Search

The aim of this study was to evaluate the progression of the light through a series of translucent posts available on the market (D.T. Light-post, R.T.D.).nine D.T. Light-posts (DTLPs) were analyzed, 3 for each available measure. Each post was trans-illuminated both in vertical trans-ilumination (VTI) and oblique trans-illumination (OTI), via a light curing unit (LCU) (V.I.P., Bisco), in complete darkness conditions, and the resulting image of the post, was digitally acquired with a 1:1 ratio. The images were then analyzed using digital image analysis software (Image Pro plus 4.1, Media Cybernetics) previously performing the light intensity calibration, of the LCU, by means a radiometer (Curing Radiometer model 100, Demetron Corp.). The evaluation of the progression of the light through the posts was conducted for each post along its longitudinal axis.no significant differences concerning VTI vs OTI for DTLP n.1 (p = 0.341) and DTLP n. 3 (p = 0.115), while for DTLP n.2 a significant difference was observed (p = 0.041); Conclusion: The results demonstrate that the greater the section of the post, the greater its ability to transmit light at a distance; also the vertical Trans-illumination of the post is to be preferred to the oblique one.

Living organisms employ glycans as recognition elements because of their large structural information density. Well-defined sugar structures are needed to fully understand and take advantage of glycan functions, but sufficient quantities of these compounds cannot be readily obtained from natural sources and have to be synthesized. Among the bottlenecks in the chemical synthesis of complex glycans is the preparation of suitably protected monosaccharide building blocks. Thus, easy, rapid, and efficient methods for building-block acquisition are desirable. Herein, we describe routes directly starting from the free sugars toward notable monosaccharide derivatives through microwave-assisted one-pot synthesis. The procedure followed the in situ generation of per-O-trimethylsilylated monosaccharide intermediates, which provided 1,6-anhydrosugars or thioglycosides upon treatment with either trimethylsilyl trifluoromethanesulfonate or trimethyl(4-methylphenylthio)silane and ZnI2, respectively, under microwave irradiation. We successfully extended the methodology to regioselective protecting group installation and manipulation toward a number of thioglucosides and the glycosylation of persilylated derivatives, all of which were conducted in a single vessel. These developed approaches open the possibility for generating arrays of suitably protected building blocks for oligosaccharide assembly in a short period with minimal number of purification stages.

Fondaparinux, a synthetic pentasaccharide based on the heparin antithrombin-binding domain, is an approved clinical anticoagulant. Although it is a better and safer alternative to pharmaceutical heparins in many cases, its high cost, which results from the difficult and tedious synthesis, is a deterrent for its widespread use. The chemical synthesis of fondaparinux was achieved in an efficient and concise manner from commercially available D-glucosamine, diacetone α-D-glucose, and penta-O-acetyl-D-glucose. The method involves suitably functionalized building blocks that are readily accessible and employs shared intermediates and a series of one-pot reactions that considerably reduce the synthetic effort and improve the yield.

Human lung epithelial cells natively offer terminal N-acetylneuraminic acid (Neu5Ac) α(2→6)-linked to galactose (Gal) as binding sites for influenza virus hemagglutinin. N-Glycolylneuraminic acid (Neu5Gc) in place of Neu5Ac is known to affect hemagglutinin binding in other species. Not normally generated by humans, Neu5Gc may find its way to human cells from dietary sources. To compare their influence in influenza virus infection, six trisaccharides with Neu5Ac or Neu5Gc α(2→6) linked to Gal and with different reducing end sugar units were prepared using one-pot assembly and divergent transformation. The sugar assembly made use of an N-phthaloyl-protected sialyl imidate for chemoselective activation and α-stereoselective coupling with a thiogalactoside. Assessment of cytopathic effect showed that the Neu5Gc-capped trisaccharides inhibited the viral infection better than their Neu5Ac counterparts.

The aim of this article is to make a comparative assessment between the modification of the soft-tissue profile, around the healing cap screws (HCSs), following both the traditional flapless surgery (TFS) and a new modified flapless surgery, named Modified Connective Tissue Punch (MCTP) technique.8 patients (3M and 5F) (mean age 54.25±11.247 years) were enrolled in this study. Sixteen two-piece implants were placed on upper jaws, 2 for each patient, 8 with TFS and 8 with MCTP technique. In each patient the implants were placed in edentulous areas, of 2 or 3 adjacent teeth long. MCTP technique was performed on the front implant site (FIS) while the TFS was performed on the rear implant site (RIS). All implants were inserted and covered with healing cap screws (HCSs). Alginate impressions were carried out at the moment of the surgery, at 1 month and 4 months post-operative. Plaster models were poured and subsequently digitally scanned, in order to measure the distance between the gingival outline and the free margin of the HCS. The recorded values were analyzed with the ANOVA test.The use of MTCP technique, in comparison to TFS, showed a significative better outcome, in terms of vertical increments, of gingiva, on the VS toward the HCSs, during the entire observation period (p = 0.000 for all).The Authors recommend the use of MCTP technique for a better vestibular soft tissue outcome in flapless implant surgery.

Purpose This study evaluated the effects of different dowel space (DS) diameters on pull-out bond strength of a cylindrical post, of threaded steel, to dentin. Materials and methods Forty-five extracted human teeth were divided in 3 groups with DSs, with the same depth (6 mm), differing for the diameter (i.e. 1.5 mm, Group 1; 1.75 mm, Group 2; 2.00 mm, Group 3). Both the diameter of the post (1.3 mm) and the composite resin cement (Panavia 21) were the same for all the samples. The samples were submitted to pull-out test by means an Universal Testing Machine (Mod. 1193, Instron) (1KN load cell, crosshead speed 0.5 mm/min). Results The mean values of the bond strength (BS) were: Group 1, 442±128.3N; Group 2, 411.3±111N; Group 3, 448.7±142.29N. While the calculated average shear bond strengths (SBSs) were: Group 1, 14.7±4.27MPa; Group 2, 11.6±3.14MPa; Group 3, 11±3.5MPa. ANOVA test showed not significative differences, among the groups, concerning the BS: Group 1 vs Group 2 (p = 0.490); Group 1 vs Group 3 (p = 0.894); Group 2 vs Group 3 (p = 0.431). Significative differences were observed, among the groups, concerning the SBS for Group 1 vs Group 2 (p = 0.032) and Group 1 vs Group 3 (p = 0.014). While a not significative difference was found, concerning this parameter, for Group 2 vs Group 3 (p = 0.641). Conclusion The cement thickness can influence the SBS of the adhesively luted posts, in our setting, the best values were obtained with a thickness of 100 μm.

The aim of this study is to determine in an experimental way through mechanical tests the static, fatigue and torque resistance of two types of implant/abutment connectors with diameters of 3.4–5.2 mm.

A new compound that is structurally related to the undecose ring structure of herbicidins has been prepared. The synthesis of this novel furanosyl-pyranone derivative was made possible through the regioselective reductive ring-opening of a 3,5-O-benzylidene-D-xylofuranose and the hetero-Diels—Alder reaction of an aldehyde and a Danishefsky-type diene. The highly functionalized pyranone derivative can be a useful precursor for the synthesis of herbicidins.

Purpose. The Authors analyzed the effect of spherical glass mega fillers (SGMF) on reducing contraction stress in dental composite resins, by means of a cavity model simulating the cuspal deflection which occurs on filled tooth cavity walls in clinical condition. Materials and methods. 20 stylized MOD cavities (C-factor = 0.83) were performed in acrylic resin. The inner surface of each cavity was sand blasted and adhesively treated in order to ensure a valid bond with the composite resin. Three different diameter of SGMF were used (i.e. 1, 1,5, 2 mm). The samples were divided in 4 groups of 5 each: Group 1 samples filled with the composite only; Group 2 samples filled with composite added with SGMFs, Ø1mm (16 spheres for each sample); Group 3 samples filled with composite added with SGMFs, Ø1,5 mm (5 spheres for each sample); Group 4 samples filled with composite added with SGMFs, Ø2 mm (2 spheres for each sample). Digital pictures were taken, in standardized settings, before and immediately after the polymerization of the composite material, placed into the cavities. With a digital image analysis software the distances from the coronal reference points of the cavity walls were measured. Then the difference between the first and second measurement was calculated. The data were analyzed by means of the ANOVA test. Results. A significative reduction on cavity walls deflection, when the composite resin is used in addiction with the SGMFs was observed. The SGMFs of smallest diameter (1mm) showed the better outcome. Conclusion. The SGMFs are reliable in reducing contraction stress in dental composite resins.

One of the most frequent reasons for failure during the maxillary sinus floor lift operation is connected to the possibility of a rupture of the Schneiderian membrane which, if lacerated, cannot perform the function of graft containment. In order to reduce the incidence of complications it is necessary to cut the hard tissue with extreme accuracy and as little trauma as possible, while saving the soft tissue. The precision of pre-operation measures obtained through endoral x-rays, dental-scans and cone-beam CT allows us to approach and cut with delicacy the sinus cortical floor. The recent development of computer guided surgery gives the possibility of planning the operation, which reduces the risk of failure. The cortical of the maxillary sinus is reduced through the use of calibrated burs and a profiler to obtain a hole that enables both access to the maxillary sinus and, subsequently, the lifting of the Schneiderian membrane. Each stage of the operation is monitored and all the devices used pass through a custom-made template, which acts as a surgical guide. The sinus was filled using fluid biomaterial distributed through a dispenser, which had been created specifically for this technique. Due to the reduction in trauma and the fact that the process is much less invasive, this technique could be a valid alternative to the techniques known and carried out to date. Work time is reduced to less than 3 minutes in the cortical thinning operation and percussive trauma is avoided.

Tuberculosis, aggravated by drug-resistant strains and HIV co-infection of the causative agent Mycobacterium tuberculosis, is a global problem that affects millions of people. With essential immunoregulatory roles, phosphatidylinositol mannosides are among the cell-envelope components critical to the pathogenesis and survival of M. tuberculosis inside its host. Here we report the first synthesis of the highly complex tetraacylated phosphatidylinositol hexamannoside (Ac2PIM6), having stearic and tuberculostearic acids as lipid components. Our effort makes use of stereoelectronic and steric effects to control the regioselective and stereoselective outcomes and minimize the synthetic steps, particularly in the key desymmetrization and functionalization of myo-inositol. A short synthesis of tuberculostearic acid in six steps from the Roche ester is also described. Mice exposed to the synthesized Ac2PIM6 exhibit increased production of interleukin-4 and interferon-γ, and the corresponding adjuvant effect is shown by the induction of ovalbumin- and tetanus toxoid-specific antibodies., Phosphatidylinositol mannosides are cell envelope components vital for the survival of M. tuberculosis. Here, the authors report an elegant and convergent total synthesis of the complex glycolipid tetraacylated phosphatidylinositol hexamannoside (Ac2PIM6) and study the immunological effects in mice.

On June 1, 1999, carbureted two-stroke engines were banned on waters within the Lake Tahoe Basin of California and Nevada. The main gasoline components MTBE (methyl tert-butyl ether) and BTEX (benzene, toluene, ethylbenzene, and xylenes) were present at detectable concentrations in all samples taken from Lake Tahoe during 1997–98 prior to the ban. Samples taken from 1999 through 2001 after the ban contained between 10 and 60 percent of the pre-ban concentrations of these compounds, with MTBE exhibiting the most dramatic change (a 90 percent decrease). MTBE and BTEX concentrations in water samples from Lake Tahoe and Lower Echo Lake were related to the amount of boat use at the sampling sites. Polycyclic aromatic hydrocarbon (PAH) compounds are produced by high-temperature pyrolytic reactions. They were sampled using semipermeable membrane sampling devices in Lake Tahoe and nearby Donner Lake, where carbureted two-stroke engines are legal. PAHs were detected in all samples taken from Lake Tahoe an...

Unusually high As and U concentrations (>100 μg/L) are widespread in shallow ground water beneath the southern Carson Desert. The high concentrations, which locally exceed 1000 μg/L, are of concern from a human health standpoint because the shallow ground water is used for domestic supply. Possible affects on wildlife are also of concern because the ground water flows into shallow lakes and marshes within wildlife refuges. Arsenic and U concentrations in ground water of the southern Carson Desert appear to be affected by evaporative concentration, redox reactions, and adsorption. The relation of these elements with Cl suggest that most of the high concentrations can be attributed to evaporative concentration of Carson River water, the primary source of recharge. Some ground water contains higher As and U concentrations that cannot be explained by evaporative concentration alone. Oxidation-reduction reactions, involving metal oxides and sedimentary-organic matter, appear to contribute As, U, inorganic C, Fe and Mn to the ground water. Arsenic in Fe-oxide was confirmed by chemical extraction and is consistent with laboratory adsorption studies. Uranium in both sedimentary-organic C and Fe-oxide coatings has been confirmed by fission tracks and petrographic examination. Arsenic concentrations in the ground water and chemical extracts of aquifer sediments are broadly consistent with adsorption as a control on some dissolved As concentrations. An apparent loss of As from some ground water as evaporative concentration proceeds is consistent with adsorption as a control on As. However, evidence for adsorption should be viewed with caution, because the adsorption model used values for the adsorbent that have not been shown to be valid for the aquifer sediments throughout the southern Carson Desert. Hydrologic and geochemical conditions in the Carson Desert are similar to other areas with high As and U concentrations in ground water, including the Salton Sea basin and southern San Joaquin Valley of California. Hydrologic and geochemical conditions that produced some sandstone-type U-ore deposits, including those in the non-marine, closed-basin sediments of the Morrison Formation near Grants, New Mexico, suggest that the Carson Desert may be a modern analog for those systems.

Objective: BUZZ is a workshop designed to enhance communication between patients and health care providers (HCPs) and results to date will be described. Background: A study of HIV patients interviewed about their treatment, identified several barriers to communication with their health care teams. Another study called BEAHIV, demonstrated low levels of agreement between patients and HCPs surrounding bothersome symptoms of ARV treatment. With a grant from Janssen, a workshop was designed by a faculty of HIV clinicians from across Canada, in conjunction with a behavioural specialist. The workshop covered several topics: identifying barriers to communication for HIV patients, learning about one's own preferred communication style, how to determine a patient's communication style, and ways to uncover issues associated with the patient's treatment, such as ARV-associated side effects. To date, 15 workshops have been conducted across the country. Results: At the end of the workshop, 85% of participants said they would start or continue to identify barriers to communication. At the start of each workshop, several before/after questions were asked. Only 45% of HCPs felt comfortable in adapting their communication towards patients with different behavioural styles prior to participating in the workshop. This increased to 84% after the workshop. Prior to the workshop, 68% of HCPs said they currently engage patients in proactive discussions surrounding ARV-associated side effects, increasing to 82% post-workshop. Prior to the workshop, 60% proactively engaged patients on the impact of ARV side effects on quality of life, which increased to 80% post-workshop. Several weeks after each workshop, a follow up with participants was conducted and it was found that many implemented changes in their practices as a result of what they learned. Conclusion: A workshop designed to enhance communication may have a beneficial effect on reducing communication barriers and enhancing HIV patient care. (Published: 11 November 2012) Citation: Abstracts of the Eleventh International Congress on Drug Therapy in HIV Infection Lico S. Journal of the International AIDS Society 2012, 15 (Suppl 4):18370 http://www.jiasociety.org/index.php/jias/article/view/18370 | http://dx.doi.org/10.7448/IAS.15.6.18370

Ground water is the main source of domestic and public supply in the Carson River Basin. Ground water originates as precipitation primarily in the Sierra Nevada in the western part of Carson and Eagle Valleys, and flows down gradient in the direction of the Carson River through Dayton and Churchill Valleys to a terminal sink in the Carson Desert. Because radionuclides dissolved in ground water can pose a threat to human health, the distribution and sources of several naturally occurring radionuclides that contribute to gross-alpha and gross-beta activities in the study area were investigated. Generally, alpha and beta activities and U concentration increase from the up-gradient to down-gradient hydrographic areas of the Carson River Basin, whereas222Rn concentration decreases. Both226Ra and228Ra concentrations are similar throughout the study area. Alpha and beta activities and U concentration commonly exceed 100 pCi/l in the Carson Desert at the distal end of the flow system. Radon-222 commonly exceeds 2,000 pCi/l in the western part of Carson and Eagle Valleys adjacent to the Sierra Nevada. Radium-226 and228Ra concentrations are Alpha-emitting radionuclides in the ground water originated from the dissolution of U-rich granitic rocks in the Sierra Nevada by CO2, oxygenated water. Dissolution of primary minerals, mainly titanite (sphene) in the granitic rocks, releases U to the water. Dissolved U is probably removed from the water by adsorption on Fe- and Mn-oxide coatings on fracture surfaces and fine-grained sediment, by adsorption on organic matter, and by coprecipitation with Fe and Mn oxides. These coated sediments are transported throughout the basin by fluvial processes. Thus, U is transported as dissolved and adsorbed species. A rise in the water table in the Carson Desert because of irrigation has resulted in the oxidation of U-rich organic matter and dissolution of U-bearing coatings on sediments, producing unusually high U concentration in the ground water. Alpha activity in the ground water is almost entirely from the decay of U dissolved in the water. Beta activity in ground water samples is primarily from the decay of40K dissolved in the water and ingrowth of238U progeny in the sample before analysis. Approximately one-half of the measured beta activity may not be present in ground water in the aquifer, but instead is produced in the sample after collection and before analysis. Potassium-40 is primarily from the dissolution of K-containing minerals, probably K-feldspar and biotite. Radon-222 is primarily from the decay of226Ra in the aquifer materials. Radium in the ground water is thought to be mainly from alpha recoil associated with the decay of Th in the aquifer material. Some Ra may be from dissolution (or desorption) or Ra-rich coatings on sediments.

We report a case of an aortic root pseudo aneurysm (PSA) that ruptured into the right pulmonary artery (RPA) causing a large left-to-right shunt and congestive heart failure. A 56-year-old man presented with New York Heart Association class III congestive heart failure 6 years after insertion of a Freestyle aortic valve bioprosthesis with reimplantation of the coronaries as button anastomoses to treat a localized aortic root dissection. Physical examination demonstrated a grade 4/6 continuous murmur at the left sternal border, bibasilar crackles, left lung base dullness, ascites, and pedal edema. Chest x-ray (portable anteroposterior film, Figure 1) showed marked cardiomegaly, prominent pulmonary vasculature, and a left pleural effusion suggestive of left ventricular volume overload. Twelve-lead ECG (Figure 2) showed sinus rhythm, biatrial enlargement, and biventricular hypertrophy with right ventricular …

Purpose Evaluate how the spherical glass mega fillers (SGMFs) can positively interfere with light diffusion when incorporated in a composite restoration. Materials and methods 30 samples (Ss) were performed, applying 2 composite layers of 3 mm each: 6 were made with composite only; 6 with a layer of SGMFs of O1.5mm within the first layer of composite; 6 with 2 overlapping layers of SGMFs of O1.5mm; 6 with a layer of SGMFs of O2mm; 6 with 2 overlapping layers of SGMFs of O2mm. The curing time was set at 40s for the first layer, and 120s for the second layer, transilluminated through the first layer. Digital pictures were taken, in standardized settings, during the transillumination, and the light intensity was measured with a digital image analysis software. Results From a lateral view the Ss with a single layer of SGMFs of O1.5mm and O2mm, the relative increments of light intensity, were of 24.37% and 33.33% respectively. Concerning the Ss made with 2 layers of SGMFs, the relative increments were of 67.99% and 66.4% respectively. In front view has emerged a relative increase rate of light intensity of 53.66% and 79.58%, in the Ss with a single layer of SGMFs of O1.5mm and of O2mm respectively. Furthermore, in the Ss with two layers of SGMFs of O1.5mm and O2mm the relative increments were of 267.53 and 319.63% respectively. Conclusion The SGMFs are reliable in facilitating light diffusion within the light-curing composite resins.

The U.S. Geological Survey, in cooperation with the Tahoe Regional Planning Agency and the Lahontan Regional Water-Quality Control Board, sampled Lake Tahoe, major tributary streams to Lake Tahoe, and several other lakes in the Lake Tahoe Basin for manmade organic compounds during 1997-99. Gasoline components were found in all samples collected from Lake Tahoe during the summer boating season. Methyl tert-butyl ether (MTBE), benzene, toluene, ethylbenzene, and xylenes (BTEX) were the commonly detected compounds in these samples. Most samples from tributary streams and lakes with no motorized boating had no detectable concentrations of gasoline components. Motorized boating activity appears to be directly linked in space and time to the occurrence of these gasoline components. Other sources of gasoline components to Lake Tahoe, such as the atmosphere, surface runoff, and subsurface flow, are minor compared to the input by motorized boating. Water sampled from Lake Tahoe during mid-winter, when motorized boating activity is low, had no MTBE and only one sample had any detectable BTEX compounds. Soluble pesticides rarely were detected in water samples from the Lake Tahoe Basin. The only detectable concentrations of these compounds were in samples from Blackwood and Taylor Creeks collected during spring runoff. Concentrations found in these samples were low, in the 1 to 4 nanograms per liter range. Organochlorine compounds were detected in samples collected from semipermeable membrane devices (SPMD’s) collected from Lake Tahoe, tributary streams, and Upper Angora Lake. In Lake Tahoe, SPMD samples collected offshore from urbanized areas contained the largest number and highest concentrations of organochlorine compounds. The most commonly detected organochlorine compounds were cisand trans-chlordane, p,p’-DDE, and hexachlorobenzene. In tributary streams, SPMD samples collected during spring runoff generally had higher combined concentrations of organochlorine compounds than those collected during baseflow conditions. Upper Angora Lake had the fewest number of organochlorine compounds detected of all lake samples. Dioxins and furans were not detected in SPMD samples from two sites in Lake Tahoe or from two tributary streams. The number of polycyclic aromatic hydrocarbon (PAH) compounds and their combined concentrations generally were higher in samples from Lake Tahoe than those from tributary streams. Areas of high-motorized boating activity at Lake Tahoe had the largest number and highest concentrations of PAH’s. PAH compounds were detected in samples from SPMD’s in four of six tributary streams during spring runoff, all tributary streams during baseflow conditions, and at all lake sites. The most commonly detected PAH’s in tributary streams during spring runoff were phenanthrene, fluoranthene, pyrene, and chrysene, and during baseflow conditions were phenanthrene, 1-methylphenanthrene, diethylnaphthalene, and pyrene. Upper Truckee River, which has an urban area in its drainage basin, had the largest number and highest combined concentration of PAH’s of all stream samples. Diver retrieving semipermeable membrane device from Lake Tahoe, near Glenbrook, Nev. Photograph by R.J. Hoffman, U.S. Geological Survey, August 1998. Abstract 1 U.S. Department of the Interior—U.S. Geological Survey1 U.S. Department of the Interior—U.S. Geological Survey Bottom-sediment from Lake Tahoe had detectable concentrations of p-cresol, a phenol, in all but one sample. A sample collected near Chambers Lodge contained phenol at an estimated concentration of 4 micrograms per kilogram (μg/kg). Bottom-sediment samples from tributary streams had no detectable concentrations of organochlorine or PAH compounds. Several compounds were detected in bottom sediment from Upper Angora Lake at high concentrations. These compounds and their concentrations were p,p’-DDD (10 μg/kg), p,p’-DDE (7.4 μg/kg), 2,6-dimethylnaphthalene (estimated at 190 μg/kg), pentachlorophenol (3,000 μg/kg), and p-cresol (4,400 μg/kg).

The Carson River Basin is an area of dramatic contrasts. The Carson River drains pristine wilderness of the forested Sierra Nevada, which provides much of the basin's water. The chemical composition of the Carson River changes from that of a fresh, untamed white-water river in the Headwaters Area to that of stagnant saline sloughs and alkali lakes in the Carson Desert. The ground-water quality, particularly in shallow aquifers, broadly mirrors the chemical changes in the river-a major source of recharge to basin-fill aquifers. Contrasts in ground-water quality within the Carson River Basin are evident across the basin, among the different aquifers, and, to a lesser extent, between shallow ground water beneath urban and agricultural land. Using current drinking-water standards as a measure of overall water quality, ground-water quality in principal aquifers in the upper basin generally is good. Principal aquifers in the upper basin are a major source of supply for municipal systems that provide water to the communities of Minden, Gardnerville, and Carson City. Precipitation falling on the Sierra Nevada, along with recharge from the Carson River in areas of heavy ground-water pumping, is the major source of recharge to principal aquifers. Except for locally high concentrations of nitrate and presence of synthetic organic compounds, water quality in principal aquifers generally results from chemical reactions with aquifer materials. Some ground water in and adjacent to the Sierra Nevada contains uranium concentrations greater than the proposed drinking-water standard. Radon activities in the Sierra Nevada locally exceed 10,000 pCi/L and are highest in the Carson River Basin. Shallow aquifers in Carson Valley contain higher concentrations of most major constituents and, compared to water in principal aquifers, more commonly contain concentrations of some minor constituents that exceed drinking-water standards. Manganese exceeds the secondary maximum contaminant level at more than 25 percent of the sampled sites. Minor constituents that exceed drinking-water standards at less than 10 percent of sampled sites are arsenic, fluoride, nitrate, and iron. Water from shallow aquifers more commonly contains concentrations of arsenic, fluoride, iron, and manganese in excess of the drinking-water standards than does water from the principal aquifers. Shallow aquifers beneath the upper basin locally contain herbicides, pesticides, and volatile organic compounds. Beneath the urban part of Carson City, prometone, trichloroethylene, and tetrachloroethylene were found at concentrations well above the laboratory minimum reporting level. Trichloroethylene was found at concentrations above the drinking-water standard. With a few exceptions, ground water beneath agricultural land in Carson Valley contained, at most, low concentrations of synthetic organic compounds. Principal aquifers beneath the sparsely populated middle Carson River Basin are recharged by precipitation falling on the uplands and, locally, by the Carson River. Concentrations of major constituents in water from principal aquifers in the lower basin generally are higher than in water from the principal aquifers of the upper basin. Concentrations of dissolved solids, iron, manganese, and sulfate more commonly exceed drinking-water standards in principal aquifers of the middle than the upper basin.

Using bDNA, the plasma viral load trend of HCV-infected patients undergoing IFN therapy was analyzed. Nine patients were enrolled, each assigned to one of three groups, based on IFN response as determined by ALT and AST level trend. HCV was genotyped using DEIA. Each patient's clinical stage was determined by liver biopsy analysis. In nonresponding patients elevated viral loads and biochemical parameters were observed. These values were not influenced by IFN treatment. In relapsed patients the cessation of IFN treatment increased viral load; this was associated with a rise in ALT and AST values. In responders ALT and AST levels remained normal; viral load was low. Patients with elevated HCV viral load showed a worsening in their liver histology during the follow-up period. These results confirm that plasma viral load is a good marker of biochemical change and disease progression.

Radionuclide gastric solid-phase emptying was studied in 10 subjects with diabetic gastroparesis comparing the acute intravenous administration of cisapride (2.5, 5, 10 mg), placebo, and metoclopramide (10 mg). No hemodynamic or electrocardiographic changes were noted. While both cisapride and metoclopramide normalized impaired solid emptying, cisapride at its highest dosage (10 mg) resulted in significantly faster gastric emptying (P = 0.003) than metoclopramide. The effects of cisapride were dose related and correlated well (r = 0.48, P less than 0.01) with the plasma drug levels. Clinical studies of chronic oral usage must take into account the dose-related response and factors affecting blood levels.

Large tufa mounds (>3 m tall, with a basal circumference of 5 m) have been discovered on the margin of Big Soda Lake, Nevada, USA. These tufa mounds are rooted at a maximum of 4 m below the current lake surface and are actively forming from groundwater seepage, which can be seen emanating from the top of the tufa mounds. Big Soda Lake is a volcanic crater lake whose water level is maintained exclusively by groundwater. The age of the tufa mounds is well constrained because prior to the development of the Newlands Irrigation Project in 1907, the water level was ∼18 m lower than the current lake level. The vertical columnar nature of the tufa mounds indicates that they formed under the lake and not subaerially. Thus, the tufa mounds are

The Lower Permian (middle Wolfcampian) Zinc Hill sequence, a 65- to 110-m-thick series of beds in the Owens Valley Group in east-central California, comprises sediment-gravity-flow deposits consisting of carbonate sediment that originated on, and siliciclastic sediment that may have been generally ponded behind, a carbonate shelf to the east and northeast. Thickness patterns and paleocurrent indicators show that the sediment forming this sequence was transported primarily southeastward and deposited in a southeast-trending, lobe-shaped body. Evidently, the sediment was carried from the shelf by sediment-gravity flows that travelled westward down the slope and then turned southeastward upon reaching a southeast-trending basin at the base of the slope. Data derived from the study of this basin, which paralleled the shelf edge and is thought to have formed parallel to a southeast-oriented segment of the Early Permian continental margin, constitute one of the most important arguments favoring a Pennsylvanian to Early Permian age of truncation of the western North American continental margin.

Natural occurrences of ground water with moderate (10 to 50 micrograms per liter) to high (greater than 50 micrograms per liter) concentrations of arsenic are common throughout much of the Western United States. High concentrations of arsenic are generally associated with one of four geochemical environments: (1) basin-fill deposits of alluvial-lacustrine origin, particularly in semiarid areas, (2) volcanic deposits, (3) geothermal systems, and (4) uranium and gold-mining areas. These findings are based on an extensive literature review, compilation of unpublished reports and data, and the review of data bases containing more than 7,000 analyses of ground-water samples for arsenic. In the first two environments, arsenic appears to be associated with sediments derived, in part, from volcanic rocks of intermediate to acidic composition. Dissolved arsenic concentrations in water from volcanic aquifers in the same regions, however, may be low (less than 10 micrograms per liter). Solid phases (minerals, amorphous solids, and sedimentary organic matter) that supply the dissolved arsenic have not been identified in most areas. Alluvial and lacustrine sedimentary deposits appear to be an important source of arsenic in volcanic areas (such as Lane County, Oregon) and in areas underlain by basin-fill deposits (such as Carson Desert in Nevada and the Tulare Lake basin in California). Mobilization of arsenic in sedimentary aquifers may be, in part, a result of changes in the geochemical environment due to agricultural irrigation. In the deeper subsurface, elevated arsenic concentrations are associated with compaction caused by groundwater withdrawals.

Introduction Geopressured geothermal waters arc present at depths greater than about 2500 m in Cenozoic and Mesozoic sedimentary rocks beneath an area of about 350 000 km2 in coastal Texas and Louisiana. The hydraulic pressure gradients in the geopressured zones are higher than hydrostatic [10.5 kPa/m (0.465 psi/ft)], and with increasing depth approach the psi/ft)], and with increasing depth approach the lithostatic pressure gradient of 22.6 kPa/m (1.0 psi/ft). The temperature gradients in the psi/ft). The temperature gradients in the geopressured zones also are higher than the gradients in the overlying normally pressured zone. The temperature gradient in geopressured zones in south Texas is 67 deg. C/km (3.7 deg. F/100 ft); the gradients decrease northward along coastal Texas and Louisiana (Fig. 1). There currently is an intensive research and development effort by public agencies and private companies to determine the feasibility of using these geopressured waters as sources of energy. Three forms of energy may be extracted from these waters:(1)thermal energy,(2)mechanical (hydraulic) energy, because these waters will be under high pressure at ground level, and(3)energy obtained pressure at ground level, and(3)energy obtained from dissolved gases, mainly methane, which may exceed the thermal energy if the waters are saturated with natural gas under subsurface conditions. This paper describes the chemical and physical parameters of selected geopressured geothermal parameters of selected geopressured geothermal waters that are important in determining their corrosion and scale-formation properties. The equations used here for predicting corrosion and scale formation apply to geopressured waters associated with oil and gas as well as geopressured waters from geothermal reservoirs. We have carried out detailed chemical analyses of 120 formation-water samples from geopressured and normally pressured production zones that range in depth from about 1000 to 5600 m. The 25 oil and gas fields sampled are in the McAllen-Pharr, Corpus Christi, and Houston-Galveston areas of Texas and in the Lafayette, LA, area. Oil and gas production is from sandstone reservoir rocks, which are mainly in the Frio Clay of Oligocene (?) age in Texas and of Miocene age in Louisiana. Chemical Composition Chemical analyses of eight formation-water samples selected as typical of the geopressured zone in their respective areas appear in Table 1, which also gives the locations of the sampled wells, subsurface temperatures, pressures, and other pertinent data. More complete chemical analyses, as well as the field and laboratory procedures used for collection, preservation, and analysis, are given in Kharaka et preservation, and analysis, are given in Kharaka et al.

Twelve chemical geothermometers based on the concentrations of silica and proportions of sodium, potassium, calcium, and magnesium in water from hot springs and geothermal wells are used successfully to estimate the subsurface temperatures of the reservoir rocks. These twelve geothermometers together with a new geothermometer based on the concentrations of lithium and sodium were used to estimate the subsurface temperatures of more than 200 formation-water samples from about 40 oil and gas fields in coastal Texas and Louisiana and the Central Valley, California. The samples were obtained from reservoir rocks ranging in depth from less than 1,000 m to about 5,600 m. Quartz, Na-K-Ca-Mg, and Na-Li geothermometers give concordant subsurface temperatures that are within 10°C of the measured values for reservoir temperatures higher than about 75°C. Na-Li, chalcedony, and a modified Na-K geothermometers give the best results for reservoir temperatures between 40°C to 75°C. Subsurface temperatures higher than about 75°C calculated by chemical geothermometers are at least as reliable as those obtained by conventional methods. Chemical and conventional methods should be used where reliable temperature data are required. End_of_Article - Last_Page 1361

Twelve chemical geothermometers based on the concentrations of silica and proportions of Na, K, Ca, and Mg in water from hot springs and geothermal wells are used successfully to estimate the subsurface temperatures of the reservoir rocks. These 12 geothermometers together with a new geothermometer based on the concentrations of Li and Na were used to estimate the subsurface temperatures of more than 200 formation-water samples from about 40 oil and gas fields in coastal Texas and Louisiana and the Central Valley, California. The samples were obtained from reservoir rocks ranging in depth from less than 1,000 m to about 5,600 m. Quartz, Na-K-Ca-Mg, and Na-Li geothermometers give concordant subsurface temperatures that are within 10°C of the measured values for reservoir temperatures higher than about 75°C. Na-Li, chalcedony, and a modified Na-K geothermometers give the best results for reservoir temperatures from 40°C to 75°C. Subsurface temperatures higher than about 75°C calculated by chemical geothermometers are at least as reliable as those obtained by conventional methods. Chemical and conventional methods should be used where reliable temperature data are required. End_of_Article - Last_Page 588