The purpose of this study was to assess the changes in duodenal composition in three nutritional states: fasted, fed, and fat-enriched fed state. Two isocaloric meals were administered to healthy ...subjects on nonconsecutive days. Subsequently, duodenal samples were collected every 30min after which they were characterized with respect to pH, lipolytic products, bile salts, phospholipids, osmolality, and surface tension. The resulting time profiles displayed fluctuating patterns, which reflect high inter- and intrasubject variability. Duodenal composition was not altered by the higher fat percentage of the fat-enriched liquid meal. Monoglycerides, amounting from 5% to 88% of total lipids, were the dominant lipolytic species, followed by free fatty acids. Within 30min after meal administration, individual intraduodenal concentrations of lipid products were 0.0–5.5, 1.0–14.9, and 3.1–22.4mg/mL in fasted, fed, and fat-enriched fed state, respectively. The corresponding values for bile salts were 2.0–9.0, 6.9–9.3, and 4.4–30.3mM and for phospholipids 0.06–2.4, 2.6–5.7, and 1.4–9.3mM, respectively. Specific trends though, were not detected. This study illustrates the variable intraluminal conditions that can result after food intake. As intraduodenal events (e.g., intraduodenal dissolution) affect absorption of poorly water soluble and/or highly lipophilic drugs, this variability may possibly contribute to the highly variable drug plasma-time profiles often observed.
After ventricular catheterization magnetic resonance (MR) imaging very often demonstrates a focal area of high signal along the drain track which corresponds to parenchymal oedema. This high signal ...seemed to be more pronounced when the frontal area was catheterized than when the junctional parieto-temporo-occipital parenchyma (or trigonal area) was catheterized. In order to confirm this impression, we prospectively studied 41 consecutive patients with normal-pressure hydrocephalus in whom both of these brain regions were catheterized for intracranial pressure monitoring. Each patient was evaluated by serial MR. The extent of the MR hypersignal induced by both catheterizations was computed from digitized MR masks. The extent of the MR high signal area was significantly greater when the frontal area was catheterized compared to the trigonal area suggesting that the frontal area could be more prone to injury.
From 1986 to 1989, 23 adult patients (average age, 70 yr) with idiopathic chronic hydrocephalus received shunts with medium-pressure Pudenz-Schulte valves for suspected normal pressure hydrocephalus. ...Prospective clinical and computed tomographic monitoring was continued for at least 5 years. We observed the formation of a hypodense subdural collection in each of 10 patients (43%). Those collections that occurred early, i.e., within the first 9 postoperative days, evolved differently from those that occurred late; only early hypodense collections became subdural hematomas (three cases). In one case, a subdural hematoma was already present 9 days after surgery, so that four patients (17%) presented a subdural hematoma within the first 2 postoperative months. Our long-term follow-up revealed three patients (13%) with hypodense subdural collections, which appeared more than 2 months after surgery. None of the collection evolved into a subdural hematoma. Thirteen patients (57%) died between 9 and 68 months (average, 20 mo) after surgery, most often of an ischemic stroke. During the 1st postoperative year, there was improvement in the condition of 22 patients (96%) who had received a ventricular shunt; 21 of these patients (91%) remained improved until death or for at least 5 years.
The performance of switching fabrics is crucial to the global quality of service offered by an interconnection networks. It is shown that highly detailed simulations can be accelerated by using a ...parallel (high performance) computer as the computational platform. The simulation model is represented totally independently of the specific computer: hence validation has to be performed only once and the acceleration and optimization of a given implementation are strictly orthogonal to the problem description.
Idiopathic normal-pressure hydrocephalus remains difficult to treat. Controversy exists as to whether or not shunting can really improve cognitive functions and whether quantified intracranial ...pressure monitoring (ICP-Mo) can predict postoperative improvement rates. Several studies have drawn attention to the lack of a prospective study concerning the surgical outcome of this condition. We have performed such a study on idiopathic normal-pressure hydrocephalus patients shunted on the basis of ICP-Mo when "high" waves (amplitude > 9 mm Hg) were present. Twenty-three patients underwent surgery. The preoperative and postoperative clinical states were assessed by a quantitative procedure blind to the ICP-Mo results. A clear postshunting improvement was seen in 96% of the patients at 1 year with a statistically significant correlation between high wave relative frequency and the grade of improvement (P < 0.05). At the same time, 66.6% of shunted patients showed a significant improvement in cognitive functions. Complications of shunting were successfully managed without residual deficits in this series. We recommend the use of quantitative ICP-Mo as a criterion for surgery and to predict the improvement grade.
Despite crowdfunding's increasing popularity as a vehicle for financing early–stage ventures, we still know relatively little about the mechanisms that drive individuals to pledge and invest via such ...online platforms. We explored the extent to which financial or nonfinancial motivations determine the decision to invest for equity or to pledge. In addition, we also looked at whether having invested for equity can crowd out individuals’ motivation to keep a pledge into the same project. Our results show that nonfinancial motives play no significant role. Furthermore, we find that having invested for equity is a positive predictor of keeping a pledge.
Policy makers take initiatives to stimulate knowledge ecosystems in technology hotspots. It is implicitly assumed that these ecosystems will lead to value networks through which the participating ...companies can realize a competitive advantage. Value networks refer to business ecosystems where the value proposition is offered by a group of companies which are mutually complementary. The strategy literature suggests that business ecosystems lead to competitive advantages for each of the partners in the ecosystem. Based on a unique hand-collected database of 138 innovative start-ups in the region of Flanders, we analyze the knowledge and business ecosystem and the financial support network. We find that the knowledge ecosystem is well structured and concentrated around a number of central actors while the business ecosystem is almost non-existent at the local level. Further, we find that the financial support network is almost 100% publicly backed and fails to bridge the knowledge and business ecosystem. The implications for policy makers who tend to focus on the development of local ecosystems are discussed.
Business incubators (BIs) have been established around the world to stimulate new business creation. Whilst it is accepted that incubation models have evolved, little is known about whether existing ...incubators have adjusted their value proposition to incorporate recent incubation paradigms or have simply remained operating as originally founded. We present data collected within seven BIs and their tenants regarding service provision and selection criteria. Our findings show that whilst BIs of all generations offer similar support services, tenants in older generation BIs make less use of the BI's service portfolio. We suggest this is a consequence of slack selection criteria and the absence of clearly defined exit policies. These results imply that older generation BIs should update their service portfolio while simultaneously imposing stricter selection criteria and introducing exit policies. Finally, we discuss the wider implications this raises for BIs' managers, prospective tenants and policy makers.
► We follow the evolution of business incubation models. ► We analyze both supply and demand of business incubation services. ► More recent generation of business incubators provide more tenants with services. ► Slack selection criteria and unclear exit policies create a mismatch between the service portfolio and tenant companies' needs. ► Implications for business incubators managers, prospective tenants and policy makers are discussed.
New ventures in nascent markets often pivot while still developing their organizational identity. A strong identity helps attract investors and employees and pivoting helps pursue new opportunities. ...How do they interact? To illuminate this process, we conduct an in-depth longitudinal field study of a new venture developing a technology to transform Internet websites for mobile devices. The venture completes a first pivot but fails during a second attempted pivot of its business model in the nascent market. Comparing the completed and the attempted pivot, our analysis suggests that new venture pivoting relies on the ability to crystallize the individual roles of organizational members (“what we do”) in line with organizational identity (“who we are”). Our findings shed light on stakeholder constraints on pivoting by scaling new ventures through the micro-mechanism of role crystallization. Our analysis also delineates the inter-temporal effects of lingering organizational identity, thereby advancing research on the organizational identity dynamics of new ventures.
•Pivoting in a scaling new venture is facilitated by role crystallization•Role crystallization contributes to a lingering organizational identity•Lingering organizational identity can hinder subsequent pivoting•Stakeholder constraints can give rise to diminishing returns from pivoting
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