Evaluation of the thermal shrinkage of titanium and the setting and thermal expansion of phosphate-boded investments

Statement of problem. There are few studies on titanium casting shrinkage, and phosphate-bonded investments for titanium casting have not produced appropriate marginal fit.Purpose. The purpose of this study was to determine the thermal shrinkage of titanium and the setting and thermal expansion of 3 phosphate-bonded investments.Material and methods. The thermal shrinkage between the melting temperature and room temperature was calculated using a titanium thermal expansion coefficient. The thermal and setting expansion were measured for 3 phosphate bonded investments: Rematitan Plus (RP) specific for titanium, Rema Exakt (RE), and Castorit Super C (CA), using different special liquid concentrations (100%, 75%, and 50%). Setting expansion was measured for cylindrical specimens 50 mm long x 8 mm in diameter with a transducer. The heating and cooling curves were obtained with a dilatometer (DIL 402 PC). The total expansion curve was drawn using software, and temperatures to obtain expansion equivalent to titanium casting shrinkage were determined (n=5). In addition, the total expansion of the control group (RP at 430 degrees C) was measured, as well as the temperatures at which the other groups achieved equivalent total expansion (n=5). Data were analyzed by 1-way ANOVA and the Tukey HSD test (alpha=.05).Results. Titanium casting shrinkage was estimated as 1.55%. RP did not achieve this expansion. RE achieved expansion of 1.55% only with a special liquid concentration of 100% at 594 degrees C. CA with all special liquid concentrations attained this expansion (351 degrees C to 572 degrees C). Total expansion of the control group was 0.86%, and the other groups reached that expansion within the range of 70 degrees C to 360 degrees C.Conclusions. Only RE and CA demonstrated sufficient expansion to compensate for titanium casting shrinkage. All groups reached total expansion equivalent to that of the control group at significantly lower temperatures.

Conjectures and theorems in the theory of entire functions

Motivated by the recent solution of Karlin's conjecture, properties of functions in the Laguerre-Polya class are investigated. The main result of this paper establishes new moment inequalities fur a class of entire functions represented by Fourier transforms. The paper concludes with several conjectures and open problems involving the Laguerre-Polya class and the Riemann xi -function.

Evaluation of water and sucrose diffusion coefficients in potato tissue during osmotic concentration

The water and sucrose effective diffusion coefficients behavior were studied in potato tubers immersed in aqueous sucrose solution, 50% (w/,A), at 27 degreesC. Water and sucrose concentration profiles were measured as function of the position for 3, 6 and 12 h of immersion. These were adjusted to a mathematical model for three components that take into account the bulk flow in a shrinking tissue and the concentration dependence of the diffusion coefficients.The binary effective coefficients were an order of magnitude lower than those for pure solutions of sucrose. These coefficients show an unusual concentration dependence. Analysis of these coefficients as functions of the concentration and position demonstrates that, cellular tissue promotes high resistance to diffusion in the tuber and also the elastic contraction of material influences the species diffusion. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

Evaluation of the thermal diffusivity of vegetable oils during frying by Thermal Lens Spectrometry

In this work we report on the use of the Thermal Lens method to verify the evolution of the thermal diffusivity of sunflower and soybean vegetable oils utilized in preparation of twenty five snacks portions. Our results show that the thermal diffusivity for sunflower oil does not change between 1 and 25 portions of fried snacks. By another hand, the soybean thermal diffusivity exhibits a little decrease for higher portion of fried snacks, indicating that for this oil the triglyceride level is reduced as a degradation process.

Cytogenetic evaluation of 20 primary breast carcinomas

Chromosome analysis was performed on samples from 20 Brazilian patients with breast cancer. All the samples were from untreated patients who presented the clinical symptoms for months or years before surgical intervention. Six cases showed axillary lymph node metastases. Clonal chromosome abnormalities were detected in all cases. The numerical alterations most frequently observed involved the loss of chromosomes X, 19, 20, and 22 followed by gain of chromosomes 9 and 8. Among the structural anomalies observed, there was preferential involvement of chromosomes 11, 6, 1, 7, 3, and 12, supporting previous reports that these chromosomes may harbour genes of importance in the development of breast tumors. Two cases with a family history of breast cancer had in common total or partial trisomy 1.

Numerical study of the coupled time-dependent Gross-Pitaevskii equation: Application to Bose-Einstein condensation

The Bose-Einstein condensate of several types of trapped bosons at ultralow temperature was described using the coupled time dependent Gross-Pitaevskii equation. Both the stationary and time evolution problems were analyzed using this approach. The ground state stationary wave functions were found to be sharply peaked near the origin for attractive interatomic interaction for larger nonlinearity while for a repulsive interatomic interaction the wave function extends over a larger region of space.

Composition for a class of generalized functions in Colombeau's theory

In Colombeau's theory, given an open subset Ω of ℝn, there is a differential algebra G(Ω) of generalized functions which contains in a natural way the space D′(Ω) of distributions as a vector subspace. There is also a simpler version of the algebra G,(Ω). Although this subalgebra does not contain, in canonical way, the space D′(Ω) is enough for most applications. This work is developed in the simplified generalized functions framework. In several applications it is necessary to compute higher intrinsic derivatives of generalized functions, and since these derivatives are multilinear maps, it is necessary to define the space of generalized functions in Banach spaces. In this article we introduce the composite function for a special class of generalized mappings (defined in open subsets of Banach spaces with values in Banach spaces) and we compute the higher intrinsic derivative of this composite function.

Environmental evaluation of cogeneration scenarios in sugar industry

The development of new techniques that allow the analysis and optimization of energy systems bearing in mind environmental issues is indispensable in a world with finite natural resources and growing demand of energy. Among the energy systems that deserve special attention, cogeneration in the sugar industry must be pointed out, because it uses efficiently a common fuel for generation of useful heat and power. Within this frame, thermoeconomical optimization - 2nd Law of Thermodynamics analysis by exergy function and economic evaluation of the thermal system - gradually is taking importance as a powerful tool to assist to the decision making process. Also, the explicit consideration of environmental issues offers a better way to explore trade-offs between different aspects to support the decisions that must be made. In this work it is used the technique of Life Cycle Analysis (LCA) which allows to consider environmental matters as an integral part of the problem, in opposite to most of the environmental approaches that only reduce residuals generation , without taking into account impacts associated to other related processes. On the other hand, the consideration of environmental issues in optimization of energy systems is a novel and promissory contribution in the state of the art of energy optimization and LCA. The system under study is a sugar plant of Tucumán (Argentina) given the particular importance that this industry had inside the regional economy of the Argentinean Northwest. Although cogeneration comes being used a while ago in sugar industry, being the main objective the generation of heat and as secondary objective the electric power generation and mechanic power to cover several needs of working machineries, to the date it is no available a versatile tool that allows to analyze economical feasible alternatives bearing in mind environmental issues. At sugar plants, steam is generated in boilers using as fuel bagasse - cellulosic fiber waste obtained crushing the sugar cane- and it is used to give useful heat and shaft work to the plant, but it can also be used to generate electricity with export opportunities to the electrical network. The great number of process alternatives outlines a serious decision making problem in order to take advantage of the resources. Although the problem turns out to be a mixed non-linear problem (MINLP), the main contribution of this work is the development of a hybrid strategy to evaluate cogeneration alternatives that combines optimization approaches with environmental indicators. This powerful tool for its versatility and robustness to analyze cogeneration systems, will be of great help in the decision making process, because of their easy implementation to analyze the kind of problems presented in the sugar industry.

Clinical and microbiological evaluation of the use of toothpaste containing 1% chlorhexidine and the influence of motivation on oral hygiene in patients with motor deficiency

Patients with motor deficiency have variable difficulties with mechanical plaque control, and as a consequence, the incidence of dental caries and periodontal disease can be higher in these patients. The objective of this study was to evaluate the clinical and microbiological efficacy of a toothpaste containing 1% chlorhexidine, which was used by patients with motor deficiency for 14 days. The reduction in plaque and gingival index and the impact on salivary microorganisms was evaluated. We conclude that the motivation of caregivers to carry out oral hygiene for patients with mental and motor deficiency is of great importance and is effective in reducing the formation of plaque as long as it is continuously reinforced. The use of chlorhexidine- containing toothpaste significantly reduced the plaque index and microorganism count between days 0 and 14. A reduction was also observed in the group that used a dentifrice without the chlorhexidine, but this difference was not significant. © 2010 Special Care Dentistry Association and Wiley Periodicals, Inc.

Infrared thermography applied to the evaluation of metabolic heat loss of chicks fed with different energy densities

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cephalometric evaluation of hyoid bone position in a patient with Down syndrome: Case report

The hyoid bone contributes to the maintenance of the airway, chewing and swallowing, given to its anatomical and functional relations to the craniocervical complex. Cephalometric analysis has great importance for orthopedics, orthodontics and oral maxillary surgery. For the treatment of patients with special care needs, the cephalometric evaluation of the position of the hyoid bone should also contribute as a complementary element for dental diagnosis and the selection of the adequate treatment. The aim of this paper is to demonstrate the alteration of the hyoid position after carrying out the functional orthopedic maxillary treatment in a 9 year-old patient with Down Syndrome. Initial cephalometric analysis revealed inadequate position of hyoid bone. The association of speech therapy to dynamic functional rehabilitation of jaws showed a positive effect in occlusal relation and facial expression. After treatment, all dimensions obtained from the hyoid triangle were higher than initial ones, except the anterior-posterior value of C3-H, which suggested function improvement of stomatognathic system. Once considered its anatomical and physiological relationship with the others structures of the stomatognathic system, cephalometric analysis of hyoid bone position was helpful to the comprehension of the craniofacial abnormalities related to chromosomal anomaly, and thus is essential to the interdisciplinary dialogue.

Molecular Evaluation of Developmental Competence of Oocytes Collected In Vivo from Buffalo and Bovine Heifers during Winter and Summer

Buffaloes and bovines are polyestrous and seasonal or annual livestock, respectively, that show reduced fertility during heat stress. To investigate whether reduced fertility is related to oocyte competence in both species, immature oocytes from buffalo and bovine heifers were collected during winter and summer and subjected to molecular analyses. In each season, heifers of both species had their follicular wave emergence synchronized with a standard protocol (Ferreira et al., 2011). Before being subjected to ovum pick up (OPU), cutaneous (CT; degrees C) and rectal (RT; degrees C) temperatures and respiratory rate (RR; breaths/min) were measured. Oocytes' RNA was extracted to evaluate the expression of target genes related to mtDNA replication/transcription (PPARGC1A, TFAM and MT-CO1), apoptosis (BAX and BCL2) and HS (HSP90AA1 and HSPA1AB). ACTB, HIST1H2AG and GAPDH were initially chosen as housekeeping genes. In buffaloes, CT (35.0 +/- 0.4 vs 23.8 +/- 0.5), RT (38.7 +/- 0.1 vs 38.0 +/- 0) and RR (21.3 +/- 1.2 vs 15.4 +/- 1.1) were higher during summer than winter. However, in bovine heifers, RT (38.7 +/- 0.1 vs 38.6 +/- 0.1) and RR (44.8 +/- 1.5 vs 40.6 +/- 1.5) were similar in both seasons, while CT (31.6 +/- 0.3 vs 30.2 +/- 0.3) was increased during summer. Reduced expression of ACTB, HIST1H2AG and GAPDH was evidenced during summer, disqualifying them as housekeeping genes. Similarly, the expression of all target genes was reduced during summer in oocytes of both species. In summary, physiological responses to heat stress seem to be more intense in buffalo than bovine heifers. However, in both species, negative effects of heat stress upon oocyte quality occur at the molecular level and affects genes related to several biological functions.

Evaluation of tensile tetention of Y-TZP crowns after long-term aging: Effect of the core substrate and crown surface conditioning

This study evaluated the effect of the core substrate type (dentin and composite resin) on the retention of crowns made of yttrium oxide stabilized tetragonal zirconia polycrystal (Y-TZP), submitted to three inner surface conditionings. For this purpose, 72 freshly extracted molars were embedded in acrylic resin, perpendicular to the long axis, and prepared for full crowns: 36 specimens had crown preparations in dentin; the remaining 36 teeth had the crowns removed, and crown preparations were reconstructed with composite resin plus fiber posts with dimensions identical to the prepared dentin. The preparations were impressed using addition silicone, and 72 Y-TZP copings for the tensile test were produced. Cementation was performed with a dual-cured cement containing phosphate monomers. For cementation, the crown preparation (dentin or resin) was conditioned with the adhesive system, and the ceramic was subjected to one of three surface treatments: isopropyl alcohol, tribochemical silica coating, or thin low-fusing glassy porcelain layer application plus silanization. After 24 hours, all specimens were submitted to thermocycling (6000 cycles) and placed in a special tensile testing device in a universal testing machine to determine failure loads. The failure modes of all samples were analyzed under a stereomicroscope. Two-way analysis of variance showed that the surface treatment and substrate type (alpha=0.05) affected the tensile retention results. The dentin substrate presented the highest tensile retention values, regardless of the surface treatment. When the substrate was resin, the tribochemical silica coating and low-fusing glaze application plus silanization groups showed the higher retention values.

Schur-Szegö composition of entire functions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

In vivo evaluation of the inflammatory response and IL-6 immunoexpression promoted by Biodentine and MTA Angelus

Aim To evaluate the inflammatory process induced by Biodentine and mineral trioxide aggregate (MTA) in rat subcutaneous tissues. Methodology A polyethylene tube filled with Biodentine (n = 20) or MTA (n = 20) was placed into the dorsal subcutaneous of forty male rats; in the control group (CG; n = 20), empty tubes were implanted. After 7, 15, 30 and 60 days, the polyethylene tubes surrounded by connective tissue were fixed and embedded in paraffin. The number of inflammatory cells was estimated in HE-stained sections; numerical density of interleukin-6 (IL-6)-immunolabelled cells was also performed. The differences amongst the groups were analysed statistically by Tukey's test (P ≤ 0.05). Results A high number of inflammatory cells and IL-6-positive cells were observed at 7 days, in all groups; however, in the Biodentine group, the number of inflammatory cells and IL-6-immunolabelled cells was significantly higher (P ≤ 0.05) in comparison with the other groups at 7 and 15 days. In the capsules of animals from all groups, a gradual and significant reduction (P ≤ 0.05) of these parameters was seen over time. At 60 days, the capsules exhibited numerous fibroblasts and bundles of collagen fibres; in addition, the number of IL-6-positive cells was not significantly different amongst Biodentine, MTA and control groups. Conclusions There was a significant regression in the inflammatory reaction in the capsules indicating, therefore, that Biodentine is a biocompatible material.