THERE IS AN URGENT NEED WORLDWIDE FOR AN UPDATED AND COMPREHENSIVE UNIVERSITY-LEVEL CRITICAL THINKING ASSESSMENT TOOL. THIS PAPER REPORTS ON THE ADAPTATION AND VALIDATION OF AN INSTRUMENT TO ASSESS CRITICAL THINKING IN SCIENTIFIC KNOWLEDGE TASKS, DEVELOPED BY A STATE UNIVERSITY, IN A SAMPLE OF 161 UNIVERSITY STUDENTS. THE PSYCHOMETRIC QUALITY OF THE ITEMS, THEIR RELIABILITY AND THEIR FACTORIAL ORGANIZATION WERE EVALUATED. AN EXPLORATORY FACTOR ANALYSIS (AFE) WAS PERFORMED TO DETERMINE THE EXISTENCE OF DIMENSIONS, ASSESSING INTERNAL CONSISTENCY AND CONSTRUCT VALIDITY USING CRONBACH'S ALPHA, AND CORRELATION BETWEEN THE ITEMS AND THE GLOBAL SCALE. THE AFE INDICATED THREE DIMENSIONS OF THE QUESTIONNAIRE, THE INTERNAL CONSISTENCY OBTAINED AN ? = .67 AND THE CORRELATION BETWEEN THE SUM OF THE SCALE AND THE ITEMS, WAS SHOWN WITH MEDIUM AND SIGNIFICANT STRENGTH (BETWEEN R = .30 AND R = .60; P < 0.001). IT IS CONCLUDED THAT THE ADAPTATION OF THE TEST HAS AN ADEQUATE INTERNAL CONSISTENCY, ALTHOUGH SOMEWHAT BELOW THE IDEAL; THE FACTORIAL STRUCTURE OF THREE VARIABLES IS MAINTAINED, WHICH ARE THE ONES THAT SUSTAIN THE CONSTRUCT THEORETICALLY.

SEARCHING FOR A LUBRICANT TO BE USED IN ARTICULAR BONE JOINTS, A NEW NEMATIC LIQUID CRYSTAL (NLC) WAS CHARACTERISED. IT IS FORMED BY DISSOLVING TETRADECYLTRIMETHYL AMMONIUM BROMIDE (TTAB), DECANOL (DEOH), SODIUM BROMIDE (NABR) AND A NATURAL MIXTURE OF LIPIDS (PL, FROM SOYBEAN) IN WATER. SMALL AMOUNTS OF DO, AND SDS-D WERE ADDED AS2H-NMR PROBES. THE MESOPHASES WERE CHARACTERISED USING2H-NMR SPECTROSCOPY, KINEMATIC VISCOSITY MEASUREMENTS, POLARISED LIGHT MICROSCOPY (PLM) AND MOLECULAR DYNAMICS (MD) SIMULATIONS. THE PRESENT SYSTEM IS SUITABLE FOR LUBRICATION APPLICATIONS, SINCE THE SOLUTION VISCOSITY IS TUNABLE FROM 49 TO 811?CP, MORE THAN TWICE THE RANGE PREVIOUSLY OBTAINED IN A SIMILAR SYSTEM. THE SOLUTION CONTAINS AN IMPORTANT PROPORTION OF A NATURAL MIXTURE OF LIPIDS EXTRACTED FROM SOYBEAN, ENHANCING BIOCOMPATIBILITY. THE WIDER RANGE OF VISCOSITY DISPLAYED BY THIS SYSTEM, WITHOUT LOSING THE NEMATIC PHASE, IS ATTRIBUTED TO THE GREATER AMOUNT OF AMPHIPHILES SUPPORTED BY THE SOLUTION AND THE SIZE AND ELONGATION OF THE AGGREGATES WHEN THE SURFACE CHARGE DENSITY IS INCREASED. THIS ELONGATION REPRESENTS A PHASE TRANSITION FROM A DISCOTIC MONOAXIAL PHASE TO BIAXIAL PHASE AND IS RESPONSIBLE FOR THE CHANGES IN QUADRUPOLAR SPLITTINGS.

SPHINGOMYELINS (SM) AND CERAMIDES (CER) WITH VERY LONG CHAIN POLYUNSATURATED FATTY ACIDS (V) ARE IMPORTANT COMPONENTS OF SPERMATOZOA MEMBRANES. IN THIS STUDY, THE MECHANICAL PROPERTIES OF BILAYERS OF SM AND CER WITH NONHYDROXY (N-V) AND 2-HYDROXY (H-V) FATTY ACID (30:5) WERE STUDIED BY MOLECULAR DYNAMICS SIMULATION AT DIFFERENT TEMPERATURES AND IN THE PRESENCE AND THE ABSENCE OF SALT. FROM OUR RESULTS, IT WAS EVIDENCED HOW N-V SM AND H-V SM BILAYERS SHOWED SIMILAR BEHAVIOR. WHEN N-V CER WAS ADDED TO A H-V SM BILAYER, THE GAUSSIAN CURVATURE MODULUS AND E-CURVE OF BINARY BILAYERS DECREASED. THIS VARIATION IN THE MECHANICAL PROPERTIES OF THE BILAYER CAN BE ASSOCIATED WITH AN INCIPIENT STEP DURING THE FECUNDATION PROCESS.

ONE OF THE MOST USEFUL APPLICATIONS OF SILVER COLLOIDAL SOLUTIONS IS IN SURFACE-ENHANCED RAMAN SPECTROSCOPY (SERS), BECAUSE THE AMPLIFICATION FACTOR OF ABOUT 106 ALLOWS THE VIBRATIONAL STUDY AND DETECTION OF HIGHLY DILUTED SPECIES IN AQUEOUS ENVIRONMENT, AND MORE RECENTLY IN EARLY DIAGNOSIS OF CANCER AND IMAGING. A USEFUL COLLOID FOR SERS IS THAT REPORTED BY LEOPOLD AND LENDL (COLLOID 1). HOWEVER, SERS RESPONSE FROM ANIONS OR RICH ELECTRON DENSITY MOLECULES HAS BEEN DIFFICULT TO OBTAIN IN THIS COLLOID. RECENTLY, A MINOR MODIFICATION OF THE SURFACE CHARGE DENSITY (COLLOID 2) ALLOWED TO OBSERVE REPRODUCIBLE SERS SPECTRUM FROM GALLATE ANION (GA?). IN THIS WORK, THE STRUCTURE OF BOTH SOLID AND SOLUTION INTERFACES WERE CHARACTERIZED USING MOLECULAR DYNAMICS. EXPERIMENTAL VALUES OF ?-POTENTIALS WERE REPRODUCED BY SIMULATIONS, AND THE CHEMICAL POTENTIAL OF GA? APPROACHING BOTH INTERFACES WAS CALCULATED USING ?UMBRELLA SAMPLING? AND THE WEIGHTED HISTOGRAMS ANALISYS METHODOLOGY (WHAM). THE CALCULATED BARRIER TO APPROACH THE INTERFACE OF COLLOID 1 IS 2.8 KJMOL?1 GREATER THAN IN COLLOID 2, AND THE STABILITY OF GA? WITH COLLOID 2 AT THE MINIMUM IS 3.5 KJMOL?1 MORE STABLE THAN WITH COLLOID 1. FINALLY, THE CALCULATED AVERAGE ORIENTATION OF GA? ADSORBED ONTO THE COLLOIDAL SURFACE IS IN EXCELLENT AGREEMENT WITH THE EXPERIMENTAL SERS OBSERVATIONS.

THIS WORK EXPLORES THE DYNAMIC BEHAVIOR OF THE THREE CLOSO-CARBORANE ISOMERS (FORMULA C2B10H12) USING MODERN SOLID-STATE MAGIC ANGLE SPINNING (MAS) NMR TECHNIQUES AND RELATES THE EXPERIMENTAL MEASUREMENTS TO THEORETICAL RESULTS OBTAINED USING MOLECULAR DYNAMICS SIMULATIONS. AT HIGH TEMPERATURES AND AT B0 = 9.4 T, THE (11)B MAS LINE WIDTHS ARE NARROW (40-90 HZ) FOR THE THREE ISOMERS. THE ROTATIONAL CORRELATION TIMES (?C) CALCULATED BY MOLECULAR DYNAMICS ARE ON THE PICOSECOND TIME SCALE, SHOWING A QUASI-ISOTROPIC ROTATION AT THESE TEMPERATURES, TYPICAL FOR LIQUID SYSTEMS. FOR ALL THREE ISOMERS, THE VALUES OF THE (11)B SPIN-LATTICE RELAXATION TIMES (T1) SHOW DISCONTINUITIES AS THE TEMPERATURE IS DECREASED, CONFIRMING THE PHASE CHANGES REPORTED IN THE LITERATURE. AT LOW TEMPERATURES, THE (11)B MAS SPECTRA OF ALL THREE ISOMERS EXHIBIT MUCH BROADER LINES. THE SIMULATIONS SHOWED THAT THE MOLECULAR REORIENTATION WAS ANISOTROPIC AROUND DIFFERENT SYMMETRY AXES FOR EACH ISOMER, AND THIS WAS SUPPORTED BY THE VALUES OF THE REDUCED QUADRUPOLAR PARAMETER PQ(EFF) DERIVED FROM """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""DYNAMIC SHIFT"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" MEASUREMENTS USING (11)B MQMAS NMR SPECTROSCOPY. THE BEHAVIOR OF PQ(EFF) AS A FUNCTION OF TEMPERATURE FOR P-CARBORANE SUGGESTS THAT MOLECULAR REORIENTATION IS ABOUT THE C5 SYMMETRY AXIS OF THE MOLECULE AT LOW TEMPERATURES, AND THIS WAS SUPPORTED BY THE MOLECULAR DYNAMICS SIMULATIONS.

WE PRESENT THE EFFECTS OF THE CONFINEMENT AND PHYSICAL DISTANCING POLICIES APPLIED DURING THE COVID-19 PANDEMIC ON THE CONCENTRATIONS OF PM10, PM2.5, NO, NO2 AND O3 IN 16 CITIES IN CENTRAL AND SOUTHERN CHILE. THE PERIOD BETWEEN MARCH AND MAY IN 2020 WAS COMPARED WITH THE CORRESPONDING MONTHS DURING 2017?2019, USING SURFACE DATA AND SATELLITE INFORMATION. THE RELATIVE PERCENT CHANGES IN THE CONCENTRATION OF ATMOSPHERIC POLLUTANTS, AND THE METEOROLOGICAL VARIABLES OBSERVED BETWEEN THESE TWO PERIODS WERE USED TO QUANTIFY THE EFFECTS OF THE LOCKDOWNS ON THE LOCAL AIR QUALITY OF THE URBAN AREAS STUDIED. THE RESULTS SHOWED STATISTICALLY SIGNIFICANT CHANGES IN 11 OF THE 16 CITIES. SIGNIFICANT RELATIVE CHANGES BETWEEN +14% AND ?33% WERE OBSERVED FOR PM10 IN 9 CITIES; WHILE STATISTICALLY SIGNIFICANT CHANGES BETWEEN -6% AND -48% WERE EVIDENT FOR PM2.5 IN 10 CITIES. SIGNIFICANT DECREASES BETWEEN ?27% AND ?55%, WERE OBSERVED IN 4 CITIES IN WHICH NO2 DATA WERE AVAILABLE; WHILE SIGNIFICANT INCREASES IN O3, BETWEEN 18% AND 43%, WERE FOUND IN 4 OF THE 5 CITIES WITH AVAILABLE DATA. THE LOCAL METEOROLOGICAL VARIABLES DID NOT SHOW SIGNIFICANT CHANGES BETWEEN BOTH PERIODS. IN ALL THE CITIES STUDIED, ONE OF THE MAIN PM SOURCES IS WOOD BURNING FOR RESIDENTIAL HEATING. ALTHOUGH THE QUARANTINE IMPOSED DURING THE HEALTH EMERGENCY COULD HAVE INDUCED AN INCREASE IN RESIDENTIAL EMISSIONS, THESE WERE COMPENSATED WITH THE REDUCTIONS IN VEHICULAR AND/OR INDUSTRIAL EMISSIONS. THEREFORE, THESE RESULTS SHOULD BE CAREFULLY INTERPRETED AND SHOULD INSPIRE NEW RESEARCH CONSIDERING THE SOCIAL, CULTURAL, AND ECONOMIC FACTORS THAT COULD ALTER THE COMMON EMISSION PATTERNS AND AIR QUALITY OF URBAN CENTERS.