Free and esterified sterols of cotton buds and anthers

Capillary gas liquid chromatography analyses were conducted on free and esterified sterol fractions of cotton (Gossypium hirsutum cv. Stoneville 213) floral buds and anthers. The free sterols of both cotton buds and anthers consist mainly of the common plant sterols sitosterol, stigmasterol and 24ζ-methylcholest-5-en-3β-ol. The composition of esterified sterols of cotton buds and anthers were similar, and consisted of pollinastanol, 31-norcycloartanol, cycloartenol, 31-norcycloartenol, 24-dehydropolinastanol and sitosterol. Desmosterol was also present in both the free and esterified sterols of anthers. The identities of the sterols were confirmed by gas chromatography-mass spectrometry analyses. Esterified sterols accounted for 46.7 and 88.7% of total sterols of cotton bud and anthers, respectively. The ratio of esterified sterol to free sterol per gram of tissue is about 8∶1 in anthers. The Δ⁵-sterols of the esterified sterols of cotton buds and anthers account for only 17 and 9.2% of the total sterols, respectively.     

Modelling and simulation of Proton Exchange Membrane fuel cell with serpentine bipolar plate using MATLAB

This report presents experimental results derived from a Proton Exchange Membrane fuel cell with a serpentine flow plate design. The investigation seeks to explore the effects of some parameters like cell operational temperature, humidification and atmospheric pressure on the general performance and efficiency of PEM fuel cell using MATLAB. A number of codes were written to generate the polarization curve for a single stack and five (5) cell stack fuel cell at various operating conditions. Detailed information of hydrogen and oxygen consumption and the effect they have on the fuel cell performance were critically analysed. The investigation concluded that the open circuit voltage generated was less than the theoretical voltage predicted in the literature. It was also noticed that an increase in current or current density reduced the voltage derived from the fuel cell stack. The experiment also clearly confirmed that when more current is being drawn from the fuel cell, more water will also be generated at the cathode section of the cell hence the need for an effective water management to improve the performance of the fuel cell. Other parameters like the stack efficiency and power density were also analysed using the experimental results obtained.     

Black students' counselor preference and attitudes toward counseling center use.

Surveyed 42 female and 33 male Black college students to determine factors related to Black student use of the university counseling center. Counselor preference, sex of client, sex of counselor, race of counselor, and type of problem were analyzed as to their effects on counseling center use. Results indicate that Black clients preferred Black counselors and that the likelihood of taking a problem to the counseling center increased as counselor preference increased. Also, the likelihood of taking a problem to the center was significantly greater if the counselor to be seen was Black rather than White. Client and counselor sex, and type of problem (personal or educational-vocational) had no effect on potential counseling center usage. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The forensic psychology section in a state hospital.

A psychology section functioning in a forensic services center is described. The legal questions that must be dealt with in such a setting are explained, and psychology's role in answering these questions is explored. The goals of treatment in a forensic unit, which focus on educating a defendant to competency for trial, are discussed, and an example of a treatment program is presented. The functions of a psychologist in a forensic setting are compared and contrasted with those of a psychologist in the general mental health field. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thickness of human cornea measured by topographic pachometry

In the hands of trained user, the topographic pachometer proves to be an instrument of acceptable clinical precision (standard deviation = 0.006mm). An examination of corneal thinning during waking hours revealed a rate of thinning which was greatest upon lid opening and which declined uniformly throughout the day (p = 0.01). An investigation into menstrually related change in corneal thickness revealed that at least 122 subjects would be required to investigate this change on an acceptable statistical basis (p = 0.05).     

The development of ketogenesis at birth in the rat

In the suckling newborn rat, blood ketone bodies begin to increase slowly 4h after birth and then rise sharply between 12 and 16h, whereas the major increase in plasma non-esterified fatty acids and liver carnitine occurs during the first 2h of life, parallel with the onset of suckling. In the starved newborn rat, which shows no increase in liver carnitine unless it is fed with a carnitine solution, the developmental pattern of the ketogenic capacity (tested by feeding a triacylglycerol emulsion, which increases plasma non-esterified fatty acids by 3-fold) is the same as in the suckling animal. This suggests that the increases in plasma non-esterified fatty acids and liver carnitine seen 2h after birth in the suckling animal are not the predominant factors inducing the switch-on of ketogenesis. Injection of butyrate to starved newborn pups resulted in a pattern of blood ketone bodies which was similar to that found after administration of triacylglycerols, but, at all time points studied, the hyperketonaemia was more pronounced with butyrate. It is suggested that, even if the entry of long-chain fatty acids into the mitochondria is a rate-limiting step, it is not the only factor controlling ketogenesis after birth in the rat. As in the adult rat, there is a reciprocal correlation between the liver glycogen content and the concentration of ketone bodies in the blood.