Application of principal component analysis to chemical characteristics of Mahon cheese

 This paper describes a method suitable for the analysis of diglycerides (DG) in cheese. The method, also suitable for other foods, is essentially based upon the solid-phase extraction (SPE) of DG followed by capillary gas chromatographic analysis with a polar stationary phase (TAP). SPE is applied to avoid the column overloading caused by triglycerides; however, SPE is able to catalyse isomerization from the 1,2-form to the 1,3-form. This introduces an error into the results, as the two forms have different origins and are produced at different stages of ripening. A comparison between the use of silica and diol phases was made and it was seen that no isomerization occurred when the diol phase was used. Repeatability and recovery trials were carried out and the coefficient of variation (relative standard error) of the former trial was approximately 10%. Finally, it is demonstrated that it is possible to re-use the SPE cartridge at least four times. Received: 15 July 1996/Revised version: 19 September 1996     

Application of UNIFAC to vegetable oil-alkane mixtures

The prediction of the vapor-liquid equilibria of vegetable oil-hexane mixtures is studied. Activity coefficients are calculated by the UNIFAC model. Different entropic contributions to activity coefficients from the literature are analyzed. These modifications improve the performance of the original UNIFAC model in vapor-liquid equilibrium calculations.     

The importance of human relationships in scientific productivity

Fifty Brazilian scientists working in life sciences were interviewed in order to explore reasons of bursts and falls in their scientific productivity. Scientists recognize specific periods of time of their career during which they are more productive. Bursts of productivity are influenced mainly by human relationships and, to a lower extent, by material conditions (equipment, grants, etc), time dedicated to work and reasons linked to the kind of work carried out. The most productive scientists tend to attribute more importance to human relations than their colleagues with lower productivity scores. Some possible reasons for this discrepancy are discussed.     

Perceived influence of life experiences on clinical psychologists' selection and development of theoretical orientations.

Investigated the types of life experiences perceived by 31 male and 9 female behavioral and psychodynamic (PD) psychologists as influential in the development of their theoretical orientation. Half of the Ss were experienced therapists (aged 31–59 yrs); the other half were clinical psychology graduate students. Ss completed a theoretical orientation survey and a checklist of variables influencing the selection of a theoretical orientation and were also interviewed individually. Results show that therapists in the PD group (1) reported significantly more mental illness in members of their families of origin, (2) offered significantly more personal as opposed to professional reasons for seeking therapy, (3) reported significantly more conflict within their families of origin when compared with therapists in the behavioral group, and (4) reported seeking personal therapy more often (95%) than therapists in the behavioral group (40%). Implications for training of therapists are discussed. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response perseveration in psychopaths: Interpersonal/affective or social deviance traits?

In order to clarify the role of the two broad components of psychopathy (interpersonal/affective and social deviance; R. D. Hare, 2003) in explaining maladaptive response perseveration in psychopaths, as well as the role of reflection after punished responses in this deficit, the authors administered a card perseveration task to 47 Spanish male inmates assessed using the Hare Psychopathy Checklist-Revised (PCL-R; R. D. Hare, 1991). Hierarchical regressions showed that psychopaths' maladaptive perseveration (more cards played and less money earned) was uniquely predicted by the social deviance features of psychopathy (PCL-R Factor 2)--particularly by its impulsive and irresponsible lifestyle facet (PCL-R Facet 3)--and not by its interpersonal/affective features (PCL-R Factor 1). Moreover, perseveration was related to a lack of reflection both after punishment and after reward feedback. The authors' results, in conjunction with previous evidence indicating perseverative deficits in several impulse control disorders, suggest that response perseveration may not be specific to psychopathy but rather is associated more generally with the externalizing dimension of psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parameters for the attractive coefficient of the patel-teja-valderrama equation of state

A three-parameter form of the temperature dependence of the attractive term in cubic van der Waals type equations of state (AS; Almeida et al., 1991; Aznar and Silva-Telles, 1992) has been applied to a generalized equation of state known as the Patel-Teja-Valderrama equation (PTV; Valderrama, 1990). The parameters of the AS model in the PTV equation of state were calculated for 457 substances of different polarity, molecular size, and chemical nature. The parameters were calculated using vapor pressure data determined through accurate equations available in the literature (Wagner 1973, Antoine 1888, Frost and Kalkwarf, 1953). The deviations between the equation of state calculations and vapor pressure information are lower than 0.5% for most fluids. The study shows that both the generalized PTV cubic equation and the AS represent good tools for pressure-temperature calculations in engineering applications.     

Microglia Response and In Vivo Therapeutic Potential of Methylprednisolone‐Loaded Dendrimer Nanoparticles in Spinal Cord Injury

The control and manipulation of cells that trigger secondary mechanisms following spinal cord injury (SCI) is one of the first opportunities to minimize its highly detrimental outcomes. Herein, the ability of surface‐engineered carboxymethylchitosan/polyamidoamine (CMCht/PAMAM) dendrimer nanoparticles to intracellularly deliver methylprednisolone (MP) to glial cells, allowing a controlled and sustained release of this corticosteroid in the injury site, is investigated. The negatively charged MP‐loaded CMCht/PAMAM dendrimer nanoparticles with sizes of 109 nm enable a MP sustained release, which is detected for a period of 14 days by HPLC. In vitro studies in glial primary cultures show that incubation with 200 μg mL^?1 nanoparticles do not affect the cells' viability or proliferation, while allowing the entire population to internalize the nanoparticles. At higher concentrations, microglial cell viability is proven to be affected in response to the MP amount released. Following lateral hemisection lesions in rats, nanoparticle uptake by the spinal tissue is observed 3 h after administration. Moreover, significant differences in the locomotor output between the controls and the MP‐loaded nanoparticle‐treated animals one month after the lesion are observed. Therefore, MP‐loaded CMCht/PAMAM dendrimer nanoparticles may prove to be useful in the reduction of the secondary injury following SCI.     

Mixed Ni/Co hydroxide nanoparticles synthesized by sonochemical method

Nickel hydroxide nanoparticles with different amounts of cobalt atoms in the structure forming a unique material, were synthesized by using ultrasonic radiation. The particles of 5 nm diameter were prepared and characterized by X-Ray diffraction, Raman and Infrared spectroscopies, and thermogravimetry. The incorporation of cobalt leads to distinct crystalline planes, showing an opened and disarranged structure, indicating the stabilization of the alpha-Ni(OH)2 phase.