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BACKGROUND: The frequency of primary joint replacement surgery continues to increase worldwide. While largely considered biologically inert entities, an increasing body of evidence continues to validate a not insignificant incidence of allergic reactions to such implants. Little previous work has explored genuinely immune-mediated reactivity in this context. In the absence of a contemporary published summary on the topic, this paper explored the current state of understanding of cobalt/chromium allergy and proposes a patient management algorithm whereby such immune reactions are clinically suggested.
METHODS: A structured, systematic literature review was performed by following PRISMA search principles to provide an updated review of this area.
RESULTS: Thirty-six topic-related articles were identified, the majority reflecting lower tiers of scientific evidence with a lack of homogeneous quantitative data to facilitate valid cohort comparisons. Largely, the available literature represented small case series\' or expert opinions.
CONCLUSIONS: Despite increasing clinical awareness and acknowledgement of true allergy to joint replacement components, this review highlighted that the evidence base underpinning the diagnosis and management of such patients is limited. Both patient-reported metal allergy or skin patch testing are grossly unreliable methods and show almost no correlation with true immune reactivity. Recent studies suggested a potential role for patient-specific in vitro cellular activation testing and/or targeted genetic testing when cobalt/chromium allergy is clinically suspected. However, while likely representing the contemporary \"best available\" approaches both can be costly undertakings, are not yet universally available, and still require broader validation in non-research settings before wider uptake can be championed.

Various conventional treatments including endocrine therapy, radiotherapy, surgery, and chemotherapy have been used for several decades to treat breast cancer; however, these therapies exhibit various life-threatening and debilitating adverse effects in patients. Additionally, combination therapies are required for prompt action as well as to prevent drug resistance toward standard breast cancer medications. Ferrite nanoparticles (NPs) are increasingly gaining momentum for their application in the diagnosis and treatment of breast cancer. Spinel ferrites are particularly used against breast cancer and have shown in vitro and in vivo better efficacy as compared to conventional cancer therapies. Magnetic resonance imaging contrast agents, magnetic particle imaging tracers, cell separation, and immune assays are some aspects related to the diagnosis of breast cancer against which different ferrite NPs have been successfully evaluated. Moreover, citrate-coated nickel ferrite, Mg/Zn ferrites, poly amidoamine dendrimers, cobalt ferrites, graphene oxide cobalt ferrites, doxorubicin functionalized cobalt ferrites, chitosan-coated zinc ferrites, PEG-coated cobalt ferrite, and copper ferrite NPs have demonstrated antiproliferative action against different breast cancer cells. Oxaliplatin-loaded polydopamine/BSA-copper ferrites, functionalized cobalt and zinc ferrites of curcumin, oxaliplatin-copper ferrite NPs, tamoxifen/diosgenin encapsulated ZnO/Mn ferrites, and fabricated core-shell fibers of doxorubicin have been developed to increase the bioavailability and anti-proliferative effect and decrease the toxicity of anticancer drugs. These ferrite NPs showed an anticancer effect at different doses in the presence or absence of an external magnetic field. The present review covers the in-depth investigations of ferrite NPs for the diagnosis and management of breast cancer.

Only few studies on contact allergy in African countries have been published. The aim of the present study was to provide an overview of the most common contact allergens identified by the use of patch tests in African countries based on a review of the existing literature. A total of twenty-four publications from eight African countries were initially identified by search in PubMed. The abstracts and method sections were screened, and 15 studies in which patch tests were actually used to identify the allergen causing the allergic contact dermatitis (ACD) were finally selected. Nickel, cobalt, chromium, fragrance mix and p-tert-butylphenol-formaldehyde resin were the dominating contact allergens responsible for 40%-90% of the positive patch test reactions. This study indicates that a targeted effort directed towards prevention, avoidance and regulation of reliably identified contact allergens could reduce the disease burden of ACD considerable in some African countries.

This study aimed to review systematically the literature about the antimicrobial action of evaluated cleansers on the Co-Cr alloy of RPD. The search was conducted in MEDLINE/PubMed, Scopus, Lilacs, Embase and Science Direct May, 2022. The review was performed based on PRISMA guidelines and recorded in Open Science Framework. Independent reviewers performed the search, selection, extraction, and analysis of the data. The risk of bias of the in vitro and clinical trials studies was analyzed by the Joanna Briggs Institute tool. A total of 187 articles were found and 9 were included. The cleansers that showed antimicrobial action were 2% and 5.25% sodium hypochlorite, 0.12% chlorhexidine and NitrAdine effervescent tablet. Polident, Corega Tabs effervescent tablets and 5 mg/mL chitosan solution showed intermediate effects. Propolis and green tea toothpaste were not effective. Three articles presented a high risk of bias and 6, low risk. The cleansers that showed the highest antimicrobial efficacy on Co-Cr alloy were 0.12% chlorhexidine digluconate and NitrAdine and can be safely used on RPD framework.

The increasing applications of silver nanomaterials (nano-Ag) and their inevitable release posed great potential risks to aquatic organisms and ecosystems. Considerable attention has been attracted on their behaviors and transformations, which were critically important for their subsequent biological toxicities and ecological effects. Therefore, the summary of the recent efforts on the environmental behavior of nano-Ag would be beneficial for understanding the environmental fate and accurate risk assessment. This review summarized the studies on various physical, chemical and biological transformations of nano-Ag, meanwhile, the influencing factors (including the intrinsic properties and environmental conditions) and related mechanisms were highlighted. Surface structure and facets of nano-Ag, abiotic conditions and natural freeze-thaw cycle processes could affect the transformations of nano-Ag under different environmental scenarios (including freshwater, seawater and wastewater). The interactions with co-present components, such as chemicals and other particles, impacted the multiple processes of nano-Ag. Besides, the contradictory effects and mechanisms by several environmental factors were summarized. Lastly, the key knowledge gaps and some aspects that deserve further investigation were also addressed. Therefore, the current review aimed to provide an overall analysis of transformation processes of nano-Ag, which will provide more available information and pave the way for the future research areas.

The increasing demand for clean fuels and sustainable products has attracted much interest in the development of active and selective catalysts for CO conversion to desirable products. This review maps the theoretical progress of the different facets of most commercial catalysts, including Co, Fe, Ni, Rh, and Ru. All relevant elementary steps involving CO dissociation and hydrogenation and their dependence on surface structure, surface coverage, temperature, and pressure are considered. The dominant Fischer-Tropsch synthesis mechanism is also explored, including the sensitivity to the structure of H-assisted CO dissociation and direct CO dissociation. Low-coordinated step sites are shown to enhance catalytic activity and suppress methane formation. The hydrogen adsorption and CO dissociation mechanisms are highly dependent on the surface coverage, in which hydrogen adsorption increases, and the CO insertion mechanism becomes more favorable at high coverages. It is revealed that the chain-growth probability and product selectivity are affected by the type of catalyst and its structure as well as the applied temperature and pressure.

Metal-on-metal (MoM) bearing surfaces were historically used for young patients undergoing total hip arthroplasty (THA), and remain commonplace in modern hip resurfacing. A substantial number of female patients with MoM bearings subsequently gave birth following implantation of the bearings before a full understanding of metal ions exposure in these patients was established. In theory, it has been postulated that metal ions released from such implants may cross the placental barrier and cause harm to the fetus. In light of this potential risk, recommendations against the use of MoM components in women of child-bearing age have been advocated. The purpose of this systematic review was to evaluate: (I) the MoM bearing types and ion levels found; (II) the concentrations of metals in maternal circulation and the umbilical cord; and (III) the presence of abnormalities in the fetus or delivered child. A comprehensive literature review was conducted of studies published between January 1st, 1975 and April 1st, 2019 using specific keywords. We defined the inclusion criteria for qualifying studies for this review as follows: (I) studies that reported on the women who experienced pregnancy and who had a MoM hip implant; (II) studies that reported on maternal metal ions blood and umbilical cord levels; and (III) studies that reported on the occurrence of fetal complications. Data on cobalt and chromium ion levels in the maternal blood and umbilical cord blood, as well as the presence of adverse effects in the infant were collected. Age at parturition and time from MoM implant to parturition were also collected. A total of six studies were included in the final analysis that reported on a total of 21 females and 21 infants born. The mean age at parturition was 31 years (range, 24 to 41 years), and the mean time from MoM implantation to parturition was 47 months (range, 11 to 119 months). Maternal blood cobalt levels were found as a weighted average of 34.09 µg/L (0.425 to 138 µg/L), while umbilical cord blood cobalt levels were found to be 22.61 µg/L (0.52 to 51.11 µg/L). Cobalt levels were reduced by an average of 34% between maternal and umbilical cord blood. Maternal cord blood chromium levels were found as a weighted average of 18.18 µg/L (0.225 to 75 µg/L), while umbilical cord chromium levels were found to be 3.96 µg/L (0.14 to 11.96 µg/L). Chromium levels were reduced by an average of 78% between maternal and umbilical cord blood. No cobalt or chromium was detected in the umbilical cord blood of three patients. Out of the 21 infants born to women with MoM implants, 20 were born healthy with no adverse effects or complications. Only one complication was recorded in single infant that did not appear to be related to the maternal MoM implant. To date, there is a lack of consensus as to whether MoM hip arthroplasty implants are to be avoided in the child-bearing female population and whether they constitute a hazard to the fetus in utero. Both chromium and cobalt ions were markedly reduced in levels when transitioning from maternal to cord blood. In particular, chromium showed a greater reduction on average than cobalt (78% vs. 34%). Based on the current evidence, there appears to be no correlation between the presence of metal ions in umbilical cord blood and complications, as none of the infants experienced abnormalities uniquely attributable to the presence of metal ions.

We report a case of a 15-year-old atopic patient presenting with delayed, severe ulcerative hypertrophic gingivitis after placement of orthodontic braces, which required removal of braces and restorative laser surgical procedures. Patch testing to multiple metals and chemicals showed weak positive reactions to steel bands and formaldehyde. The patient experienced urticarial, gingivitis, and other intraoral symptoms after patch testing and re-exposure to nickel-containing products. In contrast, nickel, cobalt, and cobalt-chromium (Co-Cr) bracket patch testing sites were negative. Nickel-caused contact dermatitis is Type IV delayed hypersensitivity reaction occurring at least 24 h after exposure. This reaction can result in intraoral blisters, ulcerations, eczematous and urticarial reactions of the face and more distant skin areas. This case illustrates the intraoral delayed response, symptom resolution after removing the braces, and brackets and local reactions upon subsequent nickel exposure, despite negative patch testing and lymphocyte stimulation test to nickel. This case further illustrates the difficulty associated with diagnosing nickel allergy.

Cobalt is a strategic and critical mineral whose demand is expected to grow rapidly. This study aims to provide a comprehensive summary of cobalt extraction and recovery research from 2012 to 2021 in the form of bibliometric analysis. The work was based on the Science Citation Index Expanded (Web of Science) and carried out using the InCites of Clarivate for bibliometric data analysis and the software VOSviewer for science mapping. By analyzing a dataset of 4967 publications, the most influential journals, countries, authors, institutions, and publications were identified, and the keyword co-occurrence networks were mapped. The China mainland produced the most publications, while the USA had the highest average number of citations per publication and the UK was the most collaborative with other countries. The keyword analysis shows that the research hotspots gradually shifted over time from early means and methods for determination of cobalt in solution to recovery of cobalt from spent lithium batteries, smelting slag, copper-cobalt ore, etc. The research will be focused on further improvement and optimization of the separation, extraction, and recovery processes of cobalt from spent batteries in recent and future years, and three approaches were promoted to facilitate economization and industrialization of the processes in this field.