regarding the relationship between optical and strength properties

Knowledge Level on Infection Control among Romanian Undergraduate and Postgraduate Dental Students

Background and Objectives: Infection control practices in dentistry should be continuously evaluated. The aim of the present study was to assess the knowledge of dental students from Iași, Romania about infection control in the dental office. Materials and Methods: Dental students and resident dentists attending the “Grigore T. Popa” University of Medicine and Pharmacy in Iași were randomly selected in accordance with ethical guidelines, and a cross-sectional, questionnaire-based online study was conducted. The questionnaire included 21 items about infection control in dentistry. A descriptive statistical analysis was performed, and the chi-square test was used for data comparison, with a cutoff point of 0.05 for statistical significance. Results: The study sample included 150 subjects (75.3% female and 24.7% male) with a mean age of 25.71 ± 4.54 years. Mode of infection transmission was known by 74% of the subjects, and 76% were aware of standard precautions, with significant differences by the year of study (p = 0.012, r = 0.002). A percentage of 20% of subjects knew the means of transmission of the hepatitis B virus (HBV) (p = 0.032, r = 0.166). Most of the subjects were not vaccinated against HBV (p = 0.002, r = −0.274). Notions of high-level disinfection and sterilization were confused by 19.5% of the subjects. Only 22% of the subjects knew the correct processing of handpieces (p = 0.048, r = −0.071). The sources of information were diverse for 64.66% of the respondents, while 31.33% of them used courses and seminars only. Conclusions: There is a need for improvement in the level of knowledge on infection control for both dental students and residents

ORAL HEALTH-RELATED QUALITY OF LIFE AND CARIES EXPERIENCE AMONG YOUNG ADULTS

Young adults represent the age group with the highest ability to understand the need of maintaining good oral health and the highest chance to adopt correct oral hygiene behaviors. Great attention should also be paid to risk factors for oral conditions, especially sugary aliments intake, which creates a suitable environment for developing dental caries. Young adults should be aware about the importance of reducing the frequency of consumption of these aliments. Smoking has negative effects on both general and oral health. It creates and maintains conditions favorable for developing oral diseases. Quitting smoking should be seen as an important recommendation, to ensure good oral health and quality of life. The impairment of oral health is strongly connected with quality of life. To quantify the impact of oral health on quality of life, the OHIP-14 questionnaire is widely used. Regarding the severity of the impact oral conditions have on quality of life, the most accused domains by subjects are physical pain, psychological discomfort and psychological disability. Oral health is directly influenced by caries experience, OHRQoL being lower as the caries prevalence is higher. To quantify the prevalence of dental caries, the DMFT index is one of the most used indicators. It evaluates, on one hand, the caries experience, and on the other hand, the exact number of decayed, missing and filled teeth. OHRQoL is a mandatory toll that helps understand the impact of oral conditions on general health. Both the OHIP-14 questionnaire and the DMFT index, are a real help to quantify the connection between oral conditions, most common of them being dental caries, and their negative effects on general health and on quality of life

How does the structure of pullulan alginate composites change in the biological environment?

Alginate and pullulan are two polysaccharides with numerous applications in the field of biomedical sciences such as wound dressing, soft and hard tissue regeneration. These materials come into contact with the human body for various time intervals, depending on their intended use. In this study, alginate-pullulan composites were synthesized and assayed in vitro as follows: bioactivity, biodegradability, swelling ratio, and biocompatibility. After 2 weeks of immersion in simulated body fluid, calcium oxalate appeared on the surface of the composites near the apatite layer. The in vitro biocompatibility assay using human fibroblastic and osteoblastic cell lines showed encouraging results; therefore, the polymeric composite proved to be non-toxic and safe for further in vivo testing. This was also reinforced by cell proliferation, necrosis, apoptosis, and surface adhesion tests. The most promising results were obtained with the composite that was prepared using an alginate: pullulan weight ratio of 1:0.75. Applying this ratio caused cellular growth on the surface of the biomaterial. The applicability of composites was limited by the appearance of calcium oxalate. However, this phenomenon could be prevented by introducing an inorganic component into the alginate-pullulan composites, such as bioactive glass.[GRAPHICS]