Wide Mesh Research Articles

Prosthetic strap system for simplified ventral hernia repair: results of a porcine experimental model

Aiming to achieve a simplified ventral hernia repair, a proprietary oval-shaped mesh was experimentally tested in a porcine model. The mesh is structured with a large central body and radiating straps. The friction of the straps passing through the tissues are hypothesized to be adequate to maintain the position of the mesh during tissue ingrowth, avoiding classic point fixation while ensuring a wide coverage of the abdomen. The mesh, having six radial straps, was placed using a sublay preperitoneal technique in four pigs. All straps were passed laterally through the abdominal wall and exteriorized from the skin. The straps were trimmed at the level of the skin, allowing the stumps to recoil into the subcutaneous space. The animals were euthanized at 1 and 4 months to determine the integration of the straps. Macroscopically, all 24 straps were firmly incorporated within the abdominal wall. The tension-free placement of the mesh by using the straps was effective. The friction of the straps passing through the tissues was adequate to keep the mesh well orientated. No dislocation of the implants was observed. The strap system also allowed a broader coverage of the abdominal wall, far beyond the wound opening. The described arm system of the aforementioned implant seems to be effective in eliminating point fixation of the mesh. The fixation arms seemed to have ensured that the mesh stayed orientated in all of the animals. A very wide lateral mesh placement was accomplished, assuring sufficient defect overlap when shrinkage occurs.

Wood chips size distribution in relation to blade wear and screen use

The study investigated the effect of wearing chipper knives on machine productivity, fuel consumption and particles size distribution. The test included two different tree species (poplar and pine), two tree parts (branches and logs) and two screen types (large and medium). Chip quality was defined by CEN international technical standards. Knife wear causes a significant reduction of chipping productivity and a remarkable increase of fuel consumption. The replacement of the standard wide mesh screen with a narrower screen has a similar effect, further decreasing productivity and increasing fuel consumption. For the same screen type and knife wear level, productivity and fuel consumption are the same for poplar and pine. Knife, tree species and tree part also have a significant impact on chip size distribution. Chips produced from logs always contain a smaller proportion of oversize particles and a higher proportion of accepts. For the same large mesh screen, poplar chips tend to be larger than pine chips and to contain a higher proportion of oversize particles. On the contrary, pine chips tend to be smaller and to contain a higher proportion of fines. The use of a narrower mesh screen on pine material does not seem to offer any significant reduction of oversize particles, whose presence is already very limited. Therefore, a standard large mesh screen should be used when chipping pine material.

Assessment of the abdominal wall function after pedicled TRAM flap surgery for breast reconstruction: Use of modified mesh repair for the donor defect

Background:The pedicled TRAM flap has been a workhorse of autologous breast reconstruction for decades. However, there has been a rising concern about the abdominal wall donor site morbidity with the use of conventional TRAM flap. This has generally been cited as one of the main reasons for resorting to “abdominal wall friendly” techniques. This study has been undertaken to assess the abdominal wall function in patients with pedicled TRAM flap breast reconstruction. The entire width of the muscle and the overlying wide disk of anterior rectus sheath were harvested with the TRAM flap in all our patients and the anterior rectus sheath defect was repaired by a Proline mesh.Materials and Methods:Abdominal wall function was studied in 21 patients who underwent simultaneous primary unipedicled TRAM flap reconstruction after mastectomy for cancer. In all the patients, the abdominal wall defect was repaired using wide sheet of Proline mesh both as inlay and onlay. The assessment tools included straight and rotational curl ups and a subjective questionnaire. The abdominal wall was also examined for any asymmetry, bulge, or hernia. The minimal follow-up was 6 months postoperative. The objective results were compared with normal unoperated volunteers.Results and Conclusions:The harvesting the TRAM flap certainly results in changes to the anterior abdominal wall that can express themselves to a variable degree. A relatively high incidence of asymptomatic asymmetry of the abdomen was seen. There was total absence of hernia in our series even after a mean follow-up period of 15.5 months. A few patients were only able to partially initiate the sit up movement and suffered an important loss of strength. In most patients, synergists took over the functional movement but as the load increased, flexion and rotation performances decreased. The lack of correlation between exercise tests and the results of the questionnaire suggests that this statistically significant impairment was functionally not important. The patients encountered little or no difficulty in theis day-to-day activities. Our modification of use of a wide mesh as inlay and onlay repair minimizes the donor site morbidity. This also avoids maneuvers meant for primary closure of the rectus sheath defects, which can result in distortion of umbilicus. Therefore, in conclusion, the unipedicled TRAM flap should be regarded as a valuable option in breast reconstruction provided careful repair of the abdominal wall defect is undertaken using Proline mesh.

Aesthetic Plastic Surgery Symposium, Toronto, Ontario, April 17–18, 2009

Dr Walter Peters, Course Director, and the University of Toronto hosted the annual symposium and Dr WRN Lindsay, our founding plastic surgeon, attended. Dr Grady Core, Dr Mark Jewell and Dr Renate Saltz were our visiting professors in addition to local speakers. This reporter noted many things of interest although it is not possible to mention them all or to attribute each to individuals. There is a trend to analyse augmentation mammaplasty to attempt to better predict outcomes and the incidence of reoperations; for example, choosing textured implants for shaped devices and smooth implants for augmentation mastopexy. Dr Saltz said shape was more important than the scar in mastopexy. Patients will accept the scar if the shape is good and long lasting and the superior pedicle or medial pedicle is useful. If the inferior pedicle is used it can be used to augment the upper pole. Dr Lista said surgery can be done faster with an improvement in quality noting that lessons can be learned from successful car manufacturers such as Toyota, the key being organization, repetition, staff training and planning. Surgical quality is now better in private clinics than in general hospitals. Sadly, general hospitals have no way to catch up because they are working on an old-fashioned model and show few signs of moving toward the future. Larger volumes mean better quality as surgery changes from the craft model, where every operation is different, to the assembly line idea, where similarities are stressed. This can be done while retaining patient personal contact and ultimately, results will speak for themselves. Ontario now spends 46% of tax revenue on health care. As revenues decrease there will be a squeeze, necessitating the adoption of new delivery models. Surgical dissection and cautery using ultrasound is on the horizon but expensive. This allows dissection without heat or smoke. Dr Core presented abdominal wall reconstructions advising the use of very wide mesh. It was noted that the complications of TRAM flaps seem to be under-reported by some. Dr Peters presented a fascinating history of injectibles. These have been widely used around the world and despite cautions and in some jurisdictions illegal (eg, silicone injections), are still being done. ‘Permanent fillers’ need to approached with caution because some develop inflammatory reactions many years later and are difficult to treat. In the past 20 years, a new class of injectible fillers has been widely used in Ukraine, Russia and China – polyacrylamide hydrogel. History has a repeated itself. As of May 2006, the Chinese Food and Drug Administration has banned its use. Drs Ford and Core presented midface rejuvenation using the lower eyelid approach by relocating lower lid fat and elevating the malar fat fad. This produces a good result without a preauricular incision, and has an acceptable recovery period. Dr Core is pleased with the transaxillary augmentation under visualization and can insert up to a 300 mL low-profile gel implant this way. The simplest incision is likely the best. Cosmetic medicine is a growth field, fuelled by lowering of insurance payments and family doctors diversifying. There was much discussion on the advantages and disadvantages of broadening one’s practise to increase traffic flow through one’s clinic. During the recession surgery seems down or postponed, but injectibles and medical aesthetics seem strong. Income sharing seems an important motivator and practice stabilizer and can lead to inequities, with nurses earning less than estheticians. A new initiative will remind the public that plastic surgeons are best qualified to do all cosmetic procedures for the safety and benefit of patients. Dr Jewell thinks the minimal access cranial suspension face-lift is a good procedure, but takes practice. The neck can be improved in some patients without much neck dissection and the three sutures are safe. The skin is released after the suture if irregularities are seen. The level of lift is vertical in front of the ear, which means a shorter scar behind the ear. It moves volume back up into the cheek. He likes size 0 PDS absorbable sutures. Dr Saltz told us abdominoplasty can be improved by suction of the sides and back before abdominoplasty then limiting the dissection lateral to the rectus abdominus. Dissection of the flap superficially, preserving perforators, is of help. Obesity and combining operations increase the complication rate. Dr Core said the key to endoscopic brow lift is fixation. The use of endoscopy seems to be waning likely due to the expense of equipment. He does midface lifts through the lower eyelid using a skin-muscle flap and elevates the malar fat pad, inserting the orbital fat pad into the naso-jugal groove. He also elevates the orbicularis oculi. The meeting was well attended and a large turnout of nurses was noted.

Laparoscopic transperitoneal repair of flank hernias: a retrospective review of 27 patients

Incisional hernias of the flank are rare with scattered case reports regarding the feasibility of laparoscopic treatment. Treatment can be technically challenging due to patient positioning and adequate mesh overlap and fixation. The aim of this study is to describe the surgical technique and present outcomes of the largest known case series of laparoscopic repair of flank hernia. A retrospective chart review was performed from April 2002 to August 2006 at two university hospitals utilizing three surgeons' experience. All patients who underwent a laparoscopic repair of a flank hernia were identified and reviewed with regards to short-term outcomes. Twenty-seven patients were identified with incisional flank hernia treated laparoscopically. Average defect size was 188 cm(2) repaired with an average mesh size of 650 cm(2). Mean operating room (OR) time was 144 min and mean length of stay (LOS) was 3.1 days. There were two reoperations within the cohort: one for a new, unrelated midline hernia 7 months after repair of the initial flank hernia and one for chronic pain with removal of a previously placed polypropylene mesh in the subcutaneous tissue of the abdominal wall. Neither patient had failure of the laparoscopic flank hernia repair. Two other patients were conservatively treated for chronic pain. Mean follow-up was 3.6 months. In the laparoscopic repair of flank hernias adequate retroperitoneal dissection and wide mesh overlap is imperative. Laparoscopic repair can be performed safely and effectively with good short-term outcomes.

Usefulness of Slimmer and Open Cell Type Stent for Endoscopic Bilateral Stenting and Endoscopic Revision in Patients with Hilar Cholangiocarcinoma

Background and Aims: Although endoscopic bilateral metal stenting in “stent in stent” fashion is currently used to treat patients with unresectable hilar cholangiocarcinoma, this method has limited application in case of tight stricture or revision of tumor recurrence, especially on the side where stenting is taken place first. This study evaluated the clinical efficacy of bilateral metal stenting using Zilver stent which is slimmer and open cell type. Methods: We conducted a prospective, uncontrolled study in a tertiary referral university hospital. In twenty eight patients with unresectable Bismuth type II or higher hilar cholangiocarcinoma, the endoscopic bilateral metal stenting in “stent in stent” method was performed. At first, Y stent with central wide open mesh was inserted and then, open cell type Zilver stent, which is preloaded in a slim delivery system (7 Fr) and easily dilated, was placed into the contralateral hepatic duct through the central portion of Y stent. Results: Technical success was achieved in 24 (85.7%) patients. Functional success was noted in 24 (100.0%) patients among 24 patients. Early complications such as pancreatitis and cholecystitis occurred in 2 (8.3%) patients. Late complications occurred in 9 (37.5%) patients. Cholecystitis occurred in 1 patient and was managed by percutaneous transhepatic gallbladder drainage. Stent obstruction by tumor ingrowth or overgrowth occurred in 8 out of 24 (33.3%) patients. These patients were managed by placement of bilateral plastic stents (4/8), percutaneous transhepatic biliary drainage (3/8), and combined method (1/8). Among 5 patients who were tried by endoscopic revision, 4 (80%) patients were managed endoscopically by bilateral plastic stents. Conclusions: Slimmer and open cell type Zilver stent is effective in endoscopic bilateral stenting for advanced hilar cholangiocarcinoma and endoscopic revision in case of tumor recurrence.

An apical symphysial technique using a wide absorbable mesh placed on the apex for primary spontaneous pneumothorax

The outcome of thoracoscopic bullectomy for primary spontaneous pneumothorax (PSP) is not satisfactory. To reduce postoperative pneumothorax recurrence after thoracoscopic bullectomy, an effective and easy surgical method is required. We tried a new method using an absorbable mesh that covered the whole apical visceral pleura. A total of 157 sides of 143 patients who underwent stapled bullectomy under thoracoscopy for PSP were reviewed retrospectively. In the apical covering group (group A), a 15 x 15-cm(2) absorbable mesh sheet was placed on the apical visceral pleura with fibrin glue. Patients in group B underwent bullectomy alone. Cumulative postoperative recurrence was compared between the groups. Recurrent cases in group A were examined clinicopathologically. Group A had 111 cases and group B had 46. There was no operative mortality. Postoperative recurrence occurred in 15 of 157 cases (9.6%): 4 in group A and 11 in group B. The cumulative postoperative 5-year recurrence rate was 3.6% in group A and 23.9% in group B (log-rank test, p = 0.013). In group A, local adhesion was seen at the apical pleurae, and inflammatory changes with foreign body giant cells were seen at the pleura covered with the mesh. Placement of a wide absorbable mesh with fibrin glue at the apical visceral pleura significantly reduced postoperative recurrence after thoracoscopic bullectomy for PSP. The mesh was thought to act as a foreign body on the pleura and induce local inflammatory adhesion between the apical pleurae after bullectomy. This was an easy and effective symphysial procedure.

Hydroxyapatite-Coated Polycaprolacton Wide Mesh as a Model of Open Structure for Bone Regeneration

In principle, three-dimensional (3D) osteoconductive grafts with a proper chemical composition, high total porosity, and fully interconnected pores are suitable carriers to provide a proper substrate for in vivo neobone tissue ingrowth. However, most porous materials carry some intrinsic limits because of their internal structure (i.e., limited macroporosity and small pore interconnection size), representing a physical constraint for a massive blood afflux and bone ingrowth and therefore for generating effective osteopermissive grafts. We therefore hypothesized that an unconventional scaffold, based on an "open-structure" concept, should not pose any limit to vascularization of grafts and consequently to the amount of bone growth. Starting from this hypothesis, we have designed and developed a 3D osteoconductive polymeric-based wide-net mesh. Polymer fibers, joining hydroxyapatite beads, were coated with a thin layer of calcium phosphate (Ca-P), coupling the osteoconductivity properties of Ca-P with the handness and bulk properties of polymers. This completely open 3D scaffold prototype was tested both in vitro and in vivo, displaying a promising in vivo blood vessel invasion and bone-forming efficiency.

Dynamic adaptation of CSMA/CA MAC protocol for wide area wireless mesh networks

Though the popular IEEE 802.11 DCF is designed primarily for Wireless LAN (WLAN) environments, today it is being widely used for wide area wireless mesh networking. The protocol parameters of IEEE 802.11 such as timeout values, interframe spaces, and slot durations, sufficient for a general WLAN environment, need to be modified in order to efficiently operate in wide area wireless mesh networks. The current wide area wireless mesh network deployments use manual configuration of these parameters to the upper limit which essentially makes the networks operate at lower system efficiency. In this paper, we propose d802.11 (dynamic 802.11) which dynamically adapts the protocol parameters in order to operate at varying link distances. In fact, in 802.11, a transmitter can face ACK/CTS timeout even when it started receiving ACK/CTS packet before the timeout value. We present three strategies, (i) multiplicative timer backoff (MTB), (ii) additive timer backoff (ATB), and (iii) link RTT memoization (LRM), to adapt the ACK_ TIMEOUT in d802.11 in order to provide better adaptation for varying link dimensions. Through extensive simulation experiments we observed significant performance improvement for the proposed strategies. We also theoretically modeled the maximum link throughput as a function of the link dimension for the proposed system. Our results show that the LRM technique provides the best adaptation compared to all other schemes.

Primary calvarial meningioma

Primary intraosseous meningioma of the skull is uncommon. We report upon a 50-year-old male patient who presented with a history of an expanding scalp mass over a few months, associated with headache. The mass was initially misdiagnosed as congenital encephalocele. It was observed for 2 months, but the headache increased in severity, and the mass increased in size. Imaging studies showed localized skull expansion at the vertex, and osteolysis of the inner and outer plates of the skull. There was brain tissue herniating through a defect in the inner plate. The patient underwent wide surgical excision, dural repair, and mesh cranioplasty, following which his headaches ceased. Histological examination showed WHO grade I meningioma.

Personal protection of long lasting insecticide-treated nets in areas of Anopheles gambiae s.s. resistance to pyrethroids

BackgroundThe development of mosquito nets pre-treated with insecticide, Long Lasting Impregnated Nets (LLINs) that last the life span of the net, is a solution to the difficulty of the re-impregnation of conventional nets. Even if they showed a good efficacy in control conditions, their efficacy in the field, particularly in areas with resistance of Anopheles gambiae to pyrethroids, is not well documented. This study compares wide (Olyset®) and small (Permanet®) mesh LLINs in field conditions, using entomological parameters.MethodsThe two LLINs were tested in a rice-growing area of south-western Burkina Faso (West Africa) with year around high density of the main malaria vector An. gambiae s.s. In the study village (VK6), there is a mixed population of two molecular forms of An. gambiae, the S-form which dominates during the rainy season and the M-form which dominates the rest of the year. The two LLINs Olyset® and Permanet® were distributed in the village and 20 matched houses were selected for comparison with four houses without treated nets.ResultsMosquito entrance rate was ten fold higher in control houses than in houses with LLINs and there was no difference between the two net types. Among mosquitoes found in the houses, 36 % were dead in LLIN houses compared to 0% in control houses. Blood feeding rate was 80 % in control houses compared to 43 % in LLIN houses. The type of net did not significantly impact any of these parameters. No mosquitoes were found inside Permanet®, whereas dead or dying mosquitoes were collected inside the Olyset®. More than 60% of mosquitoes found on top or inside the nets had had blood meals from cattle, as shown by ELISA analysis.ConclusionThe percentage of blood-fed mosquitoes in a bed net study does not necessarily determine net success. The efficacy of the two types of LLINs was comparable, during a period when the S-form of An. gambiae was carrying the kdr gene. Significantly higher numbers of mosquitoes were collected in control houses compared to intervention houses, indicating that the LLINs provided an additional deterrent effect, which enhanced their expected prevention capacity.

Endoscopic Deployment of Jostent Selfx for Malignant Hilar Biliary Stricture: A Pilot Study

Endoscopic Deployment of Jostent Selfx for Malignant Hilar Biliary Stricture: A Pilot Study Hirofumi Kawamoto, Takashi Nakanishi, Osamu Mizuno, Etsuji Ishida, Tsuneyoshi Ogawa, Yuko Okamoto, Hirotoshi Fukatsu, Yasushi Shiratori Objectives: The JoStent SelfX stent (Abbott Vascular Devices, Redwood City, California, USA) is manufactured from a nickel-titanium alloy (nitinol) with a high degree of flexibility and elasticity. The JoStent SelfX also offers a wide stent mesh, thin delivery shaft, and good pushability. Therefore, the JoStent SelfX in endoscopic deployment of partial stent-in-stent procedure may be useful in case of the hilar biliary stricture. This pilot study was conducted to evaluate the procedure of stent deployment and its short-term stent efficacy. Methods: Between March 2003 and October 2004, 17 patients (male: female 9:8, mean age 67 year old, mean observation period 146 days) with malignant hilar biliary stricture admitted to our hospital were enrolled. The patients consisted of 11 patients with hilar bile duct carcinoma, 3 with gallbladder carcinoma, and one each patient with pancreas, colon, and hepatocellular carcinoma. All patients received JoStent SelfX endoscopically. The first stent was inserted into the left lateral segment as the stent mesh space was widest at the branching. After finding the right biliary branch through the stent mesh using Naviguide (Olympus, Tokyo, Japan), the second stent was inserted into this branch as a partial stent-in-stent procedure. This procedure was termed as ‘‘L-R pattern’’. When the patients had Bismuth type 4 stricture with large tumor in the left hepatic lobe or left portal vein obstruction, the first stent was inserted into the right posterior segment and the second stent was inserted into anterior branch. This procedure was termed as ‘‘Ra-p pattern’’. Results: Classifying the pattern of stenosis according to Bismuth classification, 1 patient had type 2 stenosis, 3 patients type 3 stenosis, and 13 patients type 4 stenosis. Of these, the L-R pattern deployment was performed in 11 patients and the Ra-p pattern deployment in 6 patients. On the intention-to-treat basis, the L-R pattern deployment was not achieved in 1 patient due to the failure of passing guidewire through the stenosis. Thus, the success rate of deployment was 94% (16/17). The Ra-p deployment was performed to this patient. Conclusion: The JoStent SelfX is a suitable metallic stent to deploy in the hilar biliary stricture in partial stent-in-stent procedure. T1274 Prospective Randomized Controlled Trial of Endoscopic Sphincterotomy Compared with Endoscopic Papillary Balloon Dilatation for Bile Duct Stones: Late Complications After Stone Removal Yutaka Komatsu, Naotaka Fujita, Hiroyuki Maguchi, Ichiro Yasuda, Osamu Hasebe, Yoshinori Igarashi, Akihiko Murakami, Hidekazu Mukai, Tsuneshi Fujii, Kenji Yamao, Kensei Maeshiro Aim: To compare long term complications of the two treatments, endoscopic sphincterotomy (EST) and endoscopic papillary balloon dilation (EPBD), for bile duct stones, including stone recurrence. Methods: From March 2000 to March 2001, a randomized controlled trial was carried out involving 11 institutions. Two hundred eighty two patients who had bile duct stones less than 14 mm in minimum diameter on X-ray images were included in this study. Patients were randomized to EST or EPBD treatment groups. Follow-up data were collected by personal interview or telephone every year. Even if biliary events had not occurred, blood examination, abdominal ultrasound, MRCP and/or ERCP were performed to assess asymptomatic stone recurrence, as available. The clinical outcome after stone removal in three years was evaluated using Kaplan-Meier analysis supplemented by the log lank test. Results: See Table. Conclusion: Overall incidence of late complications in the EST group was higher than that in the EPBD group. Stone recurrence in the EST group was also more frequent than in the EPBD group. Furthermore, a higher rate of asymptomatic stone recurrence in EST group was proved by follow-up MRCP and/or ERCP. Further long-term follow-up study will elucidate the efficacy of both procedures. Abstracts

A survey of optical multicast over WDM networks

Multicast applications such as multimedia, medical imaging, digital audio and video conferencing are bandwidth-intensive. With the advance in optical technology providing abundant bandwidth, it is natural to extend the multicast concept to optical networks in order to gain enhanced performance. This paper provides a comprehensive review of optical multicast techniques, covering the main optical multicast concept, the optical multicast switches, the multicast over single-hop broadcast-and-select networks, the multicast over multi-hop wide area mesh networks, and the related challenging algorithms developed for multicast routing in the optical domain.

Recent achievements and trends of research for geophysical prospection of archaeological sites

Our times are characterized by an increasing need for prospection particularly within the context of rescue archaeology. Geophysics has an important part to play due to its ability to identify some well defined targets as well as to investigate large areas. Several recent surveys, using carefully selected methods chosen in accordance with the type of expected remain or a combination of methods in order to refine or confirm the interpretation, have demonstrated the expertise of several organisations in a wide variety of archaeological contexts. However, important improvements are still to be expected from the laboratories. Our team, working within the framework of three dissertations, is investigating several original subjects, for which the initial results are presented and discussed here: (1) The use of magnetic susceptibility measurements on wide mesh grids in order to survey extensive areas immediately prior to their occupation or destruction by large modern equipment; (2) Experiments to test a new survey device (Slingram - CS150) able to measure the magnetic susceptibility of the ground; (3) Interpretation of a series of geophysical measurements integrated with other types of data into a G.I.S.

Adhered Supported Carbon Nanotubes

Carbon nanotubes (NTs) in excess of 200 μm long are grown by catalytic pyrolysis of hydrocarbon vapors. The nanotubes grow continuously without the typical extinction due to catalyst encapsulation. A woven metal mesh supports the nanotubes creating a metal supported nanotube (MSNT) structure. The 140 μm wide mesh openings are completely filled by 70 nm diameter multiwalled nanotubes (MWNTs). The MWNTs are straight, uniform and highly crystalline. Their wall thickness is about 10 nm (30 graphite layers). The adherent NTs are not removed from the support in a Scotch tape pull test. A 12.5 cm2 capacitor made from two MSNT structures immersed in 1 M KCl has a capacitance of 0.35 F and an equivalent series resistance of 0.18 Ω. Water flows through the MSNT at a flow velocity of 1 cm/min with a pressure drop of 15 inches of water. With the support removed, the MWNTs naturally form a carbon nanocomposite (CNC) paper with a specific area of 80 m2/gm, a bulk density of 0.21 g/cm3, an open pore fraction of 0.81, and a resistivity of 0.16 Ω-cm.

Intraparietal mesh repair for parastomal hernias

Herniation is a common long-term complication after a permanent stoma and the classical non-prosthetic repairs have a high recurrence rate. This type of hernia should be considered as incisional, so a prosthetic-based repair seems to be the best choice; nevertheless, the need for another laparotomy and the ideal plane to place the mesh remain debatable. We describe our initial experience with a novel technique for parastomal hernia repair that combines mesh 1 reinforcement with a local approach, thus avoiding a laparotomy. The anatomic disposition of the rectus sheath allows us to place a wide mesh in an intraparietal/anteromuscular plane, avoiding direct contact with the intestine and providing a reinforced wall. After 13 months of follow-up (3–20 months) our 3 patients have excellent results.

Effects of fish on the microdistribution of different larval size groups of Onychogomphus uncatus (Odonata: Gomphidae)

Four types of field experiments were carried out in order to study the effects of fish predation on different size groups of burrowing larval dragonflies Onychogomphus uncatus (CHARP.). (1) The effects of the bottom feeding fish Barbatula (Nemacheilus) barbatula (L.) on three size groups of O. uncatus in three types of substrate: sand, gravel and stones, were recorded using field enclosure cages. The densities of small sized larvae inhabiting cages with stones and gravel were reduced in the presence of fish compared with fish-free controls. No effects due to fish presence were found in larger larvae. (2) The colonisation of sand, gravel and stones in the field by different size groups of O. uncatus was studied using frames filled with substrates. Substrate as well as size specific effects were found. The low density of small larvae in coarse substrates is interpreted mainly as a direct effect of predation by B. barbatula which exclusively colonised these substrates. (3) To test the effect of exclusion of all fish on colonisation of O. uncatus, frames filled with stones were exposed in a running water and half of these were protected by cages. The densities of very small and medium sized larvae in the protected substrates were higher than in those without cages. (4) In cages with a wide mesh size, which allowed a free exchange of dragonfly larvae and B. barbatula but prevented predation by large fish, the density of small larvae of O. uncatus was reduced. B. barbatula were found exclusively inside the cages. It is suggested that predation by B. barbatula using the cages as a shelter against predation by large fish was responsible for this reduction.

Aortic wall structural strengthening by intraluminal net prosthesis to arrest aneurysm progression and to prevent dissection and rupture.

The major limitation implicit in the endovascular procedures for aortic prosthetic substitution is that they cannot be used in those tracts of the aorta where important collateral branches originate (aortic arch, thoraco-abdominal tract, upper abdominal), that would be occluded by the prosthesis. In order to overcome this limitation we hypothesized the endovascular positioning of a prosthesis in the form of a wide mesh network that would be gradually and spontaneously covered by new intima and included in the aortic wall. The fabric framework linked to the aortic wall would then condition its significant, regular and uniform mechanical strengthening that fractionates and partially absorbs the centrifuge pulsatile stress of the bloodstream. The purpose of this paper is to report the results of the insertion of a braided Prolene net prosthesis in the first 7 cm of the descending aorta of ten swine. The animals were killed after 6 weeks, the substituted segment removed and aortic wall compliance measured under standardized conditions. The prosthesis was found entirely covered by new intima, well embodied in the aortic wall. The intercostal collateral included in the substituted segment was patent, as proved by bubble formation during underwater insufflation. Compliance of the prosthesis segment was significantly lower than that of the adjacent descending aorta. Histology showed a regular net prosthesis inclusion deep in the neo-intima layer. Present results indicate the technical feasibility of the procedure, achieving significant aortic wall strengthening without affecting the collateral (intercostal) circulation.

Plasticity in Web Design in the Spider Parawixia bistriata: A Response to Variable Prey Type

1. Plasticity in foraging strategies may be an evolutionary response of predators to temporally or spatially variable resources. Although orb-weaver spiders use the web to capture a variety of prey types and sizes, plasticity in web design in response to such variation has rarely been documented. 2. The spider Parawixia bistriata spun two types of webs in response to temporally fluctuating prey availability. Small webs of fine mesh were spun daily at sunset and ceptured mainly small dipterans of the genus Dorhniphora. Large webs of wide mesh were spun only during diurnal termite swarms

Applications and advantages of the Slingram electromagnetic method for archaeological prospecting

The electromagnetic Slingram method can provide three types of information simultaneously: (1) the apparent resistivity of the ground; (2) its apparent susceptibility; and (3) the characteristic signatures of buried metallic objects. To build an apparatus with these three measurement capabilities requires an appropriate choice of parameters, including frequency, coil separation, and coil orientation as well as calculations which take into account the electrical resistivity and the magnetic susceptibility of the ground. The value of the Slingram method for archaeological applications is shown by two examples: (1) a Gallo‐Roman pottery workshop investigated with measurements of the apparent susceptibility using a reduced sampling wide mesh grid technique; and (2) the study of a Bronze hoard site located in a marsh. Capabilities of the Slingram method may be improved by further study of an apparatus using several receivers which would increase the depth of investigation. Use of several frequencies would overcome difficulties related to resolving the magnetic quadrature susceptibility.