3,067 research outputs found
The antihypertensive effects of the Jamaican Cho-Cho (Sechium edule)
No full textThe experiments reported in this study constitute a preliminary investigation into the possible hypotensive effect of the Jamaican Cho-Cho (Sechium edule). Experiments were conducted in a random and blind fashion on two sub species of Sechium edule. Both the pulp and the peel were examined for hypotensive activity. Water-soluble extracts were prepared from these components of the fruit and injected into anaesthetised rats. Various cardiovascular parameters were measured including heart rate, mean arterial pressure (MAP) and several ECG intervals. We report that all extracts tested produced a fall in blood pressure with little change in ECG intervals. Extract B produced the least change in heart rate with a fall in MAP of approximately 23 mmHg. Changes in heart rate with all extracts appeared to be minimal as an ED25 value could only be determined for extract A, and ED10 values could not be evaluated for extracts C and D. The mechanism(s) by which these extracts produce their hypotensive effects could not be determined in these preliminary experiments. However, it appears not to involve direct effects on cardiac tissue. This conclusion is based on the finding that it took a minimum of 10 to 15 seconds for the hypotensive action to manifest post bolus. Future experiments will be aimed at delineating the mechanism(s) involved in decreasing MAP.Peer reviewedfinal article publishe
Considering spurious timeout in proxy for improving TCP performance in wireless networks
No full textIn this paper, we introduce a new proxy that effectively prevents unnecessary retransmissions of Transmission Control Protocol data segments from flowing over a wireless link on a path with sudden delay. The proposed Spurious Timeout Detection (STD) algorithm detects spurious timeout based on the data and acknowledge sequence number. It responses to spurious timeout by filtering unnecessary data transmissions that can cause spurious fast retransmission. Simulation result shows that proposed STD algorithm performs better than, or as well as, other end-to-end mechanisms in a certain range of data rate. (C) 2003 Published by Elsevier B.V.
Site-selective enzymatic C‒H amidation for synthesis of diverse lactams
No full textPlease note that this work has been retracted by the authors.After publication of the Report “Site-selective enzymatic C‒H amidation for synthesis of diverse lactams” in Science (1, also linked in metadata), efforts to reproduce the work showed that the enzymes do not catalyze the reactions with the activities and selectivities claimed. Careful examination of the first author’s lab notebook then revealed missing contemporaneous entries and raw data for key experiments. The authors therefore have retracted the article from Science and are now retracting the preprint from ChemRxiv. The original paper can be accessed by selecting “Version 1” of the preprint below, or by accessing https://doi.org/10.26434/chemrxiv.7711418.v1. Inha Cho, Zhi-Jun Jia, Frances H. Arnold*Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.*Corresponding author. Email: [email protected]. I. Cho, Z.-J. Jia, F. H. Arnold, Science 364, 575 (2019). DOI: 10.1126/science.aaw9068*******************************************************************************************Directed evolution of cytochrome P450 enzymes fine-tunes site selectivity of new-to-nature C‒H amidation for modular, sustainable and scalable preparation of enantio-enriched β-, γ- and δ-lactams.</p
Assessing User Attitudes Toward Mobile Commerce In The U.S. Vs. Korea: Implications For M-Commerce CRM
No full textMobile Commerce (m-commerce) relies on “customer or user interactions” via a mobile device and telecommunications infrastructure for the purpose of interacting, advertising, promoting, and selling products and services. The author of this study explored user attitudes and behavior toward m-commerce in the U.S. vs. Korea. In this paper, the author investigated comparison analysis for the U.S. vs. Korea for the following issues: 1) the factors affecting user attitudes toward mobile phone business; 2) how those factors affect perceived ease of use (EOU) and usefulness (U); 3) the effects of perceived ease of use (EOU) and usefulness (U) on overall attitudes toward the mobile phone business; and 4) how overall attitudes toward mobile phone business affect user/customer satisfaction. Surveys were conducted in two countries and the results reveal the different aspects affecting mobile phone usage in the U.S. vs. Korea. This study also found that user attitudes toward the mobile phone business significantly impact the level of m-satisfaction. Furthermore, this study provides managerial implications and offers suggestions to m-businesses.1
Real-time Multi-UAV Task Assignment in Dynamic and Uncertain Environments
No full textThis work was sponsored by the Department of the Air Force under Air Force Contract No. FA8721-05-C-0002. Opinions, interpretations, conclusions and recommendations are those of the authors and are not necessarily endorsed
by the United States Government
Gonioctena (Gonioctena) jolantae Cho 2022, new species
No full textGonioctena (Gonioctena) jolantae new species (Figs 1–2, 7, 12) Type locality. Laos: Houaphanh Province, Phou Pan Mountain. Type material. Holotype: ♂ (NHM), “NE LAOS, Hua Phan prov. Ban Saleui, Phou Pan (Mt.) - N 20°12’ E 104°01’ 1300-1900m, 3-30.iv.2014 C. Holzschuh leg. // BMNH{E} 2015-38 C. Holzschuh // NHMUK 010899434 // HOLOTYPUS Gonioctena jolantae sp. nov. des. H.W. Cho 2021”. Paratypes: 3 ♂♂, 1 ♀ (NHM), same data as holotype plus “NHMUK 010901079 // NHMUK 010901419 // NHMUK 010901067 // NHMUK 010901080 // PARATYPUS Gonioctena jolantae sp. nov. des H.W. Cho 2021”. Diagnosis. This new species is similar to G. fujiana and G. kamikawai, in that the pronotum has nine black spots and elytral punctures are arranged in irregular single or double rows. However, G. jolantae new species can be distinguished by the following characters: irregularly outlined yellowish-brown markings on the elytral humeri extend to 3/5 of the elytral base (to 1/2 of base in G. fujiana, and 1/3 to 3/5 of base in G. kamikawai); median lobe subparallel-sided with apical process narrower than median lobe shaft, the sides rounded (parallel-sided with apical process broader than median lobe shaft and sides angulate in G. fujiana; subparallel-sided with apical process narrower than median lobe shaft and sides angulate in G. kamikawai). Description. Measurements in mm (n = 3): Length of body: 5.60–6.55 (mean 6.01); width of body: 3.36–3.98 (mean 3.57); height of body: 2.13–2.66 (mean 2.36); width of head: 1.56–1.78 (mean 1.68); interocular distance: 1.02–1.18 (mean 1.09); width of apex of the pronotum: 1.76–2.10 (mean 1.93); width of base of the pronotum: 2.58–3.19 (mean 2.87); maximum width of pronotum: 2.58–3.19 (mean 2.87); length of pronotum along midline: 1.31–1.45 (mean 1.38); length of elytra along suture: 4.18–4.95 (mean 4.44). Body oblong-ovate and moderately convex (Figs 1, 2). Head dark reddish-brown with two black spots on the vertex. Mouthparts dark reddish-brown with apices of mandibles black. Antennomeres I–V yellowish-brown; VI–VII darkened; VIII–XI blackish-brown. Pronotum reddish-brown with nine black spots. Elytra coppery-brown, lateral margins yellowish-brown, with feeble metallic greenish-black lustre; humeri with black spots surrounded by irregularly defined yellowish-brown markings. Venter and legs entirely reddish-brown. Head. Vertex weakly convex, covered with moderately dense punctures, becoming denser toward the sides. Frontal suture V-shaped, coronal suture weak. Frons flat, strongly depressed at the anterior margin, covered with dense punctures. Clypeus rather narrow and trapezoidal. Anterior margin of labrum weakly concave. Mandibles with two sharp apical teeth and deep lateral excavations for maxillary palpomeres. Maxillary palpi four-segmented with apical palpomeres moderately widened, truncate apically. Antennae reaching pronotal base in male, almost reaching base in female; antennomere I robust and longest; II longer than III; III longer than IV; VI–X widened; XI about 1.54 times as long as wide. Pronotum. In dorsal view widest at or near base, moderately convexly narrowed anteriorly, anterior angles strongly produced. Anterior and lateral margins bordered; lateral margins usually distinct in dorsal view. Trichobothria absent from anterior angles, present on posterior angles. Disc covered with sparse to dense punctures; lateral sides covered with much larger and denser punctures; interspaces covered with fine and sparse punctures. Scutellum. Slightly wider than long, narrowed posteriorly. Elytra. In dorsal view moderately widened posteriorly, widest beyond middle, roundly narrowed posteriorly. Humeral calli well developed. Disc with irregular large punctures arranged in 11 irregular single or double rows, including short scutellar row; interspaces with finer sparse punctures. Epipleura mostly visible (except the apical 2/5) in lateral view. Hind wings well developed. Venter. Pronotal hypomera weakly rugose with coarse punctures on anterior 1/5. Prosternum with coarse and dense punctures bearing long setae; prosternal process enlarged apically, bordered laterally, with sparse punctures. Metaventrite with minute and sparse punctures medially, large and dense punctures laterally. Abdominal ventrites with sparse to dense punctures bearing short setae; apex of last visible abdominal ventrite weakly depressed in male. Legs. Moderately robust. Tibiae widened apically, each with tooth-like projection. Forelegs with tarsomere I slightly narrower than III in male; distinctly narrower than III in female. Tarsal claws appendiculate. Genitalia. Median lobe in dorsal view long, subparallel-sided, moderately constricted from apical 1/4 to expanded arcuate apex with rounded lateral angles (Fig. 7); in lateral view entirely thin, moderately curved, with pointed apex; distal tip of flagellum trifurcated. Spermatheca absent. Etymology. Dedicated to the well-known chrysomelidist, Professor Jolanta Świętojańska (University of Wrocław, Poland), who has always kindly supported the work of the author. Distribution. Laos: Houaphanh (Fig. 12). This species is disjunct in distribution with respect to other members of the species-group, being over 1,500 km distant from the nearest species in East China.Published as part of Cho, Hee-Wook, 2022, Two new species of the nominotypical subgenus Gonioctena Chevrolat, 1836, from China and Laos, and a proposed new species-group (Coleoptera: Chrysomelidae: Chrysomelinae), pp. 111-120 in Zootaxa 5150 (1) on page 113, DOI: 10.11646/zootaxa.5150.1.6, http://zenodo.org/record/661011
SEEDING to Enable Sensitive Electrochemical Detection of Biomarkers in Undiluted Biological Samples
No full textElectrochemical biosensors have shown great potential for simple, fast, and cost-effective point-of-care diagnostic tools. However, direct analysis of complex biological fluids such as plasma has been limited by the loss of sensitivity caused by biofouling. By increasing the surface area, the nanostructured electrode can improve detection sensitivity. However, like a double-edged sword, a large surface area increases the nonspecific adsorption of contaminating proteins. The use of nanoporous structures may prevent fouling proteins. However, there is no straightforward approach for creating nanostructured and nanoporous surfaces compatible with microfabricated thin-film electrodes. Herein, the preferential etching of chloride and surfactant-assisted anisotropic gold reduction to create homogeneous, nanostructured, and nanoporous gold electrodes is demonstrated, yielding a 190 ?? 20 times larger surface area within a minute without using templates. This process, ???surfactant-based electrochemical etch-deposit interplay for nanostructure/nanopore growth??? (SEEDING), on electrodes enhances the sensitivity and antibiofouling capabilities of amperometric biosensors, enabling direct analysis of tumor-derived extracellular vesicles (tEVs) in complex biofluids with a limit of detection of 300 tEVs ??L???1 from undiluted plasma and good discrimination between patients with prostate cancer from healthy ones with an area under the curve of 0.91 in urine and 0.90 in plasma samples
Treadmill exercise represses neuronal cell death and inflammation during Aβ-induced ER stress by regulating unfolded protein response in aged presenilin 2mutant mice
No full textAlzheimer’s disease (AD) is characterized by the deposition ofaggregated amyloid-beta (Aβ), which triggers a cellular stress response called the unfolded protein response (UPR). The UPR signaling pathway is a cellular defense system for dealing with the accumulation of misfolded proteins but switches to apoptosis when endoplasmic reticulum (ER) stress is prolonged. ER stress is involved in neurodegenerative diseases including AD, but the molecular mechanisms of neuronal apoptosis and inflammation by Aβ-induced ER stress to exercise training are not fully understood. Here, we demonstrated that treadmill exercise (TE) prevented PS2 mutation-induced memory impairment and reduced Aβ-42 deposition through the inhibition of β-secretase (BACE-1) and its product, C-99 in cortex and/or hippocampus of aged PS2 mutant mice. We also found that TE down-regulated the expression of GRP78/Bip and PDI proteins and inhibited activation of PERK, eIF2α, ATF6α, sXBP1 and JNK-p38 MAPK as well as activation of CHOP, caspase-12 and caspase-3. Moreover, TE up-regulated the expression of Bcl-2 and down-regulated the expressions of Bax in the hippocampus of aged PS2 mutant mice. Finally, the generation of TNFα and IL-1α and the number of TUNEL-positive cells in the hippocampus of aged PS2 mutant mice was also prevented or decreased by TE. These results showed that TE suppressed the activation of UPR signaling pathways as well as inhibited the apoptotic pathways of the UPR and inflammatory response following Aβ-induced ER stress. Thus, therapeutic strategies that modulate Aβ-induced ER stress through TE could represent a promising approach for the prevention or treatment of AD
sj-pdf-1-pmt-10.1177_87551225211051015 – Supplemental material for A Continuing Education Activity Durably Addressed Knowledge Gaps Related to Penicillin Allergies Among Pharmacists and Pharmacy Technicians
No full textSupplemental material, sj-pdf-1-pmt-10.1177_87551225211051015 for A Continuing Education Activity Durably Addressed Knowledge Gaps Related to Penicillin Allergies Among Pharmacists and Pharmacy Technicians by Elizabeth W. Covington, Spencer H. Durham, Christopher M. Bland, P. Brandon Bookstaver, Elias B. Chahine, Jonathan C. Cho, Fernando Diggs, Bruce M. Jones, Jeffrey A. Kyle, Kayla R. Stover, Jamie L. Wagner and Peter J. Hughes in Journal of Pharmacy Technology</p
sj-pdf-3-pmt-10.1177_87551225211051015 – Supplemental material for A Continuing Education Activity Durably Addressed Knowledge Gaps Related to Penicillin Allergies Among Pharmacists and Pharmacy Technicians
No full textSupplemental material, sj-pdf-3-pmt-10.1177_87551225211051015 for A Continuing Education Activity Durably Addressed Knowledge Gaps Related to Penicillin Allergies Among Pharmacists and Pharmacy Technicians by Elizabeth W. Covington, Spencer H. Durham, Christopher M. Bland, P. Brandon Bookstaver, Elias B. Chahine, Jonathan C. Cho, Fernando Diggs, Bruce M. Jones, Jeffrey A. Kyle, Kayla R. Stover, Jamie L. Wagner and Peter J. Hughes in Journal of Pharmacy Technology</p
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