Repositorio Ciencia Abierta Universidad del Bío-Bío

THIS WORK AIMED TO QUANTIFY AXIAL DEFORMATIONS OF A HUMAN PREMOLAR DURING OCCLUSION WITH ITS ANTAGONIST AND TO COMPARE THEM WITH THE SAME PREMOLAR RESTORED WITH A CERAMIC CROWN. THE DEFORMATIONS WERE PUT UNDER STRESS USING A MECHANICAL PRESS WITH A FORCE RANGING FROM 1 TO 100 NEWTONS. THESE DEFORMATIONS WERE QUANTIFIED USING THE OPTICAL INTERFEROMETRY TECHNIQUE WITH A LASER SOURCE (633 NM, 0.95 MW). USING A CMOS CAMERA, INTERFERENCE FRINGES WERE OBTAINED, STORED, AND SUBSEQUENTLY PROCESSED. THE PREMOLARS WERE RESTORED WITH CERASMART GC CERAMIC, USING THE CAD-CAM SYSTEM. THE AVERAGE DEFORMATIONS OF HEALTHY PREMOLARS WERE FOUND TO BE IN A RANGE OF 0.69 TO 1.74 UM, WHILE THE RESTORED ONES WERE DEFORMED IN A RANGE OF 0.53 TO 1.10 UM. THE RESULTS OF THIS WORK SHOWED THAT THE CERASMART CERAMIC MATERIAL HAD SIMILAR PROPERTIES TO THOSE OF THE NATURAL TOOTH FOR SMALL FORCES. HOWEVER, FOR HIGHER FORCES, THE CERAMICS INCREASED THE CORONAL STIFFNESS OF THE TOOTH. THIS MODIFIED THE OPTIMAL COMBINATION OF STIFFNESS, STRENGTH, AND RESILIENCE BETWEEN THE ENAMEL AND DENTIN, CAUSING A DECREASE IN THE TOOTH?S ABILITY TO DISSIPATE ENERGY; THEREFORE, THE TOOTH COULD RECEIVE MORE STRESS. THE OBSERVED MECHANICAL PROPERTIES LEAD TO THE CONCLUSION THAT THE CERASMART MATERIAL CAN BE INDICATED FOR THE RESTORATION OF ANTERIOR AND PREMOLAR TEETH IN MOST CASES WHERE A FIXED PROSTHESIS IS REQUIRED.

BACKGROUND: CITIZENSHIP PLAYS A FUNDAMENTAL ROLE IN THE MANAGEMENT OF SOCIO-NATURAL DISASTER RISK, ESPECIALLY GIVEN THE INCREASING IMPACT AND FREQUENCY OF THESE EVENTS. IN THIS CONTEXT, DISASTER RESPONSE IS MARKED BY BOTH FORMAL AND SPONTANEOUS VOLUNTEERISM. METHOD: USING A NON-PROBABILISTIC SAMPLE OF 101 VOLUNTEERS AND COMPARING THE SOCIAL REPRESENTATION OF FORMAL VOLUNTEERS WITH SPONTANEOUS VOLUNTEERS, PROTOTYPICAL AND CATEGORICAL ANALYSES OF SOCIAL REPRESENTATIONS WERE CONDUCTED. RESULTS: DIFFERENCES WERE IDENTIFIED BETWEEN FORMAL VOLUNTEERS, WHOSE SOCIAL REPRESENTATION REFLECTS A STRONG VALUE-ORIENTED AND COLLABORATIVE VISION FOCUSED ON SOCIAL CAPITAL, AND SPONTANEOUS VOLUNTEERS, WHOSE SOCIAL REPRESENTATION IS DIRECTED TOWARD PROSOCIAL VALUES, EMOTIONS, AND THE HEROIC ACTIONS ASSOCIATED WITH VOLUNTEERISM. CONCLUSIONS: NEW AVENUES ARE PROPOSED FOR EXERCISING AND STRENGTHENING FORMAL VOLUNTEERISM, ACCOMPANIED BY PROCESSES THAT ENABLE THE IDENTIFICATION OF COMMON VALUE AXES AND SUITABILITY FOR RISK-RELATED WORK. ADDITIONALLY, THE MOTIVATIONS AND ACTIONS OF SPONTANEOUS VOLUNTEERS ARE DISCUSSED. FINALLY, SUSTAINED COORDINATION IS PROPOSED AMONG INSTITUTIONS INVOLVED IN RISK MANAGEMENT, FORMAL VOLUNTEERS, AND SPONTANEOUS VOLUNTEERS TO OPTIMIZE HUMAN RESOURCE MANAGEMENT IN EMERGENCIES.

THIS STUDY INVESTIGATES THE RHEOLOGICAL AND CHEMICAL EFFECTS OF WASTE TIRE PYROLYTIC OIL (TPO) AND ITS ENCAPSULATION (POC) AS REJUVENATORS FOR ASPHALT BINDERS. DRIVEN BY THE NEED FOR SUSTAINABLE AND EFFECTIVE STRATEGIES TO RECYCLE RECLAIMED ASPHALT PAVEMENT (RAP), WE INVESTIGATED THE USE OF TPO IN TWO FORMS: AS A LIQUID ADDITIVE AND AS POLYMER CAPSULES. THE CAPSULES, MADE IN A 1:5 MASS RATIO (ONE PART POLYMER, FIVE PARTS TPO), WERE ASSESSED THROUGH TWO METHODS: RHEOLOGICAL TESTS (DYNAMIC MODULUS AND PHASE ANGLES) AND CHEMICAL COMPOSITION ANALYSIS (CARBONYL AND SULFOXIDE INDICES). THE BINDERS UNDERWENT THREE AGING LEVELS: UNAGED, PRIMARY AGING (RTFO), AND SECONDARY AGING (PAV). FIVE LIQUID TPO DOSAGES (1%, 2%, 4%, 6%, 9% BY WEIGHT) AND THREE ENCAPSULATED TPO DOSAGES (6%, 9%, 12% BY WEIGHT) WERE TESTED. RESULTS SHOW THAT TPO REDUCES STIFFNESS, INCREASES VISCOUS RESPONSE, AND LOWERS AGING INDICES, WITH HIGHER DOSAGES ENHANCING THE EFFECT. QUANTITATIVELY, 9% LIQUID TPO RESTORES PAV-AGED BINDER TO NEAR-UNAGED CONDITIONS, SUITABLE FOR RAP RECYCLING, WHILE 4% RELEASE FROM POCS ACHIEVES REJUVENATION COMPARABLE TO RTFO-AGED BINDERS, ENABLING SELF-HEALING APPLICATIONS. THE ESTIMATED RELEASE OF TPO FROM POCS DURING MIXING WAS 20-40%, ENSURING A GRADUAL SOFTENING EFFECT. THESE FINDINGS HIGHLIGHT THE POTENTIAL OF TPO AND POC IN ENHANCING ASPHALT DURABILITY AND RECYCLING.

THIS STUDY INVESTIGATES THE PRESENCE OF PESTICIDES IN RIVERS IN CHILE?S CENTRAL VALLEY, TAKING A SOCIOECOLOGICAL APPROACH THAT SEEKS TO CREATE A DIALOGUE BETWEEN SCIENTIFIC ANALYSIS AND COMMUNITY PERCEPTIONS OF THOSE WHO LIVE IN RURAL TERRITORIES. EXPLORATORY SAMPLING WAS CARRIED OUT IN THREE RIVER BASINS IN THE MAULE AND ÑUBLE REGIONS (PUTAGÁN-LONCOMILLA, ÑIQUÉN AND CHANGARAL RIVERS) DURING THE SOUTHERN SUMMER OF 2024. SAMPLES WERE TESTED FOR 535 PESTICIDES USING GAS AND LIQUID CHROMATOGRAPHY TECHNIQUES COUPLED WITH MASS SPECTROMETRY. DIURON WAS QUANTIFIED IN THE PUTAGÁN-LONCOMILLA AND ÑIQUÉN BASINS (?LOQ = 0.01 MG/L), WITH CONCENTRATIONS IN SOME CASES EXCEEDING INTERNATIONAL DRINKING WATER STANDARDS. FOSETYL-AL AND ITS DEGRADATION BYPRODUCT, PHOSPHONIC ACID, WERE ALSO QUANTIFIED IN ALL SAMPLES ANALYZED. THESE FINDINGS CONFIRM THE PERSISTENCE OF CERTAIN AGROCHEMICALS IN AQUATIC ECOSYSTEMS AND REVEAL THE NEED FOR STRICTER REGULATIONS IN CHILE. THIS STUDY ALSO HIGHLIGHTS THE IMPORTANCE OF INTEGRATING COMMUNITY KNOWLEDGE IN THE IDENTIFICATION OF POSSIBLE SOURCES OF POLLUTION. CONTINUOUS MONITORING OF PESTICIDES IN THE CENTRAL VALLEY?S RIVERS IS RECOMMENDED, IN ADDITION TO A STANDARD REGULATING THEIR PRESENCE IN SURFACE WATERS AND THE ADOPTION OF MITIGATION STRATEGIES TO REDUCE THE IMPACTS OF PESTICIDES ON HUMAN HEALTH AND THE ENVIRONMENT AND FURTHER DEVELOPMENT OF SUSTAINABLE AGRICULTURE.