Perforated Region Research Articles

Inhibitory effect of N-acetyl cysteine and ascorbic acid on the development of myringosclerosis: An experimental study

ObjectivesThis study investigated the effects of ascorbic acid and N-acetyl cysteine (NAC) antioxidants on the development of myringosclerosis (MS) in an experimental model. MethodsMyringotomies were performed in the ears of 15 guinea pigs, and Spongostan® pieces were placed on the perforated regions of the tympanic membrane. The subjects were divided randomly into three groups and treated with three different solutions on the Spongostan—group 1: (control, 0.9% saline), group 2 (ascorbic acid), and group 3 (NAC). On day 15 after treatment, specimens from the tympanic membranes were obtained and examined via light microscopy. Sclerosis and inflammation scores and the tympanic membrane thicknesses were evaluated. Immunohistochemical methods were used to evaluate the expression of VEGF, TGF-β, iNOS, and IL1-β in all groups. ResultsLower sclerosis and inflammation scores and reduced tympanic membrane thicknesses were observed in groups treated with NAC or ascorbic acid compared with the control group. Immunohistochemical studies revealed significantly less expression of VEGF, TGF-β, and iNOS in groups 2 and 3 compared with group 1. Additionally, IL1-β expression was significantly less in group 3 than in group 1. Compared with group 1, group 2 animals exhibited reduced inflammation in the lamina propria, fewer active fibroblasts, less leukocyte infiltration, and decreased thickness of the vessels; group 3 animals exhibited decreased numbers of active fibroblasts and collagen fibers in the lamina propria. ConclusionsInflammation scores, cellular infiltration, and expression of VEGF, TGF-β, and iNOS were reduced by ascorbic acid and/or NAC treatments, thereby decreasing MS development. Decreased expression of IL1-β was observed only in animals treated with NAC.

Low RC-Constant Perforated-Channel HFET

The novel HFET design using perforated channel region under the gate reduces drain and source parasitic resistances due to the current spreading effect in the source-gate and gate-drain regions. Demonstrated results for AlGaN/GaN HFET show that the RONCG time constant reduces around two times using simple and robust perforated channel device processing. These results are especially important for new generations of power switching transistors.

NASPGHAN Clinical Report on the Evaluation and Treatment of Pediatric Patients With Internal Penetrating Crohn Disease

Natural History of Pediatric Crohn Disease T he natural history of pediatric Crohn disease (CD) remains unpredictable, although some trends are observed that differentiate children from adults. Pediatric CD often presents with more severe disease and more frequent need for immunosuppressive therapy (1). Growth failure, present in 15% to 20% of patients, is a unique characteristic of pediatric CD not seen in adult-onset CD (2). Colonic disease distribution is common in patients younger than 10 years (1). The need for surgical intervention also varies, with 1 study reporting the actuarial risk of having undergone an extensive intestinal resection being 48.6% 5% in a childhood-onset group versus 14.6% 2% in the adult-onset group (P< 0.001) (1). More recently, long-term follow-up of patients enrolled in pediatric registries shows a cumulative surgical rate of 14% to 17% at 5 years and 28% at 10 years (3,4).

Anastomotic stenosis of the descending colon caused by barium granuloma formation following barium peritonitis: report of a case

Anastomotic stricture reportedly often recurs following barium peritonitis, regardless of whether the anastomotic diameter is initially sufficient. However, the causes of repetitive stricture have not been clarified. We report a case that suggests the pathophysiology of recurrent anastomotic strictures following barium peritonitis. The patient was a 39-year-old Japanese man with idiopathic perforation of the descending colon after undergoing an upper gastrointestinal barium contrast study. After emergency peritoneal lavage and diverting colostomy, created using the perforated region, the patient recovered uneventfully and 3 months later, the colostomy was closed and the perforated colon was resected. However, 7 months after colostomy closure, abdominal distention gradually developed, and colonoscopy revealed an anastomotic stricture. The patient was referred to our hospital where he underwent resection of the anastomotic stricture. The surgical specimen exhibited barium granulomas not only in the subserosa of the entire specimen, but also in the submucosa and lamina propria localized in the anastomotic site. These findings suggest that barium was embedded in the submucosa and lamina propria with manipulation of the stapled anastomosis and that the barium trapped in the anastomotic site caused persistent inflammation, resulting in an anastomotic stricture.

An unusual complication of infective endocarditis: left ventricular outflow tract perforation

A 24-year-old female was admitted to our hospital complaining of fever, chest pain, cough and dyspnoea. Physical examination revealed tachycardia with heart rate 115 bpm, dull and decreased respiratory sounds in the lower left lung field, systolodiastolic murmur at the aortic and mesocardiac area. Chest X-ray showed an increased cardiothoracic ratio and left-sided pleural effusion. The erythrocyte sedimentation rate was found to be 64 mm/h. Echocardiography revealed moderate aortic insufficiency. Pathological flow was detected at left ventricular outflow tract (LVOT) by Doppler imaging. LV free wall was seen to be compressed partially by the haematoma surrounding the heart. Chest computed tomography (CT) showed the perforation at LVOT, partial compression of LV lateral wall, main pulmonary artery, superior vena cava, and nearly complete obstruction of left pulmonary veins (Figs. 1–3). The patient underwent emergent cardiac surgery. A pseudoaneurysm sac was detected starting from the lateral side of the aorta extending through transverse sinus and including the left anterior descending coronary artery region. Aortotomy was performed. The aortic valve was detected to be bicuspid. A perforation with a diameter of 10 × 15 mm was seen just below the aortic valve (Fig. 4). The perforation was repaired with a dacron graft, and aortic valve replacement was performed. The pathological examination revealed inflammation and vegetation at the sample taken from the perforation region, which demonstrated that the aetiology of perforation was mural infective endocarditis. Mural endocarditis is an inflammation and disruption of the nonvalvular endocardial surface of the cardiac chambers. Mural endocarditis may develop on LVOT secondary to chronic aortic regurgitation due to chronic endocardial trauma. Traumatised endocardium provides a nidus for the development of bacterial vegetation. It is well known that inflammation and vegetation may cause destructive lesions and perforation usually affecting valves, and result in acute valvular regurgitation, or may result in fistula formation. But myocardial perforation and pseudoaneurysm formation has rarely been reported. Excision of the pseudoaneurysm with LV reconstruction should be the treatment of choice in patients presenting with myocardial perforation and pseudoaneurysm formation.

Influence of rock failure behaviour on predictions in sand production problems

The mechanical strength of rock in terms of shear or compressive failure has been previously adopted as a criterion for sand production and when used solely has been proven to overestimate the process. On the other hand, ignoring the mechanical strength behaviour of the material increases the tendency for inaccurate estimations of the erosion process. In this work, an equally proportionated inclusion of the mechanical strength and erosion-based criteria in sanding predictions is proposed and assessed by numerical models. Several rock failure models and their influences on the sanding process have been analysed, including models such as the Drucker–Prager (DP), the Drucker–Prager hardening (DP hardening), the Mohr–Coulomb (MC) and the Mohr–Coulomb softening (MC softening). Modelling outcomes show distinct differences in rock response to operating and boundary conditions (e.g. flow rate and drawdown), and predictions of sand production. It was confirmed by modelling results that despite the low magnitude of stresses and strains developed at the well face and perforation regions, post-yield hardening behaviour increases the estimation of the amount and intensity of sand production. Also, incorporating a post-yield softening behaviour increases the magnitude of stresses and strains; however, this effect is observed to have a negligible impact on sand production. The role of void ratio has been recognised as a dominant factor, as its evolution significantly determines the pattern and intensity of sand production. A more cautious selection and rigorous coupling of rock strength models in sand production modelling is therefore essential if accuracy of predictions is to be improved.

Establishing primary cell cultures from Branchiostoma belcheri Japanese

Since Branchiostoma (amphioxus, lancelet) was firstly found by a German zoologist in 1774 (Pallas 1774), it has caught great attention of developmentalists, geneticists and molecular biologists (Mou et al. 2002; Zhang et al. 2010; Yu et al. 2011; Guirola et al. 2012; Short et al. 2012; Yao et al. 2012). Branchiostoma shares three key features with vertebrate: a hollow dorsal neural tube, a notochord and a perforated pharyngeal region. In addition, the genome of Branchiostoma does not undergo duplication as well as lose or intense structural changes (Putnam et al. 2008). Therefore, Branchiostoma is considered the progenitor of vertebrate, and recently seems to be a model to study evolution and development of vertebrate (Holland and Holland 2001; Holland et al. 2004, 2008; Putnam et al. 2008; Li et al. 2012). Although researchers have made great effort on Branchiostoma cell culture (Wang et al. 2009), no amphioxus cell resource is available for in vitro studies. Much works about functional analysis of Branchiostoma molecules have to be carried out by using human cell lines (Yuan et al. 2009, 2010; Li et al. 2011; Xu et al. 2011; Yang et al. 2011). Over the past 50 yr, Branchiostoma primary cell culture system has not been established due to lack of knowledge about nutritional needs of invertebrate. Furthermore, the phenotype of Branchiostoma cells in various organs remains unknown. This is a tough problem holding back many valuable researches in development, immune system evolution and other related research. Thus, establishment of Branchiostoma cell culture system is rather important for basic research. In this study, we tried a series of method to culture Branchiostoma belcheri Japanese (BbJ) cells and laid a basic foundation for setting up BbJ cell culture system.

Asymptotic analysis of boundary value and spectral problems in thin perforated regions with rapidly changing thickness and different limiting dimensions

Boundary value and spectral problems for an elliptic differential equation with rapidly oscillating coefficients in a thin perforated region with rapidly changing thickness are investigated. Descriptions of asymptotic algorithms for solutions of such problems in thin regions with different limiting dimensions are combined. For a mixed inhomogeneous boundary value problem a corrector is constructed and an asymptotic estimate in the corresponding Sobolev space is established. Asymptotic bounds for eigenvalues and eigenfunctions of the Neumann spectral problems are also found. Full asymptotic expansions for the eigenvalues and eigenfunctions are constructed under certain symmetry assumptions about the structure of the thin perforated region and the coefficients of the equations.Bibliography: 21 titles.

Evaluation of the effect of perforations in the collector vessel of a steam generator on the critical stress intensity coefficient

An approach to calculating the effective critical stress intensity coefficient for mainline cracks in the perforation zone of the first-loop collector of a VVER steam generator is examined. The energy criterion is chosen as the condition for crack stability: the decrease of the elastic deformation energy which is due to the opening of a growing crack should not exceed the change of the surface energy of the crack in the process. The difference between the critical stress intensity coefficient for a mainline crack in the continuous and perforated regions is analyzed. Relations making it possible to lower the critical stress intensity coefficient as a function of the parameters of the perforation (spacing, diameter of openings) as well as the dimensions and orientation of the mainline crack in the perforation zone are presented.

A new method for productivity calculation of perforated wells in Gas condensate reservoirs

Flow in perforated regions has been the subject of numerous investigations in the past 60 years. These studies have mainly concentrated on proposing practical tools for the productivity estimation of perforated wells. The skin factor proposed can be applied in an equivalent (one dimensional radial) open-hole system replicating the flow around the actual complex three dimensional flow geometry of the perforated region. However, the majority of these studies concentrate on single-phase flow conditions. In gas condensate systems at relatively low interfacial tension (IFT) values, phase change and dependency of relative permeability on velocity and interfacial tension add significant complexity to proposing such an efficient and much needed tool for practical applications. This work is aimed at the development of a practical and convenient method for defining an effective wellbore radius of an equivalent open-hole system, replicating flow around a perforated well in gas condensate reservoirs. The new method is based on the physics of the flow and applicable for both single-phase non-Darcy and two-phase gas condensate flow systems. Since the mechanical perforation skin formulations available in the literature are not accurate for highly anisotropic formations, a new more efficient skin formulation is introduced for such applications. In these exercises the finite-element based simulator developed by Jamiolahmady et al. (2007) was used to generate the large bank of data required to confirm the integrity of the proposed practical approach for productivity calculation of perforated wells in gas condensate reservoirs.

Near-surface structure of a bicontinuous microemulsion with a transition region

The lamellar ordering of bicontinuous microemulsions adjacent to a planar hydrophilic wall is investigated experimentally by grazing-incidence small-angle neutron scattering and theoretically by computer simulations. It is shown that precise depth information in neutron scattering can be obtained by tuning the scattering length density of the overall microemulsion. Neutron reflectometry completes the characterization. The nucleation of a lamellar phase at the wall is observed, and a perforated lamellar transition region is identified at the lamellar-microemulsion interface. The thickness of the lamellar region is about 400 Å, which corresponds to two bilayers.

Ballistic Impact Behaviour of a Tempered Bainitic Steel Against 7.62 mm Armour Piercing Projectile

In this study, occurence of failure after the interaction between an armour piercing 7.62 mm caliber projectile and a tempered bainitic steel has been investigated. The shot was performed at zero degree with a projectile velocity of 840 m/s. After the shot, microstructural and fractographical examinations were carried out on the sample taken from the perforated region. In the etched sample, it was observed that the morphology of the original microstructure had changed and adiabatic shear bands (ASBs) were formed in regions close to the direction of penetration. Main failure is ductile (plastic) deformation was followed by cleavage after shot. Cracks due to adiabatic shear band and formation of abrasive wear were seen. The perforation mode of the steel was a typical petalling.

Radiographic evaluation of furcal perforations sealed with different materials in dogs' teeth

ObjectiveThe objective of this work was to evaluate, using radiographic images, the behavior of four materials used to repair root perforations in dogs' teeth. Material and MethodsSecond and third premolars of 6 dogs were used. The 48 teeth were randomly divided into 4 groups (n=12) and the perforations were sealed with one of the following materials: MTA, AH Plus, Vitremer and gutta-percha. Dogs were submitted to general anesthesia, teeth were radiographed and pulp was accessed. Perforations were done, at the maximum curve of the pulp floor, sealed and the accessed coronal cavity was filled with glass ionomer cement (Vidrion R). After 90 days, the dogs were sacrificed and the last x-ray image was taken. Images were analyzed for the presence/absence of periodontal lesions at the perforation region. Data were analyzed statistically by chi-square test at 5% significance level. ResultsThere were no statistically significant differences (p≥0.05) among AH Plus, Vitremer and gutta-percha groups. MTA produced the smallest number of periodontal lesions (p<0.05). ConclusionsIt may be concluded that none of the tested materials was able to preserve the integrity of the periodontal tissues in the furcation region, and the use of MTA resulted in the least formation of adjacent periodontal bone lesions revealed by the radiographic comparisons.

Potential-flow-based numerical study for the response of floating offshore structures with perforated columns

Perforated piles are used in near-shore breakwaters for coastal protection and deep water platforms for oil exploration. Emerged and submerged perforated cylindrical structures reduce wave–structure interactions and scouring problems considerably, but their use on a floating structure is limited. Mathematical model is developed to introduce perforated walls in floating structures and method of solution is discussed. Eigenfunction expansion approach is used to derive velocity potentials based on which hydrodynamic forces on perforated cylinders are obtained. An example tension leg platform having perforated caissons is chosen; length of the perforated region and its location on tension leg platform are varied to determine their influence on its motion. For increase in perforation length, fluid–structure interaction reduces, causing decrease in surge and pitch responses. However, increase in perforated length in the lower part of column does not significantly increase these responses; heave remains relatively unaffected regardless of the length of perforation in the columns.

Perioperative management for a patient with hypermagnesemia-induced shock with perforative peritonitis

We present a case of hypermagnesemia accompanied by perforative peritonitis. A 79-year-old woman took magnesium citrate as part of the pretreatment on the day before a scheduled colonoscopy. She developed nausea and muscle weakness, and she was complaining of left abdominal pain. Consciousness gradually worsened and she developed shock. Intestinal obstruction was recognized on abdominal X-ray and computed tomography (CT), and peritonitis was suspected. An exploratory laparotomy was scheduled for diagnosis and treatment. In the operating room, arterial blood gas analysis showed metabolic acidosis and hypermagnesemia (Mg: 2.75 mmol/l, normal range: 0.1-1.5 mmol/l). On laparotomy, adhesion around the sigmoid colon and turbid ascites were recognized. But we could not detect the apparent region of perforation. Based on these findings and the presence of hypermagnesemia, we diagnosed that the shock was caused by peritonitis due to intestinal micro-perforation, and by hypermagnesemia due to absorption of laxative. We started to treat for metabolic acidosis, and to manage the hypermagnesemia by calcium hydrochloride administration and by continuous hemodiafiltration after the operation. On day 4 of the illness, the plasma Mg level was normalized. She was extubated on day 12, and discharged on day 84. This case with complicated clinical symptoms reaffirms the difficulty and importance of making a diagnosis quickly by collecting various data.

High Velocity Flow in and Around Long Perforation Tunnels

In oil industries, wells are mostly cased and perforated rather than completing the producing formation as open-hole. This study concentrates on the steady-state flow behaviour of a single-phase fluid in and around perforated completion tunnels (up to 50 inches long) including inertial effects (Non-Darcy flow). It is shown that the pressure drop inside long perforated tunnels under high flow velocity conditions is negligible compared to that around the perforated region within the porous medium. The results also indicate that the impact of perforation parameters varies with increasing fluid velocity but approaches an asymptotic value at very high flow velocity. The perforation length is the most important parameter whereas perforation radius, rock and fluid properties have little impact on the perforation performance.

Effects of septal perforation on nasal airflow: computer simulation study

Nasal septal perforation is a structural or anatomical defect in the septum. The present study focused on the effects of septal perforation on nasal airflow and nasal patency, investigated using a computer simulation model. The effect of nasal septal perforation size on nasal airflow pattern was analysed using computer-generated, three-dimensional nasal models reconstructed using data from magnetic resonance imaging scans of a healthy human subject. Computer-based simulations using computational fluid dynamics were then conducted to determine nasal airflow patterns. The maximum velocity and wall shear stress were found always to occur in the downstream region of the septal perforation, and could potentially cause bleeding in that region, as previously reported. During the breathing process, there was flow exchange and flow reversal through the septal perforation, from the higher flow rate to the lower flow rate nostril side, especially for moderate and larger sized perforations. In the breathing process of patients with septal perforations, there is airflow exchange from the higher flow rate to the lower flow rate nostril side, especially for moderate and large sized perforations. For relatively small septal perforations, the amount of cross-flow is negligible. This cross-flow may cause the whistling sound typically experienced by patients.

The amphioxus genome sequence illuminates the evolutionary origin of vertebrates

also known as lancelets, are small, translu-cent, worm-like marine invertebrates (see cover) that spendmost of their lives buried in the sea floor, filter-feedingthrough their jawless, ciliated mouths. Originally describedas a type of mollusk—specifically, a type of sea slug—byPeter Simon Pallas in 1774, they were later reclassified asfish by Gabrielle Costa (1834) and William Yarrell (1836)who independently recognized their vertebrate-like features.These include a hollow neural tube dorsal to the gut, anotochord, a perforated pharyngeal region, a segmented bodymusculature (embryologically derived from somites), and apostanal tail. In 1886, the great Russian embryologist—andsupporter of Darwin—Alexander Kowalevsky, observedthat, unlike other vertebrates, amphioxus had an earlyembryology that was very similar to that of certain inverte-brates, planting the seeds of the idea that this animal mightrepresent a key “missing link” between vertebrates andinvertebrates (Kowalevsky 1886). These, and other studiesof amphioxus morphology and development (e.g., Lankesterand Willey 1890; Willey 1894; Conklin 1932;Herdman1904; Goodrich 1909), convincingly demonstrated thatvertebrates arose from a particular group of marine inverte-brates, effectively uniting two primary divisions within theanimal kingdom. Together, the vertebrates, urochordates(ascidians), and cephalochordates constitute the phylumChordata, all descended from a common ancestor that livedmore than 550 mya in the Precambrian period.Absent any understanding of the genetic programsregulating developmental processes, no further progresscould be made, so it took another 100 years before theadvent of molecular–biological technologies allowed anyconnection to be established between the developmentalmechanisms employed by vertebrates and invertebrates.Then, in 1984, a paper appeared showing that certainDNA-binding transcription factors previously implicatedin the determination of anterior/posterior body parts inflies—encoded by Hox genes—were also present invertebrates, including humans (McGinnis et al. 1984).This realization represented a true“paradigm shift” in ourunderstanding of the genetic connectedness between allbilaterally symmetrical animals (bilaterians), one that couldnever have been imagined by Darwin or his advocates150 years earlier.About 20 years ago, an extraordinary coincidence oc-curred. Having been characterizing Hox genes in mice as agraduate student (Krumlauf et al. 1987;Holland1988;Holland and Hogan 1988a,b), Peter Holland, then a researchfellow in the Department of Zoology at Oxford University,became interested in how Hox gene expression patternsmight inform our understanding of homologies between the

The ototoxic effect of boric acid solutions applied into the middle ear of guinea pigs

This study analyzed the ototoxic effects of boric acid solutions. Boric acid solutions have been used as otologic preparations for many years. Boric acid is commonly found in solutions prepared with alcohol or distilled water but can also be found in a powder form. These preparations are used for both their antiseptic and acidic qualities in external and middle ear infections. We investigated the ototoxic effect of boric acid solutions on guinea pigs. We are unaware of any similar, previously published study of this subject in English. The study was conducted on 28 young albino guinea pigs. Prior to application of the boric acid solution under general anesthesia, an Auditory Brainstem Response (ABRs) test was applied to the right ear of the guinea pigs. Following the test, a perforation was created on the tympanic membrane of the right ear of each guinea pig and small gelfoam pieces were inserted into the perforated area. Test solutions were administered to the middle ear for 10 days by means of a transcanal route. Fifteen days after inserting the gelfoams in all of the guinea pigs, we anasthesized the guinea pigs and removed the gelfoams from the perforated region of the ear and then performed an ABRs on each guinea pig. The ABRs were within the normal range before the applications. After the application, no significant changes were detected in the ABRs thresholds in neither the saline group nor the group administered boric acid and distilled water solution; however, significant changes were detected in the ABRs thresholds of the Gentamicine and boric acid and alcohol solution groups. We believe that a 4% boric acid solution prepared with distilled water can be a more reliable preparation than a 4% boric acid solution prepared with alcohol.

ACC/AHA 2008 Guideline Update on Valvular Heart Disease: Focused Update on Infective Endocarditis

ACC/AHA 2008 Guideline Update on Valvular Heart Disease: Focused Update on Infective Endocarditis