bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of stable isotope ratios by inductively coupled plasma mass spectrometry-impact on geological sciences
Authors: Gregoire D C
Published: November 2013

Inductively coupled plasma mass spectrometry (ICP-MS) is capable of measuring stable isotope ratios of most elements of the periodic table with a precision ranging from 0.1% to 0.5%. The relatively large sample throughput rate of ICP-MS now makes possible
survey studies of stable isotope ratios in nature involving large numbers of samples. New applications of stable isotope ratios determined by ICP-MS are now emerging in the geological sciences and promise to have a great impact on petrogenic as well as exploration geochemistry studies. Discussed are
isotope systems which are amenable to study by ICP-MS, methods employed for the determination of isotope ratios in geological materials, as well as specific examples of applications involving boron, osmium, silver, and bromine.
New selective reagents for the determination of platinum group elements and gold from geological materials
Authors: Kasper H U , Schuster M
Published: November 2013

Geochemical data on the siderophile platinum group elements in rock-generating differentiation processes of the upper mantle are still scarce, mainly due to analytical difficulties. Two major problems are to be solved for the determination of PGE and Au from
ultrabasic rocks and chromite ores: (1) the quantitative decomposition of these materials, and (2) the separation of the extremely low contents of noble metals from the interfering matrices, followed by preconcentration. Sample digestion was performed in PTFE lined high pressure decomposition
vessels with a mixture H2SO4-HF-HClO4 at temperatures up to 250þC and maximum pressure of 20 MPa over 48 hours. The resulting transparent sample solutions were tested with the new chelating agents N-acylthioureas from which N,N-diethyl-Nþ-benzoylthiourea (DEBT) yielded the best results. The PGE and
Au chelates are extracted with isobutyl methyl ketone (IBMK). The high specificity and selectivity of DEBT for the noble metals and the excellent solubility of the chelates in IBMK enables considerable preconcentration factors of up to 50. For the GFAAS determinations,
IBMK offers optimal thermal decomposition performances and lowest nonspecific background absorption. Alternatively the DEBT chelates may be separated by TLC or HPLC with silica gel as stationary phase and solvents of moderate polarity. The elaborate decomposition and separation methods were used to
analyze SARM-7, SARM-8, and some chromites from Greek ophiolite complexes. It is intended to apply these methods to the recently announced reference samples CHR-Pt+ and CHR-Bkg.
Determination of trace elements in geological sample materials using ICP-MS
Authors: Longerich H P , Jackson S E , Jenner G A , Fryer B J
Published: November 2013

The SCIEX Perkin-Elmer ICP mass spectrometer, which was installed in 1984 in the Department of Earth Sciences, has now been integrated into the department's elemental analysis facilities. ICP-MS is a routine analytical tool for many applications, determining
trace elements in approximately 5000 samples per year. In rock matrices, it has been found especially suited to determining the heavier elements, from and including Rb to U. The major elements in rock samples along with the light trace elements Sc through Ga are determined using XRF or AAS. The
trace elements Sc, Rb, Sr, Y, Zr, Nb, and Ba are determined by both XRF and ICP-MS thus serving as a quality control. Three ICP-MS packages are routinely available for elemental determinations including: 1. 33 trace elements: (Li, Be, Sc, Rb, Sr, Y, Zr, Nb, Mo, Cs, Ba, the lanthanides (La through
Lu), Hf, Ta, W, Tl, Pb, Bi, Th, and U; in whole rock and mineral separate samples following an HF-HNO3 acid dissolution. 2. rare-earths and Th in rocks with a sodium peroxide sinter procedure, and 3. precious metals (Ru, Rh, Pd, Re, Os, Ir, Pt, and Au) following a NiS and Te precipitation
collection. Procedures for determining elements in fresh waters have been developed for application to geological programs. The water analysis includes several of the light elements in addition to a selection of heavier elements which are quantifiable in fresh surface and well waters. The long term
precision and accuracy of the method will be demonstrated.
Determination of the isotope ratio 147Sm/145Nd, for application to isotope geology using ICP-MS
Authors: Longerich H P , Jackson S E , Jenner G A , Fryer B J
Published: November 2013

The decay of 147Sm to 143Nd by alpha emission, with a half life of 106 000 000 000 years, is becoming increasingly important in geological isotopic studies. Knowledge of the isotope ratio of the daughter to a reference isotope (usually 143Nd/144Nd) requires
attainment of precision (relative standard deviation less than 0.005%) much better than the ICP-MS is capable of, and is thus made using thermal ionization mass spectrometry (TIMS). However, the precision required for the isotope ratio of the parent to the reference, 147Sm/144Nd, is well within
the capability of ICP-MS. ICP-MS is used to make measurements of the intensity of two isotopes, 145Nd and 147Sm, in a fast peak jumping, data acquisition mode (0.05 seconds/isotope). The desired parameter (147Sm/144Nd) is calculated from the measured ratio (147Sm/145Nd), the known value of the ratio
(145Nd/144Nd), and a factor which corrects for the instrumental measurement characteristics of mass discrimination, oxide formation, etc. The correction factor is obtained from measurements made on a standard solution prepared from high purity Nd and Sm metals. Using 225 second/isotope measurement
times, relative standard deviations better than 0.5% are possible for samples with Sm greater than 6 ppm in the rock. Using ion-exchange procedures, solutions can be concentrated and better precisions obtained. Accuracy of the method will be demonstrated by comparison with results obtained by
TIMS.
Regional geochemical mapping in the tropical environment: bedrock reflection of Precambrian volcanosedimentary sequences in B-horizon soil strata: case studies from Nigeria/West Africa
Authors: Matheis G , Utke A
Published: November 2013

About one quarter of the Earth's land surface is covered by thick accumulations of lateritic soils, limiting the exposure of bedrock and leaving these regions the least explored. The most successful way to establish the badly needed geological and mineral
inventories of these areas is the regional application of geochemical mapping, complemented by remote sensing and geophysics. Although chemical weathering progresses rather quickly in the tropics, extensive leaching is nearly restricted to the major elements Mg, Ca, Na, K, and partly Si. Most of the
trace elements, however, retain more or less their bedrock concentrations, i.e., lithologically determined concentration ranges of the bedrock are not overruled by the weathering processes. In order to gain detailed information on the geochemical dispersion between the concealed bedrock and the
uppermost soil horizons where sampling usually takes place (uppermost 60 cm of B-horizon), various orientation surveys were carried out in different climatic zones of Nigeria, ranging from the rain forest in the south to the dry Savannah in the north. The main lithological targets were late
Proterozoic greenstone type associations which are host to Nigeria's gold resources and are equally important in revealing the Proterozoic geodynamic processes of the Nigerian basement complex. Vertical dispersion was studied in auger drilled soil profiles. The regional distribution patterns cover
selected areas over volcanosedimentary sequences, totally about 1000 km2 at a sample density of one sample per square kilometre. Various selective leaching methods were applied to gain information on clay adsorbed, hydroxide adsorbed, and total geochemical dispersion. A comparison of the resulting
geochemical maps with the most detailed published maps at scale 1:250 000 clearly demonstrated the advantage of geochemical mapping in providing more detailed information as well as pointing out inaccuracies in the existing geological maps.
Mobile field analysis for exploration and environmental geochemistry by AAS and IR: on-site evaluation of chemical and mineralogical properties
Authors: Matheis G , Ganz H , Kuster D , Utke A
Published: November 2013

The evaluation of secondary geochemical dispersion patterns is equally important for application in both exploration and environmental geochemistry. Due to the rather complex chemical processes which overprint all weathering products, the application of selective
leaching methods as well as detailed studies of the clay mineralogy are the basics of any sound interpretation. Flame-AAS has been developed as the most versatile analytical tool in the evaluation of secondary geochemical dispersion patterns. The range of target elements which can be determined
without difficulty even in a generator-powered mobile field laboratory covers a wide range of potential ore accumulations either by the ore elements directly or via suitable pathfinder elements; similarly, AAS analysis is extremely helpful in geochemical mapping surveys under different climatic
conditions as well as in environmental surveys. The mineralogical and especially the clay composition of weathering products is critical in understanding chemical adsorption effects as the key to secondary dispersion. In contrast to X-ray diffraction, infrared (IR) spectroscopy provides a rapid and
simple method to evaluate mineral compositions both qualitatively and quantitatively. Another advantage is the possibility to detect noncrystalline phases, the presence of water in a mineral and information on the nature of the silicate anion in the mineral structure. Sample preparation as well as
instrumentation (220 V power supply, no cooling system) favour the application of both AAS and IR in mobile field laboratories in any climatic or logistical conditions.
Characteristics of imaging sensor based spectrometer systems for high resolution ICP spectrometry of complex sample matrices
Authors: McGeorge S
Published: November 2013

The detection of major, minor, and trace elements in geological samples using spectrochemical techniques can be complicated by several factors including sample preparation, sample introduction, matrix interferences operating in the sample transport and excitation
regime, and spectral interferences due to the complex spectra produced by the sample. This paper will focus on the capabilities of high resolution spectrometer systems employing imaging detectors which record the emission spectra of several elements simultaneously. Imaging sensors provide unique
capabilities for the analyst when used to record spectral information. Several significant advantages include simultaneous background correction, flexible signal processing capabilities, and the ability to digitally record the sample spectrum for further review and postprocessing. One of the more
interesting aspects of image processing is the potential for spectral evaluation by the computer system to detect possible spectral interference or complex background conditions. The main theme of this paper will be the use of imaging detection systems for elemental analysis of complex sample
matrices as found in the geochemical domain. Several problem sets will be presented along with techniques that can be used to provide analytical solutions.
An on-site method for measuring aluminium speciation in shallow well water samples from areas exposed to acid rain
Authors: Meranger J C , Lett R E , Pickering T
Published: November 2013

An on-site procedure involving filtration and ion exchange has been developed to study aluminium speciation in water samples from shallow wells. Immediately following collection samples are mixed continuously with Chelex 100 ion-exchange resin for eight hours. At
intervals during the mixing cycle subsamples of the water are taken, filtered, preserved, and later analyzed for aluminium by graphite furnace atomic absorption spectrophotometry. The method has been applied to examine aluminium chemistry in water from selected shallow wells in rural areas of
eastern Canada exposed to acid rain. Results show that in weakly acid water much of the aluminium remains in polymeric forms whereas more strongly acid (pH below 5.5) well waters contain predominantly monomeric, labile aluminium.
The rapid determination of the platinum group elements and gold with nickel sulphide fire assay and neutron activation analysis (NAA)
Authors: Parry S J , Asif M
Published: November 2013

Nickel sulphide fire assay is now a routine method of preseparating the platinum group elements (PGEs) and gold before their determination using AAS, ICP, NAA, or ICP-MS. In general there has been more effort devoted to the analytical techniques than to the
preconcentration step. However, the main problems of analysis occur in the fusion and dissolution of the nickel sulphide button. The authors have been working on improving the fusion step, with the result that for most applications the technique can be straightforward and entirely free from reagent
blank problems. The major problem remaining has been the recovery of the elements, which is reproducible (81-83% PGE, 76% Au) but the losses are significant. The problem of losses may be avoided entirely if the nickel sulphide bead is analyzed directly. In the past the background effects
have given very poor sensitivities when the bead was analyzed by NAA, but the improvements made by the authors to the fusion process have resulted in a sensitive technique for direct analysis of the bead. We have developed a rapid and sensitive method which is sufficiently simple that large numbers
of samples may be processed routinely, providing an inexpensive and reliable technique for determination of the PGEs. The validity of the method has been demonstrated using certified reference materials.
An expeditious wet-chemical scheme for silicate analysis using titrimetric determination of silica
Authors: Rubeska I , Huka M
Published: November 2013

At the Geological Survey of Prague an expeditious procedure for the determination of silica has been developed and is currently used routinely. The procedure is based on sample decomposition using acids (HF + H2SO4), chemisorption of the evolving H2SiF6 on solid
potassium nitrate and acidimetric titration of the HF released by hydrolysis of the resulting K2SiF6. The sample residue from this decomposition is dissolved, transferred to a PTFE beaker and HF is fumed off. The resulting solution is then used for the determination of other sample constituents
either by chelatometry (high Al, Ca, Mg), AAS (Li, Na, K, Mn, Ti, low Al, Ca, Mg, Fe), spectrophotometry (P, high Fe) or ICP-ES (all of these). For samples containing minerals not attacked by HF the sample solution is first filtered off, incinerated, and the insoluble residue fused with a mixture of
Cs2CO3 and boric acid. After dissolution it is added to the sample solution and its SiO2 content measured by AAS or ICP-ES. This silica amount is then added to that found by titration. The PTFE vessel assembly used for the sample decomposition and the procedure for Si will be described in detail.
Results on international standard reference materials will be used to illustrate performance of the procedure. Examples of samples with unusual composition for which the procedure fails to give accurate results will be discussed. The advantage of the procedure presented is that it is independent of
reference samples with well established chemical composition and possesses the accuracy of wet-chemical procedures while considerably increasing the sample throughout. It may be applied with advantage particularly in laboratories where XRF spectrometry is not available.
Trace metal analysis-a comparison of atomic spectroscopic techniques
Authors: Tikkanen M W
Published: November 2013

This paper compares the performance characteristics of three routinely used methods for the determination of trace metal content in geochemical samples þ Atomic Absorption Spectrometry (AAS), Inductively Coupled Plasma Emission Spectroscopy (ICP-ES), and Direct
Current Plasma Emission Spectroscopy (DCP-ES). All three techniques have been shown to be capable of producing virtually any solution elemental analysis at acceptable levels of precision and accuracy. But `real world' sample analyses, as with geochemical determinations, requires that other questions
be answered, before determining which technique is the method of choice. Such considerations as sample preparation requirements, interference correction capabilities, speed, convenience, and cost must be considered. Examples of such considerations will be presented with specific application to trace
metal determination in geochemical samples.
Determination of 147Sm/144Nd isotope ratios in geological materials using inductively coupled plasma-mass spectrometry (ICP-MS)
Authors: Longerich H P
Published: November 2013

The isotope ratio 147Sm/144Nd has been determined in 12 geological reference materials using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). A fast (50 ms) peak jumping sequence of 147Sm and 146Nd is used with calibration to an external Sm/Nd standard
solution. Using 120 s data acquisition times for each isotope, the relative standard deviation (RSD) of the ratio is a function of the Sm concentration in the rock, and varies from 0.2% (at 109 ppm Sm) to 1% (at 1 ppm Sm). The values determined in this study compared to literature values for
all materials are better than 6%. For the best measured reference materials W-1, BHVO-1, and BCR-1 the relative difference in the isotope ratio is better than 0.6%.
Preliminary investigations into small nickel sulphide button preconcentration of platinum group elements, gold, and silver in geological materials
Authors: Rice T D , Waldron H M
Published: November 2013

A procedure is described for preconcentrating platinum group elements (PGE), gold and silver in a small nickel sulphide button (2.5-3.5 g) by fusion of up to 30 g of sample for one hour at 1000þC in a covered ceramic crucible. A single fusion by this procedure of
the reference pyroxenite SARM-7 has been found to collect about 98% of the total measured PGEs. With chromite samples, this procedure gives a uniform, fluid slag if the flux contains magnetic iron oxide (9 g) plus extra borax and soda ash. Inclusion of magnesium oxide in the flux appears to give
a higher recovery of platinum in SARM-7. Addition of aluminium powder (1 g) to the flux did not increase the recovery of gold in SARM-7. Possible enhancement of gold recovery by inclusion of, for example, copper (75 mg) and/or tellurium (2 mg) in the flux requires further investigation. Digestion of
pulverized buttons in a covered, spoutless beaker with 30 mL of concentrated HCl for 16 hours on a boiling water bath is likely to result in appreciable solubilization losses of palladium, iridium, gold, and probably platinum. Such losses can be avoided either by coprecipitating precious metals with
tellurium or by limiting the digestion time to three hours. Subsequent treatment of the filtered residue for a neutron activation or spectrometric finish is described. Suggestions are made for further work on the small NiS button procedure.
Persistent organic compounds in the Barents Sea: Canada-Russia collaboration on arctic pollutants
Authors: Skibo D N , Nassichuk W W
Published: November 2013

In 1991, Project 10, a new initiative on anthropogenic contaminants in the Arctic Ocean, commenced within the Canada-Russia Agreement on Cooperation in the Arctic and the North. The purpose of the project is to determine the distribution and concentration of
trace and heavy metals, radionuclides, persistent organic toxins, and mutagenic and carcinogenic compounds in seafloor sediments off Arctic Canada and Siberia. During 1992 and 1993, several hundred samples were taken from the Barents Sea. Forty samples, representing an areal distribution and several
depth profiles in the sediments, have been analyzed for: 1) polychlorinated biphenyls (PCBs); 2) organochlorine pesticides [chlorobenzenes, hexachlorocyclohexanes (HCHs), chlordanes, nonachlors, DDTs, Mirex]; and 3) polycyclic aromatic hydrocarbons (PAHs). Total PAHs and total organic carbon (TOC)
from sediments at or near the seabed are found to be positively correlated to water column depth. However, purely anthropogenic contaminants (PCBs and OC pesticides) show no such correlation.
Paleolimnology and global change on the southern Canadian prairies
Authors: Vance R E , Last W M
Published: November 2013

Field and laboratory work over the past two years has produced an extensive collection of sediment core data from lakes in southern Alberta, Saskatchewan, and Manitoba. Preliminary analyses, including physical description, photography and radiography, isolation
of plant macrofossils, development of chronostratigraphy and lithostratigraphy, as well as documentation of current lake chemistry, morphology and drainage basin characteristics, indicate that significant water level and chemical variations have occurred during the Holocene over this broad
geographic area. Because historic hydrological fluctuations in these prairie watersheds are closely related to the balance between evaporation and precipitation, climate is considered the driving force behind Holocene lake-level dynamics. Continued analyses are directed at producing a detailed
reconstruction of long-term hydrological and climatic dynamics for the southern Canadian prairies.
Cambrian and Ordovician volcanic rocks in the McKay Group and Beaverfoot Formation, western Ranges of the Rocky Mountains, southeastern British Columbia
Authors: Norford B S , Cecile M P
Published: November 2013

Basic volcaniclastics and volcanic or subvolcanic amygdaloidal rocks (flows and/or sills) are present within the Upper Cambrian part of the McKay Group and within the basal Beaverfoot Formation (Upper Ordovician) in the Hughes Range of the western Rocky Mountains
north of Cranbrook. The McKay rocks had been thought to be Late Silurian or Devonian and mapped as the SDs unit. The evidence of marine volcanism within the McKay Group of the White River Trough invites comparison with analogous depositional environments in the Selwyn Basin where similar volcanic
and intrusive activity is considered to be the key factor in the formation of several rich lead-zinc-barite deposits. The McKay Group is widely distributed within the western Rocky Mountains of southeastern British Columbia and, because of the presence of the volcanics, has the potential to contain
significant base metal deposits.
Geology of the Archean Nain Province and Paleoproterozoic Torngat Orogen in a trasect of the North River-Nutak map areas, Newfoundland (Labrador) and Quebec
Authors: Ermanovics I , Van Kranendonk M
Published: November 2013

The report, based on 1:100 000 scale bedrock mapping, describes the lithology, structure, metamorphism, geochronology, economic geology, and some geophysical characteristics of the Archean Nain Province in the east and the adjacent, early Proterozoic Torngat
orogen of Churchill (Rae) Province in the west. Nain Province is underlain by mainly granulite/amphibolite facies, migmatitic orthogneisses, and minor remnants of supracrustal and basic igneous rocks up to 3.6 Ga old. The province formed by the amalgamation of at least two terranes, after 2.7 Ga,
resulting in widespread crustal reactivation at ca. 2.56 Ga.

Discrete events in the early Proterozoic, granulite facies Torngat orogen include collision with Nain Province and crustal thickening (ca. 1860 Ma), strike-slip shear /transpression (ca. 1845-1822 Ma), and reactivation and uplift (ca. 1790-1780 Ma). The precollisional configuration of units in the
orogen immediately west of Nain Province includes the protoliths of the Tasiuyak gneiss on the margin of Churchill (Rae) Province, probably as an east-facing accretionary prism intruded by calc-alkaline plutonic rocks of a magmatic arc ca. 1880 Ma.

The orogeny transgressed eastward into Nain Province, reworking Archean gneisses and deforming the supracrustal Paleoproterozoic Ramah Group in an amphibolite facies foreland. The effects of orogeny extend 70 km east of this foreland, to the coastal reaches of Nain Province, mainly in the form of a
metamorphic waning to lower greenschist facies, affecting early Paleoproterozoic tholeiitic diabase dykes and the volcanic and sedimentary rocks of the Mugford Group.
Gene Expression Meta-Analysis identifies Cytokine Pathways and 5q Aberrations involved in Metastasis of ERBB2 Amplified and Basal Breast Cancer
Authors: Thomassen Mads , Tan Qihua , Burton Mark , Kruse Torben A.
Published: November 2013

Background

Breast tumors have been described by molecular subtypes characterized by pervasively different gene expression profiles. The subtypes are associated with different clinical parameters and origin of precursor cells. However, the biological pathways and chromosomal aberrations that differ between the subgroups are less well characterized. The molecular subtypes are associated with different risk of metastatic recurrence of the disease. Nevertheless, the performance of these overall patterns to predict outcome is far from optimal, suggesting that biological mechanisms that extend beyond the subgroups impact metastasis.

Results

We have scrutinized publicly available gene expression datasets and identified molecular subtypes in 1,394 breast tumors with outcome data. By analysis of chromosomal regions and pathways using “Gene set enrichment analysis” followed by a meta-analysis, we identified comprehensive mechanistic differences between the subgroups. Furthermore, the same approach was used to investigate mechanisms related to metastasis within the subgroups. A striking finding is that the molecular subtypes account for the majority of biological mechanisms associated with metastasis. However, some mechanisms, aside from the subtypes, were identified in a training set of 1,239 tumors and confirmed by survival analysis in two independent validation datasets from the same type of platform and consisting of very comparable node-negative patients that did not receive adjuvant medical therapy. The results show that high expression of 5q14 genes and low levels of TNFR2 pathway genes were associated with poor survival in basal-like cancers. Furthermore, low expression of 5q33 genes and interleukin-12 pathway genes were associated with poor outcome exclusively in ERBB2-like tumors.

Conclusion

The identified regions, genes, and pathways may be potential drug targets in future individualized treatment strategies.
Self-Reported Therapeutic Style in Occupational Therapy Students
Authors: Bonsaksen Tore
Published: November 2013

Introduction:

The client-therapist relationship has long been viewed as important for both the process and outcomes of occupational therapy. The recently developed Intentional Relationship Model introduced six therapeutic modes as different ways of relating to clients. Increasing students' awareness of modes, and increasing their skills in using them flexibly, has the potential of improving their subsequent practice as occupational therapists. This article aims to describe occupational therapy students' affiliation with the therapeutic modes in a variety of hypothesized practice situations. In addition, relationships between the students' affiliation with the different modes are explored.

Method:

The study had a cross-sectional design. Data were collected from 31 occupational therapy students in Norway, using the Self-Assessment of Modes Questionnaire. Descriptive analyses, repeated measures ANOVA tests, and correlation analyses were employed in the analytic procedures.

Findings:

The students identified the problem-solving mode to be their most preferred way of relating to clients, whereas the advocating mode was the least preferred. High affiliation with the problem-solving mode was significantly associated with low affiliation with the collaborating mode.

Conclusion:

Several limitations indicate that caution should be taken when comparing this study with previous research. Nonetheless, differences between the results of this study and previous work on the therapeutic modes are of interest. Possible explanations for differences are discussed, as are implications for practice and research.
Individual and Environmental Implications of Working Alliances in Occupational Therapy
Authors: Morrison Tricia
Published: November 2013

Introduction:

The therapeutic alliance is constituted of two predominant actors, the client and therapist, and is embedded within a rich environment that may both facilitate and restrict the alliance development.

Method:

A mixed-methods, prospective, multiple case study approach was used to compare the contextual characteristics and experiences of the working alliance over the course of a community-based occupational therapy intervention by four dyads, each composed of an occupational therapist and client.

Findings:

The findings of this study suggest that there are a variety of therapist, client, and environmental factors that interact with one another, each having a different impact on the process of alliance development.

Conclusion:

Although therapists must shoulder the responsibility of creating a therapeutic atmosphere conducive to sound working alliance development, there are also elements having an impact on the alliance that are outside the therapist's control. Although these findings point to development potentials for therapists to consider, related to the therapeutic use-of-self, there is also a need for vigilance in relation to career health in assuming responsibility for elements that therapists cannot always mediate.
Blogging in Occupational Therapy: Knowledge Sharing, Professional Development, and Ethical Dilemmas
Authors: Ezzamel Samia
Published: November 2013

While serving as a journal, a blog is, generally, a form of social media that can be accessed by anyone, online (Miller and Pole 2010). Blogs authored by healthcare professionals are increasingly prevalent (Lagu et al 2008). This opinion piece draws on the author's experience in exploring how blogging can develop reflective skills and the interactive forum that a blog can enable. It also raises the inherent risks of blogging, and suggests that, in order for occupational therapists to make use of this opportunity for continuing professional development, specific guidance about the use of social media needs to be created.
Current Trends and Practices Followed by Dental Technicians and Dentists in Fixed Crown and Bridges in India: A Cross-sectional Survey
Authors: Singh Balendra Pratap , Kumar Lakshya , Singh Kamleshwar , Singh Nishi , Agrawal Kaushal Kishor , Kumari Reema
Published: November 2013

Aim

To identify the current materials, design, communication and disinfection status followed by the dental laboratories in India regarding fixed prosthodontics.

Materials and methods

A prepiloted anonymous questionnaire containing 27 questions related to fixed prosthodontics was send to 472 laboratories in India. Information was obtained regarding procedure and materials for fixed prosthesis, die technique, accuracy of casts, design, communication, shade selection and disinfection practices followed by the laboratories. Questionnaire data were entered into a computer and analyzed using SPSS version 12.0 (SPSS, Inc, Chicago, IL, USA).

Results

Two hundred and sixteen of 472 dental laboratories responded (45.76% response rate). Most common pontic design in both arches was ridge lap. One hundred and fifty-four (71.29%) laboratories presented that most of the casts were not articulated. Majority of impression (66.20%) received are not accurate enough for laboratories to do their best work. One hundred and eighty (82.8%) laboratories have stated that less than 25% casts were disinfected. Most of the dentists (65.74%) were not sending work authorization form and those who were sending are not complete enough (63.42%).

Conclusion

The finding in this study indicated the weakness in technique and design of fixed prosthesis along with poor communication between dentists and laboratories in India.

How to cite this article

Singh BP, Singh K, Singh N, Agrawal KK, Kumar L, Kumari R. Current Trends and Practices Followed by Dental Technicians and Dentists in Fixed Crown and Bridges in India: A Cross-sectional Survey. Int J Prosthodont Restor Dent 2013;3(2):43-49.
Evaluation of Fracture Resistance of Reattached Vertical Fragments Bonded with Fiber-reinforced Composites: An in vitro Study
Authors: Gopal S Sujatha , Kumar B Shiva , Spoorti P , Reddy Jeetender , Ittigi Jayaprakash
Published: November 2013

Aim

Aim of this in vitro study was to evaluate the resistance to fracture of vertically fractured and reattached fragments bonded with fiber-reinforced composites.

Materials and methods

Root canals of 45 teeth were prepared, and the teeth were intentionally fractured into two separate fragments. Control groups (n = 15 each) consisted unfractured teeth with instrumented and obturated. Fractured teeth were divided into three groups (n = 15) and were attached using (1) dual-cure resin cement (RelyX U100), (2) dual-cure resin cement and polyethylene fiber (Ribbond), (3) dual-cure resin cement and glass fibers (stick-net). Force was applied at a speed of 0.5 mm/min to the root until fracture.

Results and statistical analysis

Group 1 (RelyX U100 group) demonstrated lowest fracture resistance. Group 4 (control group) showed highest fracture resistance followed by group 2 (Ribbond group) and group 3 (Stick-Net groups). Statistically no significant difference was there between groups 2, 3 and 4.

Conclusion

Vertically fractured teeth can be treated by filling the root canal space with dual-cure adhesive resin cement or by adding polyethylene fiber or glass fiber to increase the fracture resistance of the reattached tooth fragments, an alternative to extraction.

How to cite this article

Kumar BS, Spoorti P, Reddy J, Bhandi S, Gopal SS, Ittigi J. Evaluation of Fracture Resistance of Reattached Vertical Fragments Bonded with Fiber-reinforced Composites: An in vitro Study. J Contemp Dent Pract 2013;14(4):573-577.
Comparative Analysis of Colony Counts of Different Species of Oral Streptococci in Saliva of Dentulous, Edentulous and in those Wearing Partial and Complete Dentures
Authors: Madineni Praveen Kumar , Ghanta Suresh Babu , Motupalli Naveen Kumar , Bembalgi Mahanthesh , Raju P Krishnam
Published: November 2013

Objectives

To study and compare the number of colony forming units of Streptococcus mutans, Streptococcus sanguis, Streptococcus salivarius, Streptococcus mitis and Streptococcus milleri in dentulous, edentulous and in those wearing partial and complete dentures by using semi-quantitative culture method of saliva samples with calibrated standard loop

Materials

Sterile specimen collection bottles, Mitis salivarius agar plates, Standard loop, Candle jar, Incubator, Colony counter

Methodology

Study population consisted of 100 subjects with 25 in each group, with an age range of 40 to 80 years, who were attending the Department of Community Dentistry and Prosthodontics at MNR Dental College, Sangareddy, Hyderabad. Unstimulated saliva samples were collected from patients and inoculated on to Mitis salivarius agar plates using calibrated standard loop. The plates were then incubated anaerobically at 37°C for 24 hours and left at room temperature for further 24 hours. Using a colony counter, the number of colonies of each species was counted.

Results

Streptococcus mutans and Streptococcus mitis predominates in the dentulous group, Streptococcus sanguis in complete denture group, Streptococcus salivarius in edentulous group and Streptococcus milleri in removable partial denture group.

Conclusion

The results of our study are in accordance with the previous studies, which have sought to differentiate different groups of mutans streptococci using a simple calibrated standard loop.

How to cite this article

Ealla KKR, Ghanta SB, Motupalli NK, Bembalgi M, Madineni PK, Raju PK. Comparative Analysis of Colony Counts of Different Species of Oral Streptococci in Saliva of Dentulous, Edentulous and in those Wearing Partial and Complete Dentures. J Contemp Dent Pract 2013;14(4):601-604.
Periodontal Pathogens and Respiratory Diseases— Evaluating Their Potential Association: A Clinical and Microbiological Study
Authors: Nayak Rashmita , Spoorthi BR , Vadiraj S , Choudhary Gopal Krishna , Kudyar Nitin
Published: November 2013

Objective

To evaluate whether any potential association exists between respiratory diseases such as chronic obstructive pulmonary disease (COPD) and periodontal health status clinically and or microbiologically.

Materials and methods

Fifty patients of COPD (test group) and 50 Patients without COPD (control group) were recruited for the study with more than 20 years of age with at least six natural teeth. All the patients were nonsmokers. Periodontal health was assessed by measuring clinical attachment loss (CAL) and gingival bleeding by using William's graduated periodontal probe. Microbiological evaluation was done by collecting sputum samples of the subjects with respiratory diseases to find out any periodontal pathogen in the lung fluid.

Result and conclusion

The results showed that the subjects with COPD had significantly more bleeding sites (i.e. >20%) and had more of the clinical mean attachment loss (2.84 ± 0.66) than those without COPD. On the basis of the observed results of the study, we can hypothesize that the risk for COPD appeared to be significantly elevated when attachment loss was found to be severe.

Clinical significance

It is conceivable that oral interventions that improve oral health status may prove to lower the severity of lung infection in susceptible populations.

How to cite this article

Vadiraj S, Nayak R, Choudhary GK, Kudyar N, Spoorthi BR. Periodontal Pathogens and Respiratory Diseases—Evaluating Their Potential Association: A Clinical and Microbiological Study. J Contemp Dent Pract 2013;14(4):610-615.
Accuracy of Electronic Apex Locator in Enlarged Root Canals with Different Root Canal Irrigants: An in vitro Study
Authors: Sainath Dinapadu , Pasari Srikanth , Admala Shilpa Reddy , Marukala Narender Reddy , Gurram Sindhurareddy , Peddi Ravigna
Published: November 2013

Aim

To evaluate the accuracy of Root ZX-II (J Morita Corp) apex locator in enlarged root canals with different root canal irrigants.

Materials and methods

48 freshly extracted single rooted mandibular premolar teeth were used. The apical enlargement was done up to #45 K-file as the master apical file (MAF). The teeth were randomly divided into 4 groups and mounted in an experimental apparatus. The following irrigants were used during electronic canal measurements: group 1: saline; group 2: 3% NaOCl; group 3: 2% chlorhexidine; group 4: 17% EDTA. The canal measurement was done with Root ZX-II apex locator using #10 and #45 K-file. Data were analyzed by two way ANOVA and Bonferroni multiple comparison test.

Results

Statistical analysis showed that there was statistically significant difference between #10 and #45 K-file for group 1 (p < 0.01).

Conclusion

Root ZX-II was accurate in the presence of 3% NaOCl and 17% EDTA when measured with smaller and larger files. However, it was accurate in the presence of saline and 2% CHX when larger files were used.

How to cite this article

Dinapadu S, Pasari S, Admala SR, Marukala NR, Gurram S, Peddi R. Accuracy of Electronic Apex Locator in Enlarged Root Canals with Different Root Canal Irrigants: Anin vitroStudy. J Contemp Dent Pract 2013;14(4): 649-652.
Finishing and Polishing Procedures of Composite Restorations by Saudi Dentists: A Cross-sectional Study
Authors: AlQarni Mohammed Ali , Togoo Rafi A , Shahrani Ibrahim Al , Phani CR Sumanth
Published: November 2013

Aim

The purpose of this study was to assess the knowledge and practices of Saudi dentists in finishing and polishing composite restorations.

Materials and methods

A cross-sectional questionnaire-based study was conducted among 306 Saudi dentists from March to April 2012. The collected data were analyzed using Microsoft Excel 2010 program and descriptive statistics were obtained.

Results

Completed questionnaires were returned by 191 participants, giving a response rate of 62.4%. 115 (65.7%) respondents are using fine diamond finishing burs for finishing occlusal surfaces, 82 (48%) used fine aluminum oxide finishing discs for finishing facial surfaces, 130 (76%) used diamond finishing strips for finishing interproximal surfaces.121 (63.4%) respondents were of the view that the type of filler content has a major influence in providing color stability to the composite restoration and 137 (72.1%) believed nano-composites provided enhanced color stability.

Conclusion

Dentists in Saudi Arabia are aware of the benefits of proper finishing and polishing of composite restorations. They however need to use finishing and polishing burs, disks, strips and pastes in a sequential series. Usage of composite polishing pastes and composite surface sealants should be emphasized in undergraduate curriculum.

How to cite this article

AlQarni MA, Togoo RA, Al Shahrani I, Phani CRS. Finishing and Polishing Procedures of Composite Restorations by Saudi Dentists: A Cross-sectional Study. J Contemp Dent Pract 2013;14(4):657-661.
Bond Strength of Overdenture Locator Posts Cemented with Seven Luting Agents
Authors: Aleisa Khalil
Published: November 2013

Statement of the problem

Post retention is crucial factor in restoration survival. Posts are commonly failed due to loss of retention. It is unknown which luting agents would provide the maximum bond strength for Locator overdenture posts.

Aim

The aim of this study was to evaluate the bond retentive strengths of Locator overdenture posts cemented with 7 luting agents.

Materials and methods

One hundred and five single rooted human teeth were decoronated and randomly assigned to 7 groups (n = 15). Post spaces were prepared with Locator post drills to the depth of 6 mm. The Locator posts were cemented with Variolink II, RelyX ARC, Multilink N, RelyX Unicem, ParaCore, or MultiCore Flow resin luting agents. Zinc phosphate cement was served as control group. Specimens were stored in water at 37°C for 24 hours. Each specimen was loaded in tension in an Instron universal testing machine. The maximum force required to dislodge each Locator post was recorded. Means and standard deviations were calculated and data were statistically analyzed with one-way analysis of variance (ANOVA).

Results

The highest mean bond strength value for Locator posts was recorded for MultiCore® Flow group (mean = 550.1 N), while the lowest mean value was for RelyX Unicem™ resin cement group (mean = 216.8 N). A statistically significant difference in mean locator overdenture post bond strength was observed between the 7 cement types (p < 0.0001). ParaCore™ and MultiCore® Flow groups had significantly higher bond strength than all other groups, but they were not differed from each other.

Conclusion

Bond strength of Locator overdenture posts were influenced by the type of luting agents. MultiCore Flow and ParaCore resin cements offered the greatest retention.

Clinical significance

The type of luting agents had a significant effect on the retention of Locator posts. The use of Core buildup resin cements as luting agent with Locator post demonstrated the greatest retention.

How to cite this article

Aleisa K. Bond Strength of Overdenture Locator Posts Cemented with Seven Luting Agents. J Contemp Dent Pract 2013;14(4):675-680.
Color Stability of Restorative Materials in Response to Arabic Coffee, Turkish Coffee and Nescafe
Authors: Al-Samadani Khalid H
Published: November 2013

Objective

To evaluate the effect of Arabic coffee, Turkish coffee and Nescafe on the color stability of four different composite resins after a period of aging time 1, 7 and 30 days.

Materials and methods

Twenty specimens from each type of tested composite resin material were prepared. Five specimens from each tested material (Z350 XT, Artist, GC and Z250) was evaluated after storage in Arabic coffee, Turkish coffee, Nescafe and distil water (control) at 37°C in a dark container for 1, 7 and 30 days. Color measurement was done using colorimeter based on the CIE L* a* b* color scale. Color differences ΔE*ab, Δb* and Δa* among specimens immersed in distil water and staining coffee beverages were evaluated overtime. Mean values were statistically analyzed with one-way analysis of variance (ANOVA), followed by Tukey test with p < 0.05 as significance level.

Results

All tested composite resins showed increase color change after a period of 1, 7 and 30 days. The color change ΔE*ab, Δb* and Δa* exhibited by Arabic coffee, in Turkish coffee and Nescafe except Δa*. The highest total color difference ΔE*ab after 30 days was in group A Arabic coffee (ΔE > 1.5 perceivable) and not perceivable in group B Turkish coffee and group C Nescafe. For Δb* all materials discolored toward yellowness after 30 days except Arabic coffee group which shifted from yellowness toward blueness (Δb*> 1.5 perceivable).

Conclusion

The effect of staining beverages on the resin composite materials increases with time of aging toward yellowness and not perceivable in all groups except with Arabic coffee which had highest effect after 30 days and the discoloration shifted from yellowness to blueness perceivable.

How to cite this article

Al-Samadani KH. Color Stability of Restorative Materials in Response to Arabic Coffee, Turkish Coffee and Nescafe. J Contemp Dent Pract 2013;14(4):681-690.
Effect of Energy Drinks on the Color Stability of Nanofilled Composite Resin
Authors: Al-Dharrab Ayman
Published: November 2013

Objective

To study the effect of three energy drinks on the color stability of nanofilled composite resins after different periods of aging time.

Materials and methods

Composite resin disks, 6 mm diameter, 3 mm thickness were prepared from Filtec Z350 XT, Tetric EvoCeram, and Filtec Z250 XT. Specimens from each material were tested after aging with Red Bull, Bison and Power Horse energy drinks and distilled water as a control. Specimens were stored at 37°C in dark containers for 1, 7, 30 and 60 days. Color was assessed in the CIELAB using a colorimeter before and after each storage period. Color differences ΔE*ab and Δb* among specimens were measured. Mean values were statistically analyzed using one-way analysis of variance (ANOVA), with p < 0.05 as significance level.

Results

The color change ΔE*ab and Δb* occurred by Red Bull, Bison and Power Horse energy drinks was significantly different for all tested materials at all four times p < 0.05 except in the Red Bull group. All specimens showed increase in color changes toward yellowness Δb* after a period of 1, 7, 30 and 60 days. The highest total color difference ΔE*ab was found in the Red Bull group after 60 days.

Conclusion

Energy drinks used in this study had staining effect on the tested composite resin materials. The discoloration increased with aging time toward yellowness; however, it was not perceptible in all test groups after 60 days.

How to cite this article

Al-Dharrab A. Effect of Energy Drinks on the Color Stability of Nanofilled Composite Resin. J Contemp Dent Pract 2013;14(4):704-711.