Hydrophobic Surface Coating Can Reduce Toxicity of Zinc Oxide Nanoparticles to the Marine Copepod Tigriopus japonicus.

Coated zinc oxide nanoparticles (ZnO-NPs) are more commonly applied in commercial products but current risk assessments mostly focus on bare ZnO-NPs. To investigate the impacts of surface coatings, this study examined acute and chronic toxicities of six chemicals, including bare ZnO-NPs, ZnO-NPs with three silane coatings of different hydrophobicity, zinc oxide bulk particles (ZnO-BKs), and zinc ions (Zn-IONs), toward a marine copepod, Tigriopus japonicus. In acute tests, bare ZnO-NPs and hydrophobic ZnO-NPs were less toxic than hydrophilic ZnO-NPs. Analyses of the copepod's antioxidant gene expression suggested that such differences were governed by hydrodynamic size and ion dissolution of the particles, which affected zinc bioaccumulation in copepods. Conversely, all test particles, except the least toxic hydrophobic ZnO-NPs, shared similar chronic toxicity as Zn-IONs because they mostly dissolved into zinc ions at low test concentrations. The metadata analysis, together with our test results, further suggested that the toxicity of coated metal-associated nanoparticles could be predicted by the hydrophobicity and density of their surface coatings. This study evidenced the influence of surface coatings on the physicochemical properties, toxicity, and toxic mechanisms of ZnO-NPs and provided insights into the toxicity prediction of coated nanoparticles from their coating properties to improve their future risk assessment and management.

Circadian rhythm bifurcation induces flexible phase resetting by reducing circadian amplitude.

Shift-work and jet-lag-related disorders are caused by the limited flexibility of the suprachiasmatic nucleus (SCN), a master circadian clock in the hypothalamus, to adjust to new light-dark (LD) cycles. Recent findings confirmed here establish that behavioral jet lag after simulated time-zone travel is virtually eliminated following bifurcated circadian entrainment under a novel and atypical 24-h light:dark:light:dark (LDLD) cycle. To investigate the mechanisms of this fast resetting, we examined the oscillatory stability of the SCN and peripheral tissues in LDLD-bifurcated mice employing the dissection procedure as a perturbing resetting stimulus. SCN, lung, liver, and adrenal tissue were extracted at times throughout the day from female and male PER2::Luciferase knock-in mice entrained to either LDLD or a normal LD cycle. Except for adrenals, the phase of the cultured explants was more strongly set by dissection under LDLD than under normal LD. Acute bioluminescence levels of SCN explants indicate that the rhythm amplitude of PER2 is reduced and phase is altered in LDLD. Real-time quantitative PCR suggests that amplitude and rhythmicity of canonical clock genes in the lung, liver, and kidney are also significantly reduced in LDLD in vivo. Furthermore, spatiotemporal patterns of PER2 peak time in cultured SCN were altered in LDLD. These results suggest that altered gene expression patterns in the SCN caused by bifurcation likely result in fast resetting of behavior and cultured explants, consistent with previously reported mathematical models. Thus, non-invasive, simple light manipulations can make circadian rhythms more adaptable to abrupt shifts in the environmental LD cycle.

Arthroscopic Treatment of Osteochondral Lesions of the Talus Utilizing Juvenile Particulated Cartilage Allograft: A Case Series.

The treatment options for osteochondral lesions of the ankle are scarce, and newer modalities are becoming available. We describe a minimally invasive arthroscopic approach with implantation of juvenile particulated allograft to facilitate the growth of true hyaline cartilage in patients with osteochondral lesions of the talus. The purpose of this study was to subjectively review clinical outcomes using the validated Foot and Ankle Outcomes Score in patients who underwent this technique. Our technique was performed on 82 consecutive patients with average follow-up of 24 (range 9 to 86) months. We found that 28 (88%) of 32 patients who responded to the questionnaire had good or excellent results for activities of daily living; 26 (82%) of 32 patients had at least a good result for both pain and symptoms; and 25 (78%) of 32 had at least a fair result for functional sports and quality of life.

Outcome differences between recanalized malignant central airway obstruction from endoluminal disease versus extrinsic compression.

We compared the outcome of Nd:YAG laser therapy with stent placement for malignant central airway obstruction (CAO) at our center over a 10-year period. This is a retrospective review of patients undergoing Nd:YAG laser therapy or self-expanding metal stent (SEMS) placement for malignant CAO between November 2007 and October 2017. Seventy-two patients were recanalized for malignant CAO. The median (range) age was 63 (23-86) years, with 49 (68%) males. Patients underwent either laser therapy alone (N = 36), stent placement alone (N = 30), or both (N = 6). The wavelength of Nd:YAG laser used was 1064 nm, and median (range) laser energy used was 25 (15-35) W, in 377 (115-1107) pulses. Fifty-one (71%) patients died with median survival of 7.2 months. In subgroup analysis, 21 (58.3%) vs. 25 (83.3%), p = 0.03 patients died in the "laser resection" vs. "stent placement" group with longer median survival of 12.4 months in the former vs. 4.5 months, p = 0.0004 in the later. Esophageal cancer and left main bronchus involvement were significantly more common (10 (33.3%) vs. 0, p = 0.0001, and 16 (53.3%) vs. 8 (22.2%), p = 0.01), in the stent placement vs. laser resection group, respectively. Trachea or main bronchi involvement and respiratory failure on presentation requiring mechanical ventilation correlated with poorer survival. The immediate restoration of luminal patency, complication rate, and 30-day mortality was similar among the two groups. The median (range) energy used for laser therapy was 25 (15-35) W. Median of 377 pulses was used for the duration of 287.5 s. The results were compared using a Wilcoxon two-sample test, and Fischer exact test with p values considered indicative of a significant difference if less than 0.05. In patients requiring recanalization of malignant CAO, the extrinsic compression from esophageal cancer, trachea or main bronchi involvement, respiratory failure on presentation requiring mechanical ventilation, and stent placement correlated with poorer survival. Interventional pulmonology training program should emphasize on dedicated training in laser therapy as it is associated with improved survival.

Clinicians' Perceived Understanding of Biostatistical Results in the Medical Literature: A Cross-Sectional Study.

Background and objectives: The continuum of evidence-based medicine (EBM) depends solely on clinicians' commitment to keep current with the latest clinical information. Exploration on clinicians' understanding of biostatistical results in the medical literature is sparse to date. This study aimed to evaluate clinicians' perceived understanding of biostatistical results in the medical literature and the factors influencing them. Materials and Methods: A cross-sectional study was conducted among 201 clinicians at the Seberang Jaya Hospital, a cluster-lead research hospital in Northern Malaysia. A self-administered questionnaire that consisted of items on sociodemographics, validated items on clinicians' confidence level in interpreting statistical concepts, perceived understanding of biostatistics, and familiarity with different statistical methods were used. Descriptive, univariate, and multivariate analyses were conducted. Results: Perceived understanding of biostatistical results among clinicians in our sample was nearly 75%. In the final regression model, perceived understanding was significantly higher among clinicians who were able to interpret p-values with complete confidence (AOR = 3.0, 95% CI 1.1-8.1), clinicians who regularly encounter measures of central tendencies (AOR = 2.3, 95% CI 1.1-5.2), and clinicians who regularly encounter inferential statistics (AOR = 2.2, 95% CI 1.1-4.5) while appraising the medical literature. Conclusions: High perceived understanding was significantly associated with clinicians' confidence in interpreting statistical concepts and familiarity with different statistical methods. Our findings form a platform to understand clinicians' ability to appraise rigorous biostatistical results in the medical literature for the retrieval of evidence-based data to be used in routine clinical practice.

Surgical Treatment of Bone Marrow Lesion Associated with Recurrent Plantar Fasciitis: A Case Report Describing an Innovative Technique Using Subchondroplasty®.

Plantar fasciitis is one of the most common chief complaints seen in the foot and ankle clinic. With a relatively benign course, most cases are self-limiting or amendable to conservative therapy; ~90% of all plantar fasciitis cases will respond to these methods. When conservative treatment and time fail, surgical intervention can be necessary to improve outcomes. We present a novel method using Subchondroplasty® (SCP®; Zimmer Holdings, Inc.; Warsaw, IN) and revision fasciotomy in a case in which initial fasciotomy had failed. After the patient had failed to improve, a worsening underlying bone marrow lesion was identified at the origin of the plantar fascia; thus, SCP® was used with repeat fasciotomy. SCP® involves injecting calcium phosphate into bone marrow lesions to stimulate long-term bone repair. At 10 months after SCP®, the patient remained pain free and had returned to running at the final follow-up examination. This surgical treatment should be considered as an adjunctive procedure for those patients with plantar fasciitis, identifiable bone marrow lesions on magnetic resonance imaging, and continued pain when other treatment modalities have failed.

Stenotrophomonas maltophilia: A Rare Case of Osteomyelitis After an Open Distal Tibial Fracture.

Stenotrophomonas maltophilia is a gram-negative rod rarely associated with osteomyelitis. To date, only 3 cases of osteomyelitis due to this pathogen have been previously referenced. We describe the case of a 77-year-old male who developed osteomyelitis secondary to S. maltophilia infection after an open distal tibial fracture sustained by falling off a ladder. The purpose of the present case report was to highlight this highly resistant microbe as an infectious etiology.

Defect-enhanced performance of a 3D graphene anode in a lithium-ion battery.

Morphological defects were generated in an undoped 3D graphene structure via the involvement of a ZnO and Mg(OH)2 intermediate nanostructure layer placed between two layers of vapor-deposited graphene. Once the intermediate layer was etched, the 3D graphene lost support and shrank; during this process many morphological defects were formed. The electrochemical performance of the derived defective graphene utilized as the anode of a lithium (Li)-ion battery was significantly improved from ∼382 mAh g-1 to ∼2204 mAh g-1 at 0.5 A g-1 compared to normal 3D graphene. The derived defective graphene exhibited an initial capacity of 1009 mAh g-1 and retention of 83% at 4 A g-1 for 500 cycles, and ∼330 mAh g-1 at a high rate of 20 A g-1. Complicated defects such as wrinkles, pores, and particles formed during the etching of the intermediate layer, were considered to contribute to the improvement of the electrochemical performance.

Graphene-oxide-wrapped ZnMn2O4 as a high performance lithium-ion battery anode.

Cation distribution between tetrahedral and octahedral sites within the ZnMn2O4 spinel lattice, along with microstructural features, is affected greatly by the temperature of heat treatment. Inversion parameters can easily be tuned, from 5%-19%, depending on the annealing temperature. The upper limit of inversion is found for T = 400 °C as confirmed by x-ray powder diffraction and Raman spectroscopy. Excellent battery behavior is found for samples annealed at lower temperatures; after 500 cycles the specific capacity for as-prepared ZnMn2O4 is 909 mAh g-1, while ZnMn2O4 heat-treated at 300 °C is 1179 mAh g-1, which amounts to 101% of its initial capacity. Despite the excellent performance of a sample processed at 300 °C at lower charge/discharge rates (100 mAh g-1), a drop in the specific capacity is observed with rate increase. This issue is solved by graphene-oxide wrapping: the specific capacity obtained after the 400th cycle for graphene-oxide-wrapped ZnMn2O4 heat-treated at 300 °C is 799 mAh g-1 at a charge/discharge rate 0.5 A g-1, which is higher by a factor of 6 compared to samples without graphene -oxide wrapping.

Transmission electron microscopy artifacts in characterization of the nanomaterial-cell interactions.

We investigated transmission electron microscopy artifacts obtained using standard sample preparation protocols applied to the investigation of Escherichia coli cells exposed to common nanomaterials, such as TiO2, Ag, ZnO, and MgO. While the common protocols for some nanomaterials result only in known issues of nanomaterial-independent generation of anomalous deposits due to fixation and staining, for others, there are reactions between the nanomaterial and chemicals used for post-fixation or staining. Only in the case of TiO2 do we observe only the known issues of nanomaterial-independent generation of anomalous deposits due to exceptional chemical stability of this material. For the other three nanomaterials, different artifacts are observed. For each of those, we identify causes of the observed problems and suggest alternative sample preparation protocols to avoid artifacts arising from the sample preparation, which is essential for correct interpretation of the obtained images and drawing correct conclusions on cell-nanomaterial interactions. Finally, we propose modified sample preparation and characterization protocols for comprehensive and conclusive investigations of nanomaterial-cell interactions using electron microscopy and for obtaining clear and unambiguous revelation whether the nanomaterials studied penetrate the cells or accumulate at the cell membranes. In only the case of MgO and ZnO, the unambiguous presence of Zn and Mg could be observed inside the cells.

Nontraumatic Osteonecrosis of the Distal Tibia: A Case Presentation and Review of the Literature.

Osteonecrosis, although commonly occurring in the hip, can also affect the leg and foot. In the foot, it most commonly occurs in the talus. The incidence of osteonecrosis occurring in the tibia is relatively rare. We report a case of a woman who presented to our clinic with ankle pain that was idiopathic in nature. Subsequent magnetic resonance imaging showed findings consistent with osteonecrosis of the bilateral distal tibias and several other lesions located in the shoulder, hip, and calcaneus. The present report also serves as a review of both etiology and treatment of osteonecrosis as it relates to the lower extremity.

Generation of highly reactive oxygen species on metal-supported MgO(100) thin films.

The formation of highly reactive oxygen species (ROS) on metal oxide surfaces has attracted considerable interest due to their diverse applications. In this work, we have performed density functional theory calculations to investigate the co-adsorption of oxygen and water on ultrathin MgO(100) films deposited on a Mo(100) substrate. We reveal that molecular oxygen can be completely decomposed stepwise with the assistance of water. Consequently, a series of highly ROS including superoxide, hydroperoxide, hydroxyl and single oxygen adatoms are formed on Mo(100) supported MgO(100) thin films. The reaction barriers accompanied by the generation of ROS are reported, and the influence of the thickness of MgO(100) films is also discussed. The promising routes to produce these species provide valuable information to understand the importance of synergy effects between the substrate, the co-adsorbed species, and the film thickness in multiphase catalyst design.

Engineering versatile protein expression systems mediated by inteins in Escherichia coli.

We have recently employed an intein, Saccharomyces cerevisiae vascular membrane ATPase (VMA), in conjunction with efficient expression and secretory functions formed between the ompA leader sequence and the human epidermal growth factor (EGF) gene (fused at the 5' end of VMA), and the human basic fibroblast growth factor (bFGF) gene (fused at the 3' end of VMA), to engineer an efficient intein-based Escherichia coli system for high-level co-expression of EGF and bFGF as authentic mature products. Both products were found not only excreted to the culture medium but also located, surprisingly, in the cytoplasm (Kwong and Wong 2013). In this study, we employed two structurally varied inteins, VMA and Mycobacterium xenopi GyraseA (GyrA), and further demonstrated that despite acting alone, both VMA and GyrA were able to mediate successful co-expression of two widely different proteins, EGF and an endoglucanase (Eng) in E. coli. Although EGF and Eng were initially expressed as large precursors/intermediates, they were soluble and auto-cleavable to finally yield the desired products in both the cytoplasm and culture media. The results further substantiate our postulation that the aforementioned intein/E. coli approach might lead to the development of cost-effective and versatile host systems, wherein all culture fractions are involved in producing the target proteins.

Toxicity of metal oxide nanoparticles: mechanisms, characterization, and avoiding experimental artefacts.

Metal oxide nanomaterials are widely used in practical applications and represent a class of nanomaterials with the highest global annual production. Many of those, such as TiO2 and ZnO, are generally considered non-toxic due to the lack of toxicity of the bulk material. However, these materials typically exhibit toxicity to bacteria and fungi, and there have been emerging concerns about their ecotoxicity effects. The understanding of the toxicity mechanisms is incomplete, with different studies often reporting contradictory results. The relationship between the material properties and toxicity appears to be complex and diifficult to understand, which is partly due to incomplete characterization of the nanomaterial, and possibly due to experimental artefacts in the characterization of the nanomaterial and/or its interactions with living organisms. This review discusses the comprehensive characterization of metal oxide nanomaterials and the mechanisms of their toxicity.

In situ synthesis of TiO2(B) nanotube/nanoparticle composite anode materials for lithium ion batteries.

Titania nanotubes were prepared by a simple hydrothermal route. Their electrochemical performance has been examined in detail and compared to TiO2(B) nanoparticles, TiO2 anatase and P25 titania nanoparticles. The cycling and rate performance of TiO2 nanotubes is superior to both types of nanoparticles, and it can be further improved by an in situ titanium precursor treatment, which results in the formation of TiO2 nanoparticles on/between the nanotubes. The obtained specific capacity after 200 cycles at 0.2 A g(-1) charge/discharge rate remained above 130 mAh g(-1). The enhanced lithium storage properties of these samples can be attributed to their unique morphology and crystal structure.

Mechanisms of antibacterial activity of MgO: non-ROS mediated toxicity of MgO nanoparticles towards Escherichia coli.

The toxicity of metal oxide nanomaterials and their antimicrobial activity is attracting increasing attention. Among these materials, MgO is particularly interesting as a low cost, environmentally-friendly material. The toxicity of MgO, similar to other metal oxide nanomaterials, is commonly attributed to the production of reactive oxygen species (ROS). We investigated the toxicity of three different MgO nanoparticle samples, and clearly demonstrated robust toxicity towards Escherichia coli bacterial cells in the absence of ROS production for two MgO nanoparticle samples. Proteomics data also clearly demonstrate the absence of oxidative stress and indicate that the primary mechanism of cell death is related to the cell membrane damage, which does not appear to be due to lipid peroxidation.

Osteochondral Injuries of the Talus.

Osteochondral lesions of the talus are a common sequelae of trauma and are often associated with ankle sprains and ankle fractures. Because the surface of the talus is composed primarily of hyaline cartilage, the regenerative capacity of these injuries is limited. Therefore, several open and arthroscopic techniques have been described to treat osteochondral injuries of the talus and underlying bone marrow lesions. Throughout this review, these treatment options are discussed along with their indications and currently reported outcomes. A commentary on the authors' preferences among these techniques is also provided.

Antibacterial and photocatalytic activity of TiO2 and ZnO nanomaterials in phosphate buffer and saline solution.

We studied antibacterial and photocatalytic activity of anatase TiO2 and ZnO in phosphate buffer and saline solution. We found that the different anions in the suspension medium (chloride and phosphate) significantly affected the following suspension properties: the stability of nanoparticle suspension, the release of metal ions from the nanoparticles, and the production of the reactive oxygen species by the nanoparticles. As a result, antibacterial activity and photocatalytic dye degradation were also affected. However, the effect of the suspension medium was different for ZnO and TiO2. Obtained results are discussed.

Vascularized scapular free bone graft after nonunion of a tarsal navicular stress fracture: a case report.

Nonunion of a tarsal navicular stress fracture, although relatively uncommon, is often amenable to open reduction and internal fixation. Furthermore, avascular necrosis of the navicular whether intact or occurring after fracture is rare, secondary to the adequate blood supply it receives. However, persistent nonunion after primary surgical repair in conjunction with avascular necrosis often results in limited treatment options. Thus, the purpose of the present case report is to describe the surgical approach and complications of a vascularized scapular free bone graft for augmentation of revision talonavicular and naviculocuneiform arthrodesis.

Arthroscopic Cartilage Transplantation.

Arthroscopic cartilage repair has made several strides in recent years; however, no gold standard for cartilage restoration has been found. Simple treatment with bone marrow stimulation such as microfracture have shown good short-term results; however, concerns for long-term stability of cartilage repair as well as the subchondral bone health remain in question. Treatment of these lesions often comes down to surgeon preference, the aim of this study is to discuss some of the current options available on the market to further assist surgeons in their decision-making process.