Revisiting early hypothyroidism screening in infants with Down syndrome

OBJECTIVE

To identify if the incidence of hypothyroidism in infants with Down syndrome is higher than previous childhood estimates (15%) when examined prior to the standard retesting at 6 months of age.

STUDY DESIGN

A retrospective observational cohort study of 122 children with Down syndrome admitted to a university-based birthing hospital between May 2000 and March 2012. Demographic data (for example, date of birth, gender, gestational age, inborn) and diagnostic data (Down syndrome, congenital heart disease and gastrointestinal disease) were cross-linked with thyroid hormone laboratory tests (total thyroxine, free thyroxine and thyroid stimulating hormone) to determine incidence of identified hypothyroidism and thyroid testing prior to 4 months of age (n=80).

RESULT

In all, 32.5% were found to have any hypothyroidism. Of these, 14 were primary hypothyroidism (17.5%) needing supplemental T4 therapy, 12 were compensated hypothyroidism (15%) and euthyroid was identified in 54 infants (67.5%).

CONCLUSION

Despite normal newborn screens, the incidence of any hypothyroidism (early compensated hypothyroidism and primary hypothyroidism) was higher than previously reported.

Grain Orientation and Strain Measurements in Sub-Micron wide Passivated Individual Aluminum Test Structures

An X-ray microdiffraction dedicated beamline, combining white and monochromatic beam capabilities, has been built at the Advanced Light Source. The purpose of this beamline is to address the myriad problems in Materials Science and Physics that require submicron x-ray beams for structural characterization. Many such problems are found in the general area of thin films and nano-materials. For instance, the ability to characterize the orientation and strain state in individual grains of thin films allows us to measure structural changes at a very local level. These microstructural changes are influenced heavily by such parameters as deposition conditions and subsequent treatment. The accurate measurement of strain gradients at the micron and sub-micron level finds many applications ranging from the strain state under nano-indenters to gradients at crack tips. Undoubtedly many other applications will unfold in the future as we gain experience with the capabilities and limitations of this instrument. We have applied this technique to measure grain orientation and residual stress in single grains of pure Al interconnect lines and preliminary results on post-electromigration test experiments are presented. It is shown that measurements with this instrument can be used to resolve the complete stress tensor (6 components) in a submicron volume inside a single grain of Al under a passivation layer with an overall precision of about 20 MPa. The microstructure of passivated lines appears to be complex, with grains divided into identifiable subgrains and noticeable local variations of both tensile/compressive and shear stresses within single grains.

Microtexture and Strain in Electroplated Copper Interconnects

The microstructure of narrow metal conductors in the electrical interconnections on IC chips has often been identified as of major importance in the reliability of these devices. The stresses and stress gradients that develop in the conductors as a result of thermal expansion differences in the materials and of electromigration at high current densities are believed to be strongly dependent on the details of the grain structure. The present work discusses new techniques based on microbeam x-ray diffraction (MBXRD) that have enabled measurement not only of the microstructure of totally encapsulated conductors but also of the local stresses in them on a micron and submicron scale. White x-rays from the Advanced Light Source were focused to a micron spot size by Kirkpatrick-Baez mirrors. The sample was stepped under the micro-beam and Laue images obtained at each sample location using a CCD area detector. Microstructure and local strain were deduced from these images. Cu lines with widths ranging from 0.8 [.proportional]m to 5 [.proportional]m and thickness of 1 [.proportional]m were investigated. Comparisons are made between the capabilities of MBXRD and the well established techniques of broad beam XRD, electron back scatter diffraction (EBSD) and focused ion beam imagining (FIB).

Photon and Ion Beam-Induced Chemistry of Palladium Acetate Films

Electrically conducting palladium features have been produced by laser and ion beam irradiation of thin palladium acetate films. The photothermal reaction induced by scanned continuous wave Ar+ laser irradiation leads to metal lines that may exhibit periodic structure. This results from repeated propagation of “explosive” reaction fronts generated by coupling of the heat from the absorbed laser radiation with the heat of the decomposition reaction of the film. In contrast, 2 MeV He+ ion irradiation produces smooth metallic-looking features that contain up to 20% of the original carbon and 5% of the original oxygen content of the film. Films irradiated with 2 MeV Ne+ ions contain slightly lower amounts of carbon and oxygen residues, but fully exposed thick films (0.90 μm) appear black rather than metallic silver. In addition to having significantly higher purity, the laser-written features have lower resistivities than the ion beam-irradiated features. Infrared spectroscopy of the ion beam-irradiated films as a function of dose indicates a progressive loss in intensity of the characteristics acetate (COO-) vibrations. This occurs at doses lower than those associated with major C and O loss from the films. Partially ion-exposed films continue to decompose to metallic-looking material over a period of weeks after irradiation. Metallic palladium particles apparently catalyze this process.

Collision Cascades, Ionization, Spikes And Energy Transfer

The collisions of an individual energetic ion in a solid set atoms of the solid in motion and excite electronic states. The moving atoms collide with others to form a collision cascade and the electronic excitation also forms a branched trail around the track of the ion. If the densities of the energy deposition in either of these modes is high the result is called a “spike”. The low density regimes of collision and ionization cascades and evidence for the transition to non-linear high density spikes are summarized. The understanding of the latter is still quite incomplete as is also understanding of the transfer of energy between the kinetic and the electronic modes, particularly at high energy densities.

Raman Spectroscopy of Size Selected, Matrix Isolated Si Clusters

We report results of Raman spectroscopy of size selected, matrix isolated Si clusters. Cluster ions produced by laser vaporization are size selected by a quadruple mass spectrometer and co-deposited with cryogenic matrices onto a substrate at ∼15K. A surface-plasmon-polariton-enhanced Raman geometry is used to gain adequate signal.

The observed vibrational frequencies from Si4, Si6 and Si7 are compared with theoretically calculated Raman active modes based on the structures of planar rhombus, distorted octahedron and pentagonal bipyramid, respectively. The agreement is excellent. Cluster agglomeration is observed when cluster concentrations exceed ∼0.3% by volume in the matrix and/or with annealing at ∼28K, below the temperature of matrix evaporation.

Microstructure and Texture of Electroplated Copper in Damascene Structures

The transition from Al to Cu for advanced ULSI interconnects involves changes in architecture and deposition technique that will influence the microstructure and texture of the metal. Cu interconnects are typically formed within the confines of pre-patterned trenches and vias using an electroplating process with a sputtered Cu conduction layer deposited over a refractory metalbased diffusion barrier layer. In this paper, we focus on the influence of the barrier layer (PVD Ti/TiN, Ta, TaN, CVD TiN) and the effect of a vacuum break between barrier and conduction layer depositions, on the texture of the Cu lines, as examined by X-ray diffraction pole figure analysis.

A preferred (111) orientation was observed for all samples. The samples with no vacuum break between barrier and conduction layer deposition exhibited in plane anisotropy that was particularly pronounced for the Ta and TaN samples compared with the Ti/TiN sample. Focused ion beam images and transmission electron micrographs showed Cu grain size to be on the order of the trench width with a high degree of twinning, and no boundary could be distinguished between the PVD Cu conduction layer and the electroplated Cu.

Mechanical Properties of Electroplated Copper Thin Films

It is well known that the mechanical properties of thin films depend critically on film thickness However, the contributions from film thickness and grain size are difficult to separate, because they typically scale with each other. In one study by Venkatraman and Bravman, Al films, which were thinned using anodic oxidation to reduce film thickness without changing grain size, showed a clear increase in yield stress with decreasing film thickness.

We have performed a similar study on both electroplated and sputtered Cu films by using chemical-mechanical polishing (CMP) to reduce the film thickness without changing the grain size. Stress-temperature curves were measured for both the electroplated and sputtered Cu films with thicknesses between 0.1 and 1.8 microns using a laser scanning wafer curvature technique. The yield stress at room temperature was found to increase with decreasing film thickness for both sets of samples. The sputtered films, however, showed higher yield stresses in comparison to the electroplated films. Most of these differences can be attributed to the different microstructures of the films, which were determined by focused ion beam (FIB) microscopy and x-ray diffraction.

Local plasticity of Al thin films as revealed by x-ray microdiffraction

Grain-to-grain interactions dominate the plasticity of Al thin films and establish effective length scales smaller than the grain size. We have measured large strain distributions and their changes under plastic strain in 1.5-microm-thick Al 0.5% Cu films using a 0.8-microm-diameter white x-ray probe at the Advanced Light Source. Strain distributions arise not only from the distribution of grain sizes and orientation, but also from the differences in grain shape and from stress environment. Multiple active glide plane domains have been found within single grains. Large grains behave like multiple smaller grains even before a dislocation substructure can evolve.

Scanning X-ray microdiffraction with submicrometer white beam for strain/stress and orientation mapping in thin films

Scanning X-ray microdiffraction (microSXRD) combines the use of high-brilliance synchrotron sources with the latest achromatic X-ray focusing optics and fast large-area two-dimensional-detector technology. Using white beams or a combination of white and monochromatic beams, this technique allows for the orientation and strain/stress mapping of polycrystalline thin films with submicrometer spatial resolution. The technique is described in detail as applied to the study of thin aluminium and copper blanket films and lines following electromigration testing and/or thermal cycling experiments. It is shown that there are significant orientation and strain/stress variations between grains and inside individual grains. A polycrystalline film when investigated at the granular (micrometer) level shows a highly mechanically inhomogeneous medium that allows insight into its mesoscopic properties. If the microSXRD data are averaged over a macroscopic range, results show good agreement with direct macroscopic texture and stress measurements.

Efficacy and durability of ultraviolet tints in CR-39 ophthalmic lenses

BACKGROUND

Ocular protection from solar ultraviolet (UV) radiation has been emphasized in recent years as a result of the thinning of the ozone layer in the atmosphere. The purpose of this study was to evaluate the absorptive properties of UV tints in CR-39 lenses.

METHODS

We used a spectrophotometer to measure the UV transmittance of three groups of UV tinted CR-39 lenses, including (1) lenses tinted by local optical laboratories: (2) lenses tinted by us, using commercially available dyes: and (3) stock UV lenses that have UV absorptive molecules throughout the lens. We also tested the durability of these tints to daily washing/drying by measuring their UV transmittance characteristics at 3, 6, and 12 months.

RESULTS

All the tested lenses absorbed all of the UV-B and at least 99% of UV-A. The durability of these UV tints when exposed to daily washing/drying was excellent: all lenses continued to absorb all of the UV-B and at least 99% of UV-A after 1 year.

CONCLUSIONS

These data suggest that UV tinted CR-39 lenses provide protection against UV radiation that meets the ANSI Z80.3-1996 Standard for non-prescription sunglasses and fashion eyewear. Furthermore, normal daily washing/drying for 1 year does not cause a significant decrease in the protective effect of the UV tint.

Cell-specific delivery of bacteriophage-encapsidated ricin A chain

We have used covalent coupling of deglycosylated ricin A chain (RAC) to the assembly initiation/translational repression RNA stem-loop (TR) of the bacteriophage MS2 to direct encapsulation of the toxin in bacteriophage capsids. Multiple copies of the TR-RAC conjugate can be incorporated into single capsid shells. The resultant particles can then be directed to specific cells by receptor-mediated endocytosis (RME) of complexes formed with anti-MS2 coat protein antibodies or by further covalent modification of the capsids by addition of human transferrin molecules. The results suggest that bacteriophage encapsulation and targeting is an efficient way to deliver toxins in a cell-specific fashion. The system may have widespread application in the field of targeted drug delivery, including antisense reagents.

Experience with early postcesarean hospital dismissal

OBJECTIVE

Our purpose was to assess early postcesarean hospital dismissal.

STUDY DESIGN

A retrospective review was performed of all women receiving cesarean delivery over the most recent 6-month period in a busy private obstetrics practice that routinely dismisses its cesarean patients on postoperative day 2. Women who meet certain criteria (uncomplicated pregnancy, Pfannenstiel incision, uncomplicated surgery, no febrile morbidity, stable vital signs, ability to ambulate without assistance, ability to urinate without assistance, and auscultation of active bowel sounds) on postoperative day 2 are dismissed from the hospital. Outcomes were compared against women undergoing cesarean delivery during the 6 months immediately before the institution of the early dismissal program.

RESULTS

Among 147 women undergoing cesarean deliveries, 117 (80%) met the criteria for early dismissal. When compared with controls (n = 93), there was no difference in outcomes. No one in the early dismissal group required readmission to the hospital.

CONCLUSION

Among properly selected candidates, early postcesarean hospital admission is a reasonable option.

Underrecognition of tardive dyskinesia and drug-induced parkinsonism by psychiatric residents

Recognition of tardive dyskinesia (TD) and other neuroleptic, drug-induced, extrapyramidal side effects presents a major challenge in modern clinical psychopharmacology. Failure to recognize these disorders can lead to poor patient care and may contribute to societal pressure for external control of psychiatric practice. This study reports the occurrence of tardive dyskinesia and drug-induced parkinsonism (DIP) in 101 inpatients, and documents underrecognition of both disorders by resident physicians. Researchers noted TD in 28% of cases and residents only described TD (or symptoms of TD) in 12%. The researcher determined DIP prevalence rate of 26% contrasted with an 11% rate found by residents. Patients with psychotic disorders were more likely than other patients to have researcher-identified TD, whereas DIP (researcher cases) occurred more often in patients with affective diagnoses. Residents tended to miss milder cases of TD, and to miss DIP in younger patients and in patients with affective disorders. Improved teaching and clinical exams are recommended to improve recognition.