Development of natural zeolites for their use in water-treatment systems.

This paper gives an overview of research and patents concerning the use of natural zeolites in water-treatment systems in the last ten years. Furthermore, nanocomposite materials made of natural zeolites and organic and polymeric materials are also mentioned as an effective solution in water treatment. An additional emphasis is put on a variety of possibilities for further application of natural zeolite materials for environment protection and preservation.

Determination of zinc incorporation in the Zn-substituted gallophosphate ZnULM-5 by multiple wavelength anomalous dispersion techniques.

The location of isomorphously substituted zinc over eight crystallographically different gallium sites has been determined in a single-crystal study of the gallophosphate ZnULM-5, Ga((16-x))Zn(x)(PO(4))(14)(HPO(4))(2)(OH)(2)F(7), [H(3)N{CH(2)}(6)NH(3)](4), 6H(2)O, in an 11 wavelength experiment, using data from Station 9.8, SRS Daresbury. The measurement of datasets around the K edges of both Ga and Zn, as well as two reference datasets away from each absorption edge, was utilized to selectively exploit dispersive differences of each metal atom type in turn, which allowed the major sites of Zn incorporation to be identified as the metal 1 and 3 sites, M1 and M3. The preferential substitution of Zn at these sites probably arises because they are located in double four-ring (D4R) building units which can relax to accommodate the incorporation of hetero atoms. As the crystal is non-centrosymmetric, with space group P2(1)2(1)2, it was also possible to use anomalous differences to corroborate the results obtained from the dispersive differences. These results were obtained firstly from difference Fourier maps, calculated using a phase set from the refined structure from data measured at the Zr K edge. Also, refined dispersive and anomalous occupancies, on an absolute scale, could be obtained using the program MLPHARE, allowing estimates for the Zn incorporation of approximately 22 and 18 at. % at the M1 and M3 sites to be obtained. In addition, f' and f'' values for Ga and Zn at each wavelength could be estimated both from MLPHARE results, and by refinement in JANA2006. The fully quantitative determinations of the dispersive and anomalous coefficients for Ga and Zn at each wavelength, as well as metal atom occupancies over the eight metal atom sites made use of the CCP4's MLPHARE program as well as SHELXL and JANA2006. The results by these methods agree closely, and JANA2006 allowed the ready determination of standard uncertainties on the occupancy parameters, which were for M1 and M3, 20.6 (3) and 17.2 (3) at %, respectively.

Mesoporous aluminophosphate thin films with cubic pore arrangement.

Mesoporous aluminophosphate thin films with 3D cubic (Im3m) pore arrangement were synthesized for the first time. Thin films were templated with block copolymer nonionic templates Pluronic F127 and F108 and deposited on a glass substrate by dip-coating. In situ SAXS investigations show the formation of a highly ordered mesostructure upon the dip-coating process, which remains stable up to at least 670 K. A cubic mesostructure was observed also by TEM. Template removal process was monitored by TG and FT-IR. A transition from an amorphous aluminophosphate gel to a well-defined aluminophosphate framework was observed by MAS NMR.

The use of softer X-rays in the structure elucidation of microporous materials.

Microporous materials, such as zeolites and aluminophosphates, have many applications as molecular sieves and shape-selective catalysts. This is due to their three-dimensional frameworks, which contain regular pores and channels, to their high acidity, arising from Brønsted and Lewis acid active sites, and to the incorporation of transition metal atoms into framework sites. This review firstly provides an introduction into the nature and properties of these materials, and their important applications; the difficulties in their full characterization and possible methods of elucidating their structures are then outlined; finally, methods of characterization, utilizing 'softer X-rays' are introduced. The first method is the determination of low concentrations of transition metals, incorporated into the frameworks using single crystal anomalous dispersion crystallography; synchrotron radiation is used to tune to the absorption edge of the metal atom in question, in order to change its signal relative to that of the rest of the structure, thereby allowing the pinpointing of its positions and the determination of its concentration at each site in the framework. Secondly, the use of longer wavelengths in powder diffraction studies is described, which, by stretching out the powder pattern, thereby reduces the overlapping of the diffraction peaks, thus allowing the structure to be solved by conventional direct methods. Finally, the use of X-ray absorption spectroscopy to determine the metal incorporation and the nature of coordination at the metal atom sites, in Mn silicalite-1 and FAPO-36, are described.

Genealogical study of myotonic dystrophy in Istria (Croatia).

High prevalence of myotonic dystrophy (DM) of 18.1 per 100,000 has been found in Croatian region Istria, a region where a great mixture of nations occurred over the last three centuries. The objective of this study was to test the hypothesis of common ancestry in Istrian DM families. Pedigrees were constructed on the basis of extensive family history obtained from the patients in all Istrian DM families. Church records were consulted in order to improve genealogical reconstruction. Additionally, we performed haplotype analyses with two intragenic and three extragenic DNA polymorphic markers. A common ancestor couple for three of nine nucleus families was found eight generations backward, which was supported by haplotype analysis. In spite of finding an evidence of common ancestry in Croatian Istria we argue that the phenomenon of founder effect is not sufficient to explain the high DM prevalence in Istria.

Relation of CTG expansion and clinical variables to electrocardiogram conduction abnormalities and sudden death in patients with myotonic dystrophy.

We prospectively followed 63 patients with myotonic dystrophy (DM) after establishing diagnosis of DM for an average 8 years in an attempt to detect conduction disturbances (by electrocardiography and/or Holter monitoring) and sudden cardiac events (sudden death, cardiac syncope) and correlate them to potential predicting factors (CTG repeat expansion in the myotonin protein kinase gene and several clinical variables: clinical type and duration of DM, age and sex). Twenty-six patients developed conduction disturbances, five patients died suddenly, and two patients experienced cardiac syncope necessitating urgent implantation of pacemaker. Analysis showed no significant correlation between conduction disturbances and/or cardiac events and CTG expansion. Furthermore, no correlation was found with type of DM, whereas conduction disturbances and sudden cardiac events correlated with patients' age, duration of disease and male sex. Results on our cohort of DM patients show that CTG expansion has no role in predicting neither conduction abnormalities nor sudden death. It seems that risk of sudden death increases with duration of disease and age, and that risk is higher in male patients.

Characteristics of myotonic dystrophy in Istria: molecular genetic approach. Part II: Analysis of genetic polymorphisms.

One of the world highest prevalence estimates of myotonic dystrophy (DM) has been reported in the Croatian region Istria. To analyse the population genetic characteristics of DM locus in Istria, two intragenic and three extragenic polymorphic markers were tested. The Southern blot technique was used for D19S63 locus analysis, whereas PCR analysis was performed for CKMM, Alu polymorphism, DMPK (G/T) intron 9/HinfI polymorphism, and D19S207 genetic markers. The compound haplotypes segregating with DM were established. A complete association between the DM mutation and D19S63, D19S207, intron 9/HinfI polymorphism and Alu polymorphism markers were found. In all DM chromosomes: D19S63 and Alu markers had the allele 1 in common; D19S207 had the allele 3 in common, DMPK (G/T) intron 9/HinfI marker had the allele 2 in common. The analysis of CKMM polymorphism revealed genotype heterogeneity; in DM chromosomes either allele 2 or allele 4 were found. The haplotype analysis in the population of Croatian Istria supports the linkage disequilibrium between the DM mutation and Alu polymorphism, intron 9/HinfI polymorphism, D19S63 and D19S207 markers as reported worldwide. The results of the haplotype analysis suggest a common origin of the mutation in Istrian population.

Determination of the site of incorporation of cobalt in CoZnPO-CZP by multiple-wavelength anomalous-dispersion crystallography.

Data were collected from a crystal of CoZnPO-CZP {sodium cobalt-zinc phosphate hydrate, Na(6)[Co(0.2)Zn(0.8)PO(4)](6).6H(2)O} using synchrotron radiation at ELETTRA at the inflection point and 'white line' for both the cobalt and zinc K edges, and at 1.45 Å, a wavelength remote from the K edges of both metals. The data were processed using the programs DENZO and SCALEPACK. The CCP4 program suite was used for the scaling of data sets and the subsequent calculation of dispersive difference Fourier maps. Optimal scaling was achieved by using a subset of reflections with little or no contribution from the metal atoms (i.e. which were essentially wavelength independent in their intensities) and using weights based on the sigma's to obtain an overall scale factor in each case. Phases were calculated with SHELXL97 based on the refined structure using a much higher resolution and complete Cu Kalpha data set. An occupancy of 100% by zinc at the two metal-atom sites was assumed. The dispersive difference Fourier map calculated for zinc gave two peaks above the background of similar heights at the expected metal-atom sites. The peak height at the Zn1 site was a little higher than at the Zn2 site. The dispersive difference Fourier map calculated for cobalt gave just one peak above the background, at the Zn1 site, and only a small peak at the Zn2 site, thus indicating that incorporation of cobalt takes place mainly at one site. Refinement of the zinc occupancies using MLPHARE reinforces this conclusion. The chemical environment of each site is discussed.

Characteristics of myotonic dystrophy in Istria: molecular genetics approach--mutation analysis.

Myotonic dystrophy (DM) is the most prevalent myopathy in adults. In Istria one of the highest prevalence rates of 18/100,000 has been reported. Two loci, the most prevalent 19q locus with mutations in the myotonin protein kinase gene and the second locus mapped to the 3q have been so far implicated in DM. The purpose of this study was to evaluate the molecular pathogenesis in the Istrian population by the analysis of (CTG) expansion in myotonin protein kinase gene. Additionally genotype--phenotype correlation was analysed, as well as the transmission of expanded trinucleotides through generations. We investigated 27 DM patients from the 10 families that were ascertained in Istria in our previous epidemiological study. Southern blot and polymerase chain reaction (PCR) techniques were used to evaluate the (CTG) expansion. In 9 of the 10 DM families an amplification was identified as the mechanism of mutation. A correlation between the size of the (CTG) expansion and phenotype was found. Among 10 parent-child transmission analysed, one reduction, 2 stable transmissions and 7 amplifications were observed, one through the affected father. The amplification of (CTG) in the myotonin protein kinase gene was identified in the majority of Istrian DM families. Direct mutation analysis is the method of choice for clinical and prenatal diagnosis of DM.

CTG repeat analysis in lymphocytes, muscles and fibroblasts in patients with myotonic dystrophy.

The mutation responsible for DM has been identified as the amplification of a polymorphic (CTG)n repeat in the 3' untranslated region of the myotonin proteinase gene. To examine somatic instability of the repeat, we studied tissue variability of the CTG expansion of three mesodermally derived tissues: lymphocytes, cultured fibroblasts and muscle cells. In six patients with adult onset DM, the repeat region was larger in skeletal muscles and fibrolasts as compared to lymphocytes. Our findings indicate that somatic CTG instability between examined tissues might take place postnatally by a selection mechanism in lymphocytes.

A marble used as a low-vision reading aid: a case report.

An unusual low-vision remedy was encountered in which a simple dime-store marble was used in near vision tasks. Although the marble was found satisfactory as a low-vision aid, the patient could be better assisted with a commercially available magnifier of lesser dioptric power. This case serves to demonstrate a patient's ingenuity in independently solving his own low vision problem.

A semi-automated instrument for determination of acuity threshold.

A device has been constructed that permits rapid, repeatable measures of visual acuity while minimizing many of the patient and examiner errors in subjective acuity testing. The Baylor acuity meter utilizes digital logic circuitry to implement a carefully controlled psychophysical "staircase" testing procedure in a small portable unit. Comparisons of the acuity meter with conventional measurement techniques on 51 subjects yield correlations of +.74 and +.81. A test-retest correlation of +.96 was found.