Search

A Si-Ge waveguide avalanche photodiode with extremely high temperature stability is demonstrated. The breakdown voltage increases ∼4.2 mV/°C, bandwidth reduces ∼0.09%/°C, and gain-bandwidth product reduces ∼0.24%/°C with temperature increased from 30 °C to 90 °C. Additionally, it maintains superior performance with low breakdown voltage of ∼10 V, high multiplication gain of >15, high bandwidth of ∼24.6 GHz, high gain-bandwidth product of >240 GHz, high internal quantum efficiency of ∼100%, and clear eye diagrams with 64 Gbps PAM4 modulation at 90 °C.

Retained gadolinium from gadolinium-based contrast agents (GBCAs) used in MR exams has been inferred based on signal changes on serial brain MRI and subsequently demonstrated pathologically in adults. Retention has been similarly inferred in children but pathological demonstration in pediatric patients is limited. The long-term effects of retained gadolinium are unknown but are potentially of greater concern in children given their increased vulnerability from continuing development and their expected longer period of exposure. Several factors can influence gadolinium retention. In adults as well as in children, greater accumulation has been demonstrated based on MR signal changes with linear compared with macrocyclic gadolinium chelates, attributed to lower chelate affinity with linear agents. Effects of age at exposure on retention are unknown, while differences in GBCA washout rates are still under investigation and might affect gadolinium retention relative to time of GBCA administration. The purpose of this study was to confirm whether gadolinium brain deposits are present in pediatric patients who received GBCAs and to quantify the amounts present. Brain autopsy specimens from 10 pediatric patients between 1 year and 13 years of age who underwent at least one contrast-enhanced MR exam were analyzed for elemental gadolinium using inductively coupled plasma mass spectrometry. Brain samples included white matter, basal ganglia (putamen, globus pallidus), thalamus, dentate nucleus and tumor tissue as available. Type and dose of contrast agent, number and timing of contrast-enhanced MR exams and renal function (estimated glomerular filtration rate [eGFR]) were documented for each child. Patient exposures ranged from 1 dose to 20 doses of GBCAs including both macrocyclic and linear ionic agents. Gadolinium was found to be present in brain tissue in all children and was generally highest in the globus pallidus. Those who received only macrocyclic agents showed lower levels of gadolinium retention. This study demonstrates pathological confirmation of gadolinium retention in brain tissue of a series of pediatric patients exposed to GBCAs including not only linear ionic agents but also macrocyclic agents with both nonionic and ionic compounds. The distribution and deposition levels in this small pediatric population are comparable with the findings in adults. While the clinical significance of these deposits remains unknown, at this point it would be prudent to exert caution and avoid unnecessary use of GBCAs in pediatric patients.

Describes a laboratory procedure to obtain nuclear magnetic resonance (NMR) values for common organic and inorganic groups. (CP)

We report Al0.8In0.2As0.23Sb0.77 avalanche photodiodes with high gain ( $M>1300$ ) and low dark current at room temperature. Impact ionization coefficients for this material system are also extracted, indicating electron-dominant impact ionization. Low avalanche breakdown temperature dependence is demonstrated.

Digital alloy AlInAsSb avalanche photodiodes exhibit low excess noise comparable to those fabricated from Si. The electron and hole ionization coefficients are critical parameters for simulation and analysis of high-sensitivity receivers. We report ionization coefficients using a mixed injection technique that employs measurement of the gain for different incident wavelengths and a simulation algorithm.

Heat-induced antigen retrieval (HIAR) is routinely employed on aldehyde-fixed tissue sections to enhance the reactivity of antibodies that exhibit weak or no specific interactions with tissue antigens when applied in conventional immunohistochemical protocols. A major drawback of HIAR protocols is, however, the heat-induced detachment of sections from the microscope slide with resultant impaired tissue morphology or loss of the section. We developed a method in which tissue sections mounted on glass slides are temporally coverslipped, and a clamp is used to compress the sections on the microscope slide during HIAR treatment. This “pressurized coverslipping” during HIAR was tested on various formalin-fixed tissues (murine kidneys and temporal bones, human tonsils and temporal bones) that were embedded in paraffin or celloidin. The method reliably kept the sections adherent to the slide, preserved the tissue morphology, and effectively retrieved tissue antigens for improved results in immunohistochemical labeling, even for exceptionally delicate, large, and poorly adhering sections, that is, decalcified human temporal bone sections. In summary, we present a simple method for improved slide adherence and morphological preservation of tissue sections during HIAR treatment that can be combined with all HIAR protocols and that requires only basic lab equipment.

A detailed theoretical investigation of the underlying physics of low noise III-V digital alloy APDs is presented here. Based on our investigations, the criteria for developing low noise digital alloys are proposed. © 2021 The Author(s)

The measured capacitance, modulus and strength of carbon nanotube-polyaniline (CNT-PANI) composite electrodes render them promising candidates for structural energy storage devices. Here, CNT-PANI composite electrodes are manufactured with electrodeposition of PANI onto the bundle network of CNT mats produced via a floating catalyst chemical vapour deposition process. PANI comprises 0% to 30% by volume of the electrode. The composition, modulus, strength and capacitance of the electrodes is measured in the initial state, after the first charge, and after 1000 charge/discharge cycles. Electrode modulus and strength increase with increasing CNT volume fraction; in contrast, the capacitance increases with increasing PANI mass. Charging or cycling reduce the electrode modulus and strength due to a decrease in CNT bundle volume fraction caused by swelling; the electrode capacitance also decreases due to a reduction in PANI mass. A micromechanical model is able to predict the stress-strain response of pre-charged and cycled electrodes, based upon their measured composition after pre-charging and cycling. The electrodes possess up to 63% of their theoretical capacitance, and their tensile strengths are comparable to those of engineering alloys. Their capacitance and strength decrease by less than 15% after the application of 1000 charge/discharge cycles. These properties illustrate their potential as structural energy storage devices.

Monitoring population dynamics in co-culture is necessary in engineering microbial consortia involved in distributed metabolic processes or biosensing applications. However, it remains difficult to measure strain-specific growth dynamics high-throughput formats. This is especially vexing in plate-based functional screens leveraging whole-cell biosensors to detect specific metabolic signals. Here we develop an experimental high-throughput co-culture system to measure and model the relationship between fluorescence and cell abundance, combining chassis-independent recombinase-assisted genome engineering (CRAGE) and whole-cell biosensing with a PemrR-green fluorescent protein (GFP) monoaromatic reporter used in plate-based functional screening. CRAGE was used to construct E. coli EPI300 strains constitutively expressing red fluorescent protein (RFP) and the relationship between RFP expression and optical density (OD600) was determined throughout the EPI300 growth cycle. A linear equation describing the increase of normalized RFP fluorescence during deceleration phase was derived and used to predict biosensor strain dynamics in co-culture. Measured and predicted values were compared using flow cytometric detection methods. Induction of the biosensor lead to increased GFP fluorescence normalized to biosensor cell abundance, as expected, but a significant decrease in relative abundance of the biosensor strain in co-culture and a decrease in bulk GFP fluorescence. Taken together, these results highlight sensitivity of population dynamics to variations in metabolic activity in co-culture and the potential effect of these dynamics on the performance of functional screens in plate-based formats. The engineered strains and model used to evaluate these dynamics provide a framework for optimizing growth of synthetic co-cultures used in screening, testing and pathway engineering applications

High-speed high-power photodiodes are key components in microwave photonic applications including antenna remoting, generation of microwave signals, and analog optical links. With the rapid emergence of Si photonics, it is becoming increasing important to develop approaches to incorporate these photodiodes into a Si platform. For integration of III-V photodiodes on silicon, various integration approaches have been reported, including adhesive wafer bonding, direct molecular wafer bonding, and direct III-V material growth on Si. This paper will report the integration of InGaAs/InGaAsP/InP modified uni-traveling carrier photodiodes using each of these techniques. In addition, high-power Ge on Si photodiodes will be discussed.

We demonstrate the modified uni-travelling-carrier (MUTC) photodiodes achieving RF power levels of 21.7 dBm to 15 dBm in the frequency range of 39 GHz to 60 GHz, respectively, at 1064 nm wavelength. The photodiodes show good linearity with a third-order intercept point (OIP3) up to 33 dBm at 40 GHz.

We report a zero-bias photovaractor that operates up to 60 GHz. The capacitance change is based on the decrease of depletion width and the steep increase of the effective area after illumination. With photocurrent of 12 mA, the reactance at 60 GHz is changed by 280 times relative to the dark condition. S11 parameter fitting shows that the capacitance of a 50-μm diameter device increases by 37 times after illumination. Good agreement is achieved between theory and measured results.

We report avalanche photodiodes (APDs) fabricated from high-aluminum-content Al x In 1− x As y Sb1− y lattice matched to GaSb that is grown within the miscibility gap using a digital alloy approach. The material was initially characterized through a series of Al x In1− x As y Sb1− y ( x = 0.3, 0.4, 0.5, 0.6, 0.7) p-i-n structures. In order to achieve operation at telecommunications wavelengths, an Al x In1− x As y Sb 1− y separate absorption, charge, and multiplication APD has been developed. Very low excess noise, as characterized by k ∼0.01−0.05, has been achieved.

We calculate the amplitude-to-phase (AM-to-PM) noise conversion in a modified unitraveling carrier photodetector. We obtained two nulls as measured in the experiments, and we explain their origin. The nulls appear due to the transit time variation when the average photocurrent varies, and the transit time variation is due to the change of electron velocity when the average photocurrent varies. We also show that the AM-to-PM conversion coefficient depends only on the pulse energy and is independent of the pulse duration when the duration is less than 500 fs. When the pulse duration is larger than 500 fs, the nulls of the AM-to-PM conversion coefficient shift to larger average photocurrents. This shift occurs because the increase in that pulse duration leads to a decrease in the peak photocurrent. The AM-to-PM noise conversion coefficient changes as the repetition rate varies. However, the repetition rate does not change the AM-to-PM conversion coefficient as a function of input optical pulse energy. The repetition rate changes the average photocurrent. We propose a design that would in theory improve the performance of the device.

Introduction Dental models fabricated with 3-dimensional printing technologies are revolutionizing the practice of orthodontics, but they generally comprise polymeric materials that may not be suitable for certain applications, such as soldering appliances. The objective of this study was to investigate the dimensional accuracy and mechanical properties of 3-dimensional printed ceramic-based models before and after various treatments intended to improve their mechanical properties. Methods Thirty identical models were printed 3-dimensionally from a calcium sulfate-based substrate and divided into 3 groups for treatment: high heat (250°C for 30 minutes), low heat (150°C for 30 minutes), and Epsom salt treatment. Each model was scanned before and after treatment with a laser scanner, and dimensional stability was analyzed by digital superimpositions using a best-fit algorithm. The models were weighed before and after treatment to evaluate mass changes. Additionally, 3-dimensional printed cylinders treated as described above and an untreated control group were subjected to compressive mechanical testing (n = 11 per group). Results The Epsom salt treatment group had statistically significant increases in both peak compressive stress and modulus of elasticity when compared with the other treatment groups. All treatment groups had statistically significant changes in mass, with the Epsom salt group gaining mass and the 2 heat-treatment groups losing mass. The low-temperature treatment group had a statistically significantly lower mean average for dimensional deviations (0.026 ± 0.010 mm) than did the other treatment groups (0.069 ± 0.006 and 0.059 ± 0.010 mm for high temperature and Epsom salt, respectively). Conclusions Dental models printed 3-dimensionally with calcium sulfate and treated with Epsom salt showed significant improvement in compressive mechanical properties and retained clinically acceptable dimensional stability.

We demonstrate a III-V avalanche photodiode (APD) grown by heteroepitaxy on silicon. This InGaAs/InAlAs APD exhibits low dark current, gain >20, external quantum efficiency >40%, and similar low excess noise, k∼0.2, as InAlAs APDs on InP.

Zinc(II)-dipicolylamine (Zn-DPA) has been shown to specifically identify and bind to phosphatidylserine (PS), which exists in bulk in the tumor microenvironment. BPRDP056, a Zn-DPA-SN38 conjugate was designed to provide PS-targeted drug delivery of a cytotoxic SN38 to the tumor microenvironment, thereby allowing a lower dosage of SN38 that induces apoptosis in cancer cells. Micro-Western assay showed that BPRDP056 exhibited apoptotic signal levels similar to those of CPT-11 in the treated tumors growing in mice. Pharmacokinetic study showed that BPRDP056 has excellent systemic stability in circulation in mice and rats. BPRDP056 is accumulated in tumors and thus increases the cytotoxic effects of SN38. The in vivo antitumor activities of BPRDP056 have been shown to be significant in subcutaneous pancreas, prostate, colon, liver, breast, and glioblastoma tumors, included an orthotopic pancreatic tumor, in mice. BPRDP056 shrunk tumors at a lower (~20% only) dosing intensity of SN38 compared to that of SN38 conjugated in CPT-11 in all tumor models tested. A wide spectrum of antitumor activities is expected to treat all cancer types of PS-rich tumor microenvironments. BPRDP056 is a first-in-class small molecule drug conjugate for cancer therapy., Highlights • Phosphatidylserine (PS) abundant in tumor microenvironment, a tumor selective marker • BPRDP056, a novel conjugate with a PS-targeting Zn-DPA and cytotoxic payload SN38 • BPRDP056 delivered SN38 of concentrated higher amount to the tumor sites in mice. • Broad spectrum activities against pancreas, prostate, breast tumors were found. • BPRDP056 is a novel small molecule drug conjugate (SMDC) for cancer therapy.

Back-illuminated flip-chip-bonded charge-compensated modified uni-traveling-carrier photodiodes (PDs) with bandwidths in excess of 110 GHz are demonstrated. PDs with 10- and 6-μm-diameters deliver RF output power levels as high as 9.6 dBm at 100 GHz and 7.8 dBm at 110 GHz, respectively. An analytical model based on parameter extraction from S-parameter fitting was used to assess the bandwidth limiting factors.

Until the early 2000's, the avalanche photodiode (APD) was widely deployed in high-performance optical receivers that operated up to 10 Gb/s. In subsequent years, the use of APDs for high-capacity systems declined as a result of their limited gain bandwidth, the transition to coherent detection, and the development of high-efficiency modulation techniques. Recently, the rapid growth of optical-fiber communications systems that utilize baud rates up to 25 Gb/s represented by a 100-Gb/s Ethernet has led to a resurgence of research on APDs and the development of low-noise APDs with enhanced gain bandwidth. This paper presents a brief review of APD fundamentals and describes some of the recent advances.

This paper reviews progress in the field of heterogeneously integrated photodiodes with a focus on InP-based high-speed high-power modified uni-traveling carrier photodiodes on silicon-on-insulator waveguides. Discrete, balanced, and photodiode arrays are described.

We report Al0.8Ga0.2As recessed-window single-photon avalanche photodiodes with high internal single-photon detection efficiency and low dark count probability. External quantum efficiency was increased by a factor of 2 at $\lambda = 405$ nm. Annealing in arsine with hydrogen carrier gas reduced the dark count probability by a factor of 100, to $\sim 10^{-6}$ /gate with a $\sim 5$ ns gate, at room temperature. The activation energies of primary carrier traps, which give rise to afterpulsing, are extracted in a temperature range from 150 to 200 K.

Flexible electronics are being pursued as replacements for rigid consumer electronic products such as smartphones and tablets, as well as for wearable electronics, implantable medical devices, and RFIDs. Such devices require flexible batteries with electrodes that maintain their electro-chemical performance during multiple bending cycles. These electrodes typically consist of an active battery material blend with a conductive additive and a binder. Whilst the choice of active battery material is typically dictated by the desired battery power and energy requirements, there is more freedom in changing the conductive additives to cope with strain induced during the bending of flexible batteries. Here we compare the mechanical and electrical properties of free standing cathodes using lithium cobalt oxide (LiCoO 2) as the active material and 10–20 wt% of amorphous carbon powder (CP) or carbon nanotubes (CNTs) as conductive additives. We found that the CNT based electrodes showed less crack formation during bending and have a Young's modulus up to 30 times higher than CP electrodes (10 wt% loading). Further, the electrical resistance of pristine CNT electrodes is 10 times lower than CP electrodes (20 wt% loading). This difference further increases to a 28 times lower resistance for CNT films after 2000 bending cycles. These superior properties of CNT films are reflected in the electrochemical tests, which show that after bending, only the electrodes with 20 wt% of CNTs remain operational. This study therefore highlights the importance of the conductive additives for developing reliable flexible batteries.

Proper regulation of inflammatory responses is critical for effective function of microglia, in both physiological and disease states. While the mechanisms that drive microglia activation are well characterized, the pathways leading to inflammatory resolution and immune homeostasis have yet to be fully elucidated. Using RNA interference, pharmacological inhibition and genetic knockout mouse model approaches, we show that exosome release promotes immune homeostasis in activated and aged microglia. We demonstrate that induction of anti-inflammatory pathways enhances release of exosomes containing immune proteins and microRNAs. Functionally, inhibition of exosome release alters trafficking of exosome cargo, such as miR-155, in activated microglia resulting in increased cellular retention of these cargo molecules. Concordantly, we identify increased miR-155 activity leading to sustained activation of pro-inflammatory pathways as a potential mechanism underlying impaired inflammatory resolution due to inhibition of microglia exosome release. Similarly, inhibition of augmented exosome release in aged microglia exacerbates inflammatory activation, demonstrating conservation of the immune modulatory effects of exosome release in microglia. Taken together, our study identifies exosomes as novel components of an anti-inflammatory mechanism utilized by activated and aged microglia to restore immune homeostasis.

Silicon carbide Schottky diodes with thick i-regions are reported. Compared with previously reported p-i-n photodiodes, a shift of the absorption peak from 270 nm to 350 nm was observed. The responsivity curves of the Schottky diode are modeled and compared with the experimental data.Silicon carbide Schottky diodes with thick i-regions are reported. Compared with previously reported p-i-n photodiodes, a shift of the absorption peak from 270 nm to 350 nm was observed. The responsivity curves of the Schottky diode are modeled and compared with the experimental data.

The discovery and utilization of biocatalysts that selectively valorize lignocellulose is critical to the profitability of next-generation biorefineries. Here, we report the development of a refactored, whole-cell, GFP-based biosensor for high-throughput identification of biocatalysts that transform lignin into specialty chemicals from environmental DNA of uncultivable archaea and bacteria. The biosensor comprises the transcriptional regulator and promoter of the emrRAB operon of E. coli, and the configuration of the biosensor was tuned with the aid of mathematical model. The biosensor sensitively and selectively detects vanillin and syringaldehyde, and responds linearly over a wide detection range. We employed the biosensor to screen 42 520 fosmid clones comprising environmental DNA isolated from two coal beds and successfully identified 147 clones that transform hardwood kraft lignin to vanillin and syringaldehyde.

Fluorinated methoxy arenes are emerging as important motifs in both agrochemicals and pharmaceuticals. A novel technique for the synthesis of monofluoromethoxy arenes through the direct fluorodecarboxylation of carboxylic acids was developed that uses photosensitizers and N-fluorobenzenesulfonimide (NFSI). Utilization of the oxidatively mild fluorine transfer agent NFSI enabled the synthesis of fluoromethyl ethers that were previously inaccessible with decarboxylative fluorinations performed with Selectfluor. Mechanistic studies are consistent with the photosensitizer effecting oxidation of the aryloxyacetic acid.

In this work, the effects of surface ligands of cadmium selenide (CdSe) nanocrystals on energetic disorder and charge transport of poly (3-hexylthiophene-2,5-diyl):cadmium selenide (P3HT:CdSe) hybrid bulk heterojunction solar cells were studied. Photo-induced current transient spectroscopy (PICTS) was employed to quantitatively characterize the trap state energies in P3HT:CdSe hybrid solar cells from pyridine (Py) and tert-butylthiol (tBT) treated CdSe nanocrystals. A data processing workflow to extract the trap emission spectra was implemented in the form of solving an inverse problem with regularization techniques. We observed significant differences in the trap state distribution in P3HT:CdSe(tBT) compared to P3HT:CdSe(Py) solar cells, and we found that devices based on P3HT:CdSe(Py) had deeper level trap states. Additionally, transient photoconductivity measurements were performed on P3HT:CdSe solar cells for the purpose of examining the effects of ligands on charge transport. The results were self-consistent with PICTS analysis in that P3HT:CdSe(tBT) devices exhibited a greater than three-fold enhancement in carrier mobility relative to P3HT:CdSe(Py) devices, which we attributed to a decreased depth of trap states.

The performance of high power photodiodes flip-chip bonded on multi-crystal aluminum nitride (AlN), single-crystal AlN, and diamond submounts are compared. The thermal boundary conductance of submount-Ti interfaces was measured and found to be the primary impedance to heat dissipation.

We demonstrate hybrid integration of modified uni-traveling carrier photodiodes on a multi-layer silicon nitride platform using total reflection mirrors etched by focused ion beam. The hybrid photodetectors show external responsivity of 0.15 A/W and bandwidth of 3.5 GHz for devices with a diameter of 80 µm. The insertion loss of the waveguide is 3 dB and the coupling efficiency of the total reflection mirror is -3 dB. The highest RF output power is -0.5 dBm measured at 3 GHz with 9 mA photocurrent and -9 V bias.

We demonstrate hybrid integration of modified uni-traveling carrier photodiodes on a multi-layer silicon nitride platform using total internal reflection mirrors. Low-loss high-efficiency coupling of InGaAs detector on a silicon substrate has been realized.

Heterogeneous aluminium gallium nitride (Alx Ga1-xN)/aluminium nitride (AlN)/silicon carbide (SiC) based n-i-p photodetectors have been demonstrated to effectively tailor the spectral response of SiC within the solar-blind regime. The differences in polarization at the hetero-interfaces resulting in negative polarization induced charge at the Alx Ga1-xN/AlN interface and positive polarization induced charge at the AlN/SiC interface has been exploited to create a large barrier to carrier transport across the interface. This barrier impedes the collection of photo-excited holes in the Alx Ga1-xN layers and enables the selective collection of electrons photo-excited to the Γ and L conduction band valleys of SiC while blocking the collection of electrons in the M valley. In this work, the influence of device design, including the AlN layer thickness and Alx Ga1-xN composition, on the spectral response is discussed. Thin AlN barrier layers are easily overcome by electrons generated in all valleys of 4H-SiC with increasing bias voltage while thicker barrier layers successfully minimize the collection of electrons in the M valley of SiC and therefore suppress the long-wavelength response >260 nm. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Silicon photonics provides a promising platform for energy-efficient interconnects within supercomputers and data centers. However, developing a complementary metal–oxide–semiconductor compatible high-speed photodetector with low dark current has long presented a challenge in the field. In this paper, we report the first O-band InAs quantum dot (QD) waveguide photodiode (PD) heterogeneously integrated on silicon. Record low dark currents as low as 0.01 nA, responsivities of 0.34 A/W at 1310 nm and 0.9 A/W at 1280 nm, and a record high 3 dB bandwidth of 15 GHz was measured. Avalanche gain was observed and a maximum gain of up to 45 and a gain bandwidth product (GBP) of 240 GHz were achieved, which are also record high results for any QD avalanche photodetector (APD) on silicon. Additionally, we demonstrate a device sensitivity of −11 dBm at 10 Gb/s and open-eye diagrams up to 12.5 Gb/s. These QD-based PDs are able to operate as p-i-n PDs or APDs under different bias conditions and offer a promising alternative to heterogeneous InGaAs-on-silicon and SiGe counterparts in low-power optical communication links. They also leverage the same epitaxial layers and processing steps as heterogeneously integrated QD lasers, significantly simplifying the processing and reducing the cost of a fully integrated QD transceiver on silicon.

Background Therapeutic drug monitoring of immunosuppressive drugs is important in transplant patients. We developed and validated liquid chromatography–mass spectrometry (LC–MS/MS) assay for simultaneous quantitation of tacrolimus (TaC), sirolimus (SrL), and cyclosporin A (CsA) in dried blood spots (DBSs) to offer patients home sample collection, avoiding travel for blood draws. Methods After extraction, samples were analyzed by LC–MS/MS in multiple reaction monitoring mode. Results The assay was linear between 1.2–40 ng/ml for TaC and SrL, and 30–1000 ng/ml for CsA. Inter- and intra-assay CVs were ≤ 14.8% for all 3 drugs. This method correlated well with the existing clinical whole blood assay, with coefficients of determination > 0.95 for all 3 drugs. DBS quality control samples were stable for at least 30 days at − 20, 4, and 25 °C. Stability of patient DBS samples was at least 5 days at temperatures up to 60 °C, except for SrL where degradation was observed at 60 °C within 24 h. No effect of hematocrit level, blood spot volume or punch location was observed. Conclusion Immunosuppressant levels measured in DBS correlate with whole blood LC–MS/MS assay and may contribute to successful outcome of organ transplant and patient satisfaction.

Dynamic alterations in cell surface glycosylation occur in numerous biological processes that involve cell–cell communication and cell migration. We report here imaging of cell surface glycosylation in live mice using double click chemistry. Cell surface glycans were metabolically labeled using peracetylated azido-labeled N-acetylgalactosamine and then reacted, in the first click reaction, with either a cyclooctyne, in a Huisgen [3 + 2] cycloaddition, or with a Staudinger phosphine, via Staudinger ligation. The second click reaction was a [4 + 2] inverse electron demand Diels–Alder reaction between a trans-cyclooctene and a tetrazine, where the latter reagent had been fluorescently labeled with a far-red fluorophore. After administration of the fluorescent tetrazine, the bifunctional cyclooctyne-cyclooctene produced significant azido sugar-dependent fluorescence labeling of tumor, kidney, liver, spleen, and small intestine in vivo, where the kidney and tumor could be imaged noninvasively in the live mouse.

We demonstrate balanced InGaAs/InP single photon avalanche diodes operated in gated mode for a data transmission rate of up to 20 MHz. The common-mode signal cancellation realized with the balanced configuration enabled detection of small avalanche pulses. For a laser repletion rate of 20 MHz at 240 K, the dark count probability for a photon detection efficiency of 13% is $1.9\times 10^{-5}$ . The afterpulse probability is 0.3% for a 2 ns pulse width, hold-off time of 20 ns, and 10% PDE, at 240 K.

The FilmArray respiratory virus panel detects 15 viral agents in respiratory specimens using polymerase chain reaction. We performed FilmArray respiratory viral testing in a core laboratory at a regional children’s hospital that provides service 24 hours a day 7 days a week. The average and median turnaround time were 1.6 and 1.4 hours, respectively, in contrast to 7 and 6.5 hours documented 1 year previously at an on-site reference laboratory using a direct fluorescence assay (DFA) that detected 8 viral agents. During the study period, rhinovirus was detected in 20% and coronavirus in 6% of samples using FilmArray; these viruses would not have been detected with DFA. We followed 97 patients with influenza A or influenza B who received care at the emergency department (ED). Overall, 79 patients (81%) were given oseltamivir in a timely manner defined as receiving the drug in the ED, a prescription in the ED, or a prescription within 3 hours of ED discharge. Our results demonstrate that molecular technology can be successfully deployed in a nonspecialty, high-volume, multidisciplinary core laboratory.

To evaluate clinical effectiveness, color rebound and sensitivity of 22% carbamide peroxide (CP) with 3% potassium nitrate.Twenty-one participants were enrolled and treated overnight for 2 weeks with 22% CP (Venus White, Heraeus Kulzer). Visual color measurement was performed and expressed in shade guide units (SGU) of Vita Classical (VC) and Vita Bleachedguide 3D Master (BG) shade guides. Instrumental color measurements were performed using an intraoral spectrophotometer (Vita Easyshade Compact, EC). Color measurements were taken on a canine and central incisor at baseline, 2, 3, and 4 weeks. Participants documented sensitivity and data were analysed with Wilcoxon and Bonferroni correction at the 0.05 level of significance.Mean BG SGU difference immediately, 1 and 2 weeks postbleaching compared to baseline was 4.9 (2.1), 4.5 (2.2) and 4.6 (2.0), respectively. Corresponding VC values were 7.0 (3.5), 6.4 (3.3) and 6.5 (3.4), while corresponding ΔE* values were 8.3 (4.1), 8.1 (4.0) and 7.9 (3.5). For visual shade evaluation there was a significant decrease in SGU from baseline and each subsequent week, p0.001. There was no difference between week 3 and week 4 using VC or BG. For instrumental color measurements, there was no difference from week 2 to week 3 for canines and generally no difference between week 3 and week 4 for incisors.Visual and instrumental evaluation showed rebound occurred 1 week postbleaching with 22% carbamide peroxide and 3% potassium nitrate. In general, color was stable at 2 weeks postbleaching. Participants reported low sensitivity levels with a mean value of below 2 on a 0-10 scale.This study demonstrates efficacy with overnight usage of 22% carbamide peroxide with 3% potassium nitrate and demonstrates postbleaching color is stable at two weeks with low tooth sensitivity.

We report on InP-based high power modified uni-traveling carrier (MUTC) photodiodes heterogeneously integrated on silicon on diamond (SOD) waveguides. Typical dark currents of MUTC photodiodes on SOD waveguides are 20 nA at - 5 V bias voltage. A 50-μm long photodiode has an internal responsivity of 1.07 A/W at 1550 nm wavelength. The bandwidths of photodiodes with active areas of 14×25 μm2, 14×50 μm2, 14×100 μm2 and 14×150 μm2 are 22 GHz, 16 GHz, 10 GHz and 7 GHz, respectively. The maximum output RF powers of 14×100 μm2 photodiodes are 13 dBm, 14.4 dBm and 15.3 dBm at 10 GHz, respectively. The maximum DC dissipated power is 0.67 W. To our knowledge, this is the first demonstration of III-V photodiodes integrated on SOD waveguides.

High sensitivity deep ultraviolet (DUV) photodetectors operating at wavelengths shorter than 280 nm are useful for various applications, including chemical and biological identification, optical wireless communications, and UV sensing systems (1). While semiconductor avalanche photodiodes (APDs) can be more compact, lower cost and more rugged than the commonly used photomultiplier tubes (PMTs), commercially available devices such as silicon (Si) single photon counting APDs have poor DUV single photon detection efficiency. In contrast, silicon carbide (SiC) APDs are ideal for high-sensitivity detection applications, as they can possess very low dark currents, small k factor, and high gain (2). However, the responsivity of these devices diminishes at wavelengths shorter than 260 nm due to increasing absorption and carrier generation in the top doped layer of this device, the short diffusion length of minority carriers in this region, and the presence of a high density of surface states.

—We report low-noise avalanche gain from photodiodes composed of a previously uncharacterized alloy, Al x In 1-x As y Sb 1-y , grown lattice-matched on GaSb substrates. By varying the aluminum content the direct bandgap can be tuned from 0.25 eV (0% aluminum) to 1.24 eV (75% aluminum), corresponding to photon wavelengths from 5000 nm to 1000 nm, with the transition from direct-gap to indirect-gap occurring at ~1.18 eV (~72% aluminum), or 1050 nm. This has been used to fabricate separate absorption, charge, and multiplication (SACM) APDs using Al 0.7 In 0.3 As 0.3 Sb 0.7 for the multiplication region and Al 0.4 In 0.6 As 0.3 Sb 0.7 for the absorber. Gain values as high as 100 have been achieved and the excess noise factor is characterized by a k value of 0.01, which is comparable to or below that of Si. In addition, since the bandgap of the absorption region is direct, its absorption depth is 5 to 10 times shorter than indirect-bandgap silicon, potentially enabling significantly higher operating bandwidths.

We present full-depth zonal sections of total dissolved cobalt, iron, manganese, and labile cobalt from the South Atlantic Ocean. A basin-scale plume from the African coast appeared to be a major source of dissolved metals to this region, with high cobalt concentrations in the oxygen minimum zone of the Angola Dome and extending 2500 km into the subtropical gyre. Metal concentrations were elevated along the coastal shelf, likely due to reductive dissolution and resuspension of particulate matter. Linear relationships between cobalt, N2O, and O2, as well as low surface aluminum supported a coastal rather than atmospheric cobalt source. Lateral advection coupled with upwelling, biological uptake, and remineralization delivered these metals to the basin, as evident in two zonal transects with distinct physical processes that exhibited different metal distributions. Scavenging rates within the coastal plume differed for the three metals; iron was removed fastest, manganese removal was 2.5 times slower, and cobalt scavenging could not be discerned from water mass mixing. Because scavenging, biological utilization, and export constantly deplete the oceanic inventories of these three hybrid-type metals, point sources of the scale observed here likely serve as vital drivers of their oceanic cycles. Manganese concentrations were elevated in surface waters across the basin, likely due to coupled redox processes acting to concentrate the dissolved species there. These observations of basin-scale hybrid metal plumes combined with the recent projections of expanding oxygen minimum zones suggest a potential mechanism for effects on ocean primary production and nitrogen fixation via increases in trace metal source inputs.

Monte Carlo simulation is performed on a low-noise, three-stage tandem avalanche photodiode with InAlAs/InAlGaAs impact-ionization-engineered multiplication region. The simulated excess noise factor agrees well with experimental measurements. A modified structure to further reduce the excess noise is proposed.