Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 4 de 4
Filter
Add more filters










Database
Language
Publication year range
1.
Cureus ; 16(5): e60124, 2024 May.
Article in English | MEDLINE | ID: mdl-38864053

ABSTRACT

Background The term "diverticula" refers to the existence of diverticula in the gastrointestinal tract but is mainly located in the sigmoid colon and is used to describe colonic diverticulosis. Diverticula, which are sac-like protrusions in the wall of the large bowel, are becoming more prevalent globally, in both developed and developing nations. This increase in occurrence is primarily attributed to changes in dietary and lifestyle patterns. Raising public awareness can potentially contribute to a decrease in the incidence of the disease and its associated complications. Aim This study aims to assess knowledge and awareness levels among the Saudi Arabian population regarding diverticulitis and its risk factors. Methods A descriptive cross-sectional study was conducted in Saudi Arabia between 1st January 2024 to 1st April 2024 using an online questionnaire for data collection. The target population consists of individuals who are between 18 years and 45, in Saudi Arabia without a history of diverticulitis. The study questionnaire covered participants' demographic (Western, Central, Southern, Eastern, Northern) regions, knowledge, awareness and practice of diverticulitis. Results A total of 548 eligible participants completed the study questionnaire, most of them (80.3%; 395) were from the Western region including Mecca, Medina and Jeddah. Participants' ages ranged from 18 to more than 40 years with a mean age of 30.5 ± 11.9 years old. A greater percentage (72.3%) of the participants were males compared to the percentage of females, which was 27.7%. The vast majority of the study participants had an inadequate knowledge level about diverticulitis (85.9%; 471) while only 31 (5.7%) had adequate knowledge and awareness about the disease. The most reported sources of information included study courses (6.4%), media (5.3%), and physicians (4.7%) while most respondents (83.6%) had no source. Conclusion In conclusion, aside from preventive strategies, the current study found that the public knew very little about diverticulitis, including its risk factors, clinical presentation, and diagnostic process. The two significant predictors of public awareness level were age and doctors as information sources.

2.
J Am Soc Mass Spectrom ; 20(1): 60-6, 2009 Jan.
Article in English | MEDLINE | ID: mdl-18845449

ABSTRACT

Ionization of polymers in mass spectrometry is usually achieved by forming metal ion adducts. The metal ion has been shown by Wesdemiotis to often play a spectator role in the collision-induced dissociation (CID) chemistry of these species, wherein they fragment according to a free-radical mechanism similar to that found in their pyrolysis. The result is a predominance of low-mass ions in the CID mass spectrum. We have changed this behavior by generating protonated oligomers in the gas phase by first forming proton-bound complexes of the oligomers with amino acids or peptides by electrospray ionization. These complexes dissociate first by loss of the amino acid/peptide to form protonated oligomers, which then undergo a unique fragmentation chemistry. In this article we discuss the results for poly(methyl methacrylate) (PMMA) and poly(butyl acrylate) (PBA). Initially, protonated PMMA and PBA lose methanol and butanol, respectively, from the side chains of the respective monomers. The resulting PMMA-derived ion then undergoes a series of neutral losses corresponding to 32 and 28 Da, methanol and carbon monoxide. This continues as collision energy increases until a final, carbon-rich backbone ion is formed, which then undergoes a classic hydrocarbon fragmentation pattern. The PBA-derived ions are proposed to fragment by the loss of butylether molecules to form anhydride rings along the oligomer chain. The number of ether molecules lost corresponded to half the number of available side chains in the oligomer. The resulting poly-anhydride ion dissociates by small molecule loss. Mechanisms have been suggested for the fragmentation chemistry of these two classes of oligomers.


Subject(s)
Acrylates/chemistry , Polymers/chemistry , Spectrometry, Mass, Electrospray Ionization/methods , Butanols/chemistry , Methanol/chemistry , Models, Molecular , Polymethyl Methacrylate/chemistry , Protons
4.
Eur J Mass Spectrom (Chichester) ; 12(5): 301-10, 2006.
Article in English | MEDLINE | ID: mdl-17404420

ABSTRACT

Electrospray ionization (ESI-MS) and matrix assisted laser desorption-ionization (MALDI-MS) were used to determine the composition (monomer ratios) and structure (end group analysis) relative to 1H NMR spectroscopy and theoretical predictions for three different copolymers: poly(butyl acrylate/vinyl acetate) (PBA/PVAc), poly(methyl methacrylate/vinyl acetate) (PMMA/PVAc) and poly(butyl acrylate/methyl methacrylate) (PBA/PMMA). We found that the ESI results were in excellent agreement with 1H NMR spectroscopy for PBA/PVAc and PBA/PMMA copolymers whereas there was more divergence in the case of PMMA/PVAc. In the case of PBA/PMMA copolymers similar distributions of products were observe by ESI-MS and MALDI-MS with the two major products classes differing by their end-groups. One class has hydrogen and dodecylthio end groups while in the other the dodecylthio has been replaced by alpha-cyanoisopropyl from the initiator. The relative abundance of these distributions as a function of copolymer conversion for a series of reaction conditions was investigated by both ESI and MALDI. MALDI results consistently underestimated (relative to ESI) the butylacrylate monomer ratio in PBA/PMMA and the abundance of co-polymer oligomers terminated by a dodecylthio group from the chain transfer agent.

SELECTION OF CITATIONS
SEARCH DETAIL
...