Application of two-dimensional band-target entropy minimization to fluorescence data: implications for the recovery of patterns arising from only bilinear and not trilinear structures

Pattern recognition in two-dimensional (2D) spectroscopy, without recourse to spectral libraries, etc., has a number of important potential applications. In the present contribution, two blind source separation techniques (spectral reconstruction) are applied to sets of 2D fluorescence data possessing both Rayleigh scattering and Raman scattering. The two methods used are (1) two-dimensional band-target entropy minimization (2D-BTEM), which models data as a bilinear form (in terms of a weighted sum of 2D patterns) and (2) parallel factor analysis (PARAFAC), which models data as a trilinear form. In addition, an a priori estimate of the number of patterns present is not required by 2D-BTEM but is required in PARAFAC. Both 2D-BTEM and PARAFAC are successfully applied to the real three-component data, and good 2D spectral reconstructions of the three amino acids are achieved. Moreover, 2D-BTEM was also able to recover the 2D Raman scattering directly, whereas PARAFAC did not recover the 2D Raman scatter (the Raman scatter does not possess a trilinear form). The present results suggest that 2D-BTEM can be useful in a wide range of spectroscopic applications for the recovery of underlying 2D patterns.     

Remote monitoring of a multi-component liquid-phase organic synthesis by infrared emission spectroscopy: the recovery of pure component emissivities by band-target entropy minimization

A liquid-phase cycloaddition reaction near ambient temperature involving dimethyl acetylenedicarboxylate (DMAD) and cyclopentadiene (CP) as reactants was measured using a conventional Fourier transform infrared (FT-IR) spectrometer with an emission accessory. Two semi-batch experiments were performed and a total of 55 spectra were collected using a DTGS detector. Band-target entropy minimization (BTEM), a pure component spectral reconstruction technique, was applied to analyze the data set to retrieve the pure component emission spectrum from the reaction system. The estimated emission spectra of the solvent chloroform, DMAD, CP, and product, namely dimethyl bicyclo[2.2.1]-2,5-heptadiene-2,3-dicarboxylate, were all reconstructed with rather good quality. The estimated emission spectra are similar to independent FT-IR spectra of the same cycloaddition reaction. Using a least squares fit, the relative concentration profiles of the species are obtained. Because this appears to be the first time that a liquid-phase reaction has been monitored by infrared emission spectroscopy, further improvements and opportunities for general multi-phase liquid reaction monitoring are discussed.     

Fast Photolytic Release of Nano-Encapsulated Biocides for Neutralizing Bacteria

A fast-triggered photolytic technology based on the on-demand release of biocides encapsulated within phospholipid nanoparticles has been developed for the neutralization of biological contaminants such as bacteria. Fast-triggered release occurs when light sensitive molecules (photosensitizers) embedded within phospholipid particles are triggered by an external light stimulus. The photo-induced oxidation due to the stimulus causes the lipid chains to break and rapidly release their contents. When the phospholipid carriers are loaded with strong biocides, the fast-triggered release can result in the neutralization of biological contaminants in a controlled environment. It was observed that a 98% release of biocides was achieved in 12 min and 68% release achieved in 2 min through photo-induced oxidation. This method of release of biocides potentially can offer a technology for rapid decontamination inside heating, ventilation and air conditioning (HVAC) systems and surfaces such as walls, windows, etc. Moreover, biocide loaded phospholipid particles could be released as aerosols for neutralizing airborne bacteria and other biological contaminants. The appropriate choice of biocides can enable potential use in first-responder type situations and the automatic remote neutralization following bacterial contamination of air ducts or surfaces.     

Correlation of arsenic incorporation and its electrical activation in MBE HgCdTe

The behavior of arsenic for p-type doping of MBE HgCdTe layers has been studied for various annealing temperatures and arsenic doping concentrations. We have demonstrated that arsenic is in-situ incorporated into HgCdTe layers during MBE growth. The carrier concentration has been measured by the Van der Pauw technique, and the total arsenic concentration has been determined by secondary ion mass spectroscopy. After annealing at 250°C under an Hg over pressure, As-doped HgCdTe layers show highly compensated n-type properties and the carrier concentration is approximately constant (∼mid 10¹⁵ cm⁻³) until the total arsenic concentration in the HgCdTe layers approach mid 10¹⁷ cm⁻³. The source of n-type behavior does not appear to be associated with arsenic dopants, such as arsenic atoms occupying Hg vacancy sites, but rather unidentified structural defects acting as donors. When the total arsenic concentration is above mid 10¹⁷ cm⁻³, the carrier concentration shows a dependence on the arsenic concentration while remaining n-type. We conjecture that the increase in n-type behavior may be due to donor arsenic tetramers or donor tetramer clusters. Above a total arsenic concentration of 1∼2×10¹⁸ cm⁻³, after annealing at 300°C, the arsenic acceptor activation ratio rapidly decreases below 100% with increasing arsenic concentration and is smaller than that after annealing at 450°C. The electrically inactive arsenic is inferred to be in the form of neutral arsenic tetramer clusters incorporated during the MBE growth. Annealing at 450°C appears to supply enough thermal energy to break some of the bonds of neutral arsenic tetramer clusters so that the separated arsenic atoms could occupy Te sites and behave as acceptors. However, the number of arsenic atoms on Te sites is saturated at ∼2×10¹⁸ cm⁻³, possibly due to a limitation of its solid solubility in HgCdTe.     

Extremity fractures in the patient with a traumatic brain injury

Extremity fractures are common in patients with traumatic brain injuries (TBIs). These injuries are often inadequately treated and occasionally are completely missed due to the unique problems inherent to the TBI patient. However, appropriate evaluation of the TBI patient allows prompt diagnosis and optimal treatment of extremity fractures. The increased survival rate of these patients has resulted in a greater emphasis on minimizing dysfunction and disability, especially that due to concomitant orthopaedic trauma. Advances in anesthestic technique permit earlier operative fixation of extremity fractures. Most injuries, particularly those in the lower extremity, require operative stabilization to allow early mobilization and rehabilitation. Upper extremity fractures are often associated with peripheral nerve injuries. Heterotopic ossification is common, especially about the elbow and hip. Contrary to prevalent belief, fracture healing is not necessarily accelerated in the TBI patient; hypertrophic callus, myositis ossificans, and heterotopic ossification occur frequently and are often misperceived as accelerated healing.     

Perceived attractiveness as a function of support for the feminist movement: Not necessarily a put-down of women.

Conducted 2 studies to replicate and extend the findings of P. A. Goldberg et al (see record 1975-27508-001) that Ss identified photos of unattractive women significantly more frequently than those of attractive women as being supporters of the women's liberation movement. In Study 1, photos were taken of 30 undergraduate women between the ages of 18 and 22 yrs and of 30 nonstudent women over the age of 25 yrs; these women were identified as supporters or nonsupporters of the feminist movement according to their scores on the Attitudes Toward Women Scale. Ratings of the physical attractiveness of the photographed women were made by 40 university students and by 40 nonstudents over age 25 yrs. Results show that such ratings were not related to the attitude scores of the photographed women. In Study 2, 40 additional college students and 40 additional nonstudents were given the same task with similar stimuli. Results show no significant difference between the mean attractiveness score of those women selected as supporters and those selected as nonsupporters, thus failing to replicate the findings of Goldberg et al. Male undergraduates, however, did choose photographs of less attractive women as members of the feminist movement, whereas female undergraduates chose photos of more attractive women. Neither male nor female nonstudents chose differently than chance. (French summary) (3 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)