Hybrid Laser Technology for Creation of Doped Biomedical Layers

Hybrid laser technologies for deposition of thin films and basic schemes of combination of pulsed laser deposition (PLD) with magnetron sputtering and RF discharges or two lasers or three laser deposition systems are presented. Experiences with deposition of chromium doped diamond-like carbon (DLC) films for coating of prostheses are described. Layers of different chromium concentrations were prepared using hybrid systems (PLD + magnetron sputtering or by double PLD). Results of physical and mechanical characterization of film properties and biomedical tests of trivalent and toxic hexavalent chromium are given. Experiences with double laser deposition of DLC layers doped with silver are also mentioned.

Modeling and analysis of Schistosoma Argonaute protein molecular spatial conformation

Objective:To analyze the amino acid sequence composition,secondary structure,the spatial conformation of its domain and other characteristics of Argonaute protein.Methods:Bioinformatics tools and the internet server were used.Firstly,the amino acid sequence composition features of the Argonaute protein were analyzed,and the phylogenetic tree was constructed.Secondly,Argonaute protein's distribution of secondary structure and its physicochemical properties were predicted.Lastly,the protein functional expression form of the domain group was established through the Phyre-based analysis on the spatial conformation of Argonaute protein domains.Results:593 amino acids were encoded by Argonaute protein,the phylogenetic tree was constructed,and Argonaute protein's distribution of secondary structure and its physicochemical properties were obtained through analysis.In addition,the functional expression form which comprised the N-terminal PAZ domain and C-terminal Piwi domain for the Argonaute protein was obtained with Phyre.Conclusions:The information relationship between the structure and function of the Argonaute protein can be initially established with bioinformatics tools and the internet server,and this provides the theoretical basis for further clarifying the function of Schistosoma Argonaute protein.

Application of ultrasound contrast in identification and diagnosis of ocular spaceoccupying lesions

AIM: To analyze the application significance of ultrasound contrast agent in identification and diagnosis of ocular spaceoccupying lesions, and mainly analyze its advantages and problems. METHODS: Thirty-two representative literatures about the application of ultrasound contrast agent in diagnosis of spaceoccupying lesions at home and abroad were collected after focused on sorting the literature reporting the application of ultrasound contrast diagnostic technology in the diagnosis and identification of ocular spaceoccupying lesions in recent years. Its advantages and problems were retrospectively analyzed, and reasonable assessment on Existing problems was made and possible solutions to the problems were proposed. RESULTS: As a new imaging diagnostic technique, the contrast-enhanced ultrasound, which can enhance the display of tumor microcirculation vessels and improve the tumor's ultrasound diagnostic capability, was analyzed. Through sorting and comprehensively analyzing the collected literatures, the positive rate of ocular spaceoccupying lesion diagnosis could be significantly improved with ultrasound contrast technology. Thus, the vascular perfusion in normal tissues and lesions was reflected objectively. According to the lesion's perfusion characteristics of the contrast agent plus with the performance features of two-dimensional ultrasound, the ocular spaceoccupying lesions can be accurately diagnosed, and this could provide clinicians with reliable research basis in this field. CONCLUSION: Ultrasound contrast examination is a new testing method, and ultrasound contrast agent can significantly enhance the ultrasonic detection signal, clearly show the blood perfusion in vessels and tissues, increase the image contrast resolution, and improve the lesion's detection capability in the microcirculation perfusion level, especially its important value in the diagnosis of ocular tumor.

Effect of fluoride treatment on corrosion behavior of Mg-Ca binary alloy for implant application

The influence of hydrofluoric acid（HF） treatment on the corrosion behavior of the Mg-0.5Ca alloys was investigated by immersion specimen in sodium hydroxide and HF solutions with various concentrations and durations at room temperature.Microstructural evolutions of the specimens were characterized by atomic force microscopy,X-ray diffraction,field-emission scanning electron microscopy.The corrosion resistance was examined through potentiodynamic polarization and immersion test in Kokubo solution.The results revealed that the fluoride treated Mg-0.5Ca alloys produced by immersion in 40% HF provided more uniform,dense and thicker coating layer（12.6 μm） compared with the 35% HF treated specimen.The electrochemical test showed that the corrosion resistance of fluoride treated specimen was 35 times higher compared with the untreated Mg-0.5Ca alloy specimen in Kokubo solution.In vitro degradation rate of the fluoride treated specimens was much lower than untreated Mg-0.5Ca alloy in Kokubo solution.After immersion test the surface of 40% HF treated sample showed a few corrosion dots,while untreated specimens were fully covered by corrosion products and delamination.Fluoride treated Mg-0.5Ca alloy with 40% HF is a promising candidate as biodegradable implants due to its low degradation kinetics and good biocompatibility.

The effect of modification of matrix on densification efficiency of pitch based carbon composites

Using coal tar pitch as a matrix precursor to prepare carbon materials is widelyused by impregnation/carbonization processing technology.Four different grades of coaltar pitch and a natural pitch were characterized in terms of carbon yield, density, viscosity,and fractionation with solvents, as well as by thermal analysis methods.The suitability ofthese commercially available matrices for densification of 3 dimensional carbon-carboncomposites was examined.The theoretical results compared with experimental results.The highest density after impregnation was obtained using one of the coal tar pitches.Thepredicted results are in reasonable agreement with experiment data.The significance ofthis research is that a special heat treatment regime was conducted.The effects of modificationtemperature on the densification efficiency of composites were investigated andthen structure and characteristics of the composites were determined by scanning electronmicroscopy (SEM), Transmission electron microscopy (TEM) and X-Ray Diffraction (XRD).

Evolutions and Future Directions of Surgical Robotics: A Review

Although the robotics firstly appeared as an entertainment form, its capabilities have continuously advanced from the world’s first industrial robot to the surgical robotic systems which are today capable of performing many surgical maneuvers unaided. However, these surgical robots are not autonomous systems;they are designed to complete a surgeon’s abilities and converting surgeon’s movements into incredibly steady and accurate robotic movements that finally manipulate surgical instruments to assist delicate operations. This novel type of surgery is carried out in the form of minimally invasive surgical procedure and has offered valuable alternatives to enhance traditional open surgery approach. Although the surgical robotic systems began as external robots, technological progresses are directing the surgical robotic systems to endoluminal robots which consist of doing surgical maneuvers by navigating of robot through lumens of human body. Here, we will briefly review different applications of robotic systems in various fields of medicine. Then, we will discuss minimally invasive surgical systems and their role in progressing of minimally invasive surgery as a modern surgery method. By thoroughly investigating a considerable amount of published materials about the minimally invasive surgical technologies, we will study the recent research activities and commercially available samples of surgical robotic systems.

Evaluation of L929 cell morphology on anthocyanin-containing gelatin-based hydrogel for early detection of infection

Wounds heal through a complex process including four phases.Any interruption or interference in healing process can prevent wound healing.Infection is one of the most common complications preventing wounds from healing.In this study,we investigated the fibroblast cell morphology and behavior of a gelatin-based hydrogel containing anthocyanin to determine whether it can be used for early detection of infection.The experimental results ascertained that 6 h after culturing the fibroblasts,they could be well attached to the surface of the hydrogel,and 48 h after seeding,they were spread over the surface and connected with each other.After the addition of a low dose of anthocyanin,the vitality of the cell increased,and the results of the ATR-FTIR analysis showed that anthocyanin could eliminate remaining glutaraldehyde free radicals.Anthocyanin also could change its color after the addition of bacterial supernatant.Thus,hydrogels containing black carrot anthocyanin may be a potential therapeutic and diagnostic strategy to promote wound healing and early detection of infection.

Mathematical modeling of drug release from biodegradable polymeric microneedles

Transdermal drug delivery systems have overcome many limitations of other drug administration routes,such as injection pain and first-pass metabolism following oral route,although transdermal drug delivery systems are limited to drugs with low molecular weight.Hence,new emerging technology allowing high molecular weight drug delivery across the skin—known as‘microneedles’—has been developed,which creates microchannels that facilitate drug delivery.In this report,drug-loaded degradable conic microneedles are modeled to characterize the degradation rate and drug release profile.Since a lot of data are available for polylactic acid-co-glycolic acid(PLGA)degradation in the literature,PLGA of various molecular weights-as a biodegradable polymer in the polyester family-is used for modeling and verification of the drug delivery in themicroneedles.The main reaction occurring during polyester degradation is hydrolysis of steric bonds,leading to molecular weight reduction.The acid produced in the degradation has a catalytic effect on the reaction.Changes in water,acid and steric bond concentrations over time and for different radii of microneedles are investigated.To solve the partial and ordinary differential equations simultaneously,finite difference and Runge–Kutta methods are employed,respectively,with the aid of MATLAB.Correlation of the polymer degradation rate with its molecular weight and molecular weight changes versus time are illustrated.Also,drug diffusivity is related to matrix molecular weight.The molecular weight reduction and accumulative drug release within the system are predicted.In order to validate and assess the proposed model,data series of the hydrolytic degradation of aspirin(180.16 Da)-and albumin(66,000 Da)-loaded PLGA(1:1 molar ratio)are used for comparison.The proposed model is in good agreement with experimental data from the literature.Considering diffusion as themain phenomena and autocatalytic effects in the reaction,the drug release profile is predicted.Based on our results for a microneedle containing drug,we are able to estimate drug release rates before fabrication.

Bioinformatics-led design of single-chain antibody molecules targeting DNA sequences for retinoblastoma

The development of single-chain Fv antibody (scFv) by recombinant gene expression is an important milestone for cancer therapy. Single-chain antibodies are reconstructed for cancer-targeted therapy to provide good penetration into tumor tissue and to improve their pharmacokinetics in vivo, offering a clinically valuable application. The relationship needs to be analyzed that there may be some variations between the structure and function of the fusion proteins, and the relationship between the structure and function of protein molecules was obtained through analyzing relevant literature at home and abroad as well as modeling analysis. Through our analysis of the interaction region between antibody and antigen, and of the binding sites for molecular conformation, it is clear that existing antibodies need to be modified at the DNA sequence level, enhancing the biological activity of the antibodies. Based on the view that bio-molecular computer models are closely integrated with biological experiments, a bio-molecular structure-activity relationship model can be established in terms of molecular conformation, physical and chemical properties and the biological activity of single-chain antibodies. Two enlightenments are obtained from our analysis. On one hand, the structure-activity relationship is clear for new immune molecules at the gene expression level. On the other hand, a single-chain antibody molecule can be designed and optimized for the cancer-oriented treatment. In this article, we provided the theoretical and experimental basis for the development of single-chain antibodies appropriate for retinoblastoma therapy.

Application of geographical information system technology to epidemiological surveillance and prevention and cure decision-making for SARS

Objective:To expound geographical information system (GIS) technology is a very important tool when it was employed to assist to present the distribution by time and place and the model of transmission of infectious disease. Methods: We illustrated the assistant decision-making support function of GIS with an example of the spatial decision support system for SARS controlling in Shaanxi province of China which was developed by us. Results: The spatial decision support system established by applying GIS technology fulfilled the needs of real-time collection and management and dissemination SARS information and of surveillance and analysis the epidemic situation of SARS. Conclusion: Occurrence and epidemic of diseases, implement prevention and intervention measures and collocation hygienic resources are all with the characteristic of the variation of time and space, therefore, GIS technology has become a powerful tool for identifying risk factors of diseases, providing clues of causation of diseases , evaluating the effects of intervention measures and drawing a health management plan.

Application of ultrasound microbubble contrast technology in ophthalmic targeted therapy:literature analysis

AIM: To analyze the application of microbubble contrast technology in the treatment of ophthalmic diseases, mainly analyzing its advantages and existing problems. METHODS: A total of 30 representative literatures about the application of ultrasound contrast agent in gene targeted therapy at home and abroad were collected, and focusing on sorting out the literature reporting the treatment of ophthalmic diseases with microbubble contrast technology in recent years, then recalling its advantages and problems, finally making reasonable assessment on existing problems and proposing possible solutions to the problems. RESULTS: Due to its unique safety and efficacy, the treatment of ophthalmic diseases with microbubble contrast technology has increasingly drawn the attention of clinicians, but two relevant issues should be considered: first, the nature of contrast agent and the choice of corresponding ultrasound parameters; second, relative incidence of tissue bleeding, intravascular hemolysis, moderate or severe allergy as well as other side effects. CONCLUSION: Microbubble may become the carrier of targeted therapy, and as a kind of new non-invasive delivery system, the ultrasound contrast agent has broad application prospects, but its application in ophthalmic research is still in its initial stage and the safety of contrast-enhanced ultrasound still needs further study.

Dynamics Study and Analysis of Laser-Induced Transport of Nanoferrofluid in Water Using Fluorescein Isothiocyanate (FITC) as Fluorescence Marker

FITC-conjugated nanoferrofluid (FNFF) was synthesized and characterized to study the dynamic of laser-induced transport of NPs in water. The results confirmed a definite laser-induced enhanced velocity of NPs (100 μm⋅s−1) almost twice as much the without laser (i.e. Brownian motion). The diffusion coefficients of 17 × 10−6 m2⋅s−1 and 55 × 10−6 m2⋅s−1 were found for the cases without and with laser action respectively. The act of laser when switched on after NPs had reached the steady state was very prominent. The laser-induced heat and power generated by NPs were calculated 0.2μW⋅cm−3 and 0.4 pW⋅cm−2 respectively. Our experiment condition was non-adiabatic and that the heat generated was diffused into the surrounding. We considered the Maxwell’s criteria (Kp/Kw −1⋅K−1. Based on the Brownian diffusion and DLVO theory, at earlier times where the NPs are more dispersed within the medium are displaced faster. However, at later stages they become less mobile as they are agglomerated. The mechanisms for the enhanced mobility and laser transport of NPs are thought to be due to e.m.w induced force (i.e. an oscillatory motion) and laser absorptive force (i.e., photothermophoresis). A beam divergence of about 5.24°(or 91 mrad) was determined. A non-linear behaviour of laser beam was observed as a trajectory path within the water due to thermal heating hence causing the change of refractive index of medium and redistribution of NPs concentration.

A data-mining approach to biomarker identification from protein profiles using discrete stationary wavelet transform

Objective: To develop a new bioinformatic tool based on a data-mining approach for extraction of the most infor- mative proteins that could be used to find the potential biomarkers for the detection of cancer. Methods: Two independent datasets from serum samples of 253 ovarian cancer and 167 breast cancer patients were used. The samples were examined by surface- enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). The datasets were used to extract the informative proteins using a data-mining method in the discrete stationary wavelet transform domain. As a dimensionality re- duction procedure, the hard thresholding method was applied to reduce the number of wavelet coefficients. Also, a distance measure was used to select the most discriminative coefficients. To find the potential biomarkers using the selected wavelet coefficients, we applied the inverse discrete stationary wavelet transform combined with a two-sided t-test. Results: From the ovarian cancer dataset, a set of five proteins were detected as potential biomarkers that could be used to identify the cancer patients from the healthy cases with accuracy, sensitivity, and specificity of 100%. Also, from the breast cancer dataset, a set of eight proteins were found as the potential biomarkers that could separate the healthy cases from the cancer patients with accuracy of 98.26%, sensitivity of 100%, and specificity of 95.6%. Conclusion: The results have shown that the new bioinformatic tool can be used in combination with the high-throughput proteomic data such as SELDI-TOF MS to find the potential biomarkers with high discriminative power.

Photodynamic Therapy of Cancer Cells with Methanesulfonate Salts of 5-Aminolevulinic Acid and Its Derivatives

A series of 5-aminolevulinic acid and its alkylester methanesulfonates was exploited to photodynamic therapy（PDT） of human lymphocytic cells, U-937 in vitro. The PDT efficiency is influenced by the concentration and incubation time. Generally, for ALA and its alkylester methanesulfonates, the cell survival rate decreases and the accumulation ability of PplX increases with the concentration and incubation time. We found that the longer carbon chain methanesulfonates（C5-S, C6-S, C8-S） exhibit better PDT effect than ALA methanesulfonate. This possibly provides a promising route to the clinical application ofPplX-mediated PDT to cancer cell.

Establishment of management information system for SARS surveillance and control in Shaanxi province of China

Objective: To develop the management information system for SARS surveillance and control in Shaanxi province of China responding to the urgent needs for preventing and curing SARS disease. Methods: Based on geographic information system technology, the management information system for SARS disease in Shaanxi province of China was established using "SuperMap Objects 3.0" GIS development platform and Delphi 7.0.Results: The following functions were implemented in the system: the real-time collection and monitoring, management and analysis, dissemination of SARS disease information, and assistant decision-making support for prevention against SARS disease. Conclusion: The system that integrates epidemiology theories and GIS techniques together can provide a scientific, efficient means for monitoring, prevention of SARS disease in the future.

Current gamma knife treatment for ophthalmic branch of primary trigeminal neuralgia

AIM: To probe into problems existing in gamma knife treatment of ophthalmic branch of primary trigeminal neuralgia (TN), and propose a safe and effective solution to the problem. METHODS: Through sorting the literature reporting gamma knife treatment of refractory TN in recent years, this article analyzed the advantages and problems of gamma knife treatment of primary TN, and proposed reasonable assessment for existing problems and the possible solution. RESULTS: Gamma knife treatment of TN has drawn increasing attention of clinicians due to its unique non-invasion, safety and effectiveness, but there are three related issue; to be considered. The first one is the uncertainty of the optimal dose (70-90GY); the second one is the difference in radiotherapy target selection (using a single isocenter or two isocenters); and the third one is the big difference of recurrent pains (specific treatment methods need to be summarized and improved). CONCLUSION: For patients with refractory TN, gamma knife treatment can be selected when the medical treatment fails or drug side effects emerge. The analysis of a large number of TN patients receiving gamma knife treatment has shown that this is a safe and effective treatment method.

The Effects of Bone Screw Configurations on the Interfragmentary Movement in a Long Bone Fixed by a Limited Contact Locking Compression Plate

The locking compression plates (LCP) are efficient tools in open reduction and internal fixation (ORIF), especially in osteoporotic bones. Two important factors of screw density and screw position can affect the functionality of the bone plate. Several studies have assessed the influence of the screw configurations on the bone-plate stiffness, but the effects of screw positions on the interfragmentary strain, εIF of LCP construct have not been investigated yet. In this study, finite element method was used to investigate the influence of screws number and position on the interfragmentary strain of LCP-femur system for a mid-shaft fracture. Results of this study showed that by insertion of screws closer to the fracture site, εIF decreases by 2nd degree polynomial function versus screw position, but by adding the screws from the ends of the plate, or by moving and placing the screws towards the fracture site, the reduction of εIF will be linear. Results of this study were compared and are in agreement with some studies in the literature, even though their scope was mostly stability of the bone-implant system, whereas our scope was focused on the interfragmentary strain.

Silver-Doped Layers of Implants Prepared by Pulsed Laser Deposition

Physical and mechanical properties of silver-doped layers of titanium alloy Ti6Al4V and 316L steel prepared by pulsed laser deposition were studied. Metallic silver-doped coatings could be a new way for antibacterial protection in medicine. Thin films of silver and silver-doped materials were synthesized using KrF excimer laser deposition. The material was ablated from two targets, which composed either from titanium alloy with silver segments or from steel with silver segments. The concentration of silver ranged from 1.54 at.% to 4.32 at.% for steel and from 3.04 at.% to 13.05 at.% for titanium alloy. The layers properties such as silver content, structure, and adhesion were measured. Adhesion was stu- died using scratch test.

Multi-frequency bioimpedance measurements of rabbit shanks with stress fracture

Purpose: The objective of this research is to investigate whether bioimpedance is useful to indicate a shank’s physical condition during training. Methods: Bioimpedance was applied to monitor the condition of 8 rabbits’ shanks in 3 weeks, during which the rabbits were trained for regular excessive jump daily. Nine tibias in 16 developed stress fracture after the 3-week training. Results: According to the analysis of the bioimpedance data, we found that changing pattern of bioimpedance properties of shanks which were more liable to suffer from SF was different from that of shanks which were not during training. Conclusions: This suggests that bioimpedance may be used to monitor the physical condition of a limb, imply its liability to develop stress fracture, and indicate stress fracture during training.

Fabrication, Visualization and Analysis of Fluorescein Sodium Encapsulated PLGA@CS Nanoparticles as Model for Photothermomechanical Drug Delivery Using Pulsed 532 nm Laser

PLGA/CS nanoparticles containing fluorescein sodium as drug model were synthesized and characterized to investigate the feasibility of laser-induced drug delivery using pulse 532 nm. The main objective was to investigate the photothermally-induced mechanical force for transporting the nanoparticles. An argon laser was used to excite the fluorescence of the samples after irradiation. The preliminary results indicated that the drug nanoparticles encapsulated trapped by the cavitation bubbles can be transported by photothermomechanical effect. Different regions of interactions are defined and while in our case, the thermoelastic does not apply due to higher fluences, vaporization and laser-induced thermal breakdown (LITB) including the plasma formation and shock waves played an important and major role. Threshold fluences of 2.8, 18 and 102 Jcm-2 corresponding to 0.28, 1.8 and 10 GWcm-2 and 3.8, 30, and 171 MPa are determined for ablation, vaporization and LITB mechanisms respectively. The secondary microbubbles due to explosion of the primary transient cavitation bubbles played a key role in delivery process. Despite the dominant argon laser brightness, the laser-induced fluorescence spectroscopy (LIFS) demonstrated the fluorescence emission of the cavitation bubbles carrying due to the drug nanoparticles entrapped within the biogelatin after exposure to laser radiation, the irradiation, which confirms the possibility of transport of drug nanoparticles by laser cavitation. Finally, it is suggested that the nature of such photothermal and photo non-thermal mechanical effects is governed and influenced by determining and criticizing in terms of the type of nanomaterial as well as their synthesis process engineering and fabrication as they can be made case sensitive by selecting different types of materials for a specific application.