Synthesis of nanoporous materials for preconcentration and determination of trace elements by ICP-AES ; Investigation and elimination of the memory effects of mercury, gold, silver and boron in ICP-AES

Nanoporous materials with large surface area and well-ordered pore structure have been synthesized. Thiol groups were grafted on the materials' surface to make heavy metal ion pre-concentration media. The adsorption properties ofthe materials were explored. Mercury, gold and silver can be strongly adsorbed by these materials, even in the presence of alkaline earth metal ion. Though the materials can adsorb other heavy metal ions such as lead and copper, they show differential adsorption ability when several ions are present in solution. The adsorption sequence is: mercury> == silver> copper » lead and cadmium. In the second part of this work, the memory effects of mercury, gold, silver and boron were investigated. The addition of 2% L-cysteine and 1% thiourea eliminates the problems of the three metal ions completely. The wash-out time for mercury dropped from more than 20 minutes to 18 seconds, and the wash-out time for gold decreased from more than 30 minutes to 49 seconds. The memory effect of boron can be reduced by the use of mannitol.

Investigations in flow injection analysis (FIA): conventional FIA determination of chloride in water; sequential injection (SI)-FIA determination of mercury in water

Flow injection analysis (FIA) was applied to the determination of both chloride ion and mercury in water. Conventional FIA was employed for the chloride study. Investigations of the Fe3 +/Hg(SCN)2/CI-,450 nm spectrophotometric system for chloride determination led to the discovery of an absorbance in the 250-260 nm region when Hg(SCN)2 and CI- are combined in solution, in the absence of iron(III). Employing an in-house FIA system, absorbance observed at 254 nm exhibited a linear relation from essentially 0 - 2000 Jlg ml- 1 injected chloride. This linear range spanning three orders of magnitude is superior to the Fe3+/Hg(SCN)2/CI- system currently employed by laboratories worldwide. The detection limit obtainable with the proposed method was determin~d to be 0.16 Jlg ml- 1 and the relative standard deviation was determined to be 3.5 % over the concentration range of 0-200 Jig ml- 1. Other halogen ions were found to interfere with chloride determination at 254 nm whereas cations did not interfere. This system was successfully applied to the determination of chloride ion in laboratory water. Sequential injection (SI)-FIA was employed for mercury determination in water with the PSA Galahad mercury amalgamation, and Merlin mercury fluorescence detection systems. Initial mercury in air determinations involved injections of mercury saturated air directly into the Galahad whereas mercury in water determinations involved solution delivery via peristaltic pump to a gas/liquid separator, after reduction by stannous chloride. A series of changes were made to the internal hardware and valving systems of the Galahad mercury preconcentrator. Sequential injection solution delivery replaced the continuous peristaltic pump system and computer control was implemented to control and integrate all aspects of solution delivery, sample preconcentration and signal processing. Detection limits currently obtainable with this system are 0.1 ng ml-1 HgO.

American Mercury Newspaper, Vol. XXXI, No. 1571. August 9, 1814

A weekly newspaper published in Hartford, Connecticut by Elisha Babcock and Son, "(Printers of the Laws of the Union)". Babcock arrived in Hartford not long after the war in 1784 and created the Mercury. It became the leading Democratic newspaper in Connecticut and ceased not long after his death in 1821.

Massachusetts Mercury, 10 June 1800 (vol. 15, no. 46) - Newspaper

Volume 15 no. 46 of the Massachusetts Mercury dated 10 June, 1800.

The American Mercury, 5 October 1813 (vol. 30, no. 1527) - Newspaper

Volumes of interest were published between 1812 and 1815 with articles about the War of 1812. Issue for Oct. 5, 1813 includes: A report announces the arrival of Commodore Rodgers in the U.S. frigate President, in the harbor from his "brilliant cruise" of five months. There is also a list of the captures Rodgers made during his cruise. The feature item in this issue, however, is the famous dispatch sent by Oliver Hazard Perry at the Battle of Lake Erie to General William Henry Harrison. The dispatch, taken from the Chillicothe Supporter, of Sept. 15, is datelined "U.S. Brig Niagara, off the Western Sister, head of Lake Erie, September 10th, 1813, 4 P.M.", and reads: "Dear General, we have met the enemy; and they are ours! Two ships, two brigs, one schooner and one sloop. Yours with great respect and esteem." The dispatch is signed in type: O. H. Perry.

American Mercury, 16 August 1814 (vol. 31, 1572) - Newspaper

Volumes of interest were published between 1812 and 1815 with articles about the War of 1812. The 1814 Aug. issues report events of the Battle of Chippewa.

The American Mercury, 2 August 1814 (vol. 30, no. 1570)

Volumes of interest were published between 1812 and 1815 with articles about the War of 1812. The 1814 Aug. issues report events of the Battle of Chippewa

Far infrared optical properties of V and Cr doped Sb2Te3 /

The far infrared reflectance of Sb2Te3 , Sbi.97Vo.o3Te3 and Sbi.94Cr .o6Te3 was measured near normal incidence at different temperatures (between 45K and 300K). The direct current resistivities of the above samples were also measured between the temperatures of 4K and 300K. Also Kramers Kronig (KK) analyses were performed on the reflectance spectra to obtain the optical conductivities. In the doped samples, it was observed that a phonon at 62cm-1 softens to about 55cm-1 on decreasing the temperature from 295K to 45K. Also, it was observed that the plasma frequency of the doped samples is independent of doping. The scattering rate for the vanadium doped sample was seen to be greater than that for the chromium doped sample despite the fact that vanadium impurity density is less than that of chromium. The Drude-Lorentz model fits to the KK optical conductivity show that the samples used in this work are conventional metals. Definitive measurements of the temperature dependence of the scattering rate across the ferromagnetic transition await equipment changes allowing measurements at low temperature using the mercury cadmium telluride (MCT) detector.

Sample preparation and heavy metal determination by atomic spectrometry /

Microwave digestions of mercury in Standards Reference Material (SRM) coal samples with nitric acid and hydrogen peroxide in quartz vessels were compared with Teflon® vessel digestion by using flow injection cold vapor atomic absorption spectrometry. Teflon® vessels gave poor reproducibiUty and tended to deliver high values, while the digestion results from quartz vessel show good agreement with certificate values and better standard deviations. Trace level elements (Ag, Ba, Cd, Cr, Co, Cu, Fe, Mg, Mn, Mo, Pb, Sn, Ti, V and Zn) in used oil and residual oil samples were determined by inductively coupled plasma-optical emission spectrometry. Different microwave digestion programs were developed for each sample and most of the results are in good agreement with certified values. The disagreement with values for Ag was due to the precipitation of Ag in sample; while Sn, V and Zn values had good recoveries from the spike test, which suggests that these certified values might need to be reconsidered. Gold, silver, copper, cadmium, cobalt, nickel and zinc were determined by continuous hydride generation inductively coupled plasma-optical emission spectrometry. The performance of two sample introduction systems: MSIS™ and gas-liquid separator were compared. Under the respective optimum conditions, MSIS^"^ showed better sensitivity and lower detection limits for Ag, Cd, Cu, Co and similar values for Au, Ni and Zn to those for the gas-liquid separator.

Arsenic and germanium determination by hydride generation in the D.C. plasma optical emission spectrometer

Modifications to the commercial hydride generator, manufactured by Spectrametrics, resulted in improved operating procedure and enhancement of the arsenic and germanium signals. Experiments with arsenic(III) and arsenic(V) showed that identical reiults could be produced from both oxidation states. However, since arsenic(V) is reduced more slowly than arsenic(III), peak areas and not peak heights must be measured when the arsine is immediately stripped from the system (approximately 5 seconds reaction). When the reduction is allowed to proceed for 20 seconds before the arsine is stripped, peak heights may be used. For a 200 ng/mL solution, the relative standard deviation is 2.8% for As(III) and 3.8% for As(V). The detection limit for arsenic using the modified system is 0.50 ng/mL. Studies performed on As(V) standards show that the interferences from 1000 mg/L of nickel(II), cobalt(II), iron(III), copper(II), cadmium(II), and zinc(II) can be eliminated with the aid of 5 M Hel and 3% L-cystine. Conditions for the reduction of germanium to the corresponding hydride were investigated. The effect of different concentrations of HCl on the reduction of germanium to the covalent hydride in aqueous media by means of NaBH 4 solutions was assessed. Results show that the best response is accomplished at a pH of 1.7. The use of buffer solutions was similarly characterized. In both cases, results showed that the element is best reduced when the final pH of the solution after reaction is almost neutral. In addition, a more sensitive method, which includes the use of (NH4)2S208' has been developed. A 20% increase in the germanium signal is registered when compared to the signal achieved with Hel alone. Moreover, under these conditions, reduction of germanium could be accomplished, even when the solution's pH is neutral. For a 100 ng/mL germanium standard the rsd is 3%. The detection limit for germanium in 0.05 M Hel medium (pH 1.7) is 0.10 ng/mL and 0.09 ng/mL when ammonium persulphate is used in conjunction with Hel. Interferences from 1000 mg/L of iron(III), copper(II), cobalt(II), nickel(II), cadmium(II), lead(II), mercury(II), aluminum(III), tin(IV), arsenic(III), arsenic(V) and zinc(II) were studied and characterized. In this regard, the use of (NH4)ZS20S and Hel at a pH of 1.7 proved to be a successful mixture in the sbppression of the interferences caused by iron, copper, aluminum, tin, lead, and arsenic. The method was applied to the determination of germanium in cherts and iron ores. In addition, experiments with tin(IV) showed that a 15% increase in the tin signal can be accomplished in the presence of 1 mL of (NH4)2S20S 10% (m/V).

The crystal and molecular structure of 18-Crown-6 HgC12 and 18-Crown-6 Cdc12

Hg(18-Crown-6)C12 and Cd(18-Crown-6)C12 are isostructura1, space group Cl~ Z = 2. For the mercury compound, a = 10.444(2) A° , b = 11. 468(1) A° , c = 7.754(1) A° , a = 90.06(1)°, B = 82.20(1)°, Y = 90.07(1)°, Dobs = 1.87, Dca1c = 1.93, V = 920.05 13, R = 4.66%. For the cadmium compound, 000 a = 10.374(1) A, b = 11.419(2) A, c = 7.729(1) A, a = 89.95(1)°, B = 81.86(2)°, Y = 89.99(1)°, Dobs = 1.61, Dcalc = 1.64, V = 906.4613, R = 3.95%. The mercury and cadmium ions exhibit hexagonal bipyramidal coordination, with the metal ion located on a centre of symmetry in the plane of the oxygen atoms. The main differences between the two structures are an increase in the metal-oxygen distance and a reduction in the metalchloride distance when the central ion changes from Cd2+ to Hg2+. These differences may be explained in terms of the differences in hardness or softness of the metal ions and the donor atoms.

The effectiveness of a multisensory writing program in improving cursive writing ability in children with sensorimotor difficulties

It is estimated that five to ten percent of children experience sensory motor difficulties that result in various learnlng disabilitiies , among them. inabllity to output Information on paper in the appropriate manner (Ayres ,1985). The relationship between sensorimotorabillty and handwriting is well documented in the literature (Freeman,1917; Townsend , 1951; Nlkola-Ll sa, 1987). While much of the literature is inconclusive, there are findings to suggest that muitisensory handwriting programmes are an effective approach to improvlng writing abIlity in these chlldren. For a number of years, Occupational Therapists have been involved in the remediation of handwriting utllizing , amongst other approaches . multisensory programmes. While subjective assessments of effectiveness have been extremerly positive. scientIfic evaluation has been minimal . If further intervention in this area is to occur, it Is essential that the profession be able to justify the existence of such programmes . The purpose of this study was to examine what effects a multlsensory writing prog~am would have on the curslve writing ability of chlldren with sensorimotor dlfficulties. A single case with multiple baselines across be havlours design was used , with the behavlours being cursive writing abilIty of fIve distInct letter groups. The fIve groups were taught in random order, one group every two weeks , In a one-hour session. Repeated measurements of writing speed and qualIty for each letter group were made. This design was repeated over three other cases . Results of the study yielded statistical signifi cance in trend changes In specIfic letter groups for all of the chlldren following interventlon. One child achieved statistical significance In the overall change In quality , while none of the children achieved overall statistical significance In speed score changes . Teacher reports and an assessment of written language prior to and following the program suggest that Intervention may have had a positive effect on self-confidence in written output, and on the maturlty of written expression in some of the cases . Further research in this field is needed to validate the continual use of multisensory writing programmes by Occupational Theraplsts worklng with this specific population and to provide some directlon with regards to the Integration of multlsensory writing programmes within the regular academic remedial programme .

Understanding the polyvocality of autism discourse : a critical autoethnographic approach

Currently, much of the autism literature supports the notion that Pervasive Developmental Disorder (PDD) is a deviation from what is considered "normal" and, accordingly, that it is in need of early remediation. This thesis explored alternative constructions of autism and pathology by drawing on theorists from other disciplines, such as cultural studies (Deleuze & Guattari, 1987, 1965, 1972, 1975,1980, 2003), critical psychology (Parker, 1995, 2002, 2005, 2007), disability studies (Danforth,1997, 1999, 2000; Skrtic, 1995, 1996) and anti-psychiatry (Basaglia, 1987). In an attempt to show how our accounts of the world encompass constructions rooted in language and our own histories of thinking about topics that interest us, this research took an autoethnographic approach to understanding autism discourse. Instead of denying the researcher's existence and personal investment in the research, the author attempted to implicate "the self in the research by acknowledging her own assumptions, biases and ideologies about autism discourse and practice. Thus, tensions between the self and other, personal and political become woven into the fabric, creating a personal, subjective, and partial account of the phenomenon. This research was intended to explicate and interrogate some of the taken-for-granted Truths which guide our practices with people with autism. This alternative critical framework focused on understanding autism as a discourse and explored the way these dominant autism constructions function in society. Furthermore, positioning "the self in the research was meant to illustrate the fundamental need for self-reflective practice in the social sciences.

The relationship between working alliance and treatment outcomes in remedial instruction for older dyslexic children

Research in psychotherapy has demonstrated that a positive working alliance between therapist and client leads to positive treatment outcomes. Though its focus is in the area of psychotherapy, the concept of working alliance holds significant value to the area of education. Current applications of the theory in educational settings have looked at relationships between teacher and students in the broad context of classroom interaction and found significant promise. The present study investigates the application of the theory of working alliance in a sample of older reading disabled children. The study examined the psychometric properties of the Reading Alliance Scale for Children (RASC) and for Teachers (RAST) in relation to student reading ability and motivation. A sample of 254 (66.1 % male, 33.9% female) grade 6-8 students (mean age 12.7 years) were enrolled in a remedial reading program for reading disabled children. The average standard score across multiple reading measures was more than 1 SD below age-level expectations. Students responded to measures of reading achievement and motivation at pretest, after 70 hours (post 70) of remediation and at the end of the program (post 125). All participants completed measures on the working alliance relationship at post 70 and post 125. Results showed that teacher reports were most predictive of outcome compared to student reports of the working alliance relationship. Working alliance was correlated with posttest reading ability and motivation. Male students and Black students obtained the weakest working alliance reports from their teacher. Overall, findings support the view that students' relationships with teachers provide an important component of success in the classroom.

Frontal Lobe Function and Performance Monitoring following Total Sleep Deprivation

Imaging studies have shown reduced frontal lobe resources following total sleep deprivation (TSD). The anterior cingulate cortex (ACC) in the frontal region plays a role in performance monitoring and cognitive control; both error detection and response inhibition are impaired following sleep loss. Event-related potentials (ERPs) are an electrophysiological tool used to index the brain's response to stimuli and information processing. In the Flanker task, the error-related negativity (ERN) and error positivity (Pe) ERPs are elicited after erroneous button presses. In a Go/NoGo task, NoGo-N2 and NoGo-P3 ERPs are elicited during high conflict stimulus processing. Research investigating the impact of sleep loss on ERPs during performance monitoring is equivocal, possibly due to task differences, sample size differences and varying degrees of sleep loss. Based on the effects of sleep loss on frontal function and prior research, it was expected that the sleep deprivation group would have lower accuracy, slower reaction time and impaired remediation on performance monitoring tasks, along with attenuated and delayed stimulus- and response-locked ERPs. In the current study, 49 young adults (24 male) were screened to be healthy good sleepers and then randomly assigned to a sleep deprived (n = 24) or rested control (n = 25) group. Participants slept in the laboratory on a baseline night, followed by a second night of sleep or wake. Flanker and Go/NoGo tasks were administered in a battery at 1O:30am (i.e., 27 hours awake for the sleep deprivation group) to measure performance monitoring. On the Flanker task, the sleep deprivation group was significantly slower than controls (p's <.05), but groups did not differ on accuracy. No group differences were observed in post-error slowing, but a trend was observed for less remedial accuracy in the sleep deprived group compared to controls (p = .09), suggesting impairment in the ability to take remedial action following TSD. Delayed P300s were observed in the sleep deprived group on congruent and incongruent Flanker trials combined (p = .001). On the Go/NoGo task, the hit rate (i.e., Go accuracy) was significantly lower in the sleep deprived group compared to controls (p <.001), but no differences were found on false alarm rates (i.e., NoGo Accuracy). For the sleep deprived group, the Go-P3 was significantly smaller (p = .045) and there was a trend for a smaller NoGo-N2 compared to controls (p = .08). The ERN amplitude was reduced in the TSD group compared to controls in both the Flanker and Go/NoGo tasks. Error rate was significantly correlated with the amplitude of response-locked ERNs in control (r = -.55, p=.005) and sleep deprived groups (r = -.46, p = .021); error rate was also correlated with Pe amplitude in controls (r = .46, p=.022) and a trend was found in the sleep deprived participants (r = .39, p =. 052). An exploratory analysis showed significantly larger Pe mean amplitudes (p = .025) in the sleep deprived group compared to controls for participants who made more than 40+ errors on the Flanker task. Altered stimulus processing as indexed by delayed P3 latency during the Flanker task and smaller amplitude Go-P3s during the Go/NoGo task indicate impairment in stimulus evaluation and / or context updating during frontal lobe tasks. ERN and NoGoN2 reductions in the sleep deprived group confirm impairments in the monitoring system. These data add to a body of evidence showing that the frontal brain region is particularly vulnerable to sleep loss. Understanding the neural basis of these deficits in performance monitoring abilities is particularly important for our increasingly sleep deprived society and for safety and productivity in situations like driving and sustained operations.