Ecological and genetic aspects of distribution of the marginal populations of Swiss stone pine (Pinus cembra L.) in Ukrainian Carpathians

Current distributions of Swiss stone pine mostly cover the mountain regions of Europe (Alps and Carpathians). Easternmost distribution of this species is located in western Ukraine. Due to environmental fragmentation in Eastern Carpathians and competition with Norway spruce and other species, marginal populations of Swiss stone pine create isolated island, where other species are not able to cope with harsh conditions. Still, Pinus cembra L. play an important role for soil-formation and soil-protection in high elevations. The evidence of recent reduction in the area of Swiss stone pine raises the question whether the introduction of this species at lower altitudes can be successful? According to the studies conducted on reciprocal transplant experiments, Swiss stone pine population from higher elevation are able to profit in low elevation sites. Thus, parallelly with gene conservation activity, the possibilities of assisted migration should be recognized for this species

Ecological and genetic aspects of distribution of the marginal populations of Swiss stone pine (Pinus cembra L.) in Ukrainian Carpathians

Current distributions of Swiss stone pine mostly cover the mountain regions of Europe (Alps and Carpathians). Easternmost distribution of this species is located in western Ukraine. Due to environmental fragmentation in Eastern Carpathians and competition with Norway spruce and other species, marginal populations of Swiss stone pine create isolated island, where other species are not able to cope with harsh conditions. Still, Pinus cembra L. play an important role for soil-formation and soil-protection in high elevations. The evidence of recent reduction in the area of Swiss stone pine raises the question whether the introduction of this species at lower altitudes can be successful? According to the studies conducted on reciprocal transplant experiments, Swiss stone pine population from higher elevation are able to profit in low elevation sites. Thus, parallelly with gene conservation activity, the possibilities of assisted migration should be recognized for this species

Silver doped titanium oxide-PDMS hybrid coating inhibits Staphylococcus aureus and Staphylococcus epidermidis growth on PEEK

Highlights - Hybrid coatings were formulated to release antimicrobial silver. - The coatings were applied to PEEK, an important orthopedic implant material. - They inhibited bacterial growth and biofilm formation. - Sustained release of antimicrobial silver from the coatings was achieved. - Coating compositions could be adjusted for optimum properties and release. Abstract Bacterial infection remains one of the most serious issues affecting the successful installation and retention of orthopedic implants. Many bacteria develop resistance to current antibiotics, which complicates or prevents traditional antibiotic-dependent eradication therapy. In this study, a hybrid coating of titanium dioxide and polydimethylsiloxane (PDMS) was synthesized to regulate the release of silver. The coatings were benefited from the antimicrobial activity of silver ion, the biocompatibility of titanium dioxide, and the flexibility of the polymer. Three studied silver doped coatings with different titanium dioxide–PDMS ratios effectively inhibited the attachment and growth of Staphylococcus aureus and Staphylococcus epidermidis in a dose-dependent manner. The coatings were successfully applied on the discs of polyether ether ketone (PEEK), a common spinal implant material and antibacterial property of these coatings was assessed via Kirby Bauer assay. More importantly, these selected coatings completely inhibited biofilm formation. The release study demonstrated that the release rate of silver from the coating depended on doping levels and also the ratios of titanium dioxide and PDMS. This result is crucial for designing coatings with desired silver release rate on PEEK materials for antimicrobial applications

Bioactive improving the bioresponse to polymers using zirconium and tantalum hybridization

Biomaterials are to replace and/or repair damaged tissue or organs. The most two common biomaterials are metals and polymers. Each of these materials has its own strength and weakness. Metals offer good mechanical strength and bioactivity but lack flexibility. Polymers are flexible and useful in soft tissue applications, but do not provide good tissue integration. In some cases, it is desirable to have a material that shares the properties of both flexibility and improved bioactivity. The bioactivity of hybridized polymer and metal oxide materials remains largely unexplored. The objective of this study is to investigate the effects of adding transition metal oxides from zirconium and tantalum to a silicone-base polymer, on growth of human cells. Rapid screening methods were employed in this study to evaluate cellular bioresponses to coatings applied directly to the bottom of tissue culture plates using the BioIntraface™ Patented wet chemistry method

Periprosthetic Tibial Fractures After Total Knee Arthroplasty: Early and Long-Term Clinical Outcomes

BACKGROUND: Although periprosthetic fractures are increasing in prevalence, evidence-based guidelines for the optimal treatment of periprosthetic tibial fractures (PTx) are lacking. Thus, the purpose of this study is to assess the clinical outcomes in PTx after a total knee arthroplasty (TKA) which were treated with different treatment options. METHODS: A retrospective review was performed on a consecutive series of 34 nontumor patients treated at 2 academic institutions who experienced a PTx after TKA (2008-2016). Felix classification was used to classify fractures (Felix = I-II-III; subgroup = A-B-C) which were treated by closed reduction, open reduction/internal fixation, revision TKA, or proximal tibial replacement. Patient demographics and surgical characteristics were collected. Failure of treatment was defined as any revision or reoperation. Independent t-tests, one-way analysis of variance, chi-squared analyses, and Fisher\u27s exact tests were conducted. RESULTS: Patients with Felix I had more nonsurgical complications when compared to Felix III patients (P = .006). Felix I group developed more postoperative anemia requiring transfusion than Felix III group (P = .009). All fracture types had \u3e 30% revision and \u3e 50% readmission rate with infection being the most common cause. These did not differ between Felix fracture types. Patients who underwent proximal tibial replacement had higher rate of postoperative infection (P = .030), revision surgery (P = .046), and required more flap reconstructions (P = .005). CONCLUSION: PTx after a TKA is associated with high revision and readmission rates. Patients with Felix type I fractures are at higher risk of postoperative nonsurgical complications and anemia requiring transfusion. Fractures treated with proximal tibial replacement are more likely to develop postoperative infections and undergo revision surgery

Niobium oxide-polydimethylsiloxane hybrid composite coatings for tuning primary fibroblast functions

This study evaluates the potential of niobium oxide–polydimethylsiloxane (PDMS) composites for tuning cellular response of fibroblasts, a key cell type of soft tissue/implant interfaces. In this study, various hybrid coatings of niobium oxide and PDMS with different niobium oxide concentrations were synthesized and characterized using scanning electron microscopy, X-ray photoelectron spectrometry (XPS), and contact angle goniometry. The coatings were then applied to 96-well plates, on which primary fibroblasts were seeded. Fibroblast viability, proliferation, and morphology were assessed after 1, 2, and 3 days of incubation using WST-1 and calcein AM assays along with fluorescent microscopy. The results showed that the prepared coatings had distinct surface features with submicron spherical composites covered in a polymeric layer. The water contact angle measurement demonstrated that the hybrid surfaces were much more hydrophobic than the original pure niobium oxide and PDMS. The combination of surface roughness and chemistry resulted in a biphasic cellular response with maximum fibroblast density on substrate with 40 wt % of niobium oxide. The results of the current study indicate that by adjusting the concentration of niobium oxide in the coating, a desirable cell response can be achieved to improve tissue/implant interfaces