Cross Layer Routing in Cognitive Radio Network Using Deep Reinforcement Learning

Development of 5G technology and Internet of Things (IoT) devices has resulted in higher bandwidth requirements leading to increased scarcity of wireless spectrum. Cognitive Radio Networks (CRNs) provide an efficient solution to this problem. In CRNs, multiple secondary users share the spectrum band that is allocated to a primary network. This spectrum sharing of the primary spectrum band is achieved in this work by using an underlay scheme. In this scheme, the Signal to Interference plus Noise Ratio (SINR) caused to the primary due to communication between secondary users is kept below a threshold level. In this work, the CRNs perform cross-layer optimization by learning the parameters from the physical and the network layer so as to improve the end-to-end quality of experience for video traffic. The developed system meets the design goal by using a Deep Q-Network (DQN) to choose the next hop for transmitting based on the delay seen at each router, while maintaining SINR below the threshold set by primary channel. A fully connected feed-forward Multilayer Perceptron (MLP) is used by secondary users to approximate the action value function. The action value comprises of SINR to the primary user (at the physical layer) and next hop to the routers for each packet (at the network layer). The reward to this neural network is Mean Opinion Score (MOS) for video traffic which depends on the packet loss rate and the bitrate used for transmission. As compared to the implementation of DQN learning at the physical layer only, this system provides 30\% increase in the video quality for routers with small queue lengths and also achieves a balanced load on a network with routers with unequal service rates

Capturing the Biologic Onset of Inflammatory Bowel Diseases: Impact on Translational and Clinical Science

While much progress has been made in the last two decades in the treatment and the management of inflammatory bowel diseases (IBD)-both ulcerative colitis (UC) and Crohn's Disease (CD)-as of today these conditions are still diagnosed only after they have become symptomatic. This is a major drawback since by then the inflammatory process has often already caused considerable damage and the disease might have become partially or totally unresponsive to medical therapy. Late diagnosis in IBD is due to the lack of accurate, non-invasive indicators that would allow disease identification during the pre-clinical stage-as it is often done in many other medical conditions. Here, we will discuss what is known about the biologic onset and pre-clinical CD with an emphasis on studies conducted in patients' first degree relatives. We will then review the possible strategies to diagnose IBD very early in time including screening, available disease markers and imaging, and the possible clinical implications of treating these conditions at or close to their biologic onset. Later, we will review the potential impact of conducting translational research in IBD during the pre-clinical stage, especially focusing on the role of the microbiome in disease etiology and pathogenesis. Finally, we will highlight possible future developments in the field and how they can impact IBD management and our scientific knowledge of these conditions

Photosynthesis Under a Red Sun: Predicting the absorption characteristics of an extraterrestrial light-harvesting antenna

Here we discuss the feasibility of photosynthesis on Earth-like rocky planets in close orbit around ultra-cool red dwarf stars. Stars of this type have very limited emission in the \textit{photosynthetically active} region of the spectrum (400−700 nm), suggesting that they may not be able to support oxygenic photosynthesis. However, photoautotrophs on Earth frequently exploit very dim environments with the aid of highly structured and extremely efficient antenna systems. Moreover, the anoxygenic photosynthetic bacteria, which do not need to oxidize water to source electrons, can exploit far red and near infrared light. Here we apply a simple model of a photosynthetic antenna to a range of model stellar spectra, ranging from ultra-cool (2300 K) to Sun-like (5800 K). We assume that a photosynthetic organism will evolve an antenna that maximizes the rate of energy input while also minimizing fluctuations. The latter is the 'noise cancelling' principle recently reported by Arp et al. 2020. Applied to the Solar spectrum this predicts optimal antenna configurations in agreement with the chlorophyll Soret absorption bands. Applied to cooler stars, the optimal antenna peaks become redder with decreasing stellar temperature, crossing to the typical wavelength ranges associated with anoxygenic photoautotrophs at ∼3300 K. Lastly, we compare the relative input power delivered by antennae of equivalent size around different stars and find that the predicted variation is within the same order of magnitude. We conclude that low-mass stars do not automatically present light-limiting conditions for photosynthesis but they may select for anoxygenic organisms

A COMPARITIVE STUDY OF FUNCTIONAL OUTCOME OF DISPLACED ULNAR STYLOID FRACTURES TREATED CONSERVATIVELY VS OPERATIVELY ASSOCIATED WITH DISTAL END RADIUS FRACTURES TRETAED SURGICALLY

Introduction: Ulnar styloid fractures, a common injury associated with distal radius fractures, are often a subject of debate regarding their optimal management. The ulnar styloid process, situated at the distal end of the ulna, plays a significant role in the stability and function of the wrist joint, particularly influencing the function of the triangular fibrocartilage complex (TFCC). Surgical repair and conservative treatment are two major management strategies widely adopted in ulnar styloid fracture patients, but the consensus of the optimal treatment strategy is still debated. Aim and objective: The aim of this study is to assess potential differences in clinical and radiological outcomes between surgical and conservative management of ulnar styloid fractures that occur alongside distal radius fractures treated with volar plating. This evaluation will focus on the duration of fracture union and the PRWE (Patient-Rated Wrist Evaluation) score. Materials and Methods: Group A underwent conservative management and Group B underwent surgical management for ulnar styloid fracture while distal end radius fracture was operated with volar plating for both the groups.Each group has 20 patients of distal end radius fracture with ulnar styloid fracture. Patient follow up was carried at 1.5 months , 3 months and 6 months and were clinically and radiologically assessed and outcomes were graded according to PRWE Score. Results: A significant difference was observed in non-union between 2 groups with non union occurring in 45% of conservative cases, compared to 15% in the operative group .Functional outcome assessed using mean changes in the PRWE score which was 27.96 ± 10.90 for rotella type 1, 22.21 ± 7.10 for type 2, 30.77 ± 8.19 for type 3 in Group A while 20.28 ± 12.13in rotella type 1, 14.73 ± 7.64 in type 2, 22.36 ± 8.40 in rotella type 3 in Group B at 6 months follow up. Conclusion: Patients who underwent operative treatment for ulnar styloid fractures showed a statistically significant improvement in functional outcomes using PRWE Score compared to those who were treated conservatively. The incidence of complications like non-union was higher in the conservative treatment group. Radiological union of the ulnar styloid fracture was achieved more consistently and predictably in the operative group

Optimizing photosynthetic light-harvesting under stars: simple and general antenna models.

In the next 10-20 years, several observatories will aim to detect the signatures of oxygenic photosynthesis on exoplanets, though targets must be carefully selected. Most known potentially habitable exo-planets orbit cool M-dwarf stars, which have limited emission in the photosynthetically active region of the spectrum (PAR, 400 < λ < 700 nm) used by Earth's oxygenic photoautotrophs. Still, recent experiments have shown that model cyanobacteria, algae, and non-vascular plants grow comfortably under simulated M-dwarf light, though vascular plants struggle. Here, we hypothesize that this is partly due to the different ways they harvest light, reflecting some general rule that determines how photosynthetic antenna structures may evolve under different stars. We construct a simple thermodynamic model of an oxygenic antenna-reaction centre supercomplex and determine the optimum structure, size and absorption spectrum under light from several star types. For the hotter G (e.g. the Sun) and K-stars, a small modular antenna is optimal and qualitatively resembles the PSII-LHCII supercomplex of higher plants. For the cooler M-dwarfs, a very large antenna with a steep 'energy funnel' is required, resembling the cyanobacterial phycobilisome. For the coolest M-dwarfs an upper limit is reached, where increasing antenna size further is subject to steep diminishing returns in photosynthetic output. We conclude that G- and K-stars could support a range of niches for oxygenic photo-autotrophs, including high-light adapted canopy vegetation that may generate detectable bio-signatures. M-dwarfs may only be able to support low light-adapted organisms that have to invest considerable resources in maintaining a large antenna. This may negatively impact global coverage and therefore detectability

Thermodynamic limits on oxygenic photosynthesis around M-dwarf stars: Generalized models and strategies for optimization

We explore the feasibility and potential characteristics of photosynthetic light-harvesting on exo-planets orbiting in the habitable zone of low mass stars ($< 1$ M$_{\odot}$). As stellar temperature, $T_{s}$, decreases, the irradiance maximum red-shifts out of the $400 \textrm{nm} \leq \lambda < 750$ nm range of wavelengths that can be utilized by \emph{oxygenic} photosynthesis on Earth. However, limited irradiance in this region does not preclude oxygenic photosynthesis and Earth's plants, algae and cyanobacteria all possess very efficient \emph{light-harvesting antennae} that facilitate photosynthesis in very low light. Here we construct general models of photosynthetic light-harvesting structures to determine how an oxygenic photosystem would perform in different irradiant spectral fluxes. We illustrate that the process of light-harvesting, capturing energy over a large antenna and concentrating it into a small \emph{reaction centre}, must overcome a fundamental \emph{entropic barrier}. We show that a plant-like antenna cannot be adapted to the light from stars of $T_{s}<3400$ K, as increasing antenna size offers diminishing returns on light-harvesting. This can be overcome if one introduces a slight \emph{enthalpic gradient}, to the antenna. Interestingly, this strategy appears to have been adopted by Earth's oxygenic cyanobacteria, and we conclude that \emph{bacterial} oxygenic photosynthesis is feasible around even the lowest mass M-dwarf stars.Comment: 5 Figures, submitted to Astrobiology and awaiting return of revie

Dynamic splinting for knee flexion contracture following total knee arthroplasty: a case report

Total Knee Arthroplasty operations are increasing in frequency, and knee flexion contracture is a common pathology, both pre-existing and post-operative. A 61-year-old male presented with knee flexion contracture following a total knee arthroplasty. Physical therapy alone did not fully reduce the contracture and dynamic splinting was then prescribed for daily low-load, prolonged-duration stretch. After 28 physical therapy sessions, the active range of motion improved from -20° to -12° (stiff knee still lacking full extension), and after eight additional weeks with nightly wear of dynamic splint, the patient regained full knee extension, (active extension improved from -12° to 0°)

Posterior Lumbar Interbody Fusion via a Unilateral Approach

This study sought to determine the outcomes of posterior lumbar interbody fusion (PLIF), via a unilateral approach, in selected patients who presented with unilateral leg pain and segmental instability of the lumbar spine. Patients with a single level of a herniated disc disease in the lumbar spine, unilateral leg pain, chronic disabling lower back pain (LBP), and a failed conservative treatment, were considered for the procedure. A total of 41 patients underwent a single-level PLIF using two PEEK™ (Poly-Ether-Ether-Ketone) cages filled with iliac bone, via a unilateral approach. The patients comprised 21 women and 20 men with a mean age of 41 years (range: 22 to 63 years). Two cages were inserted using a unilateral medial facetectomy and a partial hemilaminectomy. At follow-up, the outcomes were assessed using the Prolo Scale. The success of the fusion was determined by dynamic lumbar radiography and/or computerized tomography scanning. All the patients safely underwent surgery without severe complications. During a mean follow-up period of 26 months, 1 patient underwent percutaneous pedicle screw fixation due to persistent LBP. A posterior displacement of the cage was found in one patient. At the last follow up, 90% of the patients demonstrated satisfactory results. An osseous fusion was present in 85% of the patients. A PLIF, via a unilateral approach, enables a solid union with satisfactory clinical results. This preserves part of the posterior elements of the lumbar spine in selected patients with single level instability and unilateral leg pain

Rhizopine biosensors for plant-dependent control of bacterial gene expression

Engineering signalling between plants and microbes could be exploited to establish host-specificity between plant-growth-promoting bacteria and target crops in the environment. We previously engineered rhizopine-signalling circuitry facilitating exclusive signalling between rhizopine-producing (RhiP) plants and model bacterial strains. Here, we conduct an in-depth analysis of rhizopine-inducible expression in bacteria. We characterize two rhizopine-inducible promoters and explore the bacterial host-range of rhizopine biosensor plasmids. By tuning the expression of rhizopine uptake genes, we also construct a new biosensor plasmid pSIR05 that has minimal impact on host cell growth in vitro and exhibits markedly improved stability of expression in situ on RhiP barley roots compared to the previously described biosensor plasmid pSIR02. We demonstrate that a sub-population of Azorhizobium caulinodans cells carrying pSIR05 can sense rhizopine and activate gene expression when colonizing RhiP barley roots. However, these bacteria were mildly defective for colonization of RhiP barley roots compared to the wild-type parent strain. This work provides advancement towards establishing more robust plant-dependent control of bacterial gene expression and highlights the key challenges remaining to achieve this goal

Internal fixation and comparisons of different fixation methods for treating distal radial fractures in adults

Objectives: To evaluate the effectiveness of internal fixation for fractures of the distal radius in skeletally mature people. Additionally, to evaluate the relative effectiveness of different surgical methods of treating these fractures. More specifically, the authors compare the effectiveness of: • internal fixation versus conservative treatment; • different methods of internal fixation, including different techniques associated with inserting implants, different implants, and different types and durations of immobilisation after internal fixation; • different fixation methods (percutaneous pinning, external fixation, internal fixation); and different combinations of surgical methods; • different techniques (e.g. use of arthroscopy) and approaches (e.g. surgical repair of the triangular fibrocartilagenous complex (fibrous tissue which binds together the distal ends of the radius and ulnar) not already covered. The authors consider these outcomes primarily in terms of patient-assessed functional outcome and satisfaction, and other measures of function and impairment, pain and discomfort, the incidence of complications, anatomical deformity and use of resources. If data allows it, the authors intend to study the outcomes in different age groups and for different types of fractures, especially whether they are extra-articular or intra-articular