Hydrodechlorination reactions on silica-supported rhodium catalysts

The objectives of this study were to investigate the pathways of the hydrodechlorination reactions over silica-supported Rh catalysts as well as identify selectivities and deactivation properties. Reaction of 1,2-dichloroethane with hydrogen over Rh/SiO2 catalyst was studied in the temperature range 200 to 300°C. Formation of two intermediates was proposed while 1,2-dichloroethane was adsorbed on the catalyst, the reactive intermediates then produce ethane, ethylene, chloroethane and methane. From the methane formation, it was inferred that the ethane hydrogenolysis occured over the Rh/SiO2 catalysts. Higher conversion to C1 and C2 hydrocarbons was observed at higher reaction temperature. The activation energy was found to be 13 Kcal/mole. Hydrodechlorination of trichloroethylene was studied to gain information on controlling parameters to manage trichloroethylene pollution emissions in vapor-degreasing applications. Reaction temperature above 150°C, longer contact time, and reactant partial pressure below 100 torr effectively promoted the conversion to hydrocarbon formation. The activation energy was 13.9 Kcal/mole. The data showed that two Cl atoms on the α( carbon did not need to be removed simultaneously during the reaction. The deactivation on Rh/SiO2 catalyst was also studied. A comparion of the ethylene hydrogenation on fresh and contaminated catalysts (after reaction with 1,1-dichloro-ethane) showed a negative effect on the product selectivity to ethane formation, for the deactivated catalyst. The varied selectivity for CH4 and C2H6 demonstrated that at least two distinct types of active sites existed on the catalyst surface

Preliminary Outcomes of Temporary Collagen Punctal Plugs for Patients with Dry Eye and Glaucoma

The aim of this study was using a temporary collagen punctal plug as a pre-test before decision of permanent punctal closure or long-term plug use for patients with dry eye disease (DED) and primary open-angle glaucoma (POAG). This case-control study was conducted at a single office in Honolulu, Hawaii from January 2017 to August 2018. In the case group, a temporary collagen plug was used in 33 eyes of 33 patients with DED and POAG who were receiving glaucoma medications with good control. On the other hand in the control group, 33 eyes of 33 patients with DED and POAG who were receiving glaucoma medications with good control were included, but punctal plug was not used. In the case group, one of the lower lid puncta was selected for the study and a canalicular rod shape plug was inserted as a therapeutic trial to predict the efficacy of long-term punctal plug placement or punctal closure. The mean changes of intraocular pressure (IOP) and improvement in symptoms/signs of DED were compared between the two study groups. Results revealed a statistically significant IOP reduction in the case group compared to the control group. Furthermore, DED improved significantly more in the case group compared to the control group (P< 0.001). We concluded that temporary punctal plug in patients with DED and POAG can significantly improve DED and lower IOP. Therefore, we could consider permanent punctal closure or long-term plug for patients with DED and POAG who responded well to temporary punctal plug without epiphora or other complications

Competition and Integration Strategy Analysis of Advertisement-Supported Social Networked Related Services

Social networking related services (SNS) become increasingly popular communication and interaction mediums over internet. As most of the SNS are free, the providers generate revenues from advertising and other extension services. This paper investigates the advertising strategy and the strategic of compatibility and co-opetition between two social networking related services.. Utilizing game theoretic model, we show that the providers will benefit from both service and business integration, however, the users are always worse when SNS services are compatibly connected. The users will always gain from the quality (features) competition, however, brand competition may hurt the customers as more disturbing ads will be exerted. In general, business integration will result in a higher diversity if ads exerted in two IM services

A Synthetical Approach for Blog Recommendation Mechanism: Trust, Social Relation, and Semantic Analysis

Weblog is a good paradigm of online social network which constitutes web-based regularly updated journals with reverse chronological sequences of dated entries, usually with blogrolls on the sidebars, allowing bloggers link to favorite site which they are frequently visited. In this study we propose an elaborate blog recommendation mechanism that combines trust model, social relation and semantic analysis and illustrate how it can be applied to a prestigious online blogging system – Wretch in Taiwan. By preliminary results of experimental study, we found some implications and empirically prove some theories in domain of social networking, and the example reveals that the proposed recommendation mechanism is quite feasible and promising

Preliminary Outcomes of Temporary Collagen Punctal Plugs for Patients with Dry Eye and Glaucoma

The aim of this study was using a temporary collagen punctal plug as a pre-test before decision of permanent punctal closure or long-term plug use for patients with dry eye disease (DED) and primary open-angle glaucoma (POAG). This case-control study was conducted at a single office in Honolulu, Hawaii from January 2017 to August 2018. In the case group, a temporary collagen plug was used in 33 eyes of 33 patients with DED and POAG who were receiving glaucoma medications with good control. On the other hand in the control group, 33 eyes of 33 patients with DED and POAG who were receiving glaucoma medications with good control were included, but punctal plug was not used. In the case group, one of the lower lid puncta was selected for the study and a canalicular rod shape plug was inserted as a therapeutic trial to predict the efficacy of long-term punctal plug placement or punctal closure. The mean changes of intraocular pressure (IOP) and improvement in symptoms/signs of DED were compared between the two study groups. Results revealed a statistically significant IOP reduction in the case group compared to the control group. Furthermore, DED improved significantly more in the case group compared to the control group (P< 0.001). We concluded that temporary punctal plug in patients with DED and POAG can significantly improve DED and lower IOP. Therefore, we could consider permanent punctal closure or long-term plug for patients with DED and POAG who responded well to temporary punctal plug without epiphora or other complications

Dynamic region of interest transcoding for multipoint video conferencing

This paper presents a region of interest transcoding scheme for multipoint video conferencing to enhance the visual quality. In a multipoint videoconference, usually there are only one or two active conferees at one time which are the regions of interest to the other conferees involved. We propose a Dynamic Sub-Window Skipping (DSWS) scheme to firstly identify the active participants from the multiple incoming encoded video streams by calculating the motion activity of each sub-window, and secondly reduce the frame-rates of the motion inactive participants by skipping these less-important subwindows. The bits saved by the skipping operation are reallocated to the active sub-windows to enhance the regions of interest. We also propose a low-complexity scheme to compose and trace the unavailable motion vectors with a good accuracy in the dropped inactive sub-windows after performing the DSWS. Simulation results show that the proposed methods not only significantly improve the visual quality on the active subwindows without introducing serious visual quality degradation in the inactive ones, but also reduce the computational complexity and avoid whole-frame skipping. Moreover, the proposed algorithm is fully compatible with the H.263 video coding standard. 1

Sodium Fluorescein Staining of the Cornea for the Diagnosis of Dry Eye: A Comparison of Three Eye Solutions

The purpose of this study was to identify which of the eye solutions is best for sodium fluorescein staining of the cornea to diagnose dry eye disease. The study included 173 eyes with suspected or known dry eye disease. The eyes were stained sequentially with sodium fluorescein and each of the following four conditions: balanced salt solution (BSS); BSS and cyclosporine 0.05% emulsion; BSS and lipids containing omega-3; and BSS, cyclosporine 0.05% emulsion, and lipids containing omega-3. Our results showed that compared to BSS alone, artificial tears with cyclosporine 0.05% emulsion and lipids containing omega-3 remain in the cornea for longer periods, thus allowing the clinician to evaluate tear break-up time and visualize corneal punctate erosions

Power Allocation and Time-Domain Artificial Noise Design for Wiretap OFDM with Discrete Inputs

Optimal power allocation for orthogonal frequency division multiplexing (OFDM) wiretap channels with Gaussian channel inputs has already been studied in some previous works from an information theoretical viewpoint. However, these results are not sufficient for practical system design. One reason is that discrete channel inputs, such as quadrature amplitude modulation (QAM) signals, instead of Gaussian channel inputs, are deployed in current practical wireless systems to maintain moderate peak transmission power and receiver complexity. In this paper, we investigate the power allocation and artificial noise design for OFDM wiretap channels with discrete channel inputs. We first prove that the secrecy rate function for discrete channel inputs is nonconcave with respect to the transmission power. To resolve the corresponding nonconvex secrecy rate maximization problem, we develop a low-complexity power allocation algorithm, which yields a duality gap diminishing in the order of O(1/\sqrt{N}), where N is the number of subcarriers of OFDM. We then show that independent frequency-domain artificial noise cannot improve the secrecy rate of single-antenna wiretap channels. Towards this end, we propose a novel time-domain artificial noise design which exploits temporal degrees of freedom provided by the cyclic prefix of OFDM systems {to jam the eavesdropper and boost the secrecy rate even with a single antenna at the transmitter}. Numerical results are provided to illustrate the performance of the proposed design schemes.Comment: 12 pages, 7 figures, accepted by IEEE Transactions on Wireless Communications, Jan. 201