232 research outputs found
Exploiting the layer-by-layer nanoarchitectonics for the fabrication of polymer capsules : A toolbox to provide multifunctional properties to target complex pathologies
Polymer capsules fabricated via the layer-by-layer (LbL) approach have attracted a great deal of attention for biomedical applications thanks to their tunable architecture. Compared to alternative methods, in which the precise control over the final properties of the systems is usually limited, the intrinsic versatility of the LbL approach allows the functionalization of all the constituents of the polymeric capsules following relatively simple protocols. In fact, the final properties of the capsules can be adjusted from the inner cavity to the outer layer through the polymeric shell, resulting in therapeutic, diagnostic, or theranostic (i.e., combination of therapeutic and diagnostic) agents that can be adapted to the particular characteristics of the patient and face the challenges encountered in complex pathologies. The biomedical industry demands novel biomaterials capable of targeting several mechanisms and/or cellular pathways simultaneously while being tracked by minimally invasive tech-niques, thus highlighting the need to shift from monofunctional to multifunctional polymer capsules. In the present review, those strategies that permit the advanced functionalization of polymer capsules are accordingly introduced. Each of the constituents of the capsule (i.e., cavity, multilayer membrane and outer layer) is thor-oughly analyzed and a final overview of the combination of all the strategies toward the fabrication of multi-functional capsules is presented. Special emphasis is given to the potential biomedical applications of these multifunctional capsules, including particular examples of the performed in vitro and in vivo validation studies. Finally, the challenges in the fabrication process and the future perspective for their safe translation into the clinic are summarized.Peer reviewe
Geometrothermodynamics of the Kehagias-Sfetsos Black Hole
The application of information geometric ideas to statistical mechanics using
a metric on the space of states, pioneered by Ruppeiner and Weinhold, has
proved to be a useful alternative approach to characterizing phase transitions.
Some puzzling anomalies become apparent, however, when these methods are
applied to the study of black hole thermodynamics. A possible resolution was
suggested by Quevedo et al. who emphasized the importance of Legendre
invariance in thermodynamic metrics. They found physically consistent results
for various black holes when using a Legendre invariant metric, which agreed
with a direct determination of the properties of phase transitions from the
specific heat.
Recently, information geometric methods have been employed by Wei et al. to
study the Kehagias-Sfetsos (KS) black hole in Horava-Lifshitz gravity. The
formalism suggests that a coupling parameter in this theory plays a role
analogous to the charge in Reissner-Nordstrom (RN) black holes or angular
momentum in the Kerr black hole and calculation of the specific heat shows a
singularity which may be interpreted as a phase transition. When the curvature
of the Ruppeiner metric is calculated for such a theory it does not, however,
show a singularity at the phase transition point.
We show that the curvature of a particular Legendre invariant ("Quevedo")
metric for the KS black hole is singular at the phase transition point. We
contrast the results for the Ruppeiner, Weinhold and Quevedo metrics and in the
latter case investigate the consistency of taking either the entropy or mass as
the thermodynamic potential.Comment: v2: some references adde
Enthalpy and the Mechanics of AdS Black Holes
We present geometric derivations of the Smarr formula for static AdS black
holes and an expanded first law that includes variations in the cosmological
constant. These two results are further related by a scaling argument based on
Euler's theorem. The key new ingredient in the constructions is a two-form
potential for the static Killing field. Surface integrals of the Killing
potential determine the coefficient of the variation of the cosmological
constant in the first law. This coefficient is proportional to a finite,
effective volume for the region outside the AdS black hole horizon, which can
also be interpreted as minus the volume excluded from a spatial slice by the
black hole horizon. This effective volume also contributes to the Smarr
formula. Since the cosmological constant is naturally thought of as a pressure,
the new term in the first law has the form of effective volume times change in
pressure that arises in the variation of the enthalpy in classical
thermodynamics. This and related arguments suggest that the mass of an AdS
black hole should be interpreted as the enthalpy of the spacetime.Comment: 21 pages; v2 references adde
Update on emergency contraception
pre-printEmergency contraception (EC) is any method used after sexual intercourse to prevent pregnancy. This article provides an overview of the history of EC methods and describes the current availability of oral and intrauterine EC. Oral forms include the Yuzpe regimen (combining ethinyl estradiol and levonorgestrel), levonorgestrel-only pills, and ulipristal acetate, which is a new emergency contraceptive drug recently approved by the US Food and Drug Administration. The copper T-380A intrauterine device can also be used for EC. Information about dosing, timing, access, and other considerations in the provision of EC is covered. Clinicians should be aware of all available options in order to counsel women in need of EC appropriately
Emergent Strain of Human Adenovirus Endemic in Iowa
We evaluated 76 adenovirus type 7 (Ad7) isolates collected in Iowa from 1992 to 2002 and found that genome type Ad7d2 became increasingly prevalent. By 2002, it had supplanted all other Ad7 genome types. The association of Ad7d2 with severe illness and death calls for heightened public health concern
Black Holes in Ho\v{r}ava Gravity with Higher Derivative Magnetic Terms
We consider Horava gravity coupled to Maxwell and higher derivative magnetic
terms. We construct static spherically symmetric black hole solutions in the
low-energy approximation. We calculate the horizon locations and temperatures
in the near-extremal limit, for asymptotically flat and (anti-)de Sitter
spaces. We also construct a detailed balanced version of the theory, for which
we find projectable and non-projectable, non-perturbative solutions.Comment: 17 pages. v2: Up to date with published version; some minor remarks
and more reference
The impact of different strategies to handle missing data on both precision and bias in a drug safety study: a multidatabase multinational population-based cohort study
BACKGROUND:
Missing data are often an issue in electronic medical records (EMRs) research. However, there are many ways that people deal with missing data in drug safety studies.
AIM:
To compare the risk estimates resulting from different strategies for the handling of missing data in the study of venous thromboembolism (VTE) risk associated with antiosteoporotic medications (AOM).
METHODS:
New users of AOM (alendronic acid, other bisphosphonates, strontium ranelate, selective estrogen receptor modulators, teriparatide, or denosumab) aged ≥50 years during 1998–2014 were identified in two Spanish (the Base de datos para la Investigación Farmacoepidemiológica en Atención Primaria [BIFAP] and EpiChron cohort) and one UK (Clinical Practice Research Datalink [CPRD]) EMR. Hazard ratios (HRs) according to AOM (with alendronic acid as reference) were calculated adjusting for VTE risk factors, body mass index (that was missing in 61% of patients included in the three databases), and smoking (that was missing in 23% of patients) in the year of AOM therapy initiation. HRs and standard errors obtained using cross-sectional multiple imputation (MI) (reference method) were compared to complete case (CC) analysis – using only patients with complete data – and longitudinal MI – adding to the cross-sectional MI model the body mass index/smoking values as recorded in the year before and after therapy initiation.
RESULTS:
Overall, 422/95,057 (0.4%), 19/12,688 (0.1%), and 2,051/161,202 (1.3%) VTE cases/participants were seen in BIFAP, EpiChron, and CPRD, respectively. HRs moved from 100.00% underestimation to 40.31% overestimation in CC compared with cross-sectional MI, while longitudinal MI methods provided similar risk estimates compared with cross-sectional MI. Precision for HR improved in cross-sectional MI versus CC by up to 160.28%, while longitudinal MI improved precision (compared with cross-sectional) only minimally (up to 0.80%).
CONCLUSIONS:
CC may substantially affect relative risk estimation in EMR-based drug safety studies, since missing data are not often completely at random. Little improvement was seen in these data in terms of power with the inclusion of longitudinal MI compared with cross-sectional MI. The strategy for handling missing data in drug safety studies can have a large impact on both risk estimates and precision
Using Datamining Techniques to Help Metaheuristics: A Short Survey
International audienceHybridizing metaheuristic approaches becomes a common way to improve the efficiency of optimization methods. Many hybridizations deal with the combination of several optimization methods. In this paper we are interested in another type of hybridization, where datamining approaches are combined within an optimization process. Hence, we propose to study the interest of combining metaheuristics and datamining through a short survey that enumerates the different opportunities of such combinations based on literature examples
Potentially inappropriate medication in older participants of the Berlin Aging Study II (BASE-II) - Sex differences and associations with morbidity and medication use
INTRODUCTION:
Multimorbidity in advanced age and the need for drug treatment may lead to polypharmacy, while pharmacokinetic and pharmacodynamic changes may increase the risk of adverse drug events (ADEs).
OBJECTIVE:
The aim of this study was to determine the proportion of subjects using potentially inappropriate medication (PIM) in a cohort of older and predominantly healthy adults in relation to polypharmacy and morbidity.
METHODS:
Cross-sectional data were available from 1,382 study participants (median age 69 years, IQR 67-71, 51.3% females) of the Berlin Aging Study II (BASE-II). PIM was classified according to the EU(7)-PIM and German PRISCUS (representing a subset of the former) list. Polypharmacy was defined as the concomitant use of at least five drugs. A morbidity index (MI) largely based on the Charlson Index was applied to evaluate the morbidity burden.
RESULTS:
Overall, 24.1% of the participants were affected by polypharmacy. On average, men used 2 (IQR 1-4) and women 3 drugs (IQR 1-5). According to PRISCUS and EU(7)-PIM, 5.9% and 22.6% of participants received at least one PIM, while use was significantly more prevalent in females (25.5%) compared to males (19.6%) considering EU(7)-PIM (p = 0.01). In addition, morbidity in males receiving PIM according to EU(7)-PIM was higher (median MI 1, IQR 1-3) compared to males without PIM use (median MI 1, IQR 0-2, p<0.001).
CONCLUSION:
PIM use occurred more frequently in women than in men, while it was associated with higher morbidity in males. As expected, EU(7)-PIM identifies more subjects as PIM users than the PRISCUS list but further studies are needed to investigate the differential impact of both lists on ADEs and outcome.
KEY POINTS:
We found PIM use to be associated with a higher number of regular medications and with increased morbidity. Additionally, we detected a higher prevalence of PIM use in females compared to males, suggesting that women and people needing intensive drug treatment are patient groups, who are particularly affected by PIM use
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