887 research outputs found
Corporate Divestitures and Family Control
This paper investigates the relationship between divestitures and firm value in family firms. Using hand-collected data on a sample of over 30,000 firm-year observations, we find that family firms are less likely than non-family firms to undertake divestitures, especially when these companies are managed by family rather than non-family-CEOs. However, we then establish that the divestitures undertaken by family firms, predominantly those run by family-CEOs, are associated with higher post-divestiture performance than their non-family counterparts. These findings indicate that family firms may fail to fully exploit available economic opportunities, potentially because they pursue multiple objectives beyond the maximization of shareholder value. These results also elucidate how the characteristics of corporate owners and managers can influence the value that firms derive from their corporate strategies
Do Analysts Add Value When They Most Can? Evidence From Corporate Spin-Offs
This article investigates how securities analysts help investors understand the value of diversification. By studying the research that analysts produce about companies that have announced corporate spin-offs, we gain unique insights into how analysts portray diversified firms to the investment community. We find that while analysts\u27 research about these companies is associated with improved forecast accuracy, the value of their research about the spun-off subsidiaries is more limited. For both diversified firms and their spun-off subsidiaries, analysts\u27 research is more valuable when information asymmetry between the management of these entities and investors is higher. These findings contribute to the corporate strategy literature by shedding light on the roots of the diversification discount and by showing how analysts\u27 research enables investors to overcome asymmetric information
Putrescine-polysaccharide conjugate as transglutaminase substrates and their possible use in producing crosslinked films
Putrescine (1,4-diaminobutane) was covalently linked to alginate and low-methoxyl pectin to synthesize new aminated polysaccharides. Both putrescine-pectin and -alginate conjugates, although the latter at higher concentrations, were found to be able to act as effective acyl acceptor transglutaminase substrates in vitro using both dimethylated casein and soy flour proteins as acyl donors. Monodansylcadaverine, a well known acyl acceptor transglutaminase substrate, dose-dependently counteracted the covalent binding of the aminated polysaccharides to the proteins. Putrescine-pectin conjugate was also tested to prepare, in combination with soy flour proteins, edible films in the presence of purified microbial transglutaminase. Characterization of the enzymatically crosslinked films showed a significant decreased water vapor permeability, with respect to the ones obtained with non-aminated pectin in the presence of transglutaminase, as well as improved mechanical properties, such as high extensibility. Possible biotechnological applications of hydrocolloid films containing putrescine-polysaccharide derivatives enzymatically crosslinked to proteins were suggested
Transglutaminase-catalyzed preparation of chitosan-ovalbumin films
Microbial transglutaminase was employed as catalyst for preparing chitosan–ovalbumin films. The films showed low solubility at a wide range
of pH and underwent to a good enzymatic hydrolysis with trypsin. The degree of swelling was reduced and the mechanical resistance of the
chitosan–ovalbumin films increased from 24 to 35MPa after enzymatic treatment with transglutaminase. The barrier efficiency toward water
vapour was slightly improved for the films prepared by transglutaminase-mediated cross-linking
Transglutaminase-catalyzed site-specific glycosidation of catalase with aminated dextran
An enzymatic approach, based on a transglutaminase-catalyzed coupling reaction, was investigated to modify bovine liver
catalase with an end-group aminated dextran derivative. We demonstrated that catalase activity increased after enzymatic glycosidation
and that the conjugate was 3.8-fold more stable to thermal inactivation at 55 ◦C and 2-fold more resistant to proteolytic
degradation by trypsin. Moreover, the transglutaminase-mediated modification also improved the pharmacokinetics behavior
of catalase, increasing 2.5-fold its plasma half-life time and reducing 3-fold the total clearance after its i.v. administration in
rats
BIOTIC AND ABIOTIC EVENTS IN A SHALLOW CARBONATE PLATFORM (UPPER CRETACEOUS, SOUTH PYRENEAN MARGIN)
Πραγματοποιήθηκε μία λεπτoμεpής ιζηματολογική και παλαιοντολογική μελέτη των αποθέσεων ανθρακικής πλατφόρμας της περιοχής Serres Marginals (νότιο περιθώριο της Λεκάνης των Πυρρηναίων) και αναγνωρίσθηκαν τρεις ακολουθίες ρηχών ανθρακικών αποθέσεων (Cl, C2 και C3). Εντός των αποθέσεων ρηχής πλατφόρμας περιγράφονται ενδιάμεσης ενέργειας υποπαλιρροιακές έως ενδοπαλιρροιακές φάσεις, αβαθείς άμμοι υψηλής ενέργειας καθώς και λιμνοθαλάσσια έως λιμναία περιβάλλοντα.A detailed sedimentological and paleontological study of the Late Santonian-Late Campanian carbonate platform deposits of the Serres Marginals area (South margin of the Pyrenean Basin) has been performed. Three depositional shallow carbonate sequences have been distinguished (CI, C2 and C3). Within the shallow platform sequences moderate energy subtidal to intertidal, high energy sand-shoal, protected lagoon and restricted lagoon to lacustrine fades have been identified
Chitosan-whey protein edible films produced in the absence or presence of transglutaminase: Analysis of their mechanical and barrier properties
Chitosan-whey protein edible films with different protein concentrations were prepared in the absence or presence of microbial transglutaminase as cross-linking agent. The films prepared in the presence of the enzyme showed low solubility at a wide range of pH, a lower degree of swelling, and good biodegradability following protease treatments. The presence of transglutaminase induced also an enhancement in film mechanical resistance and a reduction in their deformability. Finally, the barrier efficiency toward oxygen and carbon dioxide was found to be markedly improved in the cross-linked films which showed also a lower permeability to water vapor. Some potential practical applications of transglutaminase-treated chitosan-whey protein films are suggested
Antibiotic Class and Outcome in Post-stroke Infections: An Individual Participant Data Pooled Analysis of VISTA-Acute
Antibiotics; Post-stroke infections; Post-stroke pneumoniaAntibiòtics; Infeccions posteriors a un accident cerebrovascular; Pneumònia posterior a un accident cerebrovascularAntibióticos; Infecciones posteriores a un accidente cerebrovascular; Neumonía posterior a un accidente cerebrovascularIntroduction: Antibiotics used to treat post-stroke infections have differing antimicrobial and anti-inflammatory effects. Our aim was to investigate whether antibiotic class was associated with outcome after post-stroke infection. Methods: We analyzed pooled individual participant data from the Virtual International Stroke Trials Archive (VISTA)-Acute. Patients with ischemic stroke and with an infection treated with systemic antibiotic therapy during the first 2 weeks after stroke onset were eligible. Antibiotics were grouped into eight classes, according to antimicrobial mechanism and prevalence. The primary analysis investigated whether antibiotic class for any infection, or for pneumonia, was independently associated with a shift in 90 day modified Rankin Scale (mRS) using ordinal logistic regression. Results: 2,708 patients were eligible (median age [IQR] = 74 [65 to 80] y; 51% female; median [IQR] NIHSS score = 15 [11 to 19]). Pneumonia occurred in 35%. Treatment with macrolides (5% of any infections; 9% of pneumonias) was independently associated with more favorable mRS distribution for any infection [OR (95% CI) = 0.59 (0.42 to 0.83), p = 0.004] and for pneumonia [OR (95% CI) = 0.46 (0.29 to 0.73), p = 0.001]. Unfavorable mRS distribution was independently associated with treatment of any infection either with carbapenems, cephalosporins or monobactams [OR (95% CI) = 1.62 (1.33 to 1.97), p < 0.001], penicillin plus β-lactamase inhibitors [OR (95% CI) = 1.26 (1.03 to 1.54), p = 0.025] or with aminoglycosides [OR (95% CI) = 1.73 (1.22 to 2.46), p = 0.002]. Conclusion: This retrospective study has several limitations including effect modification and confounding by indication. Macrolides may have favorable immune-modulatory effects in stroke-associated infections. Prospective evaluation of the impact of antibiotic class on treatment of post-stroke infections is warranted.The Open Access Publication Fund of Charité—Universitätsmedizin Berlin and Professor Meisel as corresponding author will provide funding to cover the open access publication/article processing fe
Enzyme-Powered Gated Mesoporous Silica Nanomotors for On-Command Intracellular Payload Delivery
[EN] The introduction of stimuli-responsive cargo release capabilities on self-propelled micro- and nano- motors holds enormous potential in a number of applications in the biomedical field. Herein, we report the preparation of mesoporous silica nano-particles gated with pH-responsive supramolecular nanovalves and equipped with urease enzymes which act as chemical engines to power the nanomotors. The nanoparticles are loaded with different cargo molecules ([Ru(bpy)(3)]Cl-2 (bpy = 2,2'-bipyridine) or doxorubicin), grafted with benzimidazole groups on the outer surface, and capped by the formation of inclusion complexes between benzimidazole and cyclodextrin-modified urease. The nanomotor exhibits enhanced Brownian motion in the presence of urea. Moreover, no cargo is released at neutral pH, even in the presence of the biofuel urea, due to the blockage of the pores by the bulky benzimidazole:cyclodextrin-urease caps. Cargo delivery is only triggered on-command at acidic pH due to the protonation of benzimidazole groups, the dethreading of the supramolecular nanovalves, and the subsequent uncapping of the nanoparticles. Studies with HeLa cells indicate that the presence of biofuel urea enhances nanoparticle internalization and both [Ru(bpy)(3)]Cl-2 or doxorubicin intracellular release due to the acidity of lysosomal compartments. Gated enzyme-powered nanomotors shown here display some of the requirements for ideal drug delivery carriers such as the capacity to self-propel and the ability to "sense" the environment and deliver the payload on demand in response to predefined stimuli.A.L.-L. is grateful to La Caixa Banking Foundation for his
Ph.D. grant. A.G.-F. thanks the Spanish government for her FPU
fellowship. The authors are grateful to the Spanish Government
(MINECO Projects MAT2015-64139-C4-1, CTQ2014-58989-
PCTQ2015-71936-REDT, CTQ2015-68879-R (MICRODIA)
and CTQ2015-72471-EXP (Enzwim)), the BBVA foundation
(MEDIROBOTS), the CERCA Programme by the Generalitat
de Catalunya, and the Generalitat Valenciana (Project
PROMETEO/2018/024 and PROMETEOII/2014/061) for
support. T.P. thanks MINECO for the Juan de la Cierva
postdoctoral fellowship and the European Union's Horizon
2020 research and innovation program, under the Marie
Sk¿odowska-Curie Individual Fellowship (H2020-MSCA-IF2018, DNA-bots). A.C.H. thanks MINECO for the Severo
Ochoa fellowship. The authors would like to thank A. Miguel Lopez for the development of the python code for motion
analysis.Llopis-Lorente, A.; García-Fernández, A.; Murillo-Cremaes, N.; Hortelao, A.; Patiño, T.; Villalonga, R.; Sancenón Galarza, F.... (2019). Enzyme-Powered Gated Mesoporous Silica Nanomotors for On-Command Intracellular Payload Delivery. ACS Nano. 13(10):12171-12183. https://doi.org/10.1021/acsnano.9b067061217112183131
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