Objective: To determine the presence of bacteria by means of microbiological analysis on the surfaces contacted by the operator during the taking and processing of intraoral radiographs at different times of the day in the Oral Radiology Service of the UPCH. Materials and methods: Nine surfaces of the oral radiology service were sampled. The samples were taken at two times by the same investigator; at the beginning and the end of the activities in the service, the surfaces were swabbed with Trypticase Soy Broth (TSB). The samples were inoculated and incubated in three culture media (Plate Count Agar, Lamb’s Blood Agar and Cetrimide Agar). Then the respective Colony Forming Unit (CFU) count was performed and Gram staining was also performed. Results: A high concentration of bacteria (4180 CFU/mL) and fungi was found in the oral radiology service. Gram-positive cocci were the most frequently found microorganisms and gram-negative bacilli were less frequently found. Conclusions: There is a high contamination of bacteria in the oral radiology service. When the activities are completed, the number of bacteria decreases, but the variety of bacteria increases.

Lettuce (Lactuca sativa L.) is the main leafy vegetable grown in Brazil. Its productivity and quality are limited by the growing season, the nearby environment and the type of cultivar adopted. The objective of this work was to verify at different times of the year the best planting environment for lettuce cultivation in a semi-humid tropical climate. For this purpose, an experiment was set up in three different seasons (October–November 2014, January–March, May–July 2015). The experimental design was randomized blocks, in a 3 × 3 × 2 factorial arrangement, consisting of three seasons, three cultivars (cvs. Vera^®, Tainá^® and Rafaela^®) and two growing environments (low tunnel with beds protected with mulching consisting of soil protection with plastic fabric covering, and beds without protection or conventional cultivation) and four replicates per treatment. Plant biomass, stem length, head diameter, number of leaves per head and crop productivity were evaluated as response parameters. The results showed that the May–July period favored biomass production, head diameter and productivity. Despite the similarity between varieties, the variety Vera^® is more productive in biomass, number of leaves per head, stem length and productivity. The low tunnel planting system with mulching is adequate under the conditions evaluated for lettuce cultivation. This system in the May–July period favors a superior development in the characteristics biomass, head diameter and productivity, if compared to conventional cultivation during the October–November period.

The gravure printing process is widely utilized for large-scale, high-quality, multi-colored printing tasks executed at high press speeds. This includes a diverse range of products such as art books, greeting cards, currency, stamps, wallpaper, magazines, and more. This thesis addresses the fire risks associated with gravure printing, acknowledging the use of highly flammable materials and the potential for static charge-related incidents. Despite its prevalence, there is limited research on fire prevention and control in gravure printing. The study employs field observations, stakeholder interviews, and an extensive review of literature on fire risk and control in printing press operations in India. It analyzes the causes of fires using the fire triangle model, emphasizing the role of heat, combustible materials, and oxygen in fire incidents within the printing press environment. The thesis categorizes preventive measures into fire prevention and fire suppression actions, focusing on reducing fire load, static charge mitigation, and implementing firefighting systems. It observes that poor housekeeping, lack of awareness, and inadequate emergency control plans contribute significantly to fire hazards in press facilities. Additionally, the research identifies key factors such as high press temperatures, low humidity, improper storage, and inadequacies in firefighting systems as potential causes of fires. It emphasizes the need for optimal environmental conditions, proper storage practices, and effective firefighting infrastructure within press facilities. The study concludes with comprehensive guidelines for loss prevention and control, including management programs, housekeeping, operator training, pre-emergency planning, preventive maintenance, and plant security. It also addresses safety measures specific to gravure printing presses, such as automatic sprinkler systems, fire hydrant system, carbon dioxide flooding systems, and portable fire extinguishers. In summary, this thesis provides valuable insights into the multifaceted nature of fire risks in gravure printing presses and recommends a holistic approach for effective fire prevention and control.

Lead sulfide (PbS) is an important IV-VI semiconductor material with narrow bandwidth and wide wave width, which attracts people's attention. Nano-level PbS has many novel optoelectronic properties and has a wide range of applications in the field of optoelectronics, such as infrared optoelectronic devices, photovoltaic devices, light-emitting devices and display devices. In this paper, Pbs is produced by solvent thermal method by using lead acetate as lead source, sulfur power as sulfur source, ethylene glycol as solvent, and acetic acid to provide acidic environment. The reaction acidity, type of lead source, amount of sulfur source and other aspects will be explored. The products obtained under different conditions were characterized by X-ray diffraction (XRD), optical microscopy and scanning electron microscopy (SEM). The results showed that PbS produced at 140°C for 24 hours, using 14mL ethylene glycol and 1.2mL acetic acid has the best morphology. It has a non-planar six-arm symmetrical structure. Finally, we prepare the lead sulfide composite Ni/PbS, and characterized it.

In the context of Vietnam’s extensive international integration, economic concentration emerges as a pivotal strategy employed by businesses across various sectors, notably the retail industry, to foster expansion and bolster competitiveness within the market. As this trend evolves, it necessitates the formulation by the Vietnamese Government of a comprehensive and stringent legal framework tailored to regulate economic concentration among enterprises. Such measures are imperative to preclude the curtailment of market competition, which could potentially undermine the equity and vitality of the business environment in Vietnam. This paper meticulously examines and elucidates theoretical nuances surrounding economic concentration in the retail sector. Additionally, it scrutinizes the current landscape, assessing the impact of extant legislation governing economic concentration and the efficacy of enforcement activities in this realm within the Vietnamese retail sector. Consequently, the paper proffers judicious recommendations to enhance the efficacy of legal mechanisms governing economic concentration to foster competition and fortify Vietnam’s overall economic prowess, particularly within the retail sector.

In order to optimize the environmental factors for cucumber growth, a fertilizer and water control system was designed based on the Internet of Things (IoT) system. The IoT system monitors environmental factors such as temperature, light and soil Ec value, and uses image processing to obtain four growth indicators such as cucumber stem height, stem diameter size, number of leaves and number of fruit set to establish a single growth indicator model for temperature, light, soil Ec value and growth stage, and the four growth indicators were fused to obtain the comprehensive growth indicator I_c for cucumber, and calculates its deviation to determine the cucumber growth status. Based on the integrated growth index I_c of cucumber, a soil Ec control model was established to provide the optimal environment and fertilizer ration for cucumber at different growth stages to achieve stable and high yield of cucumber.