Antibacterial polymethylmethacrylate (PMMA)/ beta tri calsium phosphate/ zinc oxide composites for craniofacial reconstruction

Polymethylmethacrylate (PMMA) is commonly used in dental and bone reconstruction applications due to the excellent properties such as biocompatible, biologically inert and rigid. In craniofacial, traumatic injuries will result to the defect of underlying brain. Somehow, after reconstruction of scull using PMMA, the infection may occur. Thus, incorporation of antibacterial agent such as beta tricalcium phosphate (β-TCP) to the PMMA is desirable to eliminate infection. Also, the presence of β-TCP to the composites is one of the alternatives to promote cell growth to the surrounding bone tissue. Hence, in this study, PMMA composites fabricated with specified percentages of filler content of β-TCP and Zinc Oxide. The composites divided into three groups of different percentages of 5, 10, 15% β-TCP without ZnO, and another two groups, 2.5% and 5% ZnO were added 15% β-TCP. The size of β- TCP was approximately 1-5μm and ZnO was in nano size (256nm). The mechanical characteristics, chemical bonding, and physical properties of the specimen were next assessed. The characterization of specimen was then evaluated for mechanical properties, chemical bonding, physical properties. Observations of the microstructure of the fracture surface were performed by Field Emission scanning electron microscopy (FESEM). Chemical groups existed were confirmed with analysis of Fourier Transmission InfraRed (FTIR). The mechanical properties showed the improvement for PMMA composites. There is significant difference detected between PMMA pure and PMMA composites in physical properties. The cytotoxicity effect was investigated through 3-(4, 5-dimethylthiazoyl)-2-5 diphenyl-tetrazolium bromide (MTT assay), using human fetal osteoblast cell (hFOB). The hFOB cultured with 25 mg/ml PMMA filled 15% βTCP and 5% ZnO demonstrated the highest cell viability (132.73%). The percentages of cell viability of samples with 50 mg/ml and below showed no cytotoxicity effect due to their value of cell viability were more than 70%. The antibacterial properties of the PMMA composite were evaluated using agar diffusion and growth curve methods against Gram positive (Staphylococcus aureus) and gram negative (Pseudomonas aeruginosa). A significant difference was observed with the incorporation of ZnO filler in the agar diffusion test. The antibacterial property of PMMA composites were further evaluated with a growth curve and significant antibacterial activity was found on PMMA composites with 2.5% and 5% of ZnO filled. In conclusion, PMMA composites at 2.5% and 5% ZnO, are promising biomaterials that suit to be applied as implants in craniofacial reconstruction

Extinction Coefficient of Gold Nanostars

Gold nanostars (NStars) are highly attractive for biological applications due to their surface chemistry, facile synthesis, and optical properties. Here, we synthesize NStars in HEPES buffer at different HEPES/Au ratios, producing NStars of different sizes and shapes and therefore varying optical properties. We measure the extinction coefficient of the synthesized NStars at their maximum surface plasmon resonances (SPRs), which range from 5.7 × 10⁸ to 26.8 × 10⁸ M⁻¹ cm⁻¹. Measured values correlate with those obtained from theoretical models of the NStars using the discrete dipole approximation (DDA), which we use to simulate the extinction spectra of the nanostars. Finally, because NStars are typically used in biological applications, we conjugate DNA and antibodies to the NStars and calculate the footprint of the bound biomolecules.United States. National Institutes of Health (AI100190

Rapid Diagnostics for Infectious Disease using Noble Metal Nanoparticles

Rapid point-of-care (POC) diagnostic devices are needed for field-forward screening of severe acute systemic febrile illnesses such as dengue, Ebola, chikungunya, and others. Multiplexed rapid lateral flow diagnostics have the potential to distinguish among multiple pathogens, thereby facilitating diagnosis and improving patient care. We present a platform for multiplexed pathogen detection which uses gold or silver nanoparticles conjugated to antibodies to sense the presence of biomarkers for different infectious diseases. We exploit the size-dependent optical properties of Ag NPs to construct a multiplexed paperfluidic lateral flow POC sensor. AgNPs of different sizes were conjugated to antibodies that bind to specific biomarkers. Red AgNPs were conjugated to antibodies that could recognize the glycoprotein for Ebola virus, green AgNPs to those that could recognize nonstructural protein 1 for dengue virus, and orange AgNPs for non structural protein 1 for yellow fever virus. Presence of each of the biomarkers resulted in a different colored band on the test line in the lateral flow test. Thus, we were able to use NP color to distinguish among three pathogens that cause a febrile illness. Because positive test lines can be imaged by eye or a mobile phone camera, the approach is adaptable to low-resource, widely deployable settings. This design requires no external excitation source and permits multiplexed analysis in a single channel, facilitating integration and manufacturing. We will also discuss engineering the nanoparticle physical properties and surface chemistry for improving detection and also optimizing device properties, and expansion of the device to detect other diseases

Growth and physiological responses of Shorea materialis Ridl. seedlings to various light regimes and fertilizer levels under nursery condition

Relative light intensity (RLI) is one of the most significant factors that affect plant growth by controlling physiological traits of plants in terms of photosynthesis, respiration, stomatal conductance, and chlorophyll synthesis, among others. An experiment was conducted in the shade house and open area to determine the effect of three light intensities, viz. 30%, 50% and 100% RLI, and three levels of NPK fertilizer, viz. 0,1 and 2 g. plant-1 month-1 on the growth and physiological traits of Shorea materialis seedlings. During the six-months study period, survival percentage, growth performance and chlorophyll content of the species were monitored every three months, while other physiological parameters, such as photosynthetic rate, stomatal conductance, and stomatal density were recorded at the end of the experiment. The results showed that survival percentage of the seedlings was not significantly affected by different light conditions and fertilizer levels, and it was 100% for all treatment combinations. On the other hand, growth and physiological properties except stomatal density were significantly affected by both the above factors. The seedlings growing under 30% to 50% RLI were significantly better than those under full sunlight, in terms of height increment, diameter increment, leaf number increment, chlorophyll content, photosynthetic rate and stomatal conductance. In addition, the seedlings treated with 1 g NPK were significantly better than the control for photosynthetic rate and stomatal conductance. However, the seedlings fertilized with 2 g NPK were significantly greater than the control, in the matter of height increment, leaf number increment, chlorophyll content. Generally, the species should be planted under 30 to 50% RLI with 1 to 2 g of NPK (monthly) to produce a healthy and high growth of the species

Preparation, characterization, and radiolabeling of [68Ga]Nodaga-pamidronic acid: a potential PET bone imaging agent

Early diagnosis of bone metastases is crucial to prevent skeletal-related events, and for that, the non-invasive techniques to diagnose bone metastases that make use of image-guided radiopharmaceuticals are being employed as an alternative to traditional biopsies. Hence, in the present work, we tested the efficacy of a gallium-68 (68Ga)-based compound as a radiopharmaceutical agent towards the bone imaging in positron emitting tomography (PET). For that, we prepared, thoroughly characterized, and radiolabeled [68Ga]Ga-NODAGA-pamidronic acid radiopharmaceutical, a 68Ga precursor for PET bone cancer imaging applications. The preparation of NODAGA-pamidronic acid was performed via the N-Hydroxysuccinimide (NHS) ester strategy and was characterized using liquid chromatography-mass spectrometry (LC-MS) and tandem mass spectrometry (MSn). The unreacted NODAGA chelator was separated using the ion-suppression reverse phase-high performance liquid chromatography (RP-HPLC) method, and the freeze-dried NODAGA-pamidronic acid was radiolabeled with 68Ga. The radiolabeling condition was found to be most optimum at a pH ranging from 4 to 4.5 and a temperature of above 60 °C. From previous work, we found that the pamidronic acid itself has a good bone binding affinity. Moreover, from the analysis of the results, the ionic structure of radiolabeled [68Ga]Ga-NODAGA-pamidronic acid has the ability to improve the blood clearance and may exert good renal excretion, enhance the bone-to-background ratio, and consequently the final image quality. This was reflected by both the in vitro bone binding assay and in vivo animal biodistribution presented in this research

Cloaking nanoparticles with protein corona shield for targeted drug delivery

Targeted drug delivery using nanoparticles can minimize the side effects of conventional pharmaceutical agents and enhance their efficacy. However, translating nanoparticle-based agents into clinical applications still remains a challenge due to the difficulty in regulating interactions on the interfaces between nanoparticles and biological systems. Here, we present a targeting strategy for nanoparticles incorporated with a supramolecularly pre-coated recombinant fusion protein in which HER2-binding affibody combines with glutathione-S-transferase. Once thermodynamically stabilized in preferred orientations on the nanoparticles, the adsorbed fusion proteins as a corona minimize interactions with serum proteins to prevent the clearance of nanoparticles by macrophages, while ensuring systematic targeting functions in vitro and in vivo. This study provides insight into the use of the supramolecularly built protein corona shield as a targeting agent through regulating the interfaces between nanoparticles and biological systems

Characterization and source identification of fine particulate matter in urban Beijing during the 2015 Spring Festival

The Spring Festival (SF) is the most important holiday in China for family reunion and tourism. During the 2015 SF an intensive observation campaign of air quality was conducted to study the impact of the anthropogenic activities and the dynamic characteristics of the sources. During the study period, pollution episodes frequently occurred with 12 days exceeding the Chinese Ambient Air Quality Standards for 24-h average PM2.5 (75 μg/m3), even 8 days with exceeding 150 μg/m3. The daily maximum PM2.5 concentration reached 350 μg/m3 while the hourly minimum visibility was <0.8 km. Three pollution episodes were selected for detailed analysis including chemical characterization and diurnal variation of the PM2.5 and its chemical composition, and sources were identified using the Positive Matrix Factorization model. The first episode occurring before the SF was characterized by more formation of SO42− and NO3− and high crustal enrichment factors for Ag, As, Cd, Cu, Hg, Pb, Se and Zn and seven categories of pollution sources were identified, whereby vehicle emission contributed 38% to the PM2.5. The second episode occurring during the SF was affected heavily by large-scale firework emissions, which led to a significant increase in SO42−, Cl−, OC, K and Ba; these emissions were the largest contributor to the PM2.5 accounting for 36%. During the third episode occurring after the SF, SO42−, NO3−, NH4+ and OC were the major constituents of the PM2.5 and the secondary source was the dominant source with a contribution of 46%. The results provide a detailed understanding on the variation in occurrence, chemical composition and sources of the PM2.5 as well as of the gaseous pollutants affected by the change in anthropogenic activities in Beijing throughout the SF. They highlight the need for limiting the firework emissions during China's most important traditional festival

Global prevalence and genotype distribution of hepatitis C virus infection in 2015 : A modelling study

Publisher Copyright: © 2017 Elsevier LtdBackground The 69th World Health Assembly approved the Global Health Sector Strategy to eliminate hepatitis C virus (HCV) infection by 2030, which can become a reality with the recent launch of direct acting antiviral therapies. Reliable disease burden estimates are required for national strategies. This analysis estimates the global prevalence of viraemic HCV at the end of 2015, an update of—and expansion on—the 2014 analysis, which reported 80 million (95% CI 64–103) viraemic infections in 2013. Methods We developed country-level disease burden models following a systematic review of HCV prevalence (number of studies, n=6754) and genotype (n=11 342) studies published after 2013. A Delphi process was used to gain country expert consensus and validate inputs. Published estimates alone were used for countries where expert panel meetings could not be scheduled. Global prevalence was estimated using regional averages for countries without data. Findings Models were built for 100 countries, 59 of which were approved by country experts, with the remaining 41 estimated using published data alone. The remaining countries had insufficient data to create a model. The global prevalence of viraemic HCV is estimated to be 1·0% (95% uncertainty interval 0·8–1·1) in 2015, corresponding to 71·1 million (62·5–79·4) viraemic infections. Genotypes 1 and 3 were the most common cause of infections (44% and 25%, respectively). Interpretation The global estimate of viraemic infections is lower than previous estimates, largely due to more recent (lower) prevalence estimates in Africa. Additionally, increased mortality due to liver-related causes and an ageing population may have contributed to a reduction in infections. Funding John C Martin Foundation.publishersversionPeer reviewe

Association of respiratory symptoms and lung function with occupation in the multinational Burden of Obstructive Lung Disease (BOLD) study

Background Chronic obstructive pulmonary disease has been associated with exposures in the workplace. We aimed to assess the association of respiratory symptoms and lung function with occupation in the Burden of Obstructive Lung Disease study. Methods We analysed cross-sectional data from 28 823 adults (≥40 years) in 34 countries. We considered 11 occupations and grouped them by likelihood of exposure to organic dusts, inorganic dusts and fumes. The association of chronic cough, chronic phlegm, wheeze, dyspnoea, forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1)/FVC with occupation was assessed, per study site, using multivariable regression. These estimates were then meta-analysed. Sensitivity analyses explored differences between sexes and gross national income. Results Overall, working in settings with potentially high exposure to dusts or fumes was associated with respiratory symptoms but not lung function differences. The most common occupation was farming. Compared to people not working in any of the 11 considered occupations, those who were farmers for ≥20 years were more likely to have chronic cough (OR 1.52, 95% CI 1.19–1.94), wheeze (OR 1.37, 95% CI 1.16–1.63) and dyspnoea (OR 1.83, 95% CI 1.53–2.20), but not lower FVC (β=0.02 L, 95% CI −0.02–0.06 L) or lower FEV1/FVC (β=0.04%, 95% CI −0.49–0.58%). Some findings differed by sex and gross national income. Conclusion At a population level, the occupational exposures considered in this study do not appear to be major determinants of differences in lung function, although they are associated with more respiratory symptoms. Because not all work settings were included in this study, respiratory surveillance should still be encouraged among high-risk dusty and fume job workers, especially in low- and middle-income countries.publishedVersio