In this paper, we propose a cross-layer design which combines adaptive modulation and coding (AMC) at the physical layer with a hybrid automatic repeat request (HARQ) protocol at the data link layer to minimize the packet error rate (PER) and maximize the spectral efficiency. By using Markov model to predict the channel condition of next frame according to the second order statistics characteri...

background: empathy plays an important role in healthy dentist and patient relationship. hence, the aim of the study is to (a) to measure the self‑reported empathy levels among dental undergraduate and postgraduate students. (b) to review the trend of changes in empathy level with experience, age, and gender among dental undergraduate and postgraduate students. materials and methods: this cross...

Athermal random fiber networks are usually modeled by representing each fiber as a truss, a Euler-Bernoulli or a Timoshenko beam, and, in the case of cross-linked networks, each cross-link as a pinned, rotating, or welded joint. In this work we study the effect of these various modeling options on the dependence of the overall network stiffness on system parameters. We conclude that Timoshenko ...

Well-defined liquid crystal networks with controlled molecular weight between cross-links and cross-link functionality were prepared by "click" cross-linking of telechelic polymers produced by ring-opening metathesis polymerization (ROMP). The networks readily swell in a small molecule liquid crystal, 5CB, to form LC gels with high swelling ratios. These gels exhibit fast, reversible, and low-t...

Copolymers of n-hexyl and allyl isocyanates were successfully synthesized using an organotitanium(IV) catalyst initiated polymerization. Viscosity measurements indicated that molecular weight increased with decrease in monomer/initiator ratio. Monomer reactivity ratios were calculated using the copolymer composition equation, and the resulting values indicated relative randomness in the copolym...

The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Synopsis The structure of a cisplatin-modified DNA dodecamer duplex containing a 1,2-cis-{Pt(NH 3) 2 } 2+-d(GpG) cross-link has been determined at 1.77-Å resolution. Improved electron density reveals new features not seen in the originally published 2.6 Å structure. Abstract We...

A new type of interstrand cross-link resulting from the reaction of a DNA abasic site with a guanine residue on the opposing strand of the double helix was recently identified, but the chemical connectivity of the cross-link was not rigorously established. The work described here was designed to characterize the chemical structure and properties of dG-AP cross-links generated in duplex DNA. The...

The human genome is guarded against mutations by several DNA repair pathways. Common for all pathways, is the initiating event of detecting the DNA damage. This initial event is followed by the coordinated recruitment of various other DNA repair proteins needed for the repair. For instance, the MSH2/MSH6 complex detects DNA mismatches, while the MRN or KU70/KU80 complexes detect double strand b...

Ultra -high molecular weight polyethylene (UHMWPE) is the current material of choice for bearing surface applications in total joint arthroplasty. In an effort to enhance the wear properties of the material many companies have recently resorted to electron beam and gamma irradiation of the components prior to the machining. It is of considerable interest to accurately determine the dose absorbe...

Although many anticancer drugs exert their biological activity by forming DNA interstrand crosslinks (ICLs), the thermodynamics of biologically relevant long crosslinked DNAs has not been intensively studied in contrast to short duplexes. Here, we carry out computer modeling of the shift of melting temperature of long DNAs caused by ICLs taking into account crosslinking effect in itself and con...