Development of flashlamp-pumped Q-switched Ho:Tm:Cr:YAG lasers for mid-infrared LIDAR application

A flashlamp-pumped 2.1 micron Ho:Tm:Cr:YAG laser was studied for both normal mode and Q-switched operations under a wide variety of experimental conditions in order to optimize performance. Laser output energy, slope efficiency, threshold and pulselength were determined as a function of operating temperature, output mirror reflectivity, input electrical energy and Q-switch opening time. The measured normal-mode laser thresholds of a Ho(3+) (0.45 atomic percent):Tm(3+) (2.5 atomic percent):Cr(3+) (0.8 atomic percent):YAG crystal ranged form 26 to 50 J between 120 and 200 K with slope efficiencies up to 0.36 percent with a 60 percent reflective output mirror. Under Q-switched operation the slope efficiency was 90 percent of the normal-mode result. Development of solid state lasers with Ho(3+), Tm(3+) and/or Er(3+) doped crystals has been pursued by NASA for eye-dafe mid-infrared LIDAR (light detection and ranging) application. As a part of the project, the authors have been working on evaluating Ho(3+):Tm(3+):Cr(3+):YAG crystals for normal-mode and Q-switched 2.1 micron laser operations in order to determine an optimum Tm(3+) concentration under flashlamp pumping conditions. Lasing properties of the Ho(3+) in the mid-infrared region have been studied by many research groups since the early 1960's. However, the technology of those lasers is still premature for lidar application. In order to overcome the inefficiency related to narrow absorption bands of the Ho(3+), Tm(3+) and Er(3+), the erbium has been replaced by chromium. The improvement in flashlamp-pumped Ho(3+) laser efficiency has been demonstrated recently by several research groups by utilizing the broad absorption spectrum of Cr(3+) which covers the flashlamp's emission spectrum. Efficient energy transfer to the Tm(3+) and then the Ho(3+) occurs subsequently. It is known that high Tm(3+) concentration and low Ho(3+) concentration are preferred to achieve a quantum efficiency approaching two and to avoid large reabsorption losses. However, determination of the optimum Tm(3+) concentration required to ensure efficient energy transfer from Cr(3+) to Tm(3+) and from Tm(3+) to Ho(3+) has not been made in the Ho:Tm:CR:YAG crystal. The results obtained so far are given

Deficiency of Capicua disrupts bile acid homeostasis

Capicua (CIC) has been implicated in pathogenesis of spinocerebellar ataxia type 1 and cancer in mammals; however, the in vivo physiological functions of CIC remain largely unknown. Here we show that Cic hypomorphic (Cic-L-/-) mice have impaired bile acid (BA) homeostasis associated with induction of proinflammatory cytokines. We discovered that several drug metabolism and BA transporter genes were down-regulated in Cic-L-/- liver, and that BA was increased in the liver and serum whereas bile was decreased within the gallbladder of Cic-L-/- mice. We also found that levels of proinflammatory cytokine genes were up-regulated in Cic-L-/- liver. Consistent with this finding, levels of hepatic transcriptional regulators, such as hepatic nuclear factor 1 alpha (HNF1 alpha), CCAAT/enhancer-binding protein beta (C/EBP beta), forkhead box protein A2 (FOXA2), and retinoid X receptor alpha (RXR alpha), were markedly decreased in Cic-L-/- mice. Moreover, induction of tumor necrosis factor alpha (Tnf alpha) expression and decrease in the levels of FOXA2, C/EBP beta, and RXRa were found in Cic-L-/- liver before BA was accumulated, suggesting that inflammation might be the cause for the cholestasis in Cic-L-/- mice. Our findings indicate that CIC is a critical regulator of BA homeostasis, and that its dysfunction might be associated with chronic liver disease and metabolic disorders.open11810Ysciescopu

Fouling and performance of outer selective hollow fiber membrane in osmotic membrane bioreactor: Cross flow and air scouring effects

© 2019 Elsevier Ltd This study assessed impacts of cross-flow velocity (CFV) and air scouring on the performance and membrane fouling mitigation of a side-stream module containing outer-selective hollow fiber thin film composite forward osmosis membrane in osmosis membrane bioreactor (OMBR) system for urban wastewater treatment. CFV of draw solution was optimized, followed by the impact assessment of three CFVs on feed solution (FS) stream and periodic injection of air scouring into the side-stream module. Overall, the OMBR system exhibited high and stable performance with initial water flux of approximately 15 LMH, high removal efficiencies of bulk organic matter and nutrients. While FS's CFVs insignificantly affected the performance and membrane fouling, regular air scouring showed substantial impact with better performance and high efficiency in mitigating membrane fouling. These results indicated that periodic air scouring can be applied into the side-stream membrane module for efficient fouling mitigation without interruption the operation of the OMBR system

Fertilizer drawn forward osmosis process for sustainable water reuse to grow hydroponic lettuce using commercial nutrient solution

© 2017 Elsevier B.V. This study investigated the sustainable reuse of wastewater using fertilizer drawn forward osmosis (FDFO) process through osmotic dilution of commercial nutrient solution for hydroponics, a widely used technique for growing plants without soil. Results from the bench-scale experiments showed that the commercial hydroponic nutrient solution (i.e. solution containing water and essential nutrients) exhibited similar performance (i.e., water flux and reverse salt flux) to other inorganic draw solutions when treating synthetic wastewater. The use of hydroponic solution is highly advantageous since it provides all the required macro- (i.e., N, P and K) and micronutrients (i.e., Ca, Mg, S, Mn, B, Zn and Mo) in a single balanced solution and can therefore be used directly after dilution without the need to add any elements. After long-term operation (i.e. up to 75% water recovery), different physical cleaning methods were tested and results showed that hydraulic flushing can effectively restore up to 75% of the initial water flux while osmotic backwashing was able to restore the initial water flux by more than 95%; illustrating the low-fouling potential of the FDFO process. Pilot-scale studies demonstrated that the FDFO process is able to produce the required nutrient concentration and final water quality (i.e., pH and conductivity) suitable for hydroponic applications. Coupling FDFO with pressure assisted osmosis (PAO) in the later stages could help in saving operational costs (i.e., energy and membrane replacement costs). Finally, the test application of nutrient solution produced by the pilot FDFO process to hydroponic lettuce showed similar growth pattern as the control without any signs of nutrient deficiency

Cosmological constraints from Gauss-Bonnet braneworld with large-field potentials

We calculate the spectral index and tensor-to-scalar ratio for patch inflation defined by $H^2\approx \beta^2_q V^q$ and $\dot{\phi}\approx -V'/3H$, using the slow-roll expansion. The patch cosmology arisen from the Gauss-Bonnet braneworld consists of Gauss-Bonnet (GB), Randall-Sundrum (RS), and 4D general relativistic (GR) cosmological models. In this work, we choose large-field potentials of $V=V_0\phi^p$ to compare with the observational data. Since second-order corrections are rather small in the slow-roll limit, the leading-order calculation is sufficient to compare with the data. Finally, we show that it is easier to discriminate between quadratic potential and quartic potential in the GB cosmological model rather than the GR or RS cosmological models.Comment: 13 pages, title changed, version to appear in JCA

Update on Prevention, Diagnosis, and Treatment of Chronic Hepatitis B: AASLD 2018 Hepatitis B Guidance

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145507/1/cld728.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145507/2/cld728_am.pd

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Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146328/1/hep30137_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146328/2/hep30137.pd

Unresectable gastric cancer with gastric outlet obstruction and distant metastasis responding to intraperitoneal and folfox chemotherapy after palliative laparoscopic gastrojejunostomy: report of a case

<p>Abstract</p> <p>Background</p> <p>Gastric outlet obstruction (GOO) caused by unresectable gastric cancer is a challenging aspect of patient care. There have been no reports involving patients with obstructing gastric cancer and several incurable factors curatively treated by multimodal treatments.</p> <p>Case presentation</p> <p>We report a case of 55-year-old man who was diagnosed with a poorly differentiated adenocarcinoma in the pre-pyloric antrum with GOO by gastroscopy. An abdominal computed tomography (CT) scan revealed thickening of the gastric wall and adjacent fat infiltration, and a large amount of food in the stomach suggesting a passage disturbance, enlarged lymph nodes along the common hepatic and left gastric arteries, and multiple hepatic metastases. The serum carcinoembryonic antigen (CEA) level was 343 ng/ml and the carbohydrate antigen (CA) 19-9 level was within normal limits. The patient underwent a laparoscopic gastrojejunostomy for palliation of the GOO. On the 3^rdand 12^thdays after surgery, he received intraperitoneal chemotherapy with 40 mg of docetaxel and 150 mg of carboplatin. Simultaneously, combined chemotherapy with 85 mg/m²of oxaliplatin for the 1^stday and 600 mg/m²of 5-FU for 2 days (FOLFOX regimen) was administered from the 8^thpost-operative day. After completion of nine courses of FOLFOX, the patient achieved a complete response (CR) with complete disappearance of the primary tumor and the metastatic foci. He underwent a radical subtotal gastrectomy with D3 lymph node dissection 4 months after the initial palliative surgery. The pathologic results revealed no residual primary tumor and no lymph node metastasis in 43 dissected lymph nodes. He has maintained a CR for 18 months since the last operation.</p> <p>Conclusion</p> <p>Combination chemotherapy with systemic and intraperitoneal chemotherapy following laparoscopic bypass surgery showed marked efficacy in the treatment for unresectable advanced gastric cancer with GOO.</p

Low resistance n-contact for UVC LEDs by a two-step plasma etching process

The impact of plasma etching on the formation of low-resistance n-contacts on the AlGaN:Si current spreading layer during the chip fabrication of ultraviolet light-emitting diodes (UV LEDs) emitting at 265 nm is investigated. A two-step plasma etching process with a first rapid etching using BCl3/Cl2 gas mixture and a second slow etching step using pure Cl2 gas has been developed. The etching sequence provides smooth mesa side-walls and an n-AlGaN surface with reduced surface damage. Ohmic n-contacts with a contact resistivity of 3.5 × 10−4 Ωcm2 are obtained on Si-doped Al0.65Ga0.35N layers and the operating voltages of the UVC LEDs were reduced by 2 V for a current of 20 mA.BMBF, 03ZZ0134B, Zwanzig20 - Advanced UV for Life - Verbundvorhaben: UV Power; TP2: Entwicklung von high-power UVB-LEDs um 300 nmBMBF, 03ZZ0134C, Zwanzig20 - Advanced UV for Life - Verbundvorhaben: UV Power; TP3: Epitaxieentwicklung für high-power UVC-LEDs um 260 n

Plasma Electronics

Contains reports on seventeen research projects.National Science Foundation (Grant GK-57)United States Atomic Energy Commission (Contract AT(30-1)-3285)United States Atomic Energy Commission under Contract AT(30-1)-322