A New Bundling and Packaging Method Using Nonwoven Polylactide Based on Polymer Shrinkage by Carbon Dioxide

# This study evaluated the effectiveness of the light emitting diode(LED) units for composite curing. To compare its effectiveness with conventional quartz tungsten halogen (QTH) light curing unit, the micro- hardness of 2mm composite, Z250, which had been light cured by the LEDs (Ultralume LED2, FreeLight, Developing product D1) or QTH (XL 3000) were compared on the upper and lower surface. One way ANO- VA with Tukey and Paired t-test was used at 95% levels of confidence. In addition, the amount of linear polymerization shrinkage was compared between composites which were light cured by QTH or LEDs using a custom-made linometer in 10s and 60s of light curing, and the amount of linear polymerization shrinkage was compared by one way ANOVA with Tukey . The amount of polymerization shrinkage at 10s was XL3000 > Ultralume 2, 40, 60> FreeLight, D1 (P Ultralume 2, 60> Ultralume 2,40> FreeLight, D1 (P<0.05) The microhardness on the upper and lower surface was as follows; XL 3000 ABSTRACT

The main two directives of the European Commission (EC) has been regulating the automotive industry. The aforementioned directives and education of residents on environmental issues has created the need for new materials that have been produced from renewable resources and should be recycled at the end of product life cycle. The objective of this project is to develop a nonwoven materials (NWM) that would incorporate fibers of plants, which could be grown in Latvia because of suitable local climate conditions, for the use in automotive industry. Furthermore, inclusion of polymer fibers in the NWM will expand the areas of use of such material – the NWM can be transformed into a composite material by means of a thermal press. Manufacturing process of NWM consist of structure modelling and material samples manufacturing. NWM samples production process to be carried out by fibers preparation, fibers mixing, formation by airlaid method, preparation of fiber webs for fixation with a mechanical needle punching method, mechanical fixation of fiber webs, preparation of fixed fiber webs for NWM manufacturing and manufacturing of NWM by mechanical needle punching method. This article reflects the comparison of two compositions NMW (Polylactid (PLA) (60 wt%) and long flax fibres (40 wt%), and PLA (60 wt%) and technical hemp fibres (40 wt%)) with the same structure by visual appearance, geometrical parameters and tensile strength. The average surface density of hemp NWM varies in the range of 792.09 to 958,71 g•m−2 , thickness varies from 6.91 to 9.23 mm. Flax NWM average surface density is higher than hemp NWM and varies in range of 1,064 to 1,260 g•m−2, thickness of the material varies from 12.62 to 15.54 mm. For comparison, the surface density of NWM currently used in automotive industry, depending on the use of the material, varies from 100 to 1,400 g•m−2.

This study evaluated the effectiveness of a plasma arc curing (PAC) unit for packable resin composite curing. The amount and speed of polymerization shrinkage and the microhardness of packable composites were evaluated in order to compare the PAC unit's effectiveness with a quartz tungsten halogen (QTH) unit. Sure Fil (Dentsply Caulk), Pyramid (BISCO Inc) and Synergy Compact (Colténe/Whaledent) were used as the packable composites. In the case of curing with the PAC unit, the composites were light cured with Apollo 95E (DMD System Inc) for 1 second (Group 1), 2 seconds (Group 2), 3 seconds (Group 3), 6 seconds (Group 4) and 12 seconds (Group 5). For light curing with the QTH unit, the composites were light cured for 60 seconds using XL3000 (Group 6). The linear polymerization shrinkage of each composite was measured using a custom made linometer, and the data was stored in a computer every 0.5 to 0.55 seconds for a total of 60 seconds. For each composite, the amount of polymerization was compared using one-way ANOVA with Tukey at the 95% confidence level. In order to compare the speed of polymerization, the peak time (PT), showing the highest speed of polymerization and maximum speed of polymerization (Smax), were determined from the data and compared using one-way ANOVA with Tukey at the 95% confidence level for each material. Based on the statistical analysis among the PAC-cure groups (Groups 1 through 5), the group that was not statistically different from the QTH-cure group (Group 6) in the amount of linear polymerization shrinkage was determined for each material, and the corresponding curing time of the group was defined as the tentative minimum PAC-curing time (TMPT). For microhardness measurements, the samples were placed in a 2-mm thick Teflon plate. Twenty specimens, randomly divided into the PAC-cure group (Group 1) or the QTH-cure group (Group 2), were prepared for each material. In Group 1, each composite was light cured for TMPT with the PAC unit. In Group 2, each composite was light cured for 60 seconds with the QTH unit. Microhardness was measured on the upper and lower surface. For each material, the microhardness of the upper and lower surface of Groups 1 and 2 was analyzed using two-way ANOVA with Tukey at the 95% confidence level. The amount of polymerization was Group 1<Group 2<Group 3<Group 4<Groups 5, 6 in the Sure Fil composite (p<0.05); Groups 1, 2<Group 3<Groups 4, 6<Group 5 in the Synergy Compact composite (p<0.05) and Group 1 <Group 2 <Group 3 <Groups 4, 6 <Group 5 in the Pyramid composite (p<0.05) Regarding the speed of polymerization, the order of PT was G1, G2, G3<G4, G5<G6 (p<0.05). The order of Rmax was G6<G1, G2, G3, G4, G5 in Sure Fil; G6<G1<G2, G3, G4<G5 in Synergy Compact (p<0.05) and G6<G1<G2, G3<G4, G5 in Pyramid (p<0.05) On the upper surface, there was no statistical difference in microhardness between Groups 1 and 2 in all materials. On the lower surface, the microhardness of Group 2 was significantly higher than Group 1 in all materials. In all materials in Group 1 and the Synergy Compact of Group 2, microhardness of the upper surface was significantly higher than the lower surface (p<0.05). In Sure Fil and Pyramid of Group 2, there was no difference in microhardness between the upper and lower surfaces.

Past work demonstrating an association between indoor air quality and cognitive performance brought attention to the benefits of increasing outdoor air ventilation rates beyond code minimums. These code minimums were scrutinized during the COVID-19 pandemic for insufficient ventilation and filtration specifications. As higher outdoor air ventilation was recommended in response, questions arose about potential benefits of enhanced ventilation beyond infection risk reduction. This was investigated by examining associations between indoor carbon dioxide concentrations, reflective of ventilation and building occupancy, and cognitive test scores among graduate students attending lectures in university classrooms with infection risk management strategies, namely increased ventilation. Post-class cognitive performance tests (Stroop, assessing inhibitory control and selective attention; Arithmetic, assessing cognitive speed and working memory) were administered through a smartphone application to participating students (54 included in analysis) over the 2022-2023 academic year in classrooms equipped with continuous indoor environmental quality monitors that provided real-time measurements of classroom carbon dioxide concentrations. Temporally and spatially paired exposure and outcome data was used to construct mixed effects statistical models that examined different carbon dioxide exposure metrics and cognitive test scores. Model estimates show directionally consistent evidence that higher central and peak classroom carbon dioxide concentrations, indicative of ventilation and occupancy, are associated with lower cognitive test scores over the measured range included in analysis ( ~ 440-1630 ppm). The effect estimates are strongest for 95th percentile class carbon dioxide concentrations, representing peak class carbon dioxide exposures. As the COVID-19 pandemic eased, questions emerged on the benefits of increased outdoor air ventilation beyond infection reduction. This work assesses associations between carbon dioxide concentrations, indicative of ventilation and occupancy, and cognitive test scores among students in university classrooms with increased outdoor air ventilation. Although not causal, models show statistically significant evidence of associations between lower carbon dioxide concentrations and higher cognitive test scores over the low range of carbon dioxide exposures in these classrooms. While the underlying mechanisms remain unknown, higher outdoor air ventilation appears to provide additional benefits by reducing indoor air exposure and supporting student performance.

Skin substitutes are heterogeneous group of scaffolds (natural or synthetic) and cells. We hypothesize that nanofibers with layer composition made of polylactide (PLA) and sodium hyaluronate (HA) obtained using electrospinning method are a good matrix for cell adhesion and proliferation. Optimal conditions of electrospinning of PLA and HA nanofibers to create layered compositions (PLA membrane covered with HA nonwovens) were determined by modifying parameters such as the appropriate amount of solvents, polymer concentration, mixing temperature and electrospinning process conditions. By changing the parameters, it was possible to control the diameter and properties of both polymer fibers. The spinning solution were characterized by surface tension and rheology. A scanning electron microscope (SEM) was used to determine the morphology and fiber diameters: PLA and HA. Structure of the PLA/HA nonwoven was analyzed using spectroscopy (FTIR/ATR). Biocompatibility of the nonwoven with fibroblasts (ECM producers) was assessed in the in vitro conditions. The results showed that stable conditions for the formation of submicron PLA fibers were obtained using a 13% wt. solution of the polymer, dissolved in a 3:1 mixture of DCM:DMF at 45 °C. The hyaluronic fibers were prepared from a 12% wt. solution of the polymer dissolved in a 2:1 mixture of ammonia water and ethyl alcohol. All materials were biocompatible but to a different degree. The proposed laminate scaffold was characterized by a hydrophobic-hydrophilic domain surface with a maintained fiber size of both layers. The material positively underwent biocompatibility testing in contact with fibroblasts.

Although the construction of superwettability materials for oil/water separation has been developed rapidly, the postprocess of the used separation materials themselves is still a thorny problem due to their nondegradation in the natural environment. In this work, we reported the functionalization of polylactic acid (PLA) nonwoven fabric as superoleophilic and superhydrophobic material for efficient treatment of oily wastewater with eco-friendly post-treatment due to the well-known biodegradable nature of PLA matrix.

Objectives: The aim of this study was to investigate the effects of light curing method on the polymerization shrinkage of composite resins. Materials and Methods: Eight methods of four different light curing units were tested by forming 16 groups using two different composite types. Resin composite specimens weights were determined with an analytical electronic hydrostatic balance in the air and in water before and after curing. Then specific gravity values were determined. Volumetric polymerization shrinkage was calculated using mathematical formulas. Results: According to the results of this in-vitro study, polymerization shrinkage differed significantly among the light curing units. Conclusions: When the amount of polymerization shrinkage was compared, it was determined that the curing method, which has the greatest total energy density, caused the greatest amount of shrinkage. It was also found out that some of the curing units affected the shrinkage positively in soft-start mode.

CO 2-induced changes in the ERG of the fly, Sarcophaga bullata. A component analysis

Consistency in the amount of linear polymerization shrinkage in syringe-type composites

Ecological environment deteriorates drastically and rapidly, which can be ascribed to the fast advancement of international economy and technique. Hence, people become green consumers, using green products. The series of lyocell fiber, called as recycled fiber, has been pervasively used. This study used Tencel® fiber, Polylactic Acid (PLA) fiber and high absorbent fiber as well as nonwoven manufacturing, creating Tencel®/PLA/HAF composite nonwoven fabrics. Among the manufacturing parameters, an increase in Tencel® fiber ratio, needle-punching density and basis weight all contributed to heighten the mechanical properties of nonwoven fabrics. In particular, the Tencel®/PLA/HAF composite nonwoven fabric exhibited an optimum tensile strength of 68.8 N and bursting strength of 193.7 N when Tencel® fiber ratio was over 80 wt%, basis weight was 200 g/m2 and needle-punching density was 300 needle/cm2.

Carbon dioxide (CO2) is a commonly used euthanasia agent in animal facilities. This procedure is carried out by replacing oxygen with carbon dioxide in animal cages, thus providing a quick and painless method of euthanasia. Unfortunately, there has been limited research on the potential effects of human exposure to CO2 during euthanasia procedures. Following a previous carbon dioxide exposure study in the vivarium at Rowan SOM in 2016, the CO2 cylinders and euthanasia chambers have been relocated to room 153 Science Center and the vivarium has adopted a localized exhaust that helps remove the contaminant at the source. While the results from the 2016 study were within the Occupational Health and Safety (OSHA) and American Conference of Governmental Industrial Hygienist (ACGIH) carbon dioxide exposure limits, the research team replicated the study to ensure compliance at the new euthanasia chamber location.

# The purpose of present study was to evaluate the polymerization shrinkage stress and amount of linear shrinkage of composites and compomers for posterior restoration. For this purpose, linear polymerization shrinkage and polymerization stress were measured. For linear polymerization shrinklage and polymerization stress measurement, custom made Linometer (RB Dyract AP (Dentsply Detrey, Gumbh. German) Z100 (3M Dental Products, St. Paul, USA) Surefil (Dentsply Caulk, Milford, USA) Pyramid(Bisco, Schaumburg, USA) Synergy Compact (Coltene, Altstatten, Switzerland), Heliomolar (Vivadent/Ivoclar, Liechtenstein), and Compoglass (Vivadent Ivoclar/ Liechtenstein) were used. 15 measurements were made for each material. Linear poly- merization shrinkage or polymerization stress for each material was compared with one way ANOVA with Tukey at 95% levels of confidence. For linear shrinkage; Heliomolar, Surefil<Synergy Compact, Z100<Dyract AP<Pyramid, Compoglass F (p<0.05) For Shrinkage stress; Heliomolar< Z100, Pyramid<Synergy Compact, Compoglass F<Dyract AP<Heliomolar HB, Surefil (p< 0.05) ABSTRACT

Environmental protection has become an increasing concern, which makes recycling and reclaiming highly important. In addition to governmental campaigns and promotion, enterprises should examine each perspective thoroughly in order to prevent excessive resource consumption. In this study, recycled materials, including recycled far-infrared polyester (FPET) fiber, three-dimensional crimped hollow flame-retarding (TPET) fiber, and low-melting-point polyester (LPET) fiber, are used to form nonwoven fabrics. The influence of different amounts of FPET fiber, 0–80 wt %, on the properties of nonwoven fabrics was examined. The sheath of LPET fibers can be melted as a result of hot pressing, which provides cohesion between fibers that mechanically improves the nonwoven fabrics. The tensile strength, tearing strength, air permeability, and far infrared (FIR) emissivity of the nonwoven fabrics were examined, thereby determining the optimal parameters. The test results show that the thermally treated nonwoven fabrics have better mechanical properties and FIR emissivity, compared to those of non-thermally treated nonwoven fabrics. Moreover, more FPET fibers cause the mechanical properties along the cross machine direction (CD) to decrease by 9% and that along the machine direction (MD) to decrease by 5%. In particular, all the thermally treated samples exhibit a FIR emissivity of 0.8, which is health-promoting.

This study investigates the development of biodegradable nonwoven fabrics utilizing Alpinia purpurata pseudo-stem fibres, bonded with poly lactic acid (PLA) through a thermal bonding process. Given the underutilization of Alpinia purpurata fibres, this research explores their potential for sustainable textile applications. The fibres were extracted via decortication and blended with PLA at varying mass ratios (90/10, 80/20, 70/30), followed by comprehensive characterization. Evaluations included fabric mass per unit area, thickness, air permeability, tensile strength, elongation, wetting time, moisture regain and surface morphology. The results indicate that increasing PLA content enhances tensile strength but reduces air permeability and water absorption. Conversely, a higher proportion of Alpinia purpurata fibres improves breathability and moisture regain. These findings demonstrate that Alpinia purpurata fibres, in combination with PLA, can produce nonwoven fabrics with tunable properties, offering promising potential for environmentally friendly textile applications.

Product packaging serves a logistical function related to transport, storage, product safety, and information. Furthermore, packaging is an integral part of the product, but after use, it becomes unnecessary and, from this perspective, constitutes post-consumer waste, which in turn poses a threat to our environment. Therefore, in the context of sustainable development, limiting the negative impact of such packaging on our natural environment is crucial. Consumers themselves also play a significant role, as their purchasing decisions can influence producers’ responsibility and the increasing prevalence of eco-friendly packaging. Therefore, researching consumer awareness is crucial to understanding how consumer purchasing decisions can support the concept of sustainable development in the context of packaging. The aim of this study is to analyze consumer opinions regarding the characteristics of cosmetic and food product packaging and the importance of information placed on such packaging for consumers when making purchasing decisions. The study utilized a survey method and also analyzed the survey results, allowing for the identification of consumer attitudes and opinions regarding the characteristics of cosmetic and food product packaging. Furthermore, it was determined which information presented on food and cosmetic product packaging is considered crucial by consumers when making purchasing decisions.