\u3cem\u3eβ\u3c/em\u3e-Homopipitzolone

The structure of β-homopipitzolone (one of the two isomers of an intermediate product in the homocedrole synthesis) has been unequivocally established as 1 O-hydroxy-2,6,9-trimetbyltricyclo[6.3.1.01,6] dodeca-9-ene-5, II, 12-trione with relative IR,2R,6R,8S configuration

Flower colours through the lens: Quantitative measurement with visible and ultraviolet digital photography

Background: The study of the signal-receiver relationship between flowering plants and pollinators requires a capacity to accurately map both the spectral and spatial components of a signal in relation to the perceptual abilities of potential pollinators. Spectrophotometers can typically recover high resolution spectral data, but the spatial component is difficult to record simultaneously. A technique allowing for an accurate measurement of the spatial component in addition to the spectral factor of the signal is highly desirable

A phenomenographic study of the ability to address complex socio-technical systems via variation theory

Sometimes engineers fail when addressing the inherent complexity of socio-technical systems because they lack the ability to address the complexity of socio-technical systems. Teaching undergraduate engineering students how to address complex socio-technical systems, has been an educational endeavor at different levels ranging from kindergarten to post-graduate education. The literature presents different pedagogical strategies and content to reach this goal. However, there are no existing empirically-based assessments guided by a learning theory. This may be because at the same time explanations of how the skill is developed are scarce. My study bridges this gap, and I propose a developmental path for the ability to address the complex socio-technical systems via Variation Theory, and according to the conceptual framework provided by Variation Theory, my research question was “What are the various ways in which engineers address complex socio-technical systems?” I chose the research approach of phenomenography to answer my research question. I also chose to use a blended approach, Marton’s approach for finding the dimensions of variation, and the developmental approach (Australian) for finding a hierarchical relationship between the dimensions. Accordingly, I recruited 25 participants with different levels of experience with addressing complex socio-technical systems and asked them all to address the same two tasks: A design of a system for a county, and a case study in a manufacturing firm. My outcome space is a nona-dimensional (nine) developmental path for the ability to address the complexity in socio-technical systems, and I propose 9 different ways of experiencing the complexity of a socio-technical system. The findings of this study suggest that the critical aspects that are needed to address the complexity of socio-technical systems are: being aware of the use of models, the ecosystem around, start recognizing different boundaries, being aware of time as a factor, recognizing the part-whole relationships, make effort in tailoring a solution that responds to stakeholders’ needs, find the right problem, giving voice to others, and finally be aware of the need to iterat

Right-Sided Endocarditis Secondary to Aeromonas hydrophila: A Case Report

Right-sided endocarditis represents a distinct clinical condition observed in individuals with a history of parenteral drug use or those with implanted pacemakers or other intracardiac devices. Aeromonas infections, although uncommon in humans, particularly endocarditis cases, are exceedingly rare. Here, we report the case of a 72-year-old female with a medical history of arterial hypertension and chronic kidney disease undergoing hemodialysis via a tunneled permanent central venous catheter. She presented with chills and a fever of 38.3°C. Physical examination revealed a grade 3 protosystolic murmur at the tricuspid focus. Blood cultures from central and peripheral sites yielded growth of Aeromonas hydrophila. Transthoracic echocardiography demonstrated a fusiform, semi-mobile vegetation measuring 16 x 15 mm at the outlet of the superior vena cava, suggestive of endocarditis. Intravenous fluoroquinolones were initiated based on antibiogram results, leading to resolution of imaging findings after a 21-day treatment course

Thermal and mechanical properties of recycled poly(Lactic acid)

Biodegradable polymers have experienced increased attention in recent years because of their wide range of applications in biomedical, packaging and agriculture fields. PLA, poly(lactic acid), is a linear aliphatic biodegradable thermoplastic polyester, with good mechanical properties, thermal stability, processability and low environmental impact, widely used as an alternative to conventional polymers. PLA products can be recycled after use either by remelting and reprocessing the material, or by hydrolysis to basic lactic acid [1]. The object of this communication is the study of the possible variation in physical properties induced by sub sequent reprocessing cycles of PLA

K-shell photoionization of Na-like to Cl)like ions of Mg, Si, S, Ar and Ca

peer reviewe

Spectrophotometric Study of Polymeric DyesGels After a Gamma Irradiation Process for its Possible Use as a Radiation Dosimeter

This work aims to evaluate a dosimetric system composed of green malachite supported in agarose. Previous work showed that solutions of green malachite irradiated at 1 to 40 kGy present a linear behavior. This system is a gel composed of green malachite (2.5×10–3 M), sodium benzoate (1%),and agarose (1%) that was exposed tovarious doses of gamma irradiation. The irradiated systems were measured with a UV-V is spectrophotometer at 619 nm. Experimental parameters (such as dose rate, doses, and temperature) were controlled and optimized for reproducible and reliable results. More studies are needed to propose a dosimeter in the system in the range of 1.8 to 4.0 kGy

Initial pH as a determining factor of glucose consumption and lactic and acetic acid production in oral streptococci

Lactic and acetic acid production was evaluated from six strains of oral streptococci, viz Streptococcus gordonii, Streptococcus mutans, Streptococcus oralis, Streptococcus salivarius, Streptococcus sanguis and Streptococcus sobrinus cultured in the presence of 1, 5, 10 mM glucose and without glucose, at initial pH values of 5, 5.5, 6 and 7. S. sobrinus and S. salivarius caused the greatest decreases in pH. At pH values of 5 and 5.5, lactic acid and acetic acid production in the species tested was discordant with residual glucose levels. Acid production from protein was especially great in S. mutans and S. salivarius

Gamma Dosimetry Using Some Dyes in Organic Solvents Solutions at 295 and 77 K

The aim of this work is to study the behavior under irradiation of different dyes (green malachite, methyl orange, red cresol, and bromothymol blue) in organic solvents (acetone and methanol) at different gamma doses and different temperatures to propose them as possible dosimeters for low-temperature applications. For this purpose, organic dissolutions were irradiated with gamma rays in the kiloGray (kGy) range at 77 and 295 K, and the color bleaching of the solutions was followed spectrophotometrically (UV-Vis range). The response curves at different temperatures show the linear range interval from 10 to 40 kGy with correlation coefficients of 0.999 and 0.998 for some systems. This is the main reason to continue carrying out studies that allow the proposal of these systems as chemical dosimeters