The Structure And Functioning Of Social Support Systems Of Married, Single, And Divorced Mothers With Young Children

This study sought to describe more precisely the structure and functioning of the social support systems of mothers with young children. Married, single, and divorced mothers were compared in terms of the size of their social networks, their perceived amount of support, and the sources for differing types of support within that network. They were also compared on their adjustment to parenthood and levels of depression and anxiety. Married mothers were expected to have larger social networks and to perceive more support as well as to have better adjustment levels

Small-Scale Production of High-Density Dry Ice: A Variant Combination of Two Classic Demonstrations

Easily recoverable, thumb-sized pieces of high-density dry ice are conveniently produced by deposition of carbon dioxide within a test tube submerged in liquid nitrogen. A carbon dioxide-filled balloon sealed over the mouth of the test tube serves as a gas reservoir, and further permits a dramatic demonstration of both the gas-to-solid phase transition and Avogadro’s law, with complete deflation of a 2-3 L balloon requiring only about 2-3 minutes. The dry ice “cube” that forms within the test tube is readily removed after slightly warming the tube’s outer surface, and is of sufficient density to sink in an aqueous indicator solution, permitting its subsequent use for the classic demonstration of carbon dioxide’s sublimation and its acidic properties

Membrane Extraction of Aqueous Transition Metal Ions Using Commercial Nafion Gas Dryers

Membrane extraction is a widely employed technique for improving the sensitivity and/or selectivity of a chemical analysis. This paper reports a study on the membrane extraction of aqueous transition metal ions using commercially available Nafion gas dryer assemblies. Though designed and marketed for use with gaseous mixtures, results of this work indicate such assemblies can be effective for the selective extraction of aqueous mixtures after a simple pretreatment procedure not requiring physical modification of the unit. The analytical merit of this sampling approach was evaluated by examining various performance characteristics using aqueous Cu (II) as a model system

Fiber Optic Spectroelectrochemical Sensing for In-Situ Determination of Metal Ions

In-situ chemical sensing techniques are increasingly utilized for a variety of applications, including industrial process control, on-site environmental assessment, and detection of explosives and chemical and biological weapons. A common category of sensors for such purposes entails the use of optical fibers for making spectral measurements of target compounds or species derived from these compounds via physical, chemical, enzymatic or immunological reactions. A less common, but potentially advantageous approach involves the electrochemical conversion of the analyte subsequent to its spectroscopic detection. These spectroelectrochemical schemes represent versatile, essentially reagent-free analyses that could provide superior alternatives to existing methods. Reported here is a summary of progress made by the authors’ group toward the development of fiber optic spectroelectrochemical sensors for in-situ measurements. The aqueous copper (II)/copper (0) couple was chosen as a model system to investigate the merit of an analytical scheme involving (i) cathodic preconcentration of Cu2+ 2 as Cu0 followed by (ii) anodic stripping of Cu0 to Cu2+, (iii) complexation of Cu2+ by an appropriate ligand, and finally (iv) absorbance determination of the copper/ligand complex or fluorescence determination of the unbound ligand. Results are encouraging and indicate the need for further refinement of the sensor’s design and the experimental protocol in order to improve the method’s sensitivity

Easily Constructed Microscale Spectroelectrochemical Cell

The design and performance of an easily constructed cell for microscale spectroelectrochemical analysis is described. A cation exchange polymer film, Nafion, was used as a salt bridge to provide ionic contact between a small sample well containing a coiled wire working electrode and separate, larger wells housing reference and auxiliary electrodes. The cell was evaluated using aqueous ferri/ferrocyanide as a test system and shown to be capable of relatively sensitive visible absorption measurements (path lengths on the order of millimeters) and reasonably rapid bulk electrolysis (~ 5 min) of samples in the 1 to 5 µL volume range. Minor alterations to the cell design are cited that could allow for analysis of sub-microliter volumes, rapid multi-sample analysis, and measurements in the ultraviolet spectral region

Incorporating Basic Optical Microscopy in the Instrumental Analysis Laboratory

A simple and versatile approach to incorporating basic optical microscopy in the undergraduate instrumental analysis laboratory is described. Attaching a miniature CCD spectrometer to the video port of a standard compound microscope yields a visible microspectrometer suitable for student investigations of fundamental spectrometry concepts, basic principles of optical microscopy, and some interesting phenomena unique to spectral measurements performed at the microscale. Results from several such investigations and ideas for additional applications are presented

Submicroliter Electrochemistry and Spectroelectrochemistry Using Standard Electrodes and a Polymer Electrolyte Salt Bridge.

The development of spectroscopic and electrochemical devices that can accommodate very small samples is of considerable importance to many areas of science and technology. We report here on the design and characteristics of a simple apparatus for the electrochemical and spectroelectrochemical analysis of submicroliter aqueous samples. The device is easily assembled from common laboratory materials and equipment, utilizing a bifurcated fiber-optic probe, standard disk electrodes of millimeter dimensions, and a polymer electrolyte film salt bridge to enable the analysis of nanoliter-scale sample volumes in a thin-layer configuration. Excellent performance has been demonstrated via measurements on aqueous ferricyanide solutions using sample volumes as low as 20 nL

Easily Constructed Spectroelectrochemical Cell for Batch and Flow Injection Analyses

The design and performance of an easily constructed spectroelectrochemical cell suitable for batch and flow injection measurements are described. The cell is fabricated from a commercially available 5 mm quartz cuvet and employs 60 ppi reticulated vitreous carbon as the working electrode, resulting in a reasonable compromise between optical sensitivity and thin layer electrochemical behavior. The spectroelectrochemical traits of the cell in both batch and flow modes were evaluated using aqueous ferricyanide and compare favorably to those reported previously for similar cells

Regional cerebral blood flow correlates of orthographic analysis and phonetic discrimination in adults who were reading disabled children

This research study was undertaken to test a model of posterior displacement of focal perisylvian activation based on the autopsy work of Galaburda, the intraoperative work of Ojemann and Rasmussen, and neural developmental animal work. By this model, an early lesion in Wernicke's area would displace some aspects of the neuronal processing capacity originally destined for Wernicke's area to adjacent, posterior cites. Forty-one normal adult males and 47 adult males with documented childhood reading evaluations (the Orton group) performed an orthographic analysis (spelling) task. Some also did phonetic and tonal tasks. Regional cerebral blood flow was measured during task performance using the 133-Xenon inhalation method. Normal subjects showed cerebral activation at left Wernicke's area proportional to spelling task accuracy, while Orton subjects showed activation both at Wernicke's area and at the left angular gyrus such that better performers of the spelling task activated Wernicke's area more and angular gyrus less. An inverse relationship between childhood reading impairment and angular gyrus activity also was found, and this was independent of either task accuracy or adult reading attainment

Influences of energy conservation education on attitudes and behaviors of selected youths in piedmont North Carolina

The purpose of this experimental study was to examine the attitudes and behaviors of selected youths in Piedmont North Carolina toward energy conservation. The specific objectives were to determine attitudes and behaviors of selected youths toward energy conservation, to determine the influence of energy education on the attitudes and behaviors of selected youths, and to determine if there was a relationship between four variables—age, sex, geographic location, and prior energy conservation experiences—as related to energy conservation attitudes and behaviors. The sample consisted of 284 youths (127 from control groups, and 157 from experimental groups). These youths were seven to nineteen years of age, who were members of a 4-H Club affiliated with the North Carolina Agricultural Extension Service, and who resided in fourteen counties located in Piedmont North Carolina. Each youth participating in the study completed a pretest and posttest which solicited information concerning attitudes and behaviors toward energy conservation. Both groups completed the pretest in October or November, 1980, and posttests in January, 1981. The experimental groups received energy education instruction in the form of a "4-H Energy Fun Day" after completing the pretest, while the control groups received no energy-related instruction