Low Voltage-Guided Ablation of Posterior Wall Improves 5-Year Arrhythmia-Free Survival in Persistent Atrial Fibrillation

Introduction: The posterior wall (PW) has been proposed as a standard target for ablation beyond pulmonary vein antral isolation (PVI) in patients with persistent atrial fibrillation (AF). However, studies have shown inconsistent outcomes with the addition of PW ablation. The presence or absence of low voltage on the PW may explain these inconsistencies. We evaluated whether PW ablation based on the presence or absence of low voltage improves long-term arrhythmia-free outcomes. Methods: We retrospectively reviewed 5-year follow-up in 152 consecutive patients who received either standard ablation (SA) with PVI alone or PVI + PW ablation (PWA) based on physician discretion (n = 77) or voltage-guided ablation (VGA) with PVI and addition of PWA only if low voltage was present on the PW (n = 75). Results: The two groups were well matched for baseline characteristics. At 5-year follow-up, 64% of patients receiving VGA were atrial tachyarrhythmia (AT)/AF free compared to 34% receiving SA (HR 0.358 p \u3c .005). PWA had similar AF recurrence in SA and VGA groups (0.30 vs. 0.27 p = .96) but higher AT recurrence when comparing SA and VGA groups (0.39 vs. 0.15 p = .03). In multivariate analysis, both VGA and PWA predicted AF arrhythmia-free survival (HR 0.33, p = .001 and HR 0.20, p = .008, respectively). For AT, VGA predicted arrhythmia-free survival (HR 0.22, p = .028), while PWA predicted AT recurrence (HR 4.704, p = .0219). Conclusion: VGA of the posterior wall ablation beyond PVI in persistent AF significantly improves long-term arrhythmia-free survival when compared with non-voltage-guided ablation. PW ablation without voltage-guidance reduced AF recurrence but at the cost of a higher incidence of AT

Periprosthetic acetabular fractures as a complication of total hip arthroplasty

Periprosthetic acetabular fractures are rare but potentially devastating complications of total hip arthroplasty. As the number of total hip arthroplasties performed annually increases, so has the incidence of periprosthetic fractures, with the topic being spotlighted more frequently in the orthopaedic community. There is a particular sparsity of literature regarding periprosthetic acetabular fractures, with periprosthetic femoral fractures after total hip arthroplasty being traditionally far more commonly reported. This article aims to provide an up-to-date review of the epidemiology, risk factors, diagnostic challenges, classifications, and management strategies for periprosthetic acetabular fractures after total hip arthroplasty

GEOLOGICAL CHALLENGES IN HYDRAULIC FRACTURING OPERATION: A CASE STUDY IN UNDISCLOSED PETROLEUM FIELD IN OMAN

Production of hydrocarbons is hampered by obstacles known as formation damage. This damage needs to be removed or bypassed to retain well productivity. Hydraulic fracturing stimulation is one of the techniques used to overcome formation damage and enhance the productivity of the formation by maximizing the ultimate recovery. It was highlighted that there are some challenges associated with this technique and the most difficult challenges in hydraulic fracturing design and implementation are those related to geology of the reservoir. This study was, therefore, aimed at addressing the main geological challenges and providing the best low-cost solution and practice that leads to easy and successful stimulation operation. As an engineering solution in this study, fracturing geometry design was addressed to overcome geological challenges using advance simulator tool. Multiple fracking design by using computer simulation for a set of geological parameters aid on predicting the result out and avoid any complication in future production. Other challenges addressed by intelligent numerical evaluation used as a best practice in well stimulation to maximize the benefits of well production recovery. Optimizing fracturing fluid is also an important element covered in this study. An investigation was conducted on formation permeability variation for heterogeneous rock formation as one of the geological challenges faced by hydraulic fracturing operation for further understanding the geometry of fracturing for the success of stimulation operation. By fixing all other formation and pumping variables it was observed that formation permeability influences the length of fracture geometry, which could lead to stimulate out of pay zone

Serine Protease Variants Encoded by Echis ocellatus Venom Gland cDNA: Cloning and Sequencing Analysis

Envenoming by Echis saw-scaled viper is the leading cause of death and morbidity in Africa due to snake bite. Despite its medical importance, there have been few investigations into the toxin composition of the venom of this viper. Here, we report the cloning of cDNA sequences encoding four groups or isoforms of the haemostasis-disruptive Serine protease proteins (SPs) from the venom glands of Echis ocellatus. All these SP sequences encoded the cysteine residues scaffold that form the 6-disulphide bonds responsible for the characteristic tertiary structure of venom serine proteases. All the Echis ocellatus EoSP groups showed varying degrees of sequence similarity to published viper venom SPs. However, these groups also showed marked intercluster sequence conservation across them which were significantly different from that of previously published viper SPs. Because viper venom SPs exhibit a high degree of sequence similarity and yet exert profoundly different effects on the mammalian haemostatic system, no attempt was made to assign functionality to the new Echis ocellatus EoSPs on the basis of sequence alone. The extraordinary level of interspecific and intergeneric sequence conservation exhibited by the Echis ocellatus EoSPs and analogous serine proteases from other viper species leads us to speculate that antibodies to representative molecules should neutralise (that we will exploit, by epidermal DNA immunization) the biological function of this important group of venom toxins in vipers that are distributed throughout Africa, the Middle East, and the Indian subcontinent

Potential of novel desert microalgae and cyanobacteria for commercial applications and CO2 sequestration

CO2 fixation by phototrophic microalgae and cyanobacteria is seen as a possible global carbon emissions reducer; however, novel microalgae and cyanobacterial strains with tolerance to elevated temperatures and CO2 concentrations are essential for further development of algae-based carbon capture. Four novel strains isolated from the Arabian Gulf were investigated for their thermotolerance and CO2-tolerance, as well as their carbon capture capability. Two strains, Leptolyngbya sp. and Picochlorum sp., grew well at 40 °C, with productivities of 106.6 ± 10.0 and 87.5 ± 2.1 mg biomass L−1 d−1, respectively. Tetraselmis sp. isolate showed the highest biomass productivity and carbon capture rate of 157.7 ± 10.3 mg biomass L−1 d−1 and 270.8 ± 23.9 mg CO2 L−1 d−1, respectively, both at 30 °C. Under 20% CO2, the biomass productivity increased over 2-fold for both Tetraselmis and Picochlorum isolates, to 333.8 ± 41.1 and 244.7 ± 29.5 mg biomass L−1 d−1. These two isolates also presented significant amounts of lipids, up to 25.6 ± 0.9% and 28.0 ± 2.0% (w/w), as well as presence of EPA and DHA. Picochlorum sp. was found to have a suitable FAME profile for biodiesel production. Both Tetraselmis and Picochlorum isolates showed promising characteristics, making them valuable strains for further investigation towards commercial applications and CO2 capture.The authors would like to thank Mahroof Eroth, Dr. Ahmed Easa, and Dr. Abdulrahman Al Muftah from Qatar University, Andy Selwood from Cawthron Institute, and the QDVC team for their support. This work was supported by QDVC and Qatar University [Project QUEX-CAS-QDVC-14/15-7]

Visual Reasoning with Multi-hop Feature Modulation

Recent breakthroughs in computer vision and natural language processing have spurred interest in challenging multi-modal tasks such as visual question-answering and visual dialogue. For such tasks, one successful approach is to condition image-based convolutional network computation on language via Feature-wise Linear Modulation (FiLM) layers, i.e., per-channel scaling and shifting. We propose to generate the parameters of FiLM layers going up the hierarchy of a convolutional network in a multi-hop fashion rather than all at once, as in prior work. By alternating between attending to the language input and generating FiLM layer parameters, this approach is better able to scale to settings with longer input sequences such as dialogue. We demonstrate that multi-hop FiLM generation achieves state-of-the-art for the short input sequence task ReferIt --- on-par with single-hop FiLM generation --- while also significantly outperforming prior state-of-the-art and single-hop FiLM generation on the GuessWhat?! visual dialogue task.Comment: In Proc of ECCV 201

On non-local variational problems with lack of compactness related to non-linear optics

We give a simple proof of existence of solutions of the dispersion manage- ment and diffraction management equations for zero average dispersion, respectively diffraction. These solutions are found as maximizers of non-linear and non-local vari- ational problems which are invariant under a large non-compact group. Our proof of existence of maximizer is rather direct and avoids the use of Lions' concentration compactness argument or Ekeland's variational principle.Comment: 30 page

Analysis of Blood Cultures in Major Burns in Tertiary Care Burn Unit in Oman

Objectives: In this study we review blood stream infections of major burns in a tertiary care burn unit to determine the most prevalent organisms in order to have a better empirical therapy protocol. Methods: This is a retrospective study where blood stream infection of major burns (>20% Total Body Surface Area) were analysed. Results:155 patients fulfilled the criteria. Median age was 33 years.  Median TBSA was 38%. 57.42% were males and 42.58% were females. Mortality was 25.16%. 50.9% of patients had positive blood culture. Expired patients had higher TBSA, Abbreviated Burns Severity Index score and earlier first positive blood culture. The most prevalent organisms grown from all blood cultures were Acinetobacter, staphylococci, Klebsiella, Enterococcus and pseudomonas. Candida is also commonly grown in blood cultures. All Acinetobacter species are always multidrug resistant. 8 of 14 patients had multidrug resistant Klebsiella.  There were only 4 patients who had Methicilin resistant Staphylococcus Aureus (MRSA) grown. The number of blood cultures samples taken ranged from 1 to 28 (median 6). First positive blood culture showed that Staphylococcus epidermidis   and Acinetobacter are the most common organisms. Conclusion: In conclusion multidrug resistant Acinetobcater has become the most predominant microorganism grown in blood cultures of major burns in our unit. Empirical therapy should include antibiotics that are effective against it to reduce the mortality. Keywords: Infection; Blood; Burn; Resistance; Antibiotics; Culture