Paraffin wax is the most common phase change material (PCM) that has been broadly studied, leading to a reliable optimal for thermal energy storage in solar energy applications. The main advantages of paraffin are its high latent heat of fusion and low melting point that appropriate solar thermal energy application. In addition to its accessibility, ease of use, and ability to be stored at room temperature for extended periods of time, Nevertheless, improving its low thermal conductivity is still a big, noticeable challenge in recently published work. In this work, the effect of adding nano-Cu₂O, nano-Al₂O₃ and hybrid nano-Cu₂O-Al₂O₃ (1:1) at different mass concentrations (1, 3, and 5 wt%) on the thermal characteristics of paraffin wax is investigated. The measured results showed that the peak values of thermal conductivity and diffusivity are achieved at a wight concentration of 3% when nano-Cu₂O and nano-Al₂O₃ are added to paraffin wax with significant superiority for nano-Cu₂O. While both of those thermal properties are negatively affected by increasing the concentration beyond this value. The results also showed the excellence of the proposed hybrid nanoparticles compared to nano-Cu₂O and nano-Al₂O₃ as they achieve the highest values of thermal conductivity and diffusivity at a weight concentration of 5.0 wt%.

Cellulose nanocrystal, known as CNCs, is a form of material that can be produced by synthesizing carbon from naturally occurring substances, such as plants. Due to the unique properties it possesses, including a large surface area, impressive mechanical strength, and the ability to biodegrade, it draws significant attention from researchers nowadays. Several methods are available to prepare CNC, such as acid hydrolysis, enzymatic hydrolysis, and mechanical procedures. The characteristics of CNC include X-ray diffraction, transmission electron microscopy, dynamic light scattering, etc. In this article, the recent development of CNC preparation and its characterizations are thoroughly discussed. Significant breakthroughs are listed accordingly. Furthermore, a variety of CNC applications, such as paper and packaging, biological applications, energy storage, etc., are illustrated. This study demonstrates the insights gained from using CNC as a potential environmentally friendly material with remarkable properties.

Introduction: In Colombia, the last oral health study showed that about 70% of the population has partial edentulism while 5.2% will have lost all their teeth between the age of 65 and 79. Rehabilitation with implants is an increasingly used option, which requires clinical and radiographic follow-up. Panoramic radiography is a low-cost option, in which it is possible to observe areas of bone loss, mesiodistal angulation of the implant, relationship with anatomical structures and lesions suggestive of peri-implantitis. Reports and analysis of relevant data on radiographic findings associated with dental implants are required to determine the risk factors for their success in patients who use them. Objective: To determine the prevalence and characterize the findings associated with osseointegration implants in panoramic radiographs. Methods: A descriptive cross-sectional observational study was carried out with 10,000 digital panoramic radiographs selected by convenience from radiological centers in the city of Bogota, Colombia, of which 543 corresponded to the sample analyzed for the presence of implants. The following were evaluated for each implant: location, position, angulation and distances to adjacent structures, using the Clínicalview® program (Orthopantomograph OP200D, Instrumentarium, USA). Results: The frequency of radiographs with implants was 5.43% with a total of 1,791 implants, with an average of 3.2 per radiograph. They were found in greater proportion in the upper jaw with a supracrestal location and an angulation of 10.3 degrees. 32% had implant/tooth or implant/implant distances that were less than optimal. 40.9% were restored and 1.2% showed lesions compatible with periimplantitis. Conclusions: A high percentage of the implants reviewed have a risk factor that affects their long-term viability, either due to angulation, supracrestal or crestal position, proximity to teeth or other implants, or because they are not restorable.

Objective: To study the changes of growth, physiological and absorption characteristics of Pinus bungeana under ozone (O₃) stress, to elucidate the correlations among the indicators, and to determine its degree of response to O₃. Methods: The growth, physiological characteristics and O₃ uptake capacity of Pinus bungeana seedlings were measured in an open-top O₃ fumigation manual control experiment with three concentration gradients (NF: normal atmospheric O₃ concentration, NF40: normal atmospheric O₃ concentration plus 40 nmlol/mol; NF80: normal atmospheric O₃ concentration plus 80 nmol/mol), and the relationships between the characteristics of Pinus bungeana under different O₃ concentrations were investigated with correlation analysis, redundancy analysis and analysis of variance. Results: (1) Plant height growth (ΔH), diameter growth at 50 cm (ΔDBH), stomatal size (S), stomatal density (M), stomatal opening (K), stomatal conductance (G_s), net photosynthetic rate (P_n), transpiration rate (E_t), water use efficiency (WUE), maximum photochemical efficiency (F_v/F_m), chlorophyll content (CHL), whole tree water consumption (W), and O₃ uptake rate () all decreased with the increase of O₃ concentration; while intercellular CO₂ concentration () and relative conductivity (L) increased with the increase of O₃ concentration; (2) growth indicators of Pinus bungeana under O₃ stress (ΔH, ΔDBH) were the most correlated with O₃ uptake status (, W), followed by photosynthetic indicators (, WUE, ,, ) and growth indicators (ΔH, ΔDBH) and stomatal characteristics (K, M, S) under O₃ stress, some physiological indicators (L, ) were relatively weakly correlated with photosynthesis (, WUE,,, ) and stomatal (K, M, S); (3) all the indicators of Pinus bungeana were significantly different under O₃ treatments of NF and NF80 (P < 0.05), ΔH, ΔDBH, M, CHL, , , W and were most significantly different under NF and NF40 treatments, and K, S, WUE, , , , L were more significantly different under NF40 and NF80 treatments. Conclusion: The experiment proved that the growth of Pinus bungeana was slowed, photosynthetic capacity was reduced, and the absorption capacity of O₃ was further reduced by long-term exposure to high concentration of O₃. The growth of Pinus bungeana was most correlated with the changes of O₃ absorption characteristics, and the stomatal characteristics were most correlated with photosynthetic physiological characteristics, and the reduction of photosynthetic capacity etc. further led to the curtailment of its growth.

With the progress of science and technology, the research and development of silver nanoparticles has also developed. This paper attempts to prepare a silver nanoparticle by electrolyzing AgNO3 solution with electrochemical reduction method and citric acid as a complexing agent in a certain current and time. The crystal morphology and sample purity of silver nanoparticles were analyzed by X-ray diffractometer. The crystal structure of the nanoparticles was analyzed by scanning electron microscopy (SEM). The crystal structure of the nanoparticles was analyzed by X-ray diffraction. The particle size distribution of the particles was in the range of 125-199 nm, and the carbon paste electrode was modified with the prepared silver nanoparticles. The electrocatalytic activity of the carbon paste electrode was preliminarily explored.