Relative contributions of implant hydrophilicity and nanotopography to implant anchorage in bone at Early Time Points.

OBJECTIVE: To compare the contributions of implant hydrophilicity and nanotopography on anchorage in bone. The effect of elevated calcium surface chemistry on bone anchorage was also investigated. MATERIALS AND METHODS: A full factorial study design was implemented to evaluate the effects of ultraviolet (UV) light and/or sodium lactate (SL) and discrete crystalline deposition of nanocrystals (DCD) treatments on the osseointegration of dual acid-etched (AE) titanium alloy (Ti6Al4V) and grit blasted and AE (BAE) commercially pure titanium (CpTi) implants. Sodium hydroxide (NaOH)-treated CpTi implants were immersed in simulated body fluid (SBF) to increase calcium surface chemistry. Implants were placed in the femora of Wistar rats and tested using pull-out testing (BAE implants: 5, 9, 14 days) or tensile testing (AE implants: 9 days, NaOH implants: 28 days). RESULTS: Ti6Al4V-AE implants with DCD- and UV-treated surfaces significantly increased bone anchorage compared with untreated Ti6Al4V-AE alloy implants. Pull-out testing of BAE-CpTi implants with the DCD treatment showed increased disruption force values compared with surfaces without the DCD treatment at 5, 9 and 14 days by 4.1N, 13.9N and 15.5N, respectively, and UV-treated implants showed an increase at 14 days by 8.4N. No difference was found between NaOH + SBF and NaOH + H2 O groups. CONCLUSIONS: Bone anchorage of implants was found to be improved by UV-treating implants or nanotopographically complex surfaces. However, implant nanotopography was found to have a greater contribution to the overall bone anchorage and is more consistent compared with the time-dependent nature of the UV treatment.

Binary tree-like network with two-path Fusion Attention Feature for cervical cell nucleus segmentation.

Early detection of cervical lesion is of great significance in reducing mortality from cervical cancer, and segmentation of cervical cell nuclei plays an important role in screening for cervical lesion. Compared with traditional algorithms, several deep learning methods can improve the segmentation; however, due to blurred boundaries and complex gradients of medical images, the segmentation remains unsatisfactory. In addition, the existing datasets used by cervical cell nucleus segmentation research are lacking in terms of both quantity and diversity, so methods based on those datasets cannot effectively cope with challenging cases. This paper releases a new cervical cell dataset and proposes a network named Binary Tree-like Network with Two-path Fusion Attention Feature (BTTFA). The simplified diagram of BTTFA is similar to a binary tree structure and combines ResNeXt's last four layers of information by integrating adjacent pairs of layers each time; therefore, the information of multilayers can be fully integrated, and the information lost by the pooling layers can be recovered. BTTFA also applies a two-path fusion attention to selectively utilize information close to the root nodes, thereby taking full advantage of low-level detail and high-level semantic information and selectively emphasizing important features while suppressing less useful ones. Meanwhile, at some nodes of the binary tree-like network, focal loss is imposed to calculate the loss between the ground truth and the feature map during the training process. Experiments demonstrate that BTTFA performs better than the existing technology on our dataset and another public dataset.

A pilot study on using biochars as sustainable amendments to inhibit rice uptake of Hg from a historically polluted soil in a Karst region of China.

We studied the addition of two biochars (rice shell biochar (RSB) and wheat straw biochar (WSB)) to soil at doses of 24-72 t/ha on the dynamics of pH, dissolved organic carbon (DOC), sulfate, Fe(III), and Fe(II), as well as on mercury (Hg) mobility in the pore water of a polluted paddy soil, throughout the rice-growing season. The effect of biochar addition to soil on rice biomass and Hg accumulation was also investigated. The key results showed that the addition of RSB or WSB to soil improved significantly the biomass of aboveground tissues of rice plants, particularly at higher dose treatments, compared with the control. The RSB treatment noticeably decreased Hg concentration in the pore water compared to the control, throughout the rice-growing season, and this decrease was likely due to the decreased Hg mobility by the RSB by promoting the level of sulfate in the pore water, which might be reduced to sulfide to combine with Hg to form Hg sulfides. The extent of Hg concentration reduction in the pore water was less pronounced in the WSB treatments relative to the RSB treatments. Addition of RSB to soil at doses of 24-72 t/ha decreased significantly Hg contents in the stalk, bran, hull and polish rice of rice plants compared to the non-treated rice (control), particularly Hg content in the polished rice was below the Chinese safety level (< 20 ng g-1, GB2762-2012). The WSB treatments showed limited effects on rice tissues Hg. Biochar (RSB) may offer a promising method for managing the risk of Hg in paddy field by inhibiting rice Hg uptake.

Synergistic effect of polyelectrolyte multilayers and osteogenic growth medium on differentiation of human mesenchymal stem cells.

Layer-by-layer assembly of biogenic polyelectrolytes (PEL) was carried out on the surface of poly (L-lactide) to generate polyelectrolyte multilayers (PEM) that foster osteogenic differentiation of human mesenchymal stem cell (hMSC). Gelatin (GEL), hyaluronic acid (HA) and heparin (HEP) were chosen as polyanions, while chitosan (CHI) was employed as polycation. Multilayer formation was monitored by surface plasmon resonance and water contact angle measurements showing that layer formation process and surface wetting properties depended on the type of polyanions. While HEP as strong PEL led to thicker and more hydrophilic PEM, layer mass was lower for weak polyanions GEL and HA. Short-term adhesion studies with hMSC showed strong adhesion and spreading of cells on PEM composed of GEL/CHI and low spreading, motile phenotype and aggregation of hMSC on HEP/CHI or HA/CHI. Long term studies over three weeks were carried out to follow growth and differentiation of hMSC on the PEM. Weak osteogenic differentiation of hMSC was observed on GEL/CHI if cells were cultured in normal medium while no osteogenic phenotypes were observed on HEP/CHI or HA/CHI. When cells were cultured in osteogenic differentiation medium, however, PEM composed of HEP/CHI or HA/CHI promoted differentiation of hMSC towards osteoblasts, while PEM composed of GEL/CHI failed to do so. Overall, the composition of PEMs can be used as additional tool to control osteogenic differentiation of hMSC.

Biocompatibility of poly(L-lactide) films modified with poly(ethylene imine) and polyelectrolyte multilayers.

Poly(L-lactide) (PLLA) films were modified with poly(ethylene imine) (PEI) either by adsorption or covalent binding to prepare the material for immobilization of polyelectrolyte multilayers (PEM). Two different PEI, low- and high-molecular-weight (LMW or HMW, respectively) PEI, were used. The PEI modification efficiency was monitored via surface amino group density, water contact angle and X-ray photoelectron spectroscopy (XPS) measurements. Covalent binding of HMW PEI by a two-step-activation method produced the highest amino group density and the lowest water contact angle. On the other hand, the adsorption method resulted in moderate amounts of immobilized PEI on the surface. Subsequently sulphated hyaluronan and chitosan were used to form PEM on PLLA that was covalently modified with HMW PEI. Regular formation of PEM was achieved, which was demonstrated by change of water contact angles and mass increase measured with quartz crystal microbalance. An osteoblast-like cell line, MG 63, was used to test the effects of modifications on biocompatibility. Contrarily to earlier reports showing that particularly HMW PEI had certain cytotoxicity, it was found that all modifications including PEM resulted in a better biocompatibility than plain PLLA indicated by a more spread phenotype of cells, their increased growth and metabolic activity.

Immobilization of poly (ethylene imine) on poly (L-lactide) promotes MG63 cell proliferation and function.

Poly (ethylene imine) (PEI) is a polycation widely used for DNA transfection to cells but also applied as primary polycation for layer-by-layer (LBL) assembly of polyelectrolytes. The aim of the present study was to investigate the effect of modification with PEI on the biocompatibility of poly (L-lactide) (PLLA) films. PEI with different molecular weight was immobilized on PLLA by either adsorption or covalent binding. Cell morphologies, immuno-fluorescence staining, cell proliferation by lactate dehydrogenase assay and cell differentiation by alkaline phosphatase assay were utilized to assess the biocompatibility of the modified PLLA using osteoblast cell line MG63. Results revealed that PEI modification remarkably improved cell adhesion, viability, proliferation and function compared with plain PLLA. Hence, PEI-modified PLLA is acceptable as transfection vehicle for engineering of bone and other tissues, or as primary layer to allow LBL assembly to generate biomimetic surface coatings.

Recognition mechanism of theophylline-imprinted polymers: two-dimensional infrared analysis and density functional theory study.

Molecular imprinting polymers (MIPs) are synthetic materials having specific cavities tailored for a target molecule. Thoroughly understanding the molecular recognition mechanism is favorable for the rational design, preparation, and application of MIPs. In this work, theophylline (THO)-imprinted poly(acrylonitrile-co-acrylic acid) (PANCAA) films with acrylic acid (AA) as the functional monomer were fabricated and a set of concentration-dependent Fourier transform infrared (FT-IR) spectra were collected. Two-dimensional (2D) correlation analysis of the spectra and density functional theory (DFT) calculation were conducted to evaluate the molecular recognition mechanism. DFT at the B3LYP/6-31+G(d,p) level is efficacious to calculate the binding energies (DeltaE) and the theoretical vibration frequencies for the possible configurations of THO_AA complexes. An optimized cyclic hydrogen-bonded configuration (complex THO_AA1) has the highest binding energy (-16.63 kcal mol(-1)) that is more stable than others. In addition, the experimental vibrations of the carbonyl groups in the FT-IR spectra were assigned on the basis of the DFT results. Moreover, methylacrylic acid (MAA) and caffeine (CAF) as compared analogues were also investigated. The DFT-based theoretical predictions are coincident with the reported results.

Chitosan-modified poly(acrylonitrile-co-acrylic acid) nanofibrous membranes for the immobilization of concanavalin A.

Lectin affinity membranes have been receiving much attention for the separation and detection of various glycoconjugates. In this work, we present a simple and efficient method for the preparation of lectin affinity nanofibrous membranes. Chitosan-modified poly(acrylonitrile-co-acrylic acid) (PANCAA) nanofibrous membranes were first prepared by a coupling reaction between the primary amino groups of chitosan and the carboxyl groups of PANCAA electrospun membranes. Surface characterizations by attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR/ATR), X-ray photoelectron spectroscopy (XPS) and field-emission scanning electron microscopy (FESEM) confirm the chemical and morphological changes of the studied nanofibrous membranes. Fluorescence-labeled concanavalin A (FL-Con A) was then immobilized on these membranes via noncovalent binding. Analyses by fluorescence spectrophotometer (FS) and confocal laser scanning microscopy (CLSM) reveal that the immobilization of Con A onto the modified nanofibrous membranes has been successfully achieved on the basis of the electrostatic interaction and the specific recognition between Con A and chitosan. The results show that the amount of adsorbed FL-Con A increases dramatically with the increasing coupling degree of chitosan (CDC) on the nanofibrous membrane. Moreover, Con A immobilized on the chitosan-modified nanofibrous membranes (CMNMs) can remain relatively stable at pH 5.3. Therefore, it is believed that this work may provide a new kind of material for affinity application.

Phase II trial of karenitecin in patients with malignant melanoma: clinical and translational study.

PURPOSE: A phase II trial of the novel camptothecin karenitecin (BNP1350) was conducted to determine its efficacy and tolerability in patients with metastatic melanoma. Patients were biopsied to determine topoisomerase expression at baseline and response to therapy. PATIENTS AND METHODS: Eligible patients had metastatic melanoma with up to three prior chemotherapy and/or any number of immunotherapy regimens. Treatment consisted of an i.v. infusion of 1 mg/m(2) karenitecin daily for 5 days with cycles repeated every 3 weeks. Fine-needle aspiration biopsies were done before treatment and on day 3 to determine topoisomerase expression from patients' tumors. RESULTS: Forty-three patients were evaluable for response and toxicity. Most patients (72%) had stage M1C disease and were previously exposed to chemotherapy (56%). The investigational agent was well tolerated with limited gastrointestinal side effects or fatigue. The major toxicity seen was reversible noncumulative myelosuppression. One patient had a complete response after 11 months of therapy. No partial responses were seen, but 33% of the patients had disease stabilization lasting > or =3 months. Topoisomerase I, IIalpha, and IIbeta expression and localization were determined in a subset of patients. Topoisomerase I expression was highest, followed by topoisomerase IIbeta and topoisomerase IIalpha. CONCLUSION: Karenitecin was a well-tolerated investigational agent in this phase II study; side effects were generally mild and mostly hematologic. Karenitecin has significant activity in metastatic melanoma. Melanoma metastases express high levels of topoisomerase I. We did not observe any compensatory increase in topoisomerase II upon treatment with karenitecin.