Finger Test for the Diagnosis of a Critically Ill Patient with Necrotizing Fasciitis.

BACKGROUND: Necrotizing fasciitis is a life-threatening soft-tissue infection, often characterized by soft-tissue destruction, systemic toxicity, and high mortality. No single laboratory value can diagnose necrotizing fasciitis; ultimately, necrotizing fasciitis is a clinical diagnosis and therefore presents a diagnostic dilemma for many physicians. The finger probe test is useful in confirming the diagnosis when imaging studies are unobtainable or nondiagnostic. CASE REPORT: We present the case of a 70-year-old woman presenting nonverbal and obtunded with a soft-tissue infection of the right lower extremity. The only pertinent positive vital sign was tachypnea with a respiratory rate of 22 breaths/min. Physical examination revealed nonpitting edema, cold-to-touch lower extremity, and Nikolsky-positive hemorrhagic bullae. Initial laboratory test results showed white blood cell count of 38 x 109/L and lactic acid of 8.2 mg/dL. Advanced imaging was unobtainable, given the patient's worsening clinical status, and the decision was made to perform the finger probe test, which revealed absence of bleeding and presence of friable tissue and "dishwater" discharge. Consequently, the general surgery team took the patient to the operating room and performed an above-the-knee amputation and surgical debridement. Postoperative report noted nonviable tissue consistent with necrotizing fasciitis. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Necrotizing fasciitis is a life-threatening emergency that can destroy soft-tissue at a rate of 1 inch/h. When imaging is unobtainable or nondiagnostic, the finger probe test can be used in select patients to aid with diagnosis.

Zinc oxide clad limited area epitaxy semipolar III-nitride laser diodes.

We report continuous-wave (CW) blue semipolar (202¯1) III-nitride laser diodes (LDs) that incorporate limited area epitaxy (LAE) n-AlGaN bottom cladding with thin p-GaN and ZnO top cladding layers. LAE mitigates LD design limitations that arise from stress relaxation, while ZnO layers reduce epitaxial growth time and temperature. Numerical modeling indicates that ZnO reduces the internal loss and increases the differential efficiency of TCO clad LDs. Room temperature CW lasing was achieved at 445 nm for a ridge waveguide LD with a threshold current density of 10.4 kA/cm2, a threshold voltage of 5.8 V, and a differential resistance of 1.1 Ω.

Development of high performance green c-plane III-nitride light-emitting diodes.

The effect of employing an AlGaN cap layer in the active region of green c-plane light-emitting diodes (LEDs) was studied. Each quantum well (QW) and barrier in the active region consisted of an InGaN QW and a thin Al0.30Ga0.70N cap layer grown at a relatively low temperature and a GaN barrier grown at a higher temperature. A series of experiments and simulations were carried out to explore the effects of varying the Al0.30Ga0.70N cap layer thickness and GaN barrier growth temperature on LED efficiency and electrical performance. We determined that the Al0.30Ga0.70N cap layer should be around 2 nm and the growth temperature of the GaN barrier should be approximately 75° C higher than the growth temperature of the InGaN QW to maximize the LED efficiency, minimize the forward voltage, and maintain good morphology. Optimized Al0.30Ga0.70N cap growth conditions within the active region resulted in high efficiency green LEDs with a peak external quantum efficiency (EQE) of 40.7% at 3 A/cm2. At a normal operating condition of 20 A/cm2, output power, EQE, forward voltage, and emission wavelength were 13.8 mW, 29.5%, 3.5 V, and 529.3 nm, respectively.

Semipolar III-nitride laser diodes with zinc oxide cladding.

Incorporating transparent conducting oxide (TCO) top cladding layers into III-nitride laser diodes (LDs) improves device design by reducing the growth time and temperature of the p-type layers. We investigate using ZnO instead of ITO as the top cladding TCO of a semipolar (202¯1) III-nitride LD. Numerical modeling indicates that replacing ITO with ZnO reduces the internal loss in a TCO clad LD due to the lower optical absorption in ZnO. Lasing was achieved at 453 nm with a threshold current density of 8.6 kA/cm2 and a threshold voltage of 10.3 V in a semipolar (202¯1) III-nitride LD with ZnO top cladding.

Using tunnel junctions to grow monolithically integrated optically pumped semipolar III-nitride yellow quantum wells on top of electrically injected blue quantum wells.

We report a device that monolithically integrates optically pumped (20-21) III-nitride quantum wells (QWs) with 560 nm emission on top of electrically injected QWs with 450 nm emission. The higher temperature growth of the blue light-emitting diode (LED) was performed first, which prevented thermal damage to the higher indium content InGaN of the optically pumped QWs. A tunnel junction (TJ) was incorporated between the optically pumped and electrically injected QWs; this TJ enabled current spreading in the buried LED. Metalorganic chemical vapor deposition enabled the growth of InGaN QWs with high radiative efficiency, while molecular beam epitaxy was leveraged to achieve activated buried p-type GaN and the TJ. This initial device exhibited dichromatic optically polarized emission with a polarization ratio of 0.28. Future improvements in spectral distribution should enable phosphor-free polarized white light emission.

Gigabit-per-second white light-based visible light communication using near-ultraviolet laser diode and red-, green-, and blue-emitting phosphors.

Data communication based on white light generated using a near-ultraviolet (NUV) laser diode (LD) pumping red-, green-, and blue-emitting (RGB) phosphors was demonstrated for the first time. A III-nitride laser diode (LD) on a semipolar (2021¯)  substrate emitting at 410 nm was used for the transmitter. The measured modulation bandwidth of the LD was 1 GHz, which was limited by the avalanche photodetector. The emission from the NUV LD and the RGB phosphor combination measured a color rendering index (CRI) of 79 and correlated color temperature (CCT) of 4050 K, indicating promise of this approach for creating high quality white lighting. Using this configuration, data was successfully transmitted at a rate of more than 1 Gbps. This NUV laser-based system is expected to have lower background noise from sunlight at the LD emission wavelength than a system that uses a blue LD due to the rapid fall off in intensity of the solar spectrum in the NUV spectral region.

Photoelectrochemical liftoff of LEDs grown on freestanding c-plane GaN substrates.

We demonstrate a thin-film flip-chip (TFFC) process for LEDs grown on freestanding c-plane GaN substrates. LEDs are transferred from a bulk GaN substrate to a sapphire submount via a photoelectrochemical (PEC) undercut etch. This PEC liftoff method allows for substrate reuse and exposes the N-face of the LEDs for additional roughening. The LEDs emitted at a wavelength of 432 nm with a turn on voltage of ~3 V. Etching the LEDs in heated KOH after transferring them to a sapphire submount increased the peak external quantum efficiency (EQE) by 42.5% from 9.9% (unintentionally roughened) to 14.1% (intentionally roughened).

High luminous flux from single crystal phosphor-converted laser-based white lighting system.

The efficiency droop of light emitting diodes (LEDs) with increasing current density limits the amount of light emitted per wafer area. Since low current densities are required for high efficiency operation, many LED die are needed for high power white light illumination systems. In contrast, the carrier density of laser diodes (LDs) clamps at threshold, so the efficiency of LDs does not droop above threshold and high efficiencies can be achieved at very high current densities. The use of a high power blue GaN-based LD coupled with a single crystal Ce-doped yttrium aluminum garnet (YAG:Ce) sample was investigated for white light illumination applications. Under CW operation, a single phosphor-converted LD (pc-LD) die produced a peak luminous efficacy of 86.7 lm/W at 1.4 A and 4.24 V and a peak luminous flux of 1100 lm at 3.0 A and 4.85 V with a luminous efficacy of 75.6 lm/W. Simulations of a pc-LD confirm that the single crystal YAG:Ce sample did not experience thermal quenching at peak LD operating efficiency. These results show that a single pc-LD die is capable of emitting enough luminous flux for use in a high power white light illumination system.

High luminous efficacy green light-emitting diodes with AlGaN cap layer.

We demonstrate very high luminous efficacy green light-emitting diodes employing Al0.30Ga0.70N cap layer grown on patterned sapphire substrates by metal organic chemical vapor deposition. The peak external quantum efficiency and luminous efficacies were 44.3% and 239 lm/w, respectively. At 20 mA (20 A/cm2) the light output power was 14.3 mW, the forward voltage was 3.5 V, the emission wavelength was 526.6 nm, and the external quantum efficiency was 30.2%. These results are among the highest reported luminous efficacy values for InGaN based green light-emitting diodes.

4 Gbps direct modulation of 450 nm GaN laser for high-speed visible light communication.

We demonstrate high-speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high-speed visible light communication setup. Record high 4 Gbps free-space data transmission rate was achieved at room temperature.

2 Gbit/s data transmission from an unfiltered laser-based phosphor-converted white lighting communication system.

We demonstrate data transmission of unfiltered white light generated by direct modulation of a blue gallium nitride (GaN) laser diode (LD) exciting YAG:Ce phosphors. 1.1 GHz of modulation bandwidth was measured without a limitation from the slow 3.8 MHz phosphor response. A high data transmission rate of 2 Gbit/s was achieved without an optical blue-filter using a non-return-to-zero on-off keying (NRZ-OOK) modulation scheme. The measured bit error rate (BER) of 3.50 × 10(-3) was less than the forward error correction (FEC) limit of 3.8 × 10(-3). The generated white light exhibits CIE 1931 chromaticity coordinates of (0.3628, 0.4310) with a color rendering index (CRI) of 58 and a correlated color temperature (CCT) of 4740 K when the LD was operated at 300 mA. The demonstrated laser-based lighting system can be used simultaneously for indoor broadband access and illumination applications with good color stability.

Surface structured optical coatings with near-perfect broadband and wide-angle antireflective properties.

Optical thin-film coatings are typically limited to designs where the refractive index varies in only a single dimension. However, additional control over the propagation of incoming light is possible by structuring the other two dimensions. In this work, we demonstrate a three-dimensional surface structured optical coating that combines the principles of thin-film optical design with bio-inspired nanostructures to yield near-perfect antireflection. Using this hybrid approach, we attain average reflection losses of 0.2% on sapphire and 0.6% on gallium nitride for 300-1800 nm light. This performance is maintained to very wide incidence angles, achieving less than 1% reflection at all measured wavelengths out to 45° for sapphire. This hybrid design has the potential to significantly enhance the broadband and wide-angle properties for a number of optical systems that require high transparency.

Genes responding to water deficit in apple (Malus × domestica Borkh.) roots.

BACKGROUND: Individual plants adapt to their immediate environment using a combination of biochemical, morphological and life cycle strategies. Because woody plants are long-lived perennials, they cannot rely on annual life cycle strategies alone to survive abiotic stresses. In this study we used suppression subtractive hybridization to identify genes both up- and down-regulated in roots during water deficit treatment and recovery. In addition we followed the expression of select genes in the roots, leaves, bark and xylem of 'Royal Gala' apple subjected to a simulated drought and subsequent recovery. RESULTS: In agreement with studies from both herbaceous and woody plants, a number of common drought-responsive genes were identified, as well as a few not previously reported. Three genes were selected for more in depth analysis: a high affinity nitrate transporter (MdNRT2.4), a mitochondrial outer membrane translocase (MdTOM7.1), and a gene encoding an NPR1 homolog (MpNPR1-2). Quantitative expression of these genes in apple roots, bark and leaves was consistent with their roles in nutrition and defense. CONCLUSIONS: Additional genes from apple roots responding to drought were identified using suppression subtraction hybridization compared to a previous EST analysis from the same organ. Genes up- and down-regulated during drought recovery in roots were also identified. Elevated levels of a high affinity nitrate transporter were found in roots suggesting that nitrogen uptake shifted from low affinity transport due to the predicted reduction in nitrate concentration in drought-treated roots. Suppression of a NPR1 gene in leaves of drought-treated apple trees may explain in part the increased disease susceptibility of trees subjected to dehydrative conditions.

How can computerized interpretation algorithms adapt to gender/age differences in ECG measurements?

It is well known that there are gender differences in 12 lead ECG measurements, some of which can be statistically significant. It is also an accepted practice that we should consider those differences when we interpret ECGs, by either a human overreader or a computerized algorithm. There are some major gender differences in 12 lead ECG measurements based on automatic algorithms, including global measurements such as heart rate, QRS duration, QT interval, and lead-by-lead measurements like QRS amplitude, ST level, etc. The interpretation criteria used in the automatic algorithms can be adapted to the gender differences in the measurements. The analysis of a group of 1339 patients with acute inferior MI showed that for patients under age 60, women had lower ST elevations at the J point in lead II than men (57±91µV vs. 86±117µV, p<0.02). This trend was reversed for patients over age 60 (lead aVF: 102±126µV vs. 84±117µV, p<0.04; lead III: 130±146µV vs. 103±131µV, p<0.007). Therefore, the ST elevation thresholds were set based on available gender and age information, which resulted in 25% relative sensitivity improvement for women under age 60, while maintaining a high specificity of 98%. Similar analyses were done for prolonged QT interval and LVH cases. The paper uses several design examples to demonstrate (1) how to design a gender-specific algorithm, and (2) how to design a robust ECG interpretation algorithm which relies less on absolute threshold-based criteria and is instead more reliant on overall morphology features, which are especially important when gender information is unavailable for automatic analysis.

FLOT and CROSS chemotherapy regimens alter the frequency of CD27+ and CD69+ T cells in oesophagogastric adenocarcinomas: implications for combination with immunotherapy.

Combining immunostimulatory chemotherapies with immunotherapy is an attractive strategy to enhance treatment responses in oesophagogastric junctional adenocarcinoma (OGJ). This study investigates the immunostimulatory properties of FLOT, CROSS and MAGIC chemotherapy regimens in the context of OGJ using in vitro and ex vivo models of the treatment-naïve and post-chemotherapy treated tumour microenvironment. FLOT and CROSS chemotherapy regimens increased surrogate markers of immunogenic cell death (HMGB1 and HLA-DR), whereas the MAGIC treatment regimen decreased HMGB1 and HLA-DR on OGJ cells (markedly for epirubicin). Tumour-infiltrating and circulating T cells had significantly lower CD27 expression and significantly higher CD69 expression post-FLOT and post-CROSS treatment. Similarly, the supernatant from FLOT- and CROSS-treated OGJ cell lines and from FLOT- and CROSS-treated OGJ biopsies cultured ex vivo also decreased CD27 and increased CD69 expression on T cells. Following 48 h treatment with post-FLOT and post-CROSS tumour conditioned media the frequency of CD69+ T cells in culture negatively correlated with the levels of soluble immunosuppressive pro-angiogenic factors in the conditioned media from ex vivo explants. Supernatant from FLOT- and CROSS-treated OGJ cell lines also increased the cytotoxic potential of healthy donor T cells ex vivo and enhanced OGJ patient-derived lymphocyte mediated-killing of OE33 cells ex vivo. Collectively, this data demonstrate that FLOT and CROSS chemotherapy regimens possess immunostimulatory properties, identifying these chemotherapy regimens as rational synergistic partners to test in combination with immunotherapy and determine if this combinatorial approach could boost anti-tumour immunity in OGJ patients and improve clinical outcomes.

Identification of differentially expressed genes associated with changes in the morphology of Pichia fermentans on apple and peach fruit.

Pichia fermentans (strain DISAABA 726) is an effective biocontrol agent against Monilinia fructicola and Botrytis cinerea when inoculated in artificially wounded apple fruit but is an aggressive pathogen when inoculated on wounded peach fruit, causing severe fruit decay. Pichia fermentans grows as budding yeast on apple tissue and exhibits pseudohyphal growth on peach tissue, suggesting that dimorphism may be associated with pathogenicity. Two complementary suppressive subtractive hybridization (SSH) strategies, that is, rapid subtraction hybridization (RaSH) and PCR-based subtraction, were performed to identify genes differentially expressed by P. fermentans after 24-h growth on apple vs. peach fruit. Gene products that were more highly expressed on peach than on apple tissue, or vice versa, were sequenced and compared with available yeast genome sequence databases. Several of the genes more highly expressed, when P. fermentans was grown on peach, were related to stress response, glycolysis, amino acid metabolism, and alcoholic fermentation but surprisingly not to cell wall degrading enzymes such as pectinases or cellulases. The dual activity of P. fermentans as both a biocontrol agent and a pathogen emphasizes the need for a thorough risk analysis of potential antagonists to avoid unpredictable results that could negatively impact the safe use of postharvest biocontrol strategies.

Care of the patient with an autism spectrum disorder by the general physician.

Autism spectrum disorders (ASD), comprising classic autism, Asperger syndrome, Rett syndrome, childhood disintegrative disorder and pervasive development disorder-not otherwise specified, represent complex neurodevelopmental conditions characterised by impaired social interactions, difficulties with communication and repetitive, stereotyped behaviours. It is estimated that up to 1% of the general population may be affected by an ASD. Whether due to improved diagnostic techniques or a true rise in incidence, the prevalence of patients with ASD is rising, and these individuals are increasingly encountered in a variety of healthcare settings. Care givers of patients with an ASD report frequently that lack of awareness of the complications of these disorders and the method of appropriately assessing these individuals impair the effective delivery of healthcare to this patient population. It is now clear that patients with an ASD, in addition to the defining characteristics of these disorders, can present to the outpatient, emergency department and inpatient settings with a variety of psychiatric, neurological, gastrointestinal, nutritional/metabolic, dental, ophthalmological, cardiovascular, gynaecological, traumatic and musculoskeletal conditions that can require acute intervention. In addition, the common treatments given to patients with an ASD may result in side effects and complications that may require acute intervention. For physicians who encounter patients with an ASD, the combination of impaired social interactions, difficulties with communication and stereotyped behaviours creates an additional barrier to diagnosis and treatment of these individuals. Careful preparation of the examination environment, direct engagement of care givers and the patient and the use of communication techniques and pharmacological adjuncts can aid physicians in treating the patient with an ASD in the outpatient, emergency department and inpatient settings.

Identification of genes differentially expressed during interaction of resistant and susceptible apple cultivars (Malus x domestica) with Erwinia amylovora.

BACKGROUND: The necrogenic enterobacterium, Erwinia amylovora is the causal agent of the fire blight (FB) disease in many Rosaceae species, including apple and pear. During the infection process, the bacteria induce an oxidative stress response with kinetics similar to those induced in an incompatible bacteria-plant interaction. No resistance mechanism to E. amylovora in host plants has yet been characterized, recent work has identified some molecular events which occur in resistant and/or susceptible host interaction with E. amylovora: In order to understand the mechanisms that characterize responses to FB, differentially expressed genes were identified by cDNA-AFLP analysis in resistant and susceptible apple genotypes after inoculation with E. amylovora. RESULTS: cDNA were isolated from M.26 (susceptible) and G.41 (resistant) apple tissues collected 2 h and 48 h after challenge with a virulent E. amylovora strain or mock (buffer) inoculated. To identify differentially expressed transcripts, electrophoretic banding patterns were obtained from cDNAs. In the AFLP experiments, M.26 and G.41 showed different patterns of expression, including genes specifically induced, not induced, or repressed by E. amylovora. In total, 190 ESTs differentially expressed between M.26 and G.41 were identified using 42 pairs of AFLP primers. cDNA-AFLP analysis of global EST expression in a resistant and a susceptible apple genotype identified different major classes of genes. EST sequencing data showed that genes linked to resistance, encoding proteins involved in recognition, signaling, defense and apoptosis, were modulated by E. amylovora in its host plant. The expression time course of some of these ESTs selected via a bioinformatic analysis has been characterized. CONCLUSION: These data are being used to develop hypotheses of resistance or susceptibility mechanisms in Malus to E. amylovora and provide an initial categorization of genes possibly involved in recognition events, early signaling responses the subsequent development of resistance or susceptibility. These data also provided potential candidates for improving apple resistance to fire blight either by marker-assisted selection or genetic engineering.