Maternal risk factors for oral clefts: A case-control study

Introduction: A cleft lip with or without a cleft palate is one of the major congenital anomalies observed in newborns. This study explored the risk factors for oral clefts in Gorgan, Northern Iran. Materials and Methods: This hospital-based case-control study was performed in three hospitals in Gorgan, Northern Iran between April 2006 and December 2009. The case group contained 33 newborns with oral clefts and the control group contained 63 healthy newborns. Clinical and demographic factors, including date of birth, gender of the newborns, type of oral cleft, consanguinity of the parents, parental ethnicity, and the mother's parity, age, education and intake of folic acid were recorded for analysis. Results: A significant association was found between parity higher than 2 and the risk of an oral cleft (OR= 3.33, CI 95% [1.20, 9.19], P> 0.02). According to ethnicity, the odds ratio for oral clefts was 0.87 in Turkmens compared with Sistani people (CI 95% [0.25, 2.96]) and 1.11 in native Fars people compared with Sistani people (CI 95% [0.38, 3.20]). A lack of folic acid consumption was associated with an increased risk of oral clefts but this was not statistically significant (OR = 1.42, CI 95% [0.58, 3.49]). There were no significant associations between sex (OR boy/girl = 0.96, CI 95% [0.41, 2.23]), parent familial relations (OR = 1.07, CI 95% [0.43, 2.63]), mother's age and oral clefts. Conclusions: The results of this study indicate that higher parity is significantly associated with an increased risk of an oral cleft, while Fars ethnicity and a low intake of folic acid increased the incidence of oral clefts but not significantly

Incidence of cleft lip and palate in Gorgan - Northern Iran: An epidemiological study

Objective: Cleft lip with or without cleft palate is the most common orofacial congenital anomaly among live births. This study was carried out to determine the incidence rate of oral clefting in Gorgan, Northern Iran during 2004-2009. Methods: This descriptive hospital-based study was performed on 35,009 live newborns in Dezyani Hospital in Gorgan, Northern Iran during 2004-2009. All newborns were screened for oral clefts. Data including birth date, gender, type of oral clefts, parents' consanguinity, parental ethnicity and presence of other congenital anomalies were recorded for analysis. Result: The overall incidence rate of oral clefts during this 6-year period was 1.05 per 1000, or 1 per 946 live births. The incidence of cleft lip and isolated cleft palate was 0.08 and 0.37 per 1,000 live births, respectively. The ratio for different cleft types was 1:7:4 (CL: CLP: CP). The incidence of oral clefting was 1.2 per 1,000 male births and 0.86 per 1,000 female births (RR=1.40; 95% CI: 0.73-2.71). According to parental ethnicity, the incidence of oral clefting was 0.7, 1.7 and 1.26 per 1,000 in Native Fars, Turkman and Sistani, respectively. The relative risk for oral clefting in Turkman to native Fars group was 2.56 (p<0.02). In this study, 56.7% of clefts were CL+P, 8.1% were CL and 35.1% of cases were CP. CP was more common among girls (54%) than among boys (46%) but CL was more common among boys. Conclusion: The results showed that the incidence of oral clefts in the study population as being 1.05 per 1,000 live births, which has increased from 0.97 per 1,000 live births reported in an earlier study in this area. © OMSB, 2012

Molecular Dynamics Calculations of the Thermal Conductivity of Silica Based Crystals

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76214/1/AIAA-2002-3343-984.pd

Structural metrics of high-temperature lattice conductivity

An atomic structure-based model for high-temperature lattice conductivity is developed for both compact crystals and cage-bridge crystals. For compact crystals, where long-range acoustic phonons dominate, the Debye temperature TDTD and Grüneisen parameter γγ are estimated using interatomic potentials to arrive at the lattice conductivity relation. Under the assumption of homogeneous deformation, TDTD is estimated according to a simplified force constant matrix and a phenomenological combinative rule for force constants, which is applicable to an arbitrary pair of interacting atoms. Also, γγ is estimated from a general Lennard-Jones potential form and the combination of the bonds. The results predicted by the model are in close agreement with the experimental results. For cage-bridge crystals, where both short-range acoustic phonons and optical phonons may be important, a simple mean-free path model is proposed: The phonon mean-free path of such a crystal at high temperatures is essentially limited by its structure and is equal to the cage size. This model also shows good agreement with the results of experiments and molecular dynamics simulations. Based on this atomic-level model, the structural metrics of crystals with low or high lattice conductivity are discussed, and some strategies for thermal design and management are suggested.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87699/2/123507_1.pd

Enhanced nonradiative relaxation and photoluminescence quenching in random, doped nanocrystalline powders

Nonradiative relaxation and photoluminescence quenching in nanocrystalline powders doped with rare-earth elements are of interest in optical bistability, random laser, and other optoelectronic applications. Here, the luminescence quenching of a one-dimensional random medium made of multilayer nanoparticles (Y2O3)(Y2O3) doped with rare-earth elements (Yb3+)(Yb3+) is analyzed by considering the transport, transition, and interaction of the fundamental energy carriers. The nonradiative decay and luminescence quenching in random media are enhanced compared to single crystals, due to multiple scattering, enhanced absorption, and low thermal conductivity. The coherent wave treatment is used to calculate the photon absorption, allowing for field enhancement and photon localization. The luminescent and thermal emission is considered as incoherent. The size-dependent absorption coefficient and penetration depth are observed. The nonradiative decay is identified as a multiphonon relaxation process, and is found to be enhanced compared to bulk materials. The luminescence quenching and nonlinear thermal emission, occurring with increasing irradiation intensity, are predicted.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87544/2/104331_1.pd

An improved analytic solution for analysis of particle trajectories in fibrous, two‐dimensional filters

The Kuwabara solution for creeping fluid flow through periodic arrangement of cylinders is widely used in analytic and numerical studies of fibrous filters. Numerical solutions have shown that the Kuwabara solution has systematic errors, and when used for the particle trajectories in filters it results in some error in the predicted filter efficiency. The numerical solutions, although accurate, preclude further analytic treatments, and are not as compact and convenient to use as the Kuwabara solution. By reexamining the outer boundary conditions of the Kuwabara solution, a correction term to the Kuwabara solution has been derived to obtain an extended solution that is more accurate and improves prediction of the filter efficiency. By comparison with the numerical solutions, it is shown that the Kuwabara solution is the high porosity asymptote, and that the extended solution has an improved porosity dependence. A rectification is explained that can make particle collection less efficient for periodic, in‐line arrangements of fibers with particle diffusion or body force. This rectification also results in the alignment of particles with inertia (i.e., high Stokes number particles).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70636/2/PHFLE6-6-2-507-1.pd

Thermoelectric performance of films in the bismuth-tellurium and antimony-tellurium systems

Coevaporated bismuth-tellurium and antimony-tellurium films were fabricated under various deposition conditions (controlled evaporation rates of individual species, substrate temperature, and substrate material), and their thermoelectric (TE) properties (Seebeck coefficient, electrical resistivity, and carrier concentration) were measured in search of optimal TE performance. The tellurium atomic concentration was varied from 48% to 74%, the substrate temperature ranged from 130 to 300 °C, and glass, mica, magnesium oxide, and sapphire substrates were used. The chemical composition and crystal structure of the films were recorded (using microprobe and x-ray diffractometer, respectively), analyzed, and compared with available standard Bi2Te3Bi2Te3 and Sb2Te3Sb2Te3 single-crystal samples. High-performance TE films had tellurium atomic concentration around 60% and were deposited at a substrate temperature between 260 and 270 °C.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87588/2/114903_1.pd

Boundary-layer treatment of film condensation in the presence of a solid matrix

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26163/1/0000240.pd

Discharge rate of cryogens in microgravity - What ground based experimentation cannot resolve

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76407/1/AIAA-1991-3545-390.pd

Non-Darcian effects on natural convection in porous media confined between horizontal cylinders

The inertia, boundary and velocity-square terms, normally not included in the flow analysis, are included in the study of natural convection between isothermal, concentric cylinders (inner cylinder heated) filled with saturated, porous media. The results show that all of these effects reduce the heat transfer rate with the boundary term being the most significant. It is shown that since at high Rayleigh numbers the flow adjacent to the confining walls becomes of boundary-layer type, with a very thin sublayer over which the velocity reaches its maximum value, then as long as the contribution of the velocity-square term is small, Darcy's model holds for very large Rayleigh and Prandtl numbers. A flow regime diagram showing the pseudo-conduction, Darcy and non-Darcy regimes, is given.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26039/1/0000112.pd