Transmission models indicate Ebola virus persistence in non-human primate populations is unlikely

Infectious diseases that kill their hosts may persist locally only if transmission is appropriately balanced by susceptible recruitment. Great apes die of Ebola virus disease (EVD) and have transmitted ebolaviruses to people. However, understanding the role that apes and other non-human primates play in maintaining ebolaviruses in Nature is hampered by a lack of data. Recent serological findings suggest that few non-human primates have antibodies to EVD-causing viruses throughout tropical Africa, suggesting low transmission rates and/or high EVD mortality (Ayouba A et al. 2019 J. Infect. Dis. 220, 1599–1608 (doi:10.1093/infdis/jiz006); Mombo IM et al. 2020 Viruses 12, 1347 (doi:10.3390/v12121347)). Here, stochastic transmission models of EVD in non-human primates assuming high case-fatality probabilities and experimentally observed or field-observed parameters did not allow viral persistence, suggesting that non-human primate populations are highly unlikely to sustain EVD-causing infection for prolonged periods. Repeated introductions led to declining population sizes, similar to field observations of apes, but not viral persistence.     

Bandwidth allocation for video transmission with differentiated quality of experience over wireless networks

Delivering digital video content with enhanced quality of experience to the end users over error-prone multi-hop wireless networks is a challenging issue. In video transmission over such wireless networks, many network-based (packet loss, delay, etc.) and source-based (encoding quantization level etc.) parameters can impose some levels of impairment on the perceived video quality. In a video quality enhancement strategy, accurate video quality metrics play a crucial role in the designing process of optimal rate (bandwidth) allocation algorithms. Many cross-layer optimization (CLO) based rate allocation strategies have been developed for this purpose which consider different objective functions (congestion level, total packet loss, etc.) in wireless networks. The main contributions of the proposed work are twofold. At first, an optimal bandwidth allocation framework is being developed in which based on some network-specific constraints and by incorporating an accurate video quality metric, the total weighted quality of experience of some competing video sources is being optimized bases on cross-layer design techniques. Secondly, these optimal rates have been used for differentiated Quality of Experience (QoE) enforcement between multiple competing video sources. The resulting optimal rates can be used as rate-feedbacks for on-line rate adaptation of a moderate video encoder such as MPEG4. The aforementioned weight parameters are selected based on the importance of each video sequence’s quality and can be associated with some previous service level agreement (SLA) based prices. Some numerical analysis have been presented to validate the theoretical results and to verify the claims.     

Dropping Rate Reduction in Hybrid WLAN/Cellular Systems by Mobile Ad Hoc Relaying

Future mobile handsets will often be multi-mode, containing both wireless LAN (WLAN) and cellular air interfaces. When such a device is within a WLAN it can be served by the WLAN resources. As it moves out of the WLAN coverage area, it has to be served by the cellular system. Therefore, handoffs are necessary between the WLAN and the cellular system. In loosely coupled WLAN/Cellular systems the system administrator of the WLAN is different from the cellular one. Therefore, in these situations, reducing the dropping probability based on classical methods, such as using some reserved guard channels, is difficult. In this paper, we propose to use ad hoc relaying during the vertical handoff process in a hybrid WLAN/Cellular system. The method that we propose in this paper improves the dropping probability regardless of the number of reserved channels. Therefore, this method could be employed in loosely coupled hybrid systems. Both analytical reasoning and simulation results support the effectiveness of the proposed method. Pejman Khadivi received the BS and MS degrees in computer engineering (Hardware and Computer Systems Architecture) in 1998 and 2000, respectively from Isfahan University of Technology, where he is currently working toward his Ph.D. During the 2003/2004 academic year, he was a Visiting Researcher with the Electrical and Computer Engineering Department, McMaster University, ON, Canada. Different aspects of computer architecture and networking are Mr. Khadivi’s research interests specially, adhoc networks, QoS routing and seamless handoff in hybrid mobile networks. Shadrokh Samavi received the B.S. degrees in industrial technology and electrical engineering from the California State University, Fresno, in 1980 and 1982, respectively, the M.S. degree from the University of Memphis, Memphis, TN, in 1985, and the Ph.D. degree in electrical engineering from Mississippi State University, Mississippi State, in 1989. In 1995, he joined the Electrical and Computer Engineering Department, Isfahan University of Technology, Isfahan, Iran, where he was an Associative Professor. During the 2002/2003 academic year, he was a Visiting Professor with the Electrical and Computer Engineering Department, McMaster University, Hamilton, ON, Canada. His current research interests are implementation and optimization of image-processing algorithms and area-performance tradeoffs in computational circuits. Dr. Samavi is a Registered Professional Engineer (P.E.), USA, and is a member of Eta Kappa Nu, Tau Beta Pi, and the National Association of Industrial Technologists (NAIT). Hossein Saidi received the B.S. and M.S. degrees in electrical engineering (Electronics and communication Eng.) from Isfahan University of Technology (IUT), in 1986 and 1989, respectively, and the Ph.D. degree in electrical engineering from the Washington University in St. Louis, MO. in 1994.From 1994 to 1995, he was a research associates at Washington Univ. St. Louis, and in 1995 he joined the Electrical and Computer Engineering of IUT, where he is an Associate Professor. His Research interest includes ATM, high speed networking, QoS guarantees, routing, algorithms and information theory. Terence D. Todd received the B.A.Sc, M.A.Sc and Ph.D degrees in Electrical Engineering from the University of Waterloo, Waterloo, Ontario, Canada. While at Waterloo he spent 3 years as a Research Associate with the Computer Communications Networks Group (CCNG). He is currently a Professor of Electrical and Computer Engineering at McMaster University in Hamilton, Ontario, Canada.Professor Todd spent 1991 on research leave in the Distributed Systems Research Department at AT&T Bell Laboratories in Murray Hill, NJ. He also spent 1998 on research leave at The Olivetti and Oracle Research Laboratory in Cambridge, England. While at ORL he worked on the piconet project which was an early embedded wireless network testbed.Dr. Todd’s research interests include metropolitan/local area networks, wireless communications and the performance analysis of computer communication networks and systems. He currently holds the NSERC/RIM/CITO Industrial Research Chair on Pico-Cellular Wireless Internet Access Networks. Dr. Todd is a Professional Engineer in the province of Ontario and a member of the IEEE. Dongmei Zhao received the Ph.D degree in Electrical and Computer Engineering from the University of Waterloo, Waterloo, Ontario, Canada in June 2002. Since July 2002 she has been with the Department of Electrical and Computer Engineering, McMaster University, Hamilton, Ontario, Canada where she is an assistant professor. Dr. Zhao’s research interests include modeling and performance analysis, quality-of-service provisioning, access control and admission control in wireless cellular networks and integrated cellular and ad hoc networks. Dr. Zhao is a member of the IEEE.     

Preparation and preliminary evaluation of [55Co](Ⅱ)vancomycin

Co-55 (t1/2=17.53 h) was produced by 150 μA irradiation of a natural nickel target using 15 MeV protons. It was separated from the irradiated target material by two ion exchange chromatography steps with a radiochemical yield of>95% and was used for the preparation of [55Co]vancomycin ([55Co]VAN). Optimization studies were per-formed using Co-57 due to its longer half-life. Cobalt-57 (t1/2=271.79 d) was produced by irradiation of a natural nickel target with 150 μA current of 22 MeV protons. The 57Co was separated from the irradiated target material using a no-carrier-added method with a radiochemical yield of>97%. Both products were controlled for radionuelide and chemical purity. The solutions of [55Co]VAN were prepared (radiochemical yield>80%) starting with 55Co acetate and vancomycin at room temperature after 30 min. A precise solid phrase extraction (SPE) method was developed using Si Sep-Pak in order to purify/reconstitute the final formulation for animal studies. [55Co]VAN showed a radiochemical purity of more than 99%. The resultant specific activity was about 1.15 TBq/mmol. It is proved that the tracer is stable in the final product and in presence of human serum at 37℃ up to 24 h. Biodistribution study of [55Co]VAN in normal rats was undertaken for up to 72 h.     

Preparation and preliminary evaluation of [^55Co]（II）vancomycin

Co-55 (t1/2=17.53 h) was produced by 150 μA irradiation of a natural nickel target using 15 MeV protons. It was separated from the irradiated target material by two ion exchange chromatography steps with a radiochemical yield of >95% and was used for the preparation of [55Co]vancomycin ([55Co]VAN). Optimization studies were per- formed using Co-57 due to its longer half-life. Cobalt-57 (t1/2=271.79 d) was produced by irradiation of a natural nickel target with 150 μA current of 22 MeV protons. The 57Co was ...     

A sharp-selective micro strip triplexer with hairpin resonators for long-term evolution (LTE)

A compact size planar micro strip triplexer for long-term evolution (LTE) is presented. The triplexer consists of three hairpin band pass filters and a T-shaped micro strip line. T-shaped microstrip line has been used as input signal splitting structure and hairpin filters bring sharp selectivity. Input impedance matching of the structure carried out with three metalized vias in the middle of the filters. The central pass band frequencies (0.9, 1.17, and 1.5 GHz) are selected according to LTE frequency bands. The pass band of the filters include 0.88 to 0.91, 1.16 to 1.21, and 1.47 to 1.53 GHz. Isolation among the output channels are better than 40 dB. The measurement results verify the design process satisfactorily. The proposed triplexer can be used in BTS antenna for enabling more than one transmitter on a single antenna.     

Polydimethylsiloxane‐based Polyurethane/cellulose Nanocrystal Nanocomposites: From Structural Properties Toward Cytotoxicity

Silicon - Polyurethane/crystalline nanocellulose (PU/CNC) nanocomposites were fabricated through in-situ polymerization by using polydimethylsiloxane (PDMS), methylene diphenyl diisocyanate (MDI),...     

Cleanroom-Free Fabrication of Microneedles for Multimodal Drug Delivery

Microneedles have recently emerged as a powerful tool for minimally invasive drug delivery and body fluid sampling. To date, high-resolution fabrication of microneedle arrays (MNAs) is mostly achieved by the utilization of sophisticated facilities and expertise. Particularly, hollow microneedles have usually been manufactured in cleanrooms out of silicon, resin, or metallic materials. Such strategies do not support the fabrication of microneedles from biocompatible/biodegradable materials and limit the capability of multimodal drug delivery for the controlled release of different therapeutics through a combination of injection and sustained diffusion. This study implements low-cost 3D printers to fabricate relatively large needle arrays, followed by repeatable shrink-molding of hydrogels to form high-resolution molds for solid and hollow MNAs with controllable sizes. The developed strategy further enables modulating surface topography of MNAs to tailor their surface area and instantaneous wettability for controllable drug delivery and body fluid sampling. Hybrid gelatin methacryloyl (GelMA)/polyethylene glycol diacrylate (PEGDA) MNAs are fabricated using the developed strategy that can easily penetrate the skin and enable multimodal drug delivery. The proposed method holds promise for affordable, controllable, and scalable fabrication of MNAs by researchers and clinicians for controlled spatiotemporal administration of therapeutics and sample collection.