82 research outputs found

    A comprehensive review on bonding between monolithic ceramics and tooth structure with different adhesive agents.

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    Reliable bonding between the prepared tooth and monolithic ceramics can be achieved by various luting agents available on the market. The selection of luting agent and cementation technique plays an important role in the success of the restoration. With the advent of resin-based adhesive systems as luting agents, clinicians\u27 perspectives have changed to a more conservative approach. Recent systems, chemically adhere the crowns to the prepared tooth structure showing higher bond strength. To reach the aesthetic demands of the patients, all-ceramic restorations were considered over metal-ceramic crowns. Few all-ceramic crowns are brittle, the strength is dependent on the chemical structure and method of fabrication. While some all-ceramic restorations gain strength after cementation. Thus, the choice of luting agent used in cementing all-ceramic crowns is crucial. Even though many luting agents are being introduced no single luting agent fulfilled all the requirements. Among them, adhesive cements showed greater bond strength and enhanced the retention of minimal preparation, which are less retentive. Traditional non-adhesive agents can be used in retentive preparations that bond through mechanical means rather than the chemical bond seen in newer adhesive cements. Also, surface treatments of zirconia showed greater bond strengths irrespective of the luting agent being used. These include air abrasion, acid etching, applying silane couplers, and primers that increase the surface area for adhesion. The use of all-ceramic restorations, the need for surface treatments, types of surface treatments, adhesion and adhesive agents, and evidence from current in vitro research on monolithic ceramics and tooth adhesion were all discussed in this review

    An overview of applications of PEEK polymer in prosthodontics.

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    The rapid evolution of computer-aided design and computer-aided manufacturing (CAD-CAM) led to the introduction of newer materials that could be precisely milled for the fabrication of dental prostheses. PEEK (PolyEtherEtherKetone) has been explored for a number of applications for clinical dentistry, including removable dental prostheses, fixed dental prostheses, implant-supported prostheses, resin-bonded fixed dental prostheses and implant-retained overdentures. The major beneficial property of PEEK is its lower Young\u27s modulus, and as elastic as bone, providing a cushioning effect and reduction of stress transferred to abutment teeth. It is a material with high biocompatibility, good mechanical properties, high-temperature resistance, chemical stability, polishability, good wear resistance, and high bond strength with luting cements. Further, PEEK is also recommended for a wide range of CAD-CAM fabricated fixed and removable prostheses, fabrication of occlusal splints, intra-radicular posts, implant abutments and provisional restorations. PEEK material shows a property of radiolucency, which is advantageous for the evaluation of both osseointegration and tissue surrounding the implant on computed tomography. Considering these properties, PEEK is increasingly being used in implantology

    New report on the invasive Bondar's Nesting Whitefly (Paraleyrodes bondari Peracchi) on oil palm in India

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    This communication is the new report of the neotropical invasive Bondar's Nesting Whitefly (BNW) , Paraleyrodes bondari Peracchi (Hemiptera: Aleyrodidae)incidence in oil palm in India. A typical feature of BNW infestation is the presence of woolly wax nests on the abaxial surface of oil palm leaflets. The nesting whitefly population was observed to increase phenomenally on oil palm and within a year ie., from 2021 to 2022, a 100 per cent palm infestation was observed. During this period the intensity per palm increased by 24.49 per cent and per leaf increased by 63.28 per cent. Analysis of the partial mitochondrial cytochrome oxidase subunit 1 (CO1) sequences from adult specimens indicated 100% nucleotide identity with Bondar's Nesting Whitefly from coconut

    Sensor Network Deployment For Agronomical Data Gathering in Semi-Arid Regions

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    We share our experience in planning, designing and deploying a wireless sensor network of one square kilometre area. Environmental data such as soil moisture, temperature, barometric pressure, and relative humidity are collected in this area situated in the semi-arid region of Karnataka, India. It is a hope that information derived from this data will benefit the marginal farmer towards improving his farming practices. Soon after establishing the need for such a project, we begin by showing the big picture of such a data gathering network, the software architecture we have used, the range measurements needed for determining the sensor density, and the packaging issues that seem to play a crucial role in field deployments. Our field deployment experiences include designing with intermittent grid power, enhancing software tools to aid quicker and effective deployment, and flash memory corruption. The first results on data gathering look encouragin

    HIV prevention programmes for female sex workers in Andhra Pradesh, India: outputs, cost and efficiency

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    BACKGROUND: Female sex workers and their clients play a prominent role in the HIV epidemic in India. Systematic data on the outputs, cost and efficiency for HIV prevention programmes for female sex workers in India are not readily available to understand programme functioning and guide efficient use of resources. METHODS: Detailed output and cost data for the 2002–2003 fiscal year were obtained using standardised methods at 15 HIV prevention programmes for female sex worker in the state of Andhra Pradesh in southern India. The services provided and their relation to the total and unit economic costs were analysed using regression techniques. The trends for the number of sex workers provided services by the programmes since inception up to fiscal year 2004–2005 were examined. RESULTS: The 15 programmes provided services to 33941 sex workers in fiscal year 2002–2003 (range 803–6379, median 1970). Of the total number of contacts with sex workers, 41.6% were by peer educators and 58.4% by other programme staff. The number of sex worker contacts in a year by peer educators varied 74-fold across programmes as compared with a 2.7-fold variation in sex worker contacts by other programme staff. The annual economic cost of providing services to a sex worker varied 6-fold between programmes from Indian Rupees (INR) 221.8 (US4.58)toINR1369(US 4.58) to INR 1369 (US 28.29) with a median of INR 660.9 (US13.66)andmeanofINR517.8(US 13.66) and mean of INR 517.8 (US 10.70). Personnel salaries made up 34.7% of the total cost, and recurrent goods made up 38.4% of which 82.1% was for condoms. The cost per sex worker provided services had a significant inverse relation with the number of sex workers provided services by a programme (p < 0.001, R(2 )= 0.75; power function). There was no correlation between the full time equivalents of programme staff and the number of sex workers provided services by the programmes, but there was a modest inverse correlation between the number of sex workers served and the average time spent with each sex worker in the year adjusted for the full-time equivalents of programme staff (p = 0.011, R(2 )= 0.40; exponential function). The average number of sex workers provided services annually by the first batch of 7 programmes started in early 1999 plateaued after the fourth fiscal year to 3500, whereas the 8 second-batch programmes started in late 2000 reached an average of 2000 sex workers in 2004–2005 with an increasing trend up to this fourth fiscal year. CONCLUSION: The HIV prevention efforts in this Indian state would benefit from standardisation of the highly variable services provided by peer educators, who form an important part of the sex worker programmes. The cost per sex worker served decreases with increasing number of sex workers served annually, but this has to be weighed against an associated modest trend of decrease in time spent with each sex worker in some programmes

    Outputs, cost and efficiency of public sector centres for prevention of mother to child transmission of HIV in Andhra Pradesh, India

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    <p>Abstract</p> <p>Background</p> <p>Prevention of mother to child transmission (PMTCT) is an important part of the effort to control HIV. PMTCT services are mostly provided at public sector government hospitals in India. Systematic data on the cost and efficiency of providing PMTCT services in India are not available readily for further planning.</p> <p>Methods</p> <p>Cost and output data were collected at 16 sampled PMTCT centres in the south Indian state of Andhra Pradesh using standardized methods. The services provided were analysed, and the relation of unit cost of services with scale was assessed.</p> <p>Results</p> <p>In the 2005–2006 fiscal year, 125,073 pregnant women received PMTCT services at the 16 centres (range 2,939 to 20,896, median 5,679). The overall HIV positive rate among those tested was 1.67%. Of the total economic cost, the major components were personnel (47.3%) and recurrent goods (31.7%). For the 16 PMTCT centres, the average economic cost per post-HIV-test counselled pregnant woman was Indian Rupees (INR) 98.9 (US2.23),ranging2.7−foldfromINR71.4(US 2.23), ranging 2.7-fold from INR 71.4 (US 1.61) to INR 189.9 (US4.29).Theeconomiccostpermother−neonatepairwhoreceivednevirapinehadahighervariation,ranging41−foldforthe16centresfromINR4,354(US 4.29). The economic cost per mother-neonate pair who received nevirapine had a higher variation, ranging 41-fold for the 16 centres from INR 4,354 (US 98) to INR 179,175 (US4,047),averageINR10,210(US 4,047), average INR 10,210 (US 231), with very high unit cost at some centres where HIV prevalence among pregnant women and the total volume of services were both low. Scale had a significant inverse relation with both of the unit costs, per post-HIV-test counselled pregnant woman and per mother-neonate pair who received nevirapine. In addition, HIV prevalence among pregnant women had a significant inverse relation with unit cost per mother-neonate pair who received nevirapine.</p> <p>Conclusion</p> <p>Although the variation between PMTCT centres for unit cost per post-HIV-test counselled pregnant woman was modest that per mother-neonate pair receiving nevirapine was over 40-fold. The extremely high unit cost for each mother-neonate pair receiving nevirapine at some centres suggests that the new approach of combining PMTCT services with voluntary counselling and testing services that has recently been started in India could potentially offer better efficiency.</p

    New palaeomagnetic and rock magnetic results on Mesoproterozoic kimberlites from the Eastern Dharwar craton, southern India: towards constraining India's position in Rodinia

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    New palaeomagnetic and rock magnetic results are reported for 1.1 Ga Mesoproterozoic kimberlites from the distinct fields of Wajrakarur (WKF), Narayanpet (NKF) and Raichur (RKF) occurring within the Eastern Dharwar craton, southern India. In all, 35 oriented block samples were collected from ten kimberlite pipes and our results constitute first of their kind for the kimberlites from NKF and RKF. Palaeomagnetic data reveal that characteristic remanent magnetization (ChRM) directions of the studied kimberlites show a mean declination of 39 and mean inclination of −16 (N = 4, k = 37.6 and α95 = 15.2) and yield a virtual geomagnetic pole at 44.5°N, 195.4°E (dp = 8.0, dm = 15.6). This new pole position is identical to the earlier reported palaeomagnetic pole that lies at 36.8°N, 212.5°E for some Wajrakarur kimberlites and other such global results at 1100 Ma from Umkondo dolerites, Kalahari craton, southern Africa. The newly obtained palaeomagnetic pole also correlates well with the virtual geomagnetic pole (VGP) generated from the 1.1 Ga Majhgawan kimberlite, Mahoba dyke and the Bhander–Rewa sedimentary Group in the Upper Vindhyan sequence within the Bundelkhand craton of Northern India. Our results support a Mesoproterozoic closure age of the upper sedimentary horizons for the ‘Purana’ sedimentary basins and provide evidence for accretion of the northern and southern Indian cratonic blocks prior to 1.1 Ga. Our study also demonstrates that in ∼1.1 Ga palaeomagnetically based Rodinia reconstructions, India occupies a lower palaeolatitudinal position, was much separated from Australia and that East Gondwana very likely did not form an assembly until the terminal Neoproterozoic

    Petrogenesis of macrocrystic and aphanitic intrusions in Mesoproterozoic diamondiferous pipe 2 kimberlite, Wajrakarur kimberlite field, eastern Dharwar craton, southern India

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    Mesoproterozoic Pipe 2 kimberlite intruding granitic gneisses in the Wajrakarur Kimberlite Field (WKF) of Eastern Dharwar craton, southern India, is one of the first discovered pipes from this field. The two different intrusions belonging to coherent facies are observed in this kimberlite which are texturally distinct i.e., macrocrystic (with abundant macrocrysts) as well as aphanitic (devoid of or very fewer macrocrysts). Petrographic observations give evidence of presence of veined metasomatic mantle in the source region. Distinct geochemical variation is observed between macrocrystic (Mg# 75.4-76.6, SiO2: 34.3-35.4 wt%, MgO: 18.7-20.4 wt%) and aphanitic samples (Mg# 74.7-75.5, SiO2: 30.4-31.8 wt%, MgO: &#8764;21 wt%), furthermore aphanitic samples are relatively more enriched in trace and rare earth elements. Geochemical studies point out that aphanitic and macrocrystic varieties of Pipe 2 kimberlite to be products of the same mantle source but have experienced different evolutionary histories. The inferred primary magma of Pipe 2 kimberlite (for both aphanitic and macrocrystic) is suggested to have a composition of &#8764;33 wt% SiO2, Mg# &#8764;75.6 and &#8764;460 ppm Ni. Pipe 2 primary magma can be derived by using forward melting model assuming &#8764;1% partial melting of a source enriched in light REE by a factor of &#8764;11 x chondrite and almost chondritic heavy REE with 2% residual garnet. Differences between aphanitic and macrocrystic varieties in their chondrite normalized REE abundance patterns can be explained by about 5% crystal fractionation of primary magma and not by variations in the degree of partial melting. The primitive mantle normalized trace element patterns exhibit significant negative K, Sr, P, Ti and Hf anomalies that are interpreted to be characteristic of the primary magma. Combined petrology and whole rock geochemistry including compatible and incompatible element abundances and their ratios confirm that Pipe 2 kimberlite intrusions are archetypal Group I kimberlites similar to other kimberlites of EDC and not lamproites
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