Understanding and exploring the diversity of soil microorganisms in tea (Camellia sinensis) gardens: toward sustainable tea production.

Leaves of Camellia sinensis plants are used to produce tea, one of the most consumed beverages worldwide, containing a wide variety of bioactive compounds that help to promote human health. Tea cultivation is economically important, and its sustainable production can have significant consequences in providing agricultural opportunities and lowering extreme poverty. Soil parameters are well known to affect the quality of the resultant leaves and consequently, the understanding of the diversity and functions of soil microorganisms in tea gardens will provide insight to harnessing soil microbial communities to improve tea yield and quality. Current analyses indicate that tea garden soils possess a rich composition of diverse microorganisms (bacteria and fungi) of which the bacterial Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes and Chloroflexi and fungal Ascomycota, Basidiomycota, Glomeromycota are the prominent groups. When optimized, these microbes' function in keeping garden soil ecosystems balanced by acting on nutrient cycling processes, biofertilizers, biocontrol of pests and pathogens, and bioremediation of persistent organic chemicals. Here, we summarize research on the activities of (tea garden) soil microorganisms as biofertilizers, biological control agents and as bioremediators to improve soil health and consequently, tea yield and quality, focusing mainly on bacterial and fungal members. Recent advances in molecular techniques that characterize the diverse microorganisms in tea gardens are examined. In terms of viruses there is a paucity of information regarding any beneficial functions of soil viruses in tea gardens, although in some instances insect pathogenic viruses have been used to control tea pests. The potential of soil microorganisms is reported here, as well as recent techniques used to study microbial diversity and their genetic manipulation, aimed at improving the yield and quality of tea plants for sustainable production.

Use of T-Scan III in analyzing occlusal changes in molar fixed denture placement.

BACKGROUND: This study aims to analyze the longitudinal variation of occlusal force distribution prior to and after fixed restoration for molar full-crowns with T-SCAN III which provide reference for occlusal adjustment and long-term maintenance. METHODS: We enrolled a total of 20 patients who received conventional restorative treatment for molars. The occlusion examination was conducted in 3 stages (before placement, immediately after placement, and 3 months after placement) using T-SCAN III (Tekscan South Boston, MA, USA, 10.0) to examine and measure the occlusal contact areas of the full dentition. RESULTS: The results indicated that the occlusal force distribution in the molar region of the patients changed before and after the fixed restoration, but the percentages of occlusal force in the dental arch of the molar did not differ significantly before and after the restoration (P > 0.05). Three months after the fixed restoration, the percentage of occlusal force in the restored dental arches of lateral teeth increased significantly (P < 0.05). CONCLUSION: The results of this study indicated that the occlusal forces of the patients changed with tooth movement and adaptation, which is mainly reflected in the increasing occlusal force. Quantitative occlusal force analysis using T-SCAN III occlusal analyzer can provide more objective and accurate data to effectively guide clinical occlusion adjustments.

Three New Species of Russulaceae (Russulales, Basidiomycota) from Southern China.

The characterization of natural fungal diversity impacts our understanding of ecological and evolutionary processes and can lead to novel bioproduct discovery. Russula and Lactarius, both in the order Russulales, represent two large genera of ectomycorrhizal fungi that include edible as well as toxic varieties. Based on morphological and phylogenetic analyses, including nucleotide sequences of the internal transcribed spacer (ITS), the 28S large subunit of ribosomal RNA (LSU), the second largest subunit of RNA polymerase II (RPB2), the ribosomal mitochondrial small subunit (mtSSU), and the translation elongation factor 1-α (TEF1-α) gene sequences, we here describe and illustrate two new species of Russula and one new species of Lactarius from southern China. These three new species are: R. junzifengensis (R. subsect. Virescentinae), R. zonatus (R. subsect. Crassotunicatae), and L. jianyangensis (L. subsect. Zonarii).

Student perceptions toward virtual reality training in dental implant education.

Objectives: Both the shortage of professional teaching resources and the expensive dental implant supplies impede the effective training of dental undergraduate in implantology. Virtual reality (VR) technology may provide solutions to solve these problems. This pilot study was implemented to explore the usability and acceptance of a VR application in the training of dental implant among dental students at the Jinan University School of Stomatology. Methods: We designed and developed a VR system with head-mounted displays (HMDs) to assist dental implant training. Undergraduate dental students were invited to experience a 30-minute "Introduction to dental implants" VR-HMDs training module. A total of 119 dental students participated the training. Firstly, the VR interactive training on dental implant was described, illustrated and practiced. Next, a system usability scale (SUS) survey was used to verify the usability and feasibility of the VR application on training dental students. Finally, the participants were given a questionnaire to provide their perceptions and feedback of the usefulness of the VR application for training dental implant skills. Results: The SUS score was 82.00 ± 10.79, indicating a top 10 percentage ranking of the system's usabilitys. The participants' answers to the questionnaire reflected most of them exhibited strong interests in the VR system, with a tendency that the female students were more confident than the male in manipulating the VR system. The participants generally acknowledged the usefulness of VR dental implants, ranking VR value above the traditional laboratory operations, and a preference for using the VR system on learning other skills. They also gave valuable suggestions on VR dental implants for substantial improvement. However, some students were not strongly positive about the VR training in this study, the reason might lie in a more theoretical module was selected for testing, which impacted the students' ratings. Conclusions: In this study we revealed the feasibility and usability of VR applications on training dental implant among undergraduate dental students. This pilot study showed that the participants benefited from the dental implant VR training by practicing the skills repeatedly. The feedback from student participants affirmed the advantages and their acceptance of the VR application in dental education. Especially, the VR-based technology is highly conducive to clinical operating skills and surgical procedures-focused training in medical education, indicating that the VR system should be combined with the traditional practice approach in improving dental students' practical abilities.

Isolation of a highly virulent Metarhizium strain targeting the tea pest, Ectropis obliqua.

Introduction: Tea is one of the most widely consumed beverages around the world. Larvae of the moth, Ectropis obliqua Prout (Geometridae, Lepidoptera), are one of the most destructive insect pests of tea in China. E. obliqua is a polyphagus insect that is of increasing concern due to the development of populations resistant to certain chemical insecticides. Microbial biological control agents offer an environmentally friendly and effective means for insect control that can be compatible with "green" and organic farming practices. Methods: To identify novel E. obliqua biological control agents, soil and inset cadaver samples were collected from tea growing regions in the Fujian province, China. Isolates were analyzed morphologically and via molecular characterization to identity them at the species level. Laboratory and greenhouse insect bioassays were used to determine the effectiveness of the isolates for E. obliqua control. Results: Eleven isolates corresponding to ten different species of Metarhizium were identified according to morphological and molecular analyses from soil and/or insect cadavers found on tea plants and/or in the surrounding soil sampled from eight different regions within the Fujian province, China. Four species of Metarhizium including M. clavatum, M. indigoticum, M. pemphigi, and M. phasmatodeae were documented for the first time in China, and the other species were identified as M. anisopliae, M. brunneum, M. lepidiotae, M. majus, M. pinghaense, and M. robertsii. Insect bioassays of the eleven isolates of Metarhizium revealed significant variation in the efficacy of each isolate to infect and kill E. obliqua. Metarhizium pingshaense (MaFZ-13) showed the highest virulence reaching a host target mortality rate of 93% in laboratory bioassays. The median lethal concentration (LC50) and median lethal time (LT50) values of M. pingshaense MaFZ-13 were 9.6 × 104 conidia/mL and 4.8 days, respectively. Greenhouse experiments and a time-dose-mortality (TDM) models were used to further evaluate and confirm the fungal pathogenic potential of M. pingshaense MaFZ-13 against E. obliqua larvae. Discussion: Isolation of indigenous microbial biological control agents targeting specific pests is an effective approach for collecting resources that can be exploited for pest control with lowered obstacles to approval and commercialization. Our data show the presence of four different previously unreported Metarhizium species in China. Bioassays of the eleven different Metarhizium strains isolated revealed that each could infect and kill E. obliqua to different degrees with the newly isolated M. pingshaense MaFZ-13 strain representing a particularly highly virulent isolate potentially applicable for the control of E. obliqua larvae.

Application in the analysis of the occlusal force of free-end missing tooth implant restoration with T-SCAN III.

Introduction: The occlusal force of the teeth in the dental arch and the remaining adjacent natural teeth will change after implant restoration with a free-end missing tooth. This study intends to use the T-SCAN III scanner to collect dynamic quantitative data before and after the restoration of free-end implants and to explore the application of the T-SCAN III in redistributing the occlusal force of free-end implants. Methods: In this study, 24 patients with free-end implant restoration were selected, and their occlusion was tested before, immediately after, and 3 months after implant restoration. Results: In all 24 cases, the bite force of the first natural tooth adjacent to the implanted tooth after restoration changed from 19.12% ± 9.48%-12.93% ± 11.47% (p < 0.01). For additional data analysis, all cases were further subdivided by single implant and fixed bridge restorations. In 17 cases, there was a successful follow-up after 3 months. The percentage of the total bite force of dental arch with implant increased from 41.92% ± 10.78%-53.06% ± 10.71% (p < 0.01). Discussion: This study shows that the free-end implant restoration protects the remaining natural teeth, and the patient's missing dental arch bite force improves within 3 months of implant restoration.

Development of LTCC-packaged optocouplers as optical galvanic isolation for high-temperature applications.

This paper reports high-temperature optocouplers for signal galvanic isolation. Low temperature co-fired ceramic (LTCC) technology was used in the design and fabrication of the high-temperature optocoupler package. The optimal coupling behaviors, driving capabilities and response speed of the optocouplers were concentrated and investigated in this paper. Emitters and detectors with different emission and spectral wavelengths were studied to achieve optimal coupling behaviors. Relatively high coupling efficiency is achieved with emitters and detectors of emission and spectral wavelength in the red spectrum (i.e., 620-750 nm), leading to higher current transfer ratios (CTR). To further enhance the electrical performance, optocouplers with multiple detectors in parallel were designed and fabricated. CTR, leakage current and response speed (i.e., propagation delay, rise time and fall time) of the optocouplers were characterized over a range of temperatures from 25 to 250 °C. The CTR degrades at high temperatures, while the leakage current and response speed show little degradation with varying temperatures. Furthermore, the behaviors of the optocouplers with varying temperatures are modeled and analyzed.

Virtual reality approach for orthodontic education at School of Stomatology, Jinan University.

OBJECTIVES: The development of virtual reality (VR) has exerted an enormous impact on higher education. However, the VR application in dental education is still at an early stage in China. This study explored the usability of a VR application in training the practical skills of dental students. METHODS: We first utilized the "system usability scale" (SUS) to verify the validity of the VR application in this study. Next, the VR training on orthodontic bracket bonding was experienced by the participants. The subsequent survey was delivered to collect the participants' perception and evaluation of the VR system application in training the practical skills of prospective dentists. RESULTS: The SUS score was 76.17 ± 9.89, suggesting an above-average evaluation of the system's usability and maturity. The response from the questionnaire supplied relatively positive responses to the VR system application on "user experiences," "perceived usefulness of VR application on orthodontics," and "perceived ease of manipulation." The male students exhibited strong interest in manipulating the VR system and were more capable of manipulating the VR system than the female students. VR experience did not affect the participants' responses to the questions. CONCLUSIONS: Overall, the use of VR in dental education achieved the expected outcomes. Most students identified the VR training as an enjoyable learning process, and it could be repetitively experienced without further costs, which might have potential positive effects on long-term learning outcomes, although there is room to further improve the effectiveness evaluation of VR.

High-temperature analysis of optical coupling using AlGaAs/GaAs LEDs for high-density integrated power modules.

A low-temperature co-fired ceramic (LTCC)-based optocoupler design is demonstrated as a possible solution for optical isolation in high-density integrated power modules. The design and fabrication of LTCC based package are discussed. Commercially available aluminum gallium arsenide/gallium arsenide (AlGaAs/GaAs) double heterostructure is used both as emitter and photodetector in the proposed optocoupler. A detailed study on the electroluminescence and spectral response of the AlGaAs/GaAs structure is conducted at elevated temperatures. The material figure of merit parameter, D*, is calculated in the temperature range 77-800 K. The fabricated optocoupler is tested at elevated temperatures, and the results are presented.