A new algorithm for recognizing the unknot

The topological underpinnings are presented for a new algorithm which answers the question: `Is a given knot the unknot?' The algorithm uses the braid foliation technology of Bennequin and of Birman and Menasco. The approach is to consider the knot as a closed braid, and to use the fact that a knot is unknotted if and only if it is the boundary of a disc with a combinatorial foliation. The main problems which are solved in this paper are: how to systematically enumerate combinatorial braid foliations of a disc; how to verify whether a combinatorial foliation can be realized by an embedded disc; how to find a word in the the braid group whose conjugacy class represents the boundary of the embedded disc; how to check whether the given knot is isotopic to one of the enumerated examples; and finally, how to know when we can stop checking and be sure that our example is not the unknot.Comment: 46 pages. Published copy, also available at http://www.maths.warwick.ac.uk/gt/GTVol2/paper9.abs.htm

The Potential of Natural Leaf Extracts as Green Inhibitors for Mild Steel Corrosion in Hydrochloric Acid Solutions

The inhibitive and thermodynamic behavior of Abelmoschus Esculentus and Citrus Maxima leaf extracts on the corrosion of mild steel in Hydrochloric acid solutions were investigated using potentiodynamic polarization curves measurements and electrochemical impedance spectroscopy (EIS) technique. Fourier transform infrared spectroscopy (FTIR) was done to predict some suggested chemical constituent of both leaf extracts. At any given concentration Abelmoschus Esculentus leaf extract is more efficient as a corrosion inhibitor for mild steel in 0.5 M HCl solutions than Citrus Maxima leaf extract. Potentiodynamic polarization curves indicated that both leaf extracts act as mixed type inhibitors for mild steel in 0.5 M HCl solutions. The impedance responses indicated that the corrosion process takes place under activation control. The inhibition of these plant leaf extracts depends on the physical adsorption of the chemical constituents of the extracts on mild steel surface as confirmed by Scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS)

A simple thermodynamical witness showing universality of macroscopic entanglement

We show that if the ground state entanglement exceeds the total entropy of a given system, then this system is in an entangled state. This is a universal entanglement witness that applies to any physical system and yields a temperature below which we are certain to find some entanglement. Our witness is then applied to generic bosonic and fermionic many body systems to derive the corresponding "critical" temperatures that have a very broad validity.Comment: 3 pages, Torun conference, June 25-28, 200

Production of Biodiesel from Locally Available Spent Vegetable Oils

The depletion of fossil fuels prompted considerable research to find alternative fuels. Due its environmental benefits and renewable nature the production of biodiesel has acquired increasing importance with a view to optimizing the production procedure and the sources of feedstock. Millions of liters of waste frying oil are produced from local restaurants and houses every year, most are discarded into sewage systems causing damage to the networks.  This study is intended to consider aspects related to the feasibility of the production of biodiesel from waste frying oils which will solve the problem of waste frying oil pollution and reduce the cost of biodiesel production.This research studies the conversion of locally available spent vegetable oils of different origins and with different chemical compositions into an environmentally friendly fuel. The biodiesel production requirements by base catalyzed trans-esterification process for the different feed stocks are determined according to the measured physical properties. The quality of the produced biodiesel is compared to petro diesel in terms of established standard specifications

Production of Biodiesel from Locally Available Spent Vegetable Oils

The depletion of fossil fuels prompted considerable research to find alternative fuels. Due its environmental benefits and renewable nature the production of biodiesel has acquired increasing importance with a view to optimizing the production procedure and the sources of feedstock. Millions of liters of waste frying oil are produced from local restaurants and houses every year, most are discarded into sewage systems causing damage to the networks.  This study is intended to consider aspects related to the feasibility of the production of biodiesel from waste frying oils which will solve the problem of waste frying oil pollution and reduce the cost of biodiesel production.This research studies the conversion of locally available spent vegetable oils of different origins and with different chemical compositions into an environmentally friendly fuel. The biodiesel production requirements by base catalyzed trans-esterification process for the different feed stocks are determined according to the measured physical properties. The quality of the produced biodiesel is compared to petro diesel in terms of established standard specifications

ENHANCING THE ESTERIFICATION CONVERSION USING PERVAPORATION

Coupling of a pervaporation membrane unit with an esterification reactor has been undertaken with a view to improve the overall efficiency of the esterification process through removal of one of the products. The esterification reaction of acetic acid with methanol in the presence of two alternative heterogeneous catalysts Nafion resin (NR) and silica sulfuric acid (SSA) is investigated on the laboratory scale. The system consists of a batch reactor externally coupled with pervaparation (PV) module containing a Nafion membrane. The effect of different parameters on the esterification / pervaporation system is explored. The studied parameters include reactants molar ratio, temperature, and catalyst weight percent. The results show that the water diffusion through the PV membrane helps to break the thermodynamic equilibrium barrier of reversible esterification reaction and improve the reaction conversion. The maximum conversion reached 96.76 % after 60 min at 60 ºC, 3% silica sulfuric acid as catalyst, with a reactant to acid molar ratio of 8:1, and a membrane surface area to reactor volume of 1.3 cm-1.

DNA copy number changes in young gastric cancer patients with special reference to chromosome 19

Only a few cytogenetic and genetic studies have been performed in gastric cancer patients in young age groups. In the present study we used the comparative genomic hybridisation (CGH) method to characterise frequent DNA copy number changes in 22 gastric cancer patients of 45 years or younger and three gastric cancer cell lines established from patients younger than 45 years. Analysis of DNA copy number changes revealed frequent DNA copy number increases at chromosomes 17q (52%), 19q (68%) and 20q (64%). To confirm the CGH results and to characterise the amplicon region on the most frequently amplified chromosome, chromosome 19, we carried out fluorescence in situ hybridisation (FISH) analysis and Southern blot analysis. Fluorescence in situ hybridisation with the bacterial artificial chromosome (BAC) clone mapped to 19q12 indicated a copy number increase in all eight tumour specimens studied. Southern blot analysis of six tumour specimens and three tumour cell lines, with five probes mapped to the 19q12-13.2 region, suggested cyclin E to be one of the candidate target genes in the 19q region for gastric cancer tumorigenesis. Cyclin E protein overexpression was verified in tumours with amplification on chromosome 19. Further studies are required to investigate the biological and clinical significance of 19q amplicon and cyclin E upregulation in gastric cancer of young patient

An exploratory randomized controlled trial evaluating text prompts in Lebanon to encourage health‐seeking behavior for hypertension

Aims of the study The current study evaluates the effectiveness of an opportunistic mobile screening on the percentage of people who are aware of whether they may be hypertensive (in an observational study) and the effectiveness of reminder prompts on the percentage of people who seek further medical attention (in a randomized controlled trial). Methods used to conduct the study The screening of 1227 participants (529 female) was conducted during the registration period of the 2018 Beirut International Marathon in Lebanon. Next, 266 participants whose screening indicated hypertension (64 Female) were randomly allocated to a treatment group or a control group in a 1:1 fashion. The treatment group received a reminder prompt to seek further medical attention for their potential hypertension and the control group did not. The overt nature of the text message meant that participants in the treatment group could not be blinded to their group allocation. The primary outcome is participants’ self‐reports of whether they sought further medical attention. Results of the study For the opportunistic screening, a 25% prevalence rate and a 24% awareness rate of hypertension was indicated. A McNemar analysis suggested that the screening increased participant awareness (X2 (N =1227)=72.16, p <0.001). For the randomized controlled trial, 219 participants provided follow‐up data via a phone call (82% retention). A Chi‐squared analysis suggested that the reminder prompt successfully encouraged more participants to seek further medical attention, 45.5% treatment group vs. 28.0% control group (X 2(1, N =219)=7.19, p =0.007, φ =0.18). Conclusions drawn and clinical implications Extra support in the form of a brief reminder message can increase the percentage of people who seek further medical attention after attending an opportunistic screening at a marathon event. The discussion reviews how the results align with previous research, strengths and limitations of the current study, and implications for future research and practice

Chromosomal aberrations in benign and malignant Bilharzia-associated bladder lesions analyzed by comparative genomic hybridization

BACKGROUND: Bilharzia-associated bladder cancer (BAC) is a major health problem in countries where urinary schistosomiasis is endemic. Characterization of the genetic alterations in this cancer might enhance our understanding of the pathogenic mechanisms of the disease but, in contrast to nonbilharzia bladder cancer, BAC has rarely been the object of such scrutiny. In the present study, we aimed to characterize chromosomal imbalances in benign and malignant post-bilharzial lesions, and to determine whether their unique etiology yields a distinct cytogenetic profile as compared to chemically induced bladder tumors. METHODS: DNAs from 20 archival paraffin-embedded post-bilharzial bladder lesions (6 benign and 14 malignant) obtained from Sudanese patients (12 males and 8 females) with a history of urinary bilharziasis were investigated for chromosomal imbalances using comparative genomic hybridization (CGH). Subsequent FISH analysis with pericentromeric probes was performed on paraffin sections of the same cases to confirm the CGH results. RESULTS: Seven of the 20 lesions (6 carcinomas and one granuloma) showed chromosomal imbalances varying from 1 to 6 changes. The most common chromosomal imbalances detected were losses of 1p21-31, 8p21-pter, and 9p and gain of 19p material, seen in three cases each, including the benign lesion. CONCLUSION: Most of the detected imbalances have been repeatedly reported in non-bilharzial bladder carcinomas, suggesting that the cytogenetic profiles of chemical- and bilharzia-induced carcinomas are largely similar. However, loss of 9p seems to be more ubiquitous in BAC than in bladder cancer in industrialized countries

The inflammatory microenvironment in colorectal neoplasia

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