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  • Open access
  • 96 Reads
Potential of inert dust and Insect growth regulators against different life stages of Red Flour Beetle (Tribolium castaneum)

Tribolium castaneum is a major pest of stored products, in warmer climates. It infests seeds, kernels and other products, that have already been wounded by other pests during harvest and storage. Red flour beetle is a secondary pest it feed on the broken grains or on the remains of primary pest. Experiment was conducted to evaluated the efficacy of inert dust and IGR’s against the different life stages of T. castaneum through direct feeding bioassay. IGR’s were tested on 20, 10, 5, 2.5, 1.25, 0.75ppm and white kaolin clay was tested on 30, 25, 20, 15, 10g/kg. Two formulations of diatomaceous earth (100% pure food grade and calcium bentonite clay) of dose (400, 500, 600, 700 and 800 mg/kg and 500, 400, 250, 200 and 100mg/kg, respectively) were tested under lab conditions (22±2 °C, R. H. 55±5%, photo period 8 L:16 D). Results showed that white kaolin clay gave maximum control followed by Lufenuron> diatomaceous earth (100% food grade)> Methoxyfenozide> DE (calcium bentonite clay)> Pyriproxyfen after 21 days. Results also showed that all the treatments are dose and time dependent for the effective control. Further research work should be needed on residual studies to detect the deposited chemicals.

  • Open access
  • 62 Reads
Investigation of the Effect of Whitening Mouthwashes on the Translucency of Composite Resins at Different Times

The aim of this study is to evaluate the effect of whitening mouthwashes on translucency change (ΔTP) at different times of composite resins after coloring with coffee. In the study, a total of 90 samples (30 samples from each composite resin) were prepared from resin materials (Estelite Σ Quick, G-Aenial Anterior; Omnichroma). After kept in coffee for 12 days, the samples were divided into three subgroups (n=10). The initial (T0) measurement of TP values ​​were recorded. Control groups were kept in distilled water and the other groups were kept in two different mouthwashes (Listerine Advanced White, Crest 3D White). TP values ​​at the end of 24 hours (T1) and 72 hours (T2) were recorded. TP values ​​were determined using the CIEDE2000 formula. Two-way analysis of variance and Tukey test were used (p< 0.05). The lowest ΔTP value was observed in the control group at T0-T1 and T0-T2 times. The highest ΔTP value was observed in Crest 3D White mouthwash at T0-T2 time. However, there was no difference with Listerine Advance White. Among the composites, the highest ΔTP value was found in G-Aenial Anterior at T0-T2 time, and the lowest ΔTP value was found in Omnichroma at T0-T1 time. Whitening mouthwashes caused an increase in the translucency values of resin composites over time. It should be noted that long-term use of whitening mouthwashes may affect the translucency values of composite resins.

  • Open access
  • 36 Reads
Lyotropic Liquid Crystal Precursor as an Innovative Herpes Simplex Virus Vector for Melanoma Therapy

Oncolytic virotherapy has become the frontier of biological therapy for tumor treatment in recent years, especially the Herpes Simplex Virus-1 (HSV-1) approved by the U.S. Food and Drug Administration (FDA). However, current commercial formulations using HSV-1 require strict storage conditions (-80°C) to cope with its unstable characteristics. In addition, direct injection of HSV-1 may lead to virus migration to nontumor tissues or cause unexpected immune responses representing a therapeutic risk. Herein, we developed an HSV-loaded lyotropic liquid crystal precursor (LLCP) system with in situ gelation properties as the vector for HSV-1. The prepared HSV-LLCP showed a rapid gelling property (within 2 s) and the shear viscosity ranged from 5 to 9 mPa·s, indicating its excellent drug delivery performance. Upon encapsulating in LLCP, the storage conditions were improved to -4°C within 28 days, and the HSV-1 was protected with its unique crystal lattice. The release behavior of HSV-1 LLCP showed a triphasic sustained-release pattern during the experiment period, avoiding the potential side effects. In addition, HSV-LLCP exhibited a superior oncolytic activity compared to HSV-1 solution in murine melanoma B16 cells. This study showed that HSV-LLCP would become an alternative and promising HSV-1 vector with high safety and stability for melanoma treatment in the clinic.

  • Open access
  • 32 Reads
A spatially resolved temperature measurement system for a honeybee colony brood box

Honeybee colonies are dependent on suitable temperature conditions for healthy colony development. Here we design, build, test, and demonstrate the use of a spatially resolved temperature measurement system for a honeybee colony brood box. We adapted a British National hive by building ten customised brood frames, each equipped with forty-eight temperature sensors, equating to four-hundred and eighty sensors across the hive. Thermistors were chosen for the temperature sensor in particular because they give a suitable measurement range. Each frame was connected to three sixteen-channel analogue multiplexers, the resulting analogue voltage was further digitized with a Teensy 3.5 microcontroller with data automatically saved using a Raspberry Pi. Two different spatially resolved temperature measurement hive systems were built. The first used four layers of foundation wax to embed the sensor array, and after populating it with a colony, the honeybees removed the wax exposing the sensors before building new honeycomb. A second system was produced which used a single sheet of foundation wax onto which the sensors were laid, and a swarm was introduced to it. The colony accepted the system and was found to build normal comb on the frames. Highly valuable spatially resolved temperature data was collected over this period. Consequently, we demonstrate two spatially resolved temperature measurement systems for a honeybee colony corresponding data and pros and cons will be discussed.

  • Open access
  • 36 Reads
Effect of curing on MOD cavities restored with two different composites using two distinct techniques
, , , , , ,

Background. It’s well known that polymerization process hides negative aspects such as cuspal deflection mainly caused by shrinkage and temperature rise. Therefore, the purpose of this study was to assess the latter aspects of flowable and packable bulk-fill composites applied to mesio-occlusal-distal (MOD) cavities with bulk-fill or incremental layering technique.

Methods.The linear shrinkage and mechanical properties of two bulk-fill composites with different properties (high viscosity and low viscosity) were analyzed with an extensometer and compressive tests. Subsequently, cusp deformation and temperature rise recorded in MOD cavities of first maxillary human premolars restored with both bulk-fill and incremental layering techniques were evaluated. A thermocouple placed 1 mm below the cavity floor was used to measure temperature rise, meanwhile cusp deflection was appreciated with an extensometer.

Results.Shrinkage profiles recorder for flowable composite was significantly higher (p<0.5) than that of packable one; in addition, compression tests showed better results for the latter. The cuspal deflection measured in incremental technique was higher than that of bulk-fill technique for both flowable and packable composites. For each composite and technique, a temperature enhancement from 1.4 to 1.7 °C was observed.

Conclusions.No significant difference was observed for cusp deflection in both restorative techniques using both composites. Apparently, the higher Young’s modulus of the not very shrinkable packable composite and the lower Young’s modulus of the very shrinkable flowable composite seemed to balance the cusp distance variation. The small temperature rise observed in the present study during curing suggests that the process may be safe for pulp tissue.

  • Open access
  • 23 Reads
Digital design of high-precision magnetic field for hydrogen maser

Hydrogen maser is the time and frequency reference source of metrology, punctuality and scientific research in China, and it is the core equipment of national important projects such as deep space exploration, navigation and positioning. In this paper, a scheme to realize the digitization of magnetic field of hydrogen atomic clock is presented. We first design a simple programmable precise current source. And then we use a microprocessor-based intelligent control algorithm to automatically find the maximum power point corresponding to the output voltage of the single-chip microcomputer. Finally, the constant output voltage. In the actual test process, we designed the constant current source circuit output current step quantity can achieve 5uA high precision, spectrum analyzer sampling efficiency and the control system work accuracy is very high.

  • Open access
  • 29 Reads
In vitro evaluation of dental composites on human dental pulp stem cells differentiation

Dental composite materials can exert different effects. Particularly, monomers could influence the odontogenic differentiation in human dental pulp stem cells (hDPSCs). This preliminary study aimed to evaluate cytotoxicity of two novel composites and whether they can affect mineralization of hDPSCs. Ceram.x SpectraTM, a nanohybrid composite with pre-polymerized Sphere-Tec particles, and Admira Fusion, a nanohybrid restorative material with the innovative technology ORMOCER were tested. The samples and the eluates were prepared according to ISO 10993-12:2012. We treated hDPSCs in undifferentiated state with eluates for 4 days and performed MTT assay to evaluate cytotoxicity. The effect of the eluates on the hDPSCs mineralization capacity was evaluated after osteogenic differentiation by alizarin red staining and alkaline phosphatase (ALP) activity test. We assessed different dilutions of both eluates and observed that undiluted Ceram.x eluates were significantly cytotoxic over time, reducing cell viability of about 51,7% as compared to untreated cells. Further, the eluates obtained from ORMOCER technology composite did not display any adverse effect on hDPSCs viability. Moreover, we assessed that Ceram.x limited osteogenic activity of hDPSCs, while Admira Fusion did not appear to show any adverse effect. Our results show that composite with conventional dental monomer might exert cytotoxicity on hDPSCs as compared to ORMOCER technology. Indeed, the limited cell differentiation caused by Ceram.x could be explained by its cytotoxic effect. In this regard, the study is continuing to define cellular changes induced by the composites and to further identify the optimal dental composite resin for clinical use.

  • Open access
  • 77 Reads
Clinical Applications Of The Algorithm “Pipeline Advanced Contrast Enhancement (Pace)” In Dental Radiology

The Panoramic radiography is the result of a radiological technique that allows the reproduction of the dental arches and the support structures of a unique image. The clinical utility of panoramic radiography allows the overall assessment as well as the detection of structural abnormalities and/or possibly related to pathological lesions. The disadvantage of this technique is related to the lower quality of the images compared to endoral radiographs and TC scans, but especially to the attempt to represent a three-dimensional, curved anatomic region on a two-dimensional plane. This inevitably leads to geometric distortions of shape, enlargements, and overlaps that adversely affect the detection of any pathological entities. However, the most important advantage is the possibility of reducing patient exposure to ionizing rays.

The aim of digital radiology is to improve the characteristics of radiological machinery (through increasingly innovative and sophisticated data processing software and hardware) in order to obtain high quality images while reducing dosimetry, and to reduce "disturbing elements" in radiological images.

To overcome the limitations of the panoramic technique and to improve the quality of radiological images, and thus the effectiveness of diagnosis, image optimization software can be used.

In this regard, a tool called Pipeline for Advanced Contrast Enhancement (PACE) is being developed: this is an algorithm that allows image quality to be improved by optimizing contrast and reducing brightness inhomogeneity, resulting in increased definition, making details more evident.

The purpose of the proposed investigation is to evaluate if the application of the PACE algorithm in dental radiology could be an advantage because of the possibility of enhancing the quality of radiological images to make details of anatomical structures and related pathological lesions more obvious.

  • Open access
  • 41 Reads
Selection of conventional photoinitiators to produce biocompatible UV epoxidized soybean oil resin mixtures for 3D printing technology

The use of natural-based resins as matrices for 3D printing is currently an expanding area with a considerable potential to explore. These materials, in addition to presenting high biocompatibility, come from renewable natural resources, making them very attractive in terms of cost and environmental needs. In the production of objects by photopolymerization, natural-based resins can be used with photoinitiators, making them amenable to UV-curing. Thus, the choice of natural resins, photoinitiators and light sources, which allow proposing new formulations, with the biocompatibility properties of the natural material, and which can compete with those available on the market, justify research in this area. Whitin this context, five conventional photoinitiators namely, benzophenone, 2,2-dimethoxy-2-phenylacetophenone, ethylphenyl (2,4,6-trimetylbenzoyl) phosphinate, 2-chlorothioxannthen-9-one and 2-isopropylthioxanthone were tested and evaluated to promote de UV-curing of a natural resin derived from epoxidized soybean oil. Different mixtures were prepared, with 1-0.01% of photoinitiators (w/w, initial resin basis) and operational parameters such as time and wave-length source, were tested. Cured mixtures were evaluated concerning physicochemical structure, mechanical and biological properties. Results showed that, of the five photoinitiators studied, the most suitable to produce epoxidized soybean oil resin mixtures for 3D printing was ethylphenyl (2,4,6-trimetylbenzoyl) phosphinate. With its use, even in reduced amounts 0.01% (w/w), it was possible to produce transparent films and print pieces by stereolithography, with greater thickness, than those displayed by similar pieces prepared from mixtures of the same resin with other photoinitiators. The mechanical properties were similar to those obtained for the pieces produced with a commercial resin, which was used as reference, and no antibacterial activity was evidenced against Escherichia coli and Staphylococcus aureus by these new materials.

  • Open access
  • 27 Reads
Composite materials based on calcium polyphosphate, PVA and Mg2+ for bone applications

Polyphosphate (PP) is an inorganic polymer formed by the condensation of orthophosphate groups and represented by the formula [PO3-]n. Due to its properties, such as biocompatibility and low toxicity, polyphosphate presents itself as a biomimetic compound of hydroxyapatite, the main constituent of bone tissue. PP can be applied, for bone tissue applications, as a ceramic material in the form of calcium polyphosphate (CPP), due to its chemical similarity with hydroxyapatite. Thus, CPP has been used to develop scaffolds for bone tissue repair. However, CPP does not have adequate mechanical properties for application in bone, requiring the use of substances that add other properties to the material, such as resistance to compression and tension. For this, polymers, ions, and nanoparticles have been used as additives. In this context, this work presents the development of composite materials based on CPP, PVA, and Mg2+ as candidates for bone applications. The production of materials was based on the precipitation of CPP in an aqueous medium containing a pre-solubilized polymer, followed by the addition of Mg2+. The materials were characterized by TGA, SEM, EDS, and Raman. The results confirmed the formation of the composites, presenting a porous structure and containing a Ca/P ratio of 0.90. Thus, these composites have the potential to be applied in bone regeneration applications.