Anaphylaxis from administration of intravenous thiamine

The routine administration of intravenous thiamine in the emergency department has become widespread. Although anaphylaxis from intravenous thiamine is felt to be uncommon, it can be life threatening. The authors present such a case and review the literature regarding this clinical entity. This case of anaphylactic reaction appears to be the first instance reported since 1946 in the US literature. However a review revealed that cases of anaphylaxis from thiamine have been reported with some regularity in the non-US literature. Given the large number of patients treated without side effects, it seems that thiamine is relatively safe. However, this case illustrates that the assumption that thiamine is a drug with a completely innocuous nature is not totally accurate.

The relationship between body mass index and quality of life in community-living older adults living in the United States

BACKGROUND

Carrying excess weight is associated with various chronic conditions especially in older adults, and can have a negative influence on the quality of life of this population.

OBJECTIVE

The objective of this study was to estimate the independent (i.e. adjusted for demographic, socioeconomic and health status differences) impact of Body Mass Index (BMI) on health-related quality of life.

DESIGN

A mail survey was sent to 60,000 older adults living in 10 states.

METHODS

The survey assessed quality of life using the average physical component scores (PCS) and mental component scores (MCS) obtained from the Veterans Rand 12-item (VR-12) health status tool embedded in the survey. Ordinary least squares (OLS) regression techniques were used to estimate the independent impact of each BMI category on quality of life, compared to the impact of other chronic conditions.

RESULTS

A total of 22,827 (38%) eligible sample members responded to the survey. Of those, 2.2% were underweight, 38.5% had a normal BMI, 37.0% were overweight, 18.5% were obese and 1.9% were morbidly obese. Following OLS regression techniques, respondents' PCS values were statistically significantly lower for the underweight, overweight, obese and morbidly obese BMI categories, compared to the normal BMI group. Compared with all other chronic conditions, being morbidly obese (-6.0 points) had the largest negative impact on the PCS. Underweight was the only BMI category with a statistically significantly lower MCS value.

CONCLUSIONS

The greatest negative impacts of the various BMI categories on quality of life were on physical rather than mental aspects, especially for those in the underweight, obese and morbidly obese categories, more so than many other chronic conditions.

Scrotal temperature in spinal cord injury

Twenty-five spinal cord-injured (SCI) males and 25 normal volunteers were studied for their scrotal and thigh temperatures by using contact liquid crystal thermography. The initial temperature was recorded after transfer and disrobing which took about 2 minutes. Later temperature was recorded 10 minutes after exposing the genitalia to room air (20-22 degrees C). The initial scrotal and thigh temperatures of SCI subjects were significantly higher than those of normal volunteers (32.8 +/- 0.8 degrees C v 31.6 +/- 0.4 degrees C; 32.9 +/- 0.8 degrees C v 31.7 +/- 0.4 degrees C, respectively, P < 0.001), although their rectal temperatures were not different. The scrotal and thigh hyperthermia of SCI subjects disappeared after 10 minutes of exposure to room air. There was no significant difference between scrotal and thigh temperatures in either the SCI subjects or the normal volunteers in the later temperature reading. Sitting in a wheelchair for 2 hours results in an increase of average 0.8 degrees C of scrotal and thigh temperature in five normal volunteers. Our study suggests that scrotal hyperthermia of SCI subjects is mainly the result of local factors such as a prolonged sitting position, adduction of the thighs, the cushion's insulating effect and infrequent movement of the buttocks. Adequate ventilation of the scrotal area can overcome the impaired scrotal heat dissipation of SCI subjects. Liquid crystal thermography is a useful, noninvasive method for detecting hyperthermia in SCI subjects.

Disruption of Lipid Raft Function Increases Expression and Secretion of Monocyte Chemoattractant Protein-1 in 3T3-L1 Adipocytes

The adipocyte is unique in its capacity to store lipids. In addition to triglycerides, the adipocyte stores a significant amount of cholesterol. Moreover, obese adipocytes are characterized by a redistribution of cholesterol with depleted cholesterol in the plasma membrane, suggesting that cholesterol perturbation may play a role in adipocyte dysfunction. We used methyl-β-cyclodextrin (MβCD), a molecule with high affinity for cholesterol, to rapidly deplete cholesterol level in differentiated 3T3-L1 adipocytes. We tested whether this perturbation altered adipocyte secretion of monocyte chemoattractant protein-1 (MCP-1), a chemokine that is elevated in obesity and is linked to obesity-associated chronic diseases. Depletion of cholesterol by MβCD increased MCP-1 secretion as well as the mRNA and protein levels, suggesting perturbation at biosynthesis and secretion. Pharmacological inhibition revealed that NF-κB, but not MEK, p38 and JNK, was involved in MβCD-stimulated MCP-1 biosynthesis and secretion in adipocytes. Finally, another cholesterol-binding drug, filipin, also induced MCP-1 secretion without altering membrane cholesterol level. Interestingly, both MβCD and filipin disturbed the integrity of lipid rafts, the membrane microdomains enriched in cholesterol. Thus, the depletion of membrane cholesterol in obese adipocytes may result in dysfunction of lipid rafts, leading to the elevation of proinflammatory signaling and MCP-1 secretion in adipocytes.

Beaming light from a subwavelength metal slit surrounded by dielectric surface gratings

In this article, we demonstrate that a subwavelength metal slit surrounded by dielectric surface gratings possesses a directional beaming effect. We propose a surface plasmon diffraction scheme to explain the three kinds of beaming conditions. The numerical simulations of the illustrative structures undertaken used a Finite Difference Time Domain (FDTD) Method and a Rigorous Coupled Wave Analysis (RCWA) Method. Our simulations were found to be consistent and in agreement with the experimental results. In comparison with other metal structures, we find that dielectric metal structures offer better performance as well as the advantage of being able to be efficiently mass produced for large volume industrial applications.

Formation and photodissociation of M(+)-C(6)H(6) (M(+) = V(+) and Ta(+)) and Ta(+)-C(6)H(4) complexes in a time-of-flight mass spectrometer

A series of cyclic hydrocarbons were introduced to react with V(+) and Ta(+) using a pulsed beam expansion source in a time-of-flight mass spectrometer. The third-row metal Ta(+) displayed high reactivity in dehydrogenation to form benzyne complexes, whereas benzene complexes were the terminal products for V(+). M(+)-C(6)H(6) (M(+) = V(+) and Ta(+)) and Ta(+)-C(6)H(4) were selected to perform the photodissociation experiments. In contrast to the V(+) fragment formation via simple cleavage of the V(+)-C(6)H(6) bond, a photoinduced loss of C(2)H(2) occurred in both the Ta(+)-C(6)H(6) and Ta(+)-C(6)H(4) complexes. Plausible explanations involved in the formation of Ta(+)-C(6)H(6) and Ta(+)-C(6)H(4) complexes are given for observing such photo-induced dissociation. The observed photodissociation in Ta(+)-C(6)H(6) is analogous to the dissociative process previously investigated in metal ion-molecule reactions. The photodissociation spectrum of Ta(+)-C(6)H(4) was obtained by recording the appearance of Ta(+)-C(4)H(2) as a function of wavelength and yielded a dissociation energy of 91 +/- 1 kcal mol(-1).

Rapid diagnosis of tuberculosis directly from clinical specimens using a gene chip

The aim of this study was to explore a gene chip capable of detecting the presence of Mycobacterium tuberculosis isolates directly in clinical sputum specimens and to compare it with current molecular detection techniques. At first, we selected 13 M. tuberculosis-specific target genes to construct a gene chip for rapid diagnosis. Using the membrane array method, we diagnosed M. tuberculosis by gene chip directly from 246 sputum specimens from patients suspected of having tuberculosis. Among 80 M. tuberculosis complex (MTBC) culture-positive sputum specimens, the MTBC detection rate was 62.5% (50/80) by PCR-restriction fragment length polymorphism (RFLP), 70% (56/80) by acid-fast staining, and 85% (68/80) by the membrane array method. Furthermore, subspecies showed different gene expression patterns in the membrane array. In conclusion, MTBC could be detected directly in sputum by the membrane array method. The rapidity of detection and the capability of differentiating subspecies could make this method useful in the control and prevention of tuberculosis.

Integrated photonic coupler based on frustrated total internal reflection

An optical coupler for integrated photonic circuits is presented and analyzed. The coupler is based on frustrated total internal reflection (FTIR) and offers high efficiency in a compact footprint. Analytic expressions for the transmission and reflection coefficients of the coupler are obtained using a plane-wave theory and experimentally verified. Finite-difference time-domain modeling of FTIR is discussed and modeling results of the coupler are presented. A parametric discussion of the FTIR coupler provides design tools for making 3 dB couplers.

Recording Bessel-like beam shapes generated by plasmonics lens

In our study, we spun a negative photoresist layer on top of a plasmonic lens which was formed by adopting a metallic ring structure with a nano-scale width opening. We recorded the beam shape of the Bessel-like beam emitting from the plasmonic lens which formed a high aspect ratio structure. We found that the high aspect ratio structure was higher after exposure as the inner and outer diameter had increased. In addition, we used an oblique incidence on the negative resist metallic ring structure to produce an inclined micro-structure. Different exposure results were obtained with the two different metal thicknesses. Therefore, in our study, we not only proved that it is possible to record the shape of a Bessel-like beam, but we also demonstrated that it is possible to create a plasmonic lens which is capable of creating a high aspect ratio structure through exposure.

Similarities and differences for light-induced surface plasmons in one- and two-dimensional symmetrical metallic nanostructures

Two types of double-sided nanostructure, one possessing a slit aperture with parallel grooves and the other possessing a circular aperture with concentric grooves, were fabricated to examine the similarities and differences of their diffraction behavior in one-dimensional (1-D) and two-dimensional (2-D) nanostructures. Based on the projection-slice theory, we conjecture that the surface plasmons in these two different nano-scale grooves possess similar modes. A localized surface plasmon (LSP) was used to examine the transmission characteristics induced by the apertures. The transmission characteristics of the slitted nanostructure and the circular nanostructure aperture were then measured. We coupled the transmission spectra measured from these two apertures with a 1-D parallel groove transmission curve simulated by a 1-D rigorous coupled wave analysis. Measured spectra results show reasonable agreement with the simulated data. We propose that the apparent blueshift observed in the peak frequency of a 2-D nanostructure is due to the difference in the shape of the aperture and the spot transmission characteristics of 1-D and 2-D systems as induced by a LSP.

Simulation and fabrication of subwavelength structures for a nanometer feature enabling lens-less laser writers

A set-up was proposed to propagate submicrometer light beams without resorting to the conventional approach of using a lens. The main target was to develop a method of either by passing or circumventing the diffraction limit to develop a new optical head for a laser writer system with submicrometer resolution. Starting from using surface plasma theory to explain the mechanism of extraordinary transmission phenomenon, we move to discuss the fabrication processes for free-standing metal films and the corresponding transmission light beam images in the far field. A finite difference time domain (FDTD) method was adopted to simulate the electromagnetic field distribution of transmission light beams from the near field to the far field. The experimental results confirm that surface structures on the incident side of incoming light beams can excite surface plasma and enhance the throughput energy of transmission light beams. In addition, we also established that surface structures on the exit side can suppress the diffraction effect and make transmission light beams directional. The experimental and simulation results were found to agree well with each other, which validates the effectiveness of the FDTD simulation approach. As a free-standing film was too fragile to be of practical use, a proposition to develop a substrate-based nanostructured film to ease the construction of an optical head for a laser writer was developed.

Enhancing intensity of emitted light from a ring by incorporating a circular groove

We fabricated a ring containing a single circular groove (RCG) on silver film and which was supported on a glass substrate. We found that by changing the mean radius of the circular groove, the light intensity emitted from the RCG can be modulated by using the scattering light from the circular groove. In addition, we also fabricated circular grooves with the same depth but of different widths so that we could examine the scattering light behavior of the grooves. Herein, we propose a theoretical model which takes into account the amplitude modulation of the cylindrical waves. Our results showed that our proposed model agreed well with the experimental results.