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PurposeTo describe patient-reported pain and function 12 months after proximal row carpectomy (PRC). Secondary outcomes included return to work, grip strength, range of wrist motion, satisfaction with treatment results, and complications.MethodsThis cohort study was part of the British Society for Surgery of the Hand Studyathon 2021, using ongoing routinely-collected data of 304 eligible patients who underwent PRC (73% scapholunate advanced collapse, 11% scaphoid nonunion advanced collapse wrist; 11% Kienböck, 5% other indications) from Xpert Clinics, the Netherlands between 2012–2020. The primary outcome was the Patient Rated Wrist/Hand Evaluation total score (range, 0–100, lower scores indicate better performance).ResultsOf the 304 patients, the primary outcome was available in 217 patients. The total Patient Rated Wrist/Hand Evaluation score improved from 60 (95% confidence interval [CI], 57–63) to 38 (95% CI, 35–41) at 3 months, and 26 (95% CI, 23–29) at 12 months. The pain and function subscales improved by 18 (95% CI, 17–20) and 16 (95% CI, 14–18) points, respectively. At 12 months, 82% had returned to work at a median time of 12 (95% CI, 9–14) weeks following PRC. Grip strength did not improve. Wrist flexion and extension demonstrated a clinically irrelevant decrease. Satisfaction with treatment result was excellent in 27% of patients, good in 42%, fair in 20%, moderate in 6%, and poor in 5%. Complications occurred in 11% of patients, and conversion to wrist arthroplasty occurred in 2 patients.ConclusionA clinically relevant improvement in patient-reported pain and function was observed at 3 months after PRC, with continued improvement to 12 months. These data can be used for shared-decision making and expectation management.Type of study/level of evidenceTherapeutic IV

Helicobacter spp. are Gram-negative bacteria that cause a spectrum of disease in the gut, biliary tree and liver. Many Helicobacter spp. produce a range of cholesteryl α-glucosides that have the potential to act as pathogen associated molecular patterns. We report a highly stereoselective α-glucosylation of cholesterol using 3,4,6-tri-O-acetyl-2-O-benzyl-D-glucopyranosyl N-phenyl-2,2,2-trifluoroacetimidate, which allowed the synthesis of cholesteryl α-glucoside (αCG) and representative Helicobacter spp. cholesteryl 6-O-acyl-α-glucosides (αCAGs; acyl = C12:0, 14:0, C16:0, C18:0, C18:1). All αCAGs, irrespective of the nature of their acyl chain composition, strongly agonised signalling through the C-type lectin receptor Mincle from human and mouse to similar degrees. By contrast, αCG only weakly signalled through human Mincle, and did not signal through mouse Mincle. These results provide a molecular basis for understanding of the immunobiology of non-pylori Helicobacter infections in humans and other animals.

Natural killer T (NKT) cells detect lipids presented by CD1d. Most studies focus on type I NKT cells that express semi-invariant αβ T cell receptors (TCR) and recognize α-galactosylceramides. However, CD1d also presents structurally distinct lipids to NKT cells expressing diverse TCRs (type II NKT cells), but our knowledge of the antigens for type II NKT cells is limited. An early study identified a nonlipidic NKT cell agonist, phenyl pentamethyldihydrobenzofuransulfonate (PPBF), which is notable for its similarity to common sulfa drugs, but its mechanism of NKT cell activation remained unknown. Here, we demonstrate that a range of pentamethylbenzofuransulfonates (PBFs), including PPBF, activate polyclonal type II NKT cells from human donors. Whereas these sulfa drug–like molecules might have acted pharmacologically on cells, here we demonstrate direct contact between TCRs and PBF-treated CD1d complexes. Further, PBF-treated CD1d tetramers identified type II NKT cell populations expressing αβTCRs and γδTCRs, including those with variable and joining region gene usage (TRAV12-1–TRAJ6) that was conserved across donors. By trapping a CD1d–type II NKT TCR complex for direct mass-spectrometric analysis, we detected molecules that allow the binding of CD1d to TCRs, finding that both selected PBF family members and short-chain sphingomyelin lipids are present in these complexes. Furthermore, the combination of PPBF and short-chain sphingomyelin enhances CD1d tetramer staining of PPBF-reactive T cell lines over either molecule alone. This study demonstrates that nonlipidic small molecules, which resemble sulfa drugs implicated in systemic hypersensitivity and drug allergy reactions, are targeted by a polyclonal population of type II NKT cells in a CD1d-restricted manner.

Type I and type II natural killer T (NKT) cells are restricted to the lipid antigen-presenting molecule CD1d. While we have an understanding of the antigen reactivity and function of type I NKT cells, our knowledge of type II NKT cells in health and disease remains unclear. Here we describe a population of type II NKT cells that recognise and respond to the microbial antigen, α-glucuronosyl-diacylglycerol (α-GlcADAG) presented by CD1d, but not the prototypical type I NKT cell agonist, α-galactosylceramide. Surprisingly, the crystal structure of a type II NKT TCR-CD1d-α-GlcADAG complex reveals a CD1d F’-pocket-docking mode that contrasts sharply with the previously determined A’-roof positioning of a sulfatide-reactive type II NKT TCR. Our data also suggest that diverse type II NKT TCRs directed against distinct microbial or mammalian lipid antigens adopt multiple recognition strategies on CD1d, thereby maximising the potential for type II NKT cells to detect different lipid antigens., Natural killer T (NKT) cells include type I that express semi-invariant T cell receptor (TCR), and type II that cover a broader repertoire. Here the authors describe the crystal structure of a type II NKT TCR complexed with CD1d/antigen to propose that type II NKT TCRs may adapt multiple CD1d docking modes to maximise antigen recognition efficacy.

Helicobacter pylori is a pathogenic bacterium causing gastritis and malignancy; however, the underlying mechanism is not fully understood. Nagata et al. purify and identify virulent metabolites of H. pylori modified from host lipid that exacerbate inflammation through C-type lectin receptors., Helicobacter pylori causes gastritis, which has been attributed to the development of H. pylori–specific T cells during infection. However, the mechanism underlying innate immune detection leading to the priming of T cells is not fully understood, as H. pylori evades TLR detection. Here, we report that H. pylori metabolites modified from host cholesterol exacerbate gastritis through the interaction with C-type lectin receptors. Cholesteryl acyl α-glucoside (αCAG) and cholesteryl phosphatidyl α-glucoside (αCPG) were identified as noncanonical ligands for Mincle (Clec4e) and DCAR (Clec4b1). During chronic infection, H. pylori–specific T cell responses and gastritis were ameliorated in Mincle-deficient mice, although bacterial burdens remained unchanged. Furthermore, a mutant H. pylori strain lacking αCAG and αCPG exhibited an impaired ability to cause gastritis. Thus H. pylori–specific modification of host cholesterol plays a pathophysiological role that exacerbates gastric inflammation by triggering C-type lectin receptors.

The innate immune receptor Mincle senses lipid-based molecules derived from pathogens, commensals and altered self. Based on emerging structure-activity relationships we design simple alkyl 6-O-acyl-b-D-glucosides that are effective agonists of Mincle and signal with potency on par with the prototypical ligand trehalose dimycolate.

The International Atomic Energy Agency has coordinated an international project addressing climate change and landscape development in post-closure safety assessments of solid radioactive waste disposal. The work has been supported by results of parallel on-going research that has been published in a variety of reports and peer reviewed journal articles. The project is due to be described in detail in a forthcoming IAEA report. Noting the multi-disciplinary nature of post-closure safety assessments, here, an overview of the work is given to provide researchers in the broader fields of radioecology and radiological safety assessment with a review of the work that has been undertaken. It is hoped that such dissemination will support and promote integrated understanding and coherent treatment of climate change and landscape development within an overall assessment process. The key activities undertaken in the project were: identification of the key processes that drive environmental change (mainly those associated with climate and climate change), and description of how a relevant future may develop on a global scale; development of a methodology for characterising environmental change that is valid on a global scale, showing how modelled global changes in climate can be downscaled to provide information that may be needed for characterising environmental change in site-specific assessments, and illustrating different aspects of the methodology in a number of case studies that show the evolution of site characteristics and the implications for the dose assessment models. Overall, the study has shown that quantitative climate and landscape modelling has now developed to the stage that it can be used to define an envelope of climate and landscape change scenarios at specific sites and under specific greenhouse-gas emissions assumptions that is suitable for use in quantitative post-closure performance assessments. These scenarios are not predictions of the future, but are projections based on a well-established understanding of the important processes involved and their impacts on different types of landscape. Such projections support the understanding of, and selection of, plausible ranges of scenarios for use in post-closure safety assessments.

The fidelity of acylation regioselectivity in the synthesis of mixed glycosyl diacylglycerols can be accurately measured by quantitative 13C NMR spectroscopy using a 1-13C-labelled fatty acid and a paramagnetic relaxation enhancement agent. Exquisite regioselectivity is achieved using a stepwise acylation/substitution of a glycosyl β-bromohydrin, which is applied to the total synthesis of Streptococcus pneumoniae Glc-DAG-s2.

Mineral oils are employed as liquid dielectric insulators in many high voltage transformers. It is recognised that the dielectric properties of these oils degrade over time with continued exposure to high voltages and thermal stress. This breakdown can be monitored using FTIR spectroscopy or electrical techniques. In this work the mineral oils have been thermally stressed by exposure to 120°C over a prolonged time period with changes to the electrical breakdown voltage and FTIR spectra measured at frequent intervals. Different samples of oil were prepared with some exposed to Kraft paper, copper or a combination of the two. The ratio of oil: copper: Kraft paper was consistent with that commonly found in transformers. Results show that the growth of the carboxylic acid peak can be correlated with a total acid number (TAN) through a calibration process which is less time consuming, won’t overestimate TAN and is an alternative to titration.

Microbes produce a wide range of small molecule glycoconjugates that constitute unique molecular signatures. These molecules are recognized by a range of detection systems, triggering immune responses to microbial pathogens and commensals. The antigen-presenting molecules of the CD1 class, CD1a-d, capture lipidic molecules and present them to diverse and innate-like T cell populations including natural killer T cells and germline-encoded mycolyl reactive T cells. The antigen-presenting molecule MR1 captures vitamin B metabolites and presents them to mucosal associated invariant T cells. In both cases, recognition of the small molecule-antigen presenting molecule complexes occurs through T cell receptors on the surface of T lymphocytes. The pattern recognition receptors macrophage C-type lectin (MCL) and macrophage inducible C-type lectin (Mincle) receptors sense glycolipids and through signalling initiate cellular activation, shaping immune responses to peptide antigens, including the differentiation of naïve T cells into conventional effector T helper cells. In this review, we provide an overview of the diverse structures of immunogenic lipidic molecules and vitamin B metabolites and their recognition by select systems of the immune system. Future advances in our understanding of the roles of such molecules in innate and adaptive immune responses will require the coordinated efforts of synthetic and natural products chemists, immunologists and biologists.

N-Phenyltrifluoroacetimidoyl chloride (PTFAI-Cl) is a reagent widely used for the preparation of glycosyl N-phenyltrifluoroacetimidates. However, the most commonly applied method requires carbon tetrachloride, a hepatotoxic reagent that has been phased out under the Montreal Protocol. We report a new synthesis of N-phenyltrifluoroacetimidoyl chloride (PTFAI-Cl) using dichlorotriphenylphosphane and triethylamine.

In February 1986, 40 out of 75 adult patients with haemophilia A attending St. James's University Hospital were human immunodeficiency virus (HIV) antibody positive. Over a three-year period these patients were prospectively studied with regard to possible prognostic indicators for the development of the acquired immune deficiency syndrome (AIDS). Using the Centres for Disease Control (CDC) classification of HIV infection, 17 patients (42.5%) developed group 4 disease during this time, giving an actuarial three-year progression rate of 44%, and 5 patients (12.5%) died. The following parameters measured at recruitment were found independently to predict progression to AIDS: a serum beta 2-m level of greater than 3.5 mg/l, (chi 2 = 15.95, P less than 0.001), a serum IgA level of greater than 4.5 milligram(s) (chi 2 = 6.08, P less than 0.02) and p24 antigenaemia (chi 2 = 5.7, P less than 0.05). The actuarial three-year progression rate in those patients abnormal by two or more of these parameters was 100% (n = 7), compared to only 7% in patients who were normal by all three values (n = 15). CD4+ lymphocyte counts and CD4+:CD8+ ratios were significantly lower in HIV positive compared with HIV negative patients (P less than 0.01), but did not predict the development of AIDS.

Geiger-mode avalanche photodiodes (GM-APDs) grown by organometallic vapor phase epitaxy are of interest for several low-light-level applications, including laser radars and single-photon-counting optical communications. Materials systems based on GaInAsP lattice matched to InP are critical to the performance of GM-APDs at both 1.06- and 1.55 - μ m wavelengths. Growth temperature, growth rate, and V/III ratio were investigated to determine the effect each had on important device parameters, dark count rate and after-pulsing. Improvements of growth conditions led to a 44% reduction in dark count rate (DCR), but after-pulsing behavior, and thus dead time of GM-APDs was unaffected. The improvement of growth conditions has led to devices with DCRs at 300 K of 8 × 10 9 Hz / cm 2 with dead times still at approximately 1 μ s .

Chemical hydrides, such as sodium borohydride ( NaBH 4 ) , offer promising gravimetric and volumetric hydrogen storage densities. The overall system energy density depends on the reactor performance. In this study, a novel intergrated reactor design in which catalyst bed is integrated with a heat exchanger for autothermal operation showed significant improvements in reactor performance. Over 200% enhancement in reactor throughput was achieved with the integrated reactor at 99% fuel conversion with constant reaction temperature profiles over a wide range of fuel flow rates. Impacts of improved performance on system operation and overall energy density of chemical hydride based hydrogen storage system were also discussed.

Arrays of InP-based avalanche photodiodes (APDs) with InGaAsP absorber regions have been fabricated and characterized in the Geiger mode for photon-counting applications. Measurements of APDs with InGaAsP absorbers optimized for 1.06 mum wavelength show dark count rates (DCRs)

For Geiger-mode avalanche photodiodes, the two most important performance metrics for most applications are dark count rate (DCR) and photon detection efficiency (PDE). In 1.06-mum separate-absorber-avalanche (multiplier) InP-based devices, the primary sources of dark counts are tunneling through defect levels in the InP avalanche region and thermal generation in the InGaAsP absorber region. PDE is the probability that a photon will be absorbed (quantum efficiency) times the probability that the electron-hole pair generated will actually cause an avalanche. A device model based on experimental data that can simultaneously predict DCR and PDE as a function of overbias and temperature is presented. This model has been found useful in predicting changes in performance as various device parameters, such as avalanche layer thickness, are modified. This has led to designs that are capable simultaneously of low DCR and high PDE

Catalytic hydrolysis of sodium borohydride is a promising technology for hydrogen storage. In this study, we report the performance of Millennium Cell Hydrogen on Demand TM ( HOD TM ) hydrogen storage system using a supported catalyst. Dynamic reactor startup and response characteristics were measured using a fixed-bed catalyst reactor at various hydrogen demand conditions. The catalyst reactor was operated without need of fuel preheating. Catalyst durability of more than 700 h was demonstrated with a sodium borohydride conversion over 95% at a liquid feed hourly space velocity (LHSV) of about 15 h - 1 and under a system pressure of 483 kPa.

Wavelength stabilization of high-power pump lasers for fiber amplifier applications involves complex interactions between the laser chip and the fiber Bragg grating (FBG). We present a comprehensive theoretical model for the window of operation in the coherence collapse (CC) regime while maintaining wavelength locking in 980-nm FBG-stabilized pumps. Experimental data from the development of a 500-mW grating stabilized pump verifies the theory. We also provide the first evidence that the critical feedback distance for CC operation of longer laser diode chips is sensitive to detuning.

Given current concerns about global climate change, there is an urgent need to quantify and monitor accurately the magnitude of present day terrestrial carbon sinks. This may be achieved by driving ecosystem simulation models (ESMs) spatially with remotely sensed estimates of ecological variables, such as leaf area index (LAI). Conventional procedures for analysing digital remotely sensed images rely upon pixel-based methods, using spectral information from each pixel to allocate it to a land cover type or estimate a surface property (e.g. LAI). Groups of pixels, within areas assumed to be ‘thematically homogeneous’, will not necessarily provide the same allocation or estimation due to data noise, atmospheric effects and natural variation of the surface. Pixels on the boundary between areas are an additional problem as their spectral information derives from more than one surface type. If contextual information on the spatial pattern and structure of the landscape could be included in the analysis (e.g. forest inventory polygons, agricultural land parcels), then the accuracy of the allocations or estimations (e.g. of LAI) could be increased. Polygon-based approaches, where all pixels within a defined area are presumed similar and so can be combined prior to analysis, offer a solution. These approaches are implemented most efficiently within an integrated GIS where raster and ancillary data can be analysed with reference to vector land polygons. A procedure using remotely sensed data in a polygon format to produce accurate spatial estimates of LAI (on which to drive an ESM) is described. In relation to a pixel-based procedure, the polygon-based procedure provided: (1) increased accuracy, (2) more appropriate and realistic representations of the environment and (3) a powerful and flexible framework for further data analysis.

Dense arrays of single-mode slab-coupled optical waveguide lasers with a pitch of 40 µm have achieved 483 W from a single 1 cm wide bar.

Dense array slab-coupled optical waveguide lasers (DASCOWLs) consist of several hundred single-mode SCOWL lasers on a monolithic bar. Near diffraction-limited output of the SCOWLs is preserved with spacing down to 40μm. Greater than 200W CW operation of a 4% FF, 100-element, 100μm-pitch, centimeter wide DASCOWL bar has been demonstrated, corresponding to

Since the pudendal nerve innervates the external urethral sphincter, pudendal nerve injury and resultant neuroregeneration should affect voiding behavior. In this study, neuroregenerative activity of pudendal nerve was correlated to the changes in urinary behavior in female rats. Eighteen female rats underwent bilateral pudendal nerve crush, and 17 to 21 age-matched rats were used as unoperated controls. Urinary volume and frequency were recorded 6 and 13 days post-operatively (dpo). Initiation of pudendal nerve regeneration was indicated by an upregulation of beta(II) tubulin mRNA in the dorsolateral motoneurons (DLM), as measured at 7 and 14 dpo by in situ hybridization with radio-labeled beta(II) tubulin cDNA. At 6 dpo, mean volume voided by the crush group was significantly decreased compared to the control group during the light cycle (P < 0.05). At 7 dpo, the DLM mRNA level was significantly increased in the nerve crush group compared to the control group (P < 0.05). At 13 dpo, there were no differences in volume or frequency between the two groups, suggesting a return to normal voiding behavior. At 14 dpo, there was no significant difference in DLM mRNA levels between crush and control groups. Initiation of nerve regeneration occurs before normalization of voiding behavior after pudendal nerve crush. This data suggest that treatments to accelerate nerve regeneration would improve functional recovery of neurologically based incontinence.

Carbon-14 was added to the epilimnion of a small Canadian Shield lake to investigate primary production and carbon dynamics. The nature of the spike and subsequent monitoring allowed the investigation of both short-term and longer-term processes relevant to evaluating impacts of accidental and routine releases and of solid waste disposal. Data from this experiment were used in the BIOMOVS II program as a validation test for modelling the fate of the 14 C added to the lake. Four models were used: (1) a simple probabilistic mass balance model of a lake; (2) a relatively complex deterministic model; (3) a complex deterministic model; and (4) a more complex probabilistic model. Endpoints were 14 C concentrations in water, sediment and lake whitefish over a thirteen year period. Each model produced reasonable predictions when compared to the range of the observed data and when uncertainty in model predictions is taken into consideration. The simple lake model did not account for internal recycling of 14 C and, in this respect, its predictions were not as realistic as those of the more complex models for concentrations in water. However, the simple model predictions for the 14 C inventory remaining in lake sediment were closest to the observed values. Overall, the more complex probabilistic model was the most accurate in simulating 14 C concentrations in water and in whitefish but it overestimated 14 C retention in the lake sediments, as did the other complex models. Choice of parameter values for transfer rate to sediment and gaseous evasion are important in influencing model predictions. Although predicted concentrations of 14 C in fish of dynamic models were more accurate than those using equilibrium bioconcentration factors typically used in assessments, large variability in observed 14 C concentrations in whitefish emphasizes the need for a better understanding of the important processes that influence these contaminant concentrations.

Airborne imaging spectrometers can record spatially-explicit information on the absorption features associated with foliar biochemicals in a forest canopy. The spectra of a single species pine canopy were recorded by the National Aeronautics and Space Administration's (NASA) Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). Up to three wavebands were correlated to the concentration of chlorophyll, nitrogen, lignin, and cellulose (R/sup 2/=0.96,0.94,0.93, and 0.61, respectively) and the content of these four biochemicals (R/sup 2/=0.98,0.91,0.88, and 0.92, respectively). The AVIRIS data were used, for the first time, to map the content of these biochemicals within the forest canopy and the accuracy was between 3-7% of the mean.

Three physical field models were constructed to assess the effects on soil of a chromated fluoride wood preservative treatment used at the groundline of creosoted electricity distribution poles. One model contained an untreated aged creosoted pole section in sandy loam soil, the second contained a remedially treated aged creosoted pole section in sandy loam soil and the third a similarly treated section in sand-amended sandy loam soil. The models were subjected to the equivalent of 6 months simulated rainfall exposure, and soil samples recovered from each model soilbed were used for the determination of soil dehydrogenase activity, fluoride and total chromium concentrations. Soil dehydrogenase activity was measured on both rye meal-supplemented and unsupplemented soil samples. Irrespective of supplementation, significant reductions in dehydrogenase activity were associated with increased soil concentrations of leached preservative constituents which were found within 5 cm of the treated pole sections. These reductions were enhanced by the lower organic matter content of the sand-amended soil. Supplementation with rye meal resulted in raised levels of dehydrogenase activity in all soil samples, which highlighted the negative effects of preservative soil contamination on microbial activity.

Decisions on permitting, controlling and monitoring releases of radioactivity into the environment rely on a great variety of factors. Important among these is the prospective assessment of radionuclide behavior in the environment, including migration and accumulation among and within specific environmental media, and the resulting environmental and human health impacts. Models and techniques to undertake such assessments have been developed over several decades based on knowledge of the ecosystems involved, as well as monitoring of previous radionuclide releases to the environment, laboratory experiments and other related research. This paper presents developments in the assessment of radiation doses and related research for some of the key radionuclides identified as of potential significance in the context of releases to the biosphere from disposal facilities for solid radioactive waste. Since releases to the biosphere from disposal facilities involve transfers from the geosphere to the biosphere, an important aspect is the combined effects of surface hydrology, near-surface hydrogeology and chemical gradients on speciation and radionuclide mobility in the zone in which the geosphere and biosphere overlap (herein described as the geosphere-biosphere subsystem). In turn, these aspects of the environment can be modified as a result of environmental change over the thousands of years that have to be considered in radioactive waste disposal safety assessments. Building on the experience from improved understanding of the behavior of the key radionuclides, this paper proceeds to describe development of a generic methodology for representing the processes and environmental changes that are characteristic of the interface between the geosphere and the biosphere. The information that is provided and the methodology that is described are based on international collaborative work implemented through the BIOPROTA forum, www.bioprota.org.

We report short (5 ns), high-power (>1 W), spectrally narrow optical pulses generated by a 1060-nm slab-coupled optical waveguide laser (SCOWL) soldered directly to a custom BiCMOS driver chip.

We present an architecture for scaling the brightness of semiconductor laser sources, demonstrating 40 W coherently combined power in a single, diffraction-limited beam from an array of 47 single-pass optical amplifiers at 1064 nm.

An approach for the realization of a single heterostructure for multiple optical device applications in a photonic integrated circuit environment is addressed from the standpoint of building into the heterostructure separate device features. In particular, a low compositionally graded depressed cladding laser structure is shown to have a large mode, compared to a structure optimized for maximum confinement factor, and a radiation loss an order of magnitude lower than for a structure without the inner cladding, features which are important for fiber coupling and for compact bends. By incorporating a narrow gap section into the barrier layer, a bulk electroabsorption modulator can be integrated into the same structure that contains quantum wells for optical amplifiers. Data are presented on the device properties of a single heterostructure when used as large optical cavity lasers, s-bends, and bulk electroabsorption modulators. The only laser parameter affected by the incorporation of the modulator is the transparency current density which is increased 25% over standard structures. The performance of rib delineated s-bends is exceeded only by native oxide defined small optical cavity laser structures. The electroabsorption modulator, which was activated in a disordered section under reverse bias, had a modulation depth approximately 1/3 that predicted by model studies which was attributed to the depletion electric field profile. Methods for improving the modulation depth while lowering the transparency current density are outlined.

We report on highly reliable, high-power, and high-performance 980-nm quantum-well laser chips and modules. Ridge waveguide laser diode chips with 750-mW output power and 500-mW fiber Bragg grating stabilized modules have been achieved and Telcordia-qualified. Long-term reliability tests show a very low failure rate of 400 FIT (failures in time) at 900-mA operating current or 500-mW module power. The kink-free fiber coupled module output power can be as high as 640 mW with grating stabilization, which produces very good wavelength stability and power stability. A further improved structure shows a record continuous-wave rollover chip power of 1.6 W for the 5-/spl mu/m-wide ridge waveguide laser diodes.

We report high-performance 980-nm ridge waveguide quantum-well lasers with extremely low vertical beam divergence of 13/spl deg/. A very small aspect ratio of 1.6 is obtained at high operating power of 900 mW. In addition to the more circular beam, low threshold, high efficiency, high characteristic temperature, and high output power of over 1.18 W are achieved. The fiber coupled output power can be as high as 680 mW with fiber Bragg grating stabilization. Excellent wavelength and power stability are also demonstrated.

An InGaAs-GaAs-AlGaAs strained layer quantum-well ring laser with a tetragonal cavity consisting of one symmetric and one asymmetric corner reflector both fabricated by reactive ion etching is described. Two beams emit from one facet with inclined angles predicted by Snell's Law. An increase of the threshold with incident angle is observed. Longitudinal mode behavior and L-I characteristics, which indicate the presence of strong competition between clockwise and counter-clockwise traveling waves, are described. >

Adiabatically flared slab-coupled optical waveguide lasers (SCOWLs) at 1.06 µm wavelength have been studied, achieving a large fundamental mode and a 32% increase in COD power. Capabilities and limitations of the taper mechanism are discussed.

SCOWAs have produced 1.5 W of output power with a 44 mW seed. Arrays of 47 SCOWA elements have demonstrated a raw power of 57 W. Coherent beam combining of these arrays will be discussed.

Slab-coupled optical waveguide lasers (SCOWLs) and amplifiers (SCOWAs) are inherently low-confinement structures with large nearly-circular modes that are easily coupled to optical fibers or collimated for free-space applications. Recently SCOWL powers have increased to 3 W by increasing the cavity length to 1 cm and improving the heat removal. SCOWAs are coherently combined using active phase control to achieve a very high-brightness source. Our coherent beam combining system consists of single-pass amplifiers with angled-facet SCOWAs that suppress feedback. Single-pass, 5-mm long, SCOWAs have now been demonstrated with 1.5 W CW output with only 50 mW seed power. Arrays of 47 SCOWAs have demonstrated a raw power of 57 W with 50 mW of seed power per element. A coherent beam combining demonstration is currently being assembled.

The development of a high-brightness semiconductor diode laser/amplifier concept, which utilizes a slab-coupled optical waveguide (SCOW) region to achieve several important advances in performance, is presented. SCOW devices are capable of single-spatial-mode operation with a single-lobed, large-area, low-aspect-ratio beam. The SCOW concept is applicable to a wide variety of semiconductor material systems and wavelengths of interest. To date, SCOW devices have been demonstrated in the InGaAs/AlGaAs/GaAs, InGaAsP/InP, and AlGaAsSb/GaAs. High-power lasers and optical amplifiers have been developed for numerous applications, including arrays for wavelength and coherent beam combining, narrow-linewidth external cavity lasers, and mode-locked lasers.

The decrease in the number of synaptic NMDA receptors produced by prior i.c.v. injections of antisense oligonucleotides was examined in the CA1 stratum radiatum of hippocampal slices. Isolated NMDA and AMPA receptor-mediated components of extracellular synaptic responses were compared in slices obtained from control animals and from animals treated for 48 h with an 18-mer phosphorothioate antisense oligodeoxynucleotide directed against NMDA-R1. In slices ipsilateral to the injected hemisphere, the synaptic NMDA component was decreased by 29% compared with the contralateral side and by 34% compared with animals injected with vehicle alone. At the same time, synaptic AMPA receptor-mediated components were not affected. These results are consistent with a rapid turnover rate of synaptic NMDA-R1 and demonstrate the feasibility of antisense oligonucleotide techniques for the depletion of specific synaptic receptor channels.

Slab-coupled optical waveguide lasers (SCOWLs) have now reached 3 W of CW power. Also, a high peak-power directly-modulated laser transmitter has recently been demonstrated with a fully-packaged hybrid-integrated driver.

Angled slab-coupled optical waveguide amplifiers (SCOWAs) at 1 µm wavelength have been demonstrated with 1.5 W of output power with a 44 mW seed. Application of this technology for coherent beam combining will be discussed.

The optical properties of strained-layer InGaAs-GaAs-AlGaAs quantum-well lasers with a cavity comprised of a single cleaved facet and a dry etched corner reflector (CR) is described. For comparison, these data are contrasted with data for Fabry-Perot lasers made from the same material and having either two cleaved facets or one cleaved and one straight-etched facet. The etched CR exhibits higher overall reflectivity than the straight-etched and cleaved facet structures, resulting in lower threshold current density and higher efficiency. However, near-field measurements indicate that improvement in reflectivity from the etched CRs is offset by their tendency to favor off-order transverse modes. >

E-selectin is an adhesion molecule transiently and specifically expressed on endothelial cells upon stimulation with cytokines. We wished to determine whether methylation could play a role in cell-type specific expression of this gene. We found that the E-selectin promoter in cultured endothelial cells is under-methylated in comparison with non-expressing HeLa cells. Plasmid constructs carrying a reporter driven by the E-selectin promoter and methylated in vitro are no longer transcribed in either an in vitro transcription system or in transiently transfected cells. We identified the NF-κB site in the promoter as the likely target for this methylation-mediated repression by testing a minimal promoter carrying only this and an associated element. We conclude that methylation is likely to play a role in blocking E-selectin expression in non-endothelial cells.

Slab-coupled optical waveguide lasers (SCOWLs) are ideal structures for high-power semiconductor lasers. Recently, 2 W CW has been achieved in these lasers with good reliability in both pulsed and CW operation at lower power levels.

No Abstract

A slab-coupled optical waveguide laser is wavelength stabilized with a fiber Bragg grating and characterized under a narrow pulse high repetition rate direct modulation scheme suitable for efficient pulse position modulation format optical communication systems.

Amoxycillin and clavulanic acid show good activity against Legionella pneumophila in vitro, and synergy has been observed between the two agents. However, in tissue culture studies, amoxycillin was inactive against intracellular legionellae, whereas clavulanic acid and amoxycillin plus clavulanic acid were as effective as erythromycin in preventing bacterial growth. These latter findings were reflected in the results of therapy of a L. pneumophila pneumonia in the neutropenic rat. Amoxycillin was ineffective in reducing bacterial counts in the lungs of infected animals, but clavulanic acid and amoxycillin-clavulanic acid produced bactericidal effects similar to those of erythromycin. The data illustrate the bactericidal activity of amoxycillin-clavulanic acid and clavulanic acid against intracellular L. pneumophila in contrast to the lack of activity of amoxycillin.

At this stage it is impossible to specify the requirements on low activation materials in a comprehensive way. Instead, simplified criteria are proposed as a general means of establishing the compositional guidelines for selecting and designing these materials. An approach to criteria development is described, comprising: • - comprehensive identification of potentially relevant types of radiological impact: • - identification of the important radionuclides for each element for each type of impact: • - assessment of the radiological impacts associated with the use of unit amount of each element. Overall consequences can then be scaled according to design information and radiologically-based requirements on materials can be inferred. Conclusions are presented from a study following this approach, identifying objectives and specifications for materials with respect to each area of radiological impact.

InGaAs-GaAs-AlGaAs strained-layer distributed-feedback (DFB) ridge-waveguide lasers requiring a single metalorganic chemical vapor deposition (MOCVD) growth step are shown to operate in a single longitudinal mode up to 2.2*I/sub th/ with an antireflection (AR) coating applied to one facet under room temperature, pulsed conditions. A value of kL=0.33 has been determined from threshold gain calculations for coated and uncoated devices. Weak lateral optical confinement, provided by unpumped lateral gratings is demonstrated by the absence of antiguiding effects, and a real lateral index step of approximately 4*10/sup -3/ is determined from near-field emission patterns. >

Avalanche Photodiode (APD) photon counting arrays are finding an increasing role in defense applications in laser radar and optical communications. As these system concepts mature, the need for reliable screening, test, assembly and packaging of these novel devices has become increasingly critical. MIT Lincoln Laboratory has put significant effort into the screening, reliability testing, and packaging of these components. To provide rapid test and measurement of the APD devices under development, several custom parallel measurement and Geiger-mode (Gm) aging systems have been developed. Another challenge is the accurate attachment of the microlens arrays with the APD arrays to maximize the photon detection efficiency. We have developed an active alignment process with single µm precision in all six degrees of freespace alignment. This is suitable for the alignment of arrays with active areas as small as 5 µm. Finally, we will discuss a focal plane array (FPA) packaging qualification effort, to verify that single photon counting FPAs can survive in future airborne systems.