Modeling burial induced changes in physical sandstone properties - A case-study of North Sea and Norwegian Sea sandstone formations

The changes in physical properties of sandstones with burial depth are a result of mechanical and chemical compaction processes. These processes are affected by rock microstructure, pressure regimes and temperature history. Data from 30 wells have been used to investigate and compare the changes in porosity, bulk density, elastic moduli and wave propagation velocities between the mid-Jurassic sandstones of the Etive Fm. in the North Sea and the Garn Fm. in the Norwegian Sea. At shallow burial depths (less than 2 km) the changes of the physical properties are governed by effective stress. A mechanical compaction model is used to describe the porosity loss and the bulk density increase with depth, whereas the friable-sand theory is used to explain the changes in elastic moduli and wave propagation velocities. For both formations, the under predictions by the models in the porosity, bulk moduli and P-wave velocity values from the data suggest high depositional porosities (0.40) and small amounts of quartz cement at depths of 1.6-2.0 km. At greater burial depths and temperatures (greater than 2 km, and greater than 75°C) quartz cementation is the main controlling factor in the changes of the physical properties. The porosity loss and the bulk density increase with depth are explained by means of a quartz cement precipitation model, and the contact-cement theory is used to describe the changes in elastic moduli and wave propagation velocities. High porosities (greater than 0.15) at great burial depths (greater than 4 km) suggest the presence of higher amounts of clay coatings in both formations, and they may also be a result of high overpressures. The great variations in porosity and bulk modulus values for Garn sandstones encountered at same depths, indicate that the Garn Fm. is less well sorted and more affected by different types of quartz deposition than the Etive Fm. The contact-cement model main over prediction trend for the bulk modulus of highly overpressured sandstones enlightens the effects of different pressure regimes in the chemical compaction domain

Review of Musculoskeletal Injuries and Prevention in the Endoscopy Practitioner

Practitioners of endoscopy often experience musculoskeletal pain and injury (most often in the back, neck, shoulders, hands, wrists, and thumbs) that are associated with the minute and repetitive strain that is placed on these areas during endoscopic procedures. This review of the current documentation of endoscopy-related pain and injuries among practitioners finds that such problems are widespread and specific in kind as well as strongly correlated with high procedure volume and procedure duration. Research on the nature and impact of cumulative trauma and overuse syndromes in other professions such as dentistry, pianists, production labor, and athletics is brought to bear on the work of the endoscopist. A more thorough understanding of the nature and prevalence of work-related pain and injury sustained by endoscopists should inform further development of ergonomic practices and equipment design. This article reviews current recommendations for ergonomic design in the endoscopy procedure space and finds that reported compliance with those recommendations is quite low. Strategies for the management of the risk of musculoskeletal injuries related to the practice of endoscopy include compliance with currently recommended ergonomic practices, education of trainees in ergonomic technique when practicing endoscopy, and research toward the modification and development of more ergonomic endoscopes and procedure spaces

A hydraulically driven colonoscope

BACKGROUND: Conventional colonoscopy requires a high degree of operator skill and is often painful for the patient. We present a preliminary feasibility study of an alternative approach where a self-propelled colonoscope is hydraulically driven through the colon. METHODS: A hydraulic colonoscope which could be controlled manually or automatically was developed and assessed in a test bed modelled on the anatomy of the human colon. A conventional colonoscope was used by an experienced colonoscopist in the same test bed for comparison. Pressures and forces on the colon were measured during the test. RESULTS: The hydraulic colonoscope was able to successfully advance through the test bed in a comparable time to the conventional colonoscope. The hydraulic colonoscope reduces measured loads on artificial mesenteries, but increases intraluminal pressure compared to the colonoscope. Both manual and automatically controlled modes were able to successfully advance the hydraulic colonoscope through the colon. However, the automatic controller mode required lower pressures than manual control, but took longer to reach the caecum. CONCLUSIONS: The hydraulic colonoscope appears to be a viable device for further development as forces and pressures observed during use are comparable to those used in current clinical practice

Mogućnost primene okare kao sekundarne sirovine u proizvodnji hraniva za ribe

Poslednjih godina istraživanju soje poklanja se velika pažnja zbog povoljnih zdravstvenih efekata. Mnoge studije su utvrdile u zrnu soje prisustvo komponenti poput proteina, dijetalnih vlakana, masnih kiselina, izoflavona i drugih fitohemikalija, koje povoljno deluju na organizam. Sirova okara, poznata i kao "sojina pulpa", je nusprodukt u priozvodnji sojinog mleka. To je belo-žućkasta materija koja se sastoji od nerastvorljivih delova semena soje (uglavnom semenjače) koji ostaju na filteru pri filtriranju usitnjenog kuvanog zrna soje pri proizvodnji sojinog mleka (Jimenez-Escrig et al., 2008). Cilj ovog rada je bio da se proceni uticaj metoda polupogonskog postrojenja koje koristi hidrotermičku obradu sojinog zrna u proizvodnji sojinog mleka (HTC obrada; visoka temperatura i povišen pritisak/kratko vreme) na sadržaj i aktivnost hranljivih komponenti okare, pripremane od šest različitih genotipova soje, kao i da se proceni mogućnost korišćenja okare u pripremi hrane za ribe. Može se pretpostaviti da će primenjeni HTC postupak, koji je sličan procesu ekstrudiranja, koji se najčešće koriste u proizvodnji hrane za ribe (visoka temperatura/kratako vreme), dati okaru povoljnih svojstava, pogodna za ishranu riba. Pored toga, obzirom da je optimalna pH vrednost vode za uzgoj riba od 7.0 do 8.0 (Zhanga et al., 2011), različita od izoelektrične tačke (Ip) glavnih proteina okare može se pretpostaviti da se proteini okare neće taložiti u mulju, već će ostati da plutaju u vodi. Glavne komponente okare dobijene primenjenim HTC postupkom su ugljeni hidrati (51.25-59.25%) i proteini (31.81-40.36%). Mateos-Aparicio et al. (2010b) ističu veoma povoljnu antioksidativnu aktivnost okare, koju uglavnom pripisuju polisharidima semenjače sojinog zrna, pre svega pektinima, iako ističu da se ne može isključiti ni doprinos belančevina. Ovakva istraživanja ukazuju na mogućnost delovanja okare kao komponete u ishrani riba u smislu odbrane od antioksidativnog stresa. Visok sadržaj proteina, čini okaru potencijalno dobrim izvorom biljnih proteina, niske cene, za ishranu ljudi i životinja. Visok sadržaj i vrlo dobre funkcionalne karakteristike proteina okare (Mateos-Aparicio et al., 2010a), ukazuju na to da mogu biti pogodni kao dopuna hrane za ribu u smislu vezivnog medijuma za druge aktivne i hranljive komponente u proizvodu, pri čemu doprinose nutritivnoj vrednosti hraniva. Štaviše, odnos esencijalnih amino kiselina u ukupnom aminokiselinskom sastavu proteina okare je sličan kao u sojinom mleku i tofuu (Vang i Cavins, 1989). Glavni proteini okare su bazni, 7S globulin (Bg7S; 24.61-28.37%) i glicinin (11S globulin; 28.49-33.11%). Poznato je da je Bg7S glikoprotein bogat cisteinom (Omi et al., 1996) što povećava nutritivnu vrednost proizvoda. Proteini soje nisu nutritivno idealni proteini, obzirom da ispoljavaju neželjeni efekat na metabolizam nakon konzumiranja sirove sojine sačme, što se pripisuje prisustvu tripsin inhibitora (TI) i lektina. Tripsin inhibitorska aktivnost ispitivanih uzoraka je veoma mala (4.82-7.99%) što ukazuje da okara ne bi ispoljavala antinutritivni efekat na organizam, tim pre što se veruje da postizanje zadovoljavajućeg nivoa TIA dovoljno smanjuje aktivnost lektina, obzirom da su inhibitori termički stabilniji nego lektini (Friedman i Brendon, 2001)

Feasibility of joystick guided colonoscopy

The flexible endoscope is increasingly used to perform minimal invasive interventions. A novel add-on platform allows single-person control of both endoscope and instrument at the site of intervention. The setup changes the current routine of handling the endoscope. This study aims to determine if the platform allows effective and efficient manipulation to position the endoscope at potential intervention sites throughout the bowel. Five experts in flexible endoscopy first performed three colonoscopies on a computer simulator using the conventional angulation wheels. Next they trained with the joystick interface to achieve their personal level of intubation time with low pain score. 14 PhD students (novices) without hands-on experience performed the same colonoscopy case using either the conventional angulation wheels or joystick interface. Both novice groups trained to gain the average expert level. The cecal intubation time, pain score and visualization performance (% of bowel wall) were recorded. All experts reached their personal intubation time in 6 ± 6 sessions. Three experts completed their learning curve with low pain score in 8 ± 6 sessions. The novices required 11 ± 6 sessions using conventional angulation wheels, and 12 ± 6 sessions using the joystick interface. There was no difference in the visualization performance between the novice and between the expert groups. This study shows that the add-on platform enables endoscope manipulation required to perform colonoscopy. Experts need only a relatively short training period. Novices are as effective and as efficient in endoscope manipulation when comparing the add-on platform with conventional endoscope contro

Guiding principles for the development and application of solid-phase phosphorus adsorbents for freshwater ecosystems

While a diverse array of phosphorus (P)-adsorbent materials is currently available for application to freshwater aquatic systems, selection of the most appropriate P-adsorbents remains problematic. In particular, there has to be a close correspondence between attributes of the P-adsorbent, its field performance, and the management goals for treatment. These management goals may vary from a rapid reduction in dissolved P to address seasonal enrichments from internal loading, targeting external fluxes due to anthropogenic sources, or long term inactivation of internal P inventories contained within bottom sediments. It also remains a challenge to develop new methods and materials that are ecologically benign and cost-effective. We draw on evidence in the literature and the authors’ personal experiences in the field, to summarise the attributes of a range of P-adsorbent materials. We offer 'guiding principles' to support practical use of existing materials and outline key development needs for new materials

Water-soluble carbohydrates accumulation in peduncle of wheat and its relationship to morpho-anatomical and productive traits

Water-soluble carbohydrates (WSC) accumulating in internodes of the wheat stem can be a consequential contributor to grain filling, especially under stress conditions. In this study the WSC content and the WSC specific content (WSCSC) per unit of length were determined in the uppermost internode (peduncle) of the main stem at 10 days after anthesis across 44 wheat genotypes in two-year field trials. The defoliation was done at 10 days after anthesis by cutting off all leaf blades and defoliated plants were grown along with the intact control plants. Among 16 morphological, anatomical and developmental traits, the area of pith intercellular of peduncle, chlorophyll content in flag leaf and the flag leaf area appeared to be most important for WSC accumulation in peduncle. High WSCSC genotypes tended to have higher grain weight per spike than low WSCSC genotypes both in defoliated and control plants

A pilot study of transrectal endoscopic ultrasound elastography in inflammatory bowel disease

BACKGROUND: Using standard diagnostic algorithms it is not always possible to establish the correct phenotype of inflammatory bowel disease which is essential for therapeutical decisions. Endoscopic ultrasound elastography is a new endoscopic procedure which can differentiate the stiffness of normal and pathological tissue by ultrasound. Therefore, we aimed to investigate the role of transrectal ultrasound elastography in distiction between Crohn's disease and ulcerative colitis. ----- METHODS: A total 30 Crohn's disease, 25 ulcerative colitis, and 28 non-inflammatory bowel disease controls were included. Transrectal ultrasound elastography was performed in all patients and controls. In all ulcerative coltis patients and 80% of Crohn's disease patients endoscopy was performed to assess disease activity in the rectum. ----- RESULTS: Significant difference in rectal wall thickness and strain ratio was detected between patients with Crohn's disease and controls (p = 0.0001). CD patients with active disease had higher strain ratio than patients in remission (p = 0.02). In ulcerative colitis group a significant difference in rectal wall thickness was found between controls and patients with active disease (p = 0.03). A significant difference in rectal wall thickness (p = 0.02) and strain ratio (p = 0.0001) was detected between Crohn's disease and ulcerative colitis patient group. Crohn's disease patients with active disease had a significantly higher strain ratio compared to ulcerative colitis patients with active disease (p = 0.0001). ----- CONCLUSION: Transrectal ultrasound elastography seems to be a promising new diagnostic tool in the field of inflammatory bowel disease. Further study on a larger cohort of patients is needed to definitely assess the role of transrectal ultrasound elastography in inflammatory bowel disease