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1.
Pharmacoecon Open ; 6(4): 619-628, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35750956

RESUMO

OBJECTIVE: This study aimed to analyze the healthcare resource use (HCRU) and associated costs of multiple myeloma (MM) using German claims data. METHODS: Anonymized claims data from one of the largest sickness funds in Germany were analyzed. Costs and HCRU were calculated from the perspective of the statutory health insurance. To analyze MM-associated incremental costs in a most recent calendar period for an overall MM population (31 March 2018-31 March 2019), a prevalent cohort of MM patients (continuously insured during 01 January 2010 until 31 March 2019 or death; two or more outpatient and/or one inpatient MM diagnoses [ICD-10: C90.0-] and alive on 31 March 2018) was compared with a control group (not diagnosed with MM) employing propensity-score matching. Additionally, to describe MM-associated HCRU and costs for treated patients per line of treatment (lot), a cohort of newly treated patients was considered (≥ 12 months' pre-index period without MM treatment). Therapy lines were determined based on observed days of medication supply, treatment switches, and treatment discontinuations. RESULTS: Overall, 2523 prevalent MM patients (52.0% female, mean age: 71.3 years) and 1673 newly treated MM patients (50.2% female, mean age: 73.0 years) met the selection criteria and were included in the analyses. After matching, a non-MM counterpart could be identified for 2474 prevalent out of 2523 MM patients. MM-associated incremental HCRU was characterized by an increased number of hospitalizations and a higher number of outpatient specialist visits (per patient-year [ppy] 0.48 additional hospitalizations and 3.80 additional specialist visits; p < 0.001), being also drivers of the associated total incremental add-on costs (15,381.09 € ppy, p < 0.001). Among newly treated patients, total direct costs ppy increased as patients received subsequent treatments (1st lot: 67,681,55 €; 4th lot+: 114,934.01 €), driven by outpatient MM prescriptions (1st lot: 28,692.32 €; 4th lot+: 62,980.72 €). CONCLUSION: The economic burden of MM is driven by outpatient prescriptions, inpatient hospitalizations, and outpatient specialist visits. Treatment and overall costs increase substantially when patients move to later lines of treatment.

2.
Phys Chem Miner ; 49(5): 14, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35535269

RESUMO

A system of edge cracks was applied to polished (010) surfaces of K-rich gem-quality alkali feldspar by diffusion-mediated cation exchange between oriented feldspar plates and a Na-rich NaCl-KCl salt melt. The cation exchange produced a Na-rich layer at and beneath the specimen surface, and the associated strongly anisotropic lattice contraction lead to a tensile stress state at the specimen surface, which induced fracturing. Cation exchange along the newly formed crack flanks produced Na-enriched diffusion halos around the cracks, and the associated lattice contraction and tensile stress state caused continuous crack growth. The cracks nucleated with non-uniform spacing on the sample surface and quickly attained nearly uniform spacing below the surface by systematic turning along their early propagation paths. In places, conspicuous wavy cracks oscillating several times before attaining their final position between the neighboring cracks were produced. It is shown that the evolution of irregularly spaced towards regularly spaced cracks including the systematic turning and wavyness along the early propagation paths maximizes the rate of free energy dissipation in every evolutionary stage of the system. Maximization of the dissipation rate is suggested as a criterion for selection of the most probable evolution path for a system undergoing chemically induced diffusion mediated fracturing in an anisotropic homogeneous brittle material. Supplementary Information: The online version contains supplementary material available at 10.1007/s00269-022-01183-9.

3.
AIDS Care ; 34(6): 698-707, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-33896276

RESUMO

The DUALIS study demonstrated efficacy and safety of switching to dolutegravir plus ritonavir-boosted darunavir (DRV/r) (2DR) as compared to standard-of-care-therapy with two nucleoside reverse transcriptase inhibitors + DRV/r (3DR) in pretreated people living with HIV (PLWH), 48 weeks after switching. This DUALIS sub-study investigates health-related-quality-of-life (HrQoL) in this study-population. The Hospital Anxiety and Depression Scale (HADS) and the Medical Outcome Survey-HIV (MOS-HIV) were used assessing anxiety and depression symptoms, respectively HrQoL. Data were collected at baseline, 4, 24, and 48 weeks after randomization. Outcome scores were dichotomized and used as criteria in longitudinal models identifying differential developments. Odds ratios (ORs) with 95% confidence intervals (CIs) were computed as main measures of effects. ORs<1 indicate better results for HADS, and worse for MOS-HIV scores in the 2DR compared to 3DR group. In total, 263 subjects were randomized and treated (2DR n=131, 3DR n=132; median age 48 years). Significant different progressions could only be found for HADS-Depression scores (OR=.87, 95% CI: .78, .98, p=.02). While HADS-Depression scores decreased in the 2DR group, they increased in 3DR group. This sub-study showed no disadvantages regarding HrQoL in PLWH after switching to DTG+DRV/r. Considering lifelong requirements for antiretroviral medication, close attention to HrQL is required.


Assuntos
Fármacos Anti-HIV , Infecções por HIV , Fármacos Anti-HIV/uso terapêutico , Darunavir/farmacologia , Darunavir/uso terapêutico , Infecções por HIV/tratamento farmacológico , Compostos Heterocíclicos com 3 Anéis , Humanos , Pessoa de Meia-Idade , Oxazinas , Piperazinas , Piridonas , Qualidade de Vida , Ritonavir/farmacologia , Ritonavir/uso terapêutico , Carga Viral
4.
Pharm Res ; 37(4): 79, 2020 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-32253523

RESUMO

PURPOSE: Development of zeta potential changing SEDDS containing newly synthesized derivative stearic acid phosphotyrosine amide. METHODS: Stearoyl chloride was conjugated with phosphotyrosine, which is substrate for the brush border enzyme intestinal alkaline phosphate. The synthesized derivative was implemented in different SEDDS formulations and the zeta potential changing properties and the concluding mucus diffusion abilities were evaluated. RESULTS: Stearic acid phosphotyrosine amide was successfully synthesized and incorporated into SEDDS. A SEDDS formulation containing the new derivative showed a zeta potential of -14 mV before, and + 2 mV after enzymatic cleavage by intestinal alkaline phosphatase. Experiments on a Caco-2 monolayer demonstrated that the phosphate cannot only be cleaved by isolated enzyme, but also by enzyme, which was expressed by cells. The mucus diffusion abilities of the untreated, negatively charged SEDDS were significantly higher compared to the enzymatically cleaved, positively charged SEDDS. CONCLUSION: The developed stearic acid phosphotyrosine represents a promising excipient for zeta potential changing SEDDS. Graphical Abstract.


Assuntos
Amidas/química , Portadores de Fármacos/síntese química , Fosfotirosina/química , Estearatos/química , Animais , Células CACO-2 , Bovinos , Sobrevivência Celular/efeitos dos fármacos , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Emulsificantes/química , Emulsões , Excipientes/química , Humanos , Mucosa Intestinal/metabolismo , Propriedades de Superfície
5.
Nanomaterials (Basel) ; 10(3)2020 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-32182652

RESUMO

Motivated by often contradictory literature reports on the dependence of the surface energy of gold nanoparticles on the variety of its size and shape, we performed an atomistic study combining molecular mechanics and ab initio calculations. We show that, in the case of Au nanocubes, their surface energy converges to a value for ( 0 0 1 ) facets of bulk crystals. A fast convergence to a single valued surface energy is predicted also for nanospheres. However, the value of the surface energy is larger in this case than that of any low-index surface facet of bulk Au crystal. This fact can be explained by the complex structure of the surface with an extensive number of broken bonds due to edge and corner atoms. A similar trend was obtained also for the case of cuboctahedrons. Since the exact surface area of the nanoparticles is an ill-defined quantity, we have introduced the surface-induced excess energy and discuss this quantity as a function of (i) number of atoms forming the nano-object or (ii) characteristic size of the nano-object. In case (i), a universal power-law behaviour was obtained independent of the nanoparticle shape. Importantly, we show that the size-dependence of the surface is hugely reduced if the surface area correction is considered due to its expansion by the electronic cloud, a phenomenon specifically important for small nanoparticles.

6.
Bone ; 130: 115102, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31669254

RESUMO

Lamellar bone is known to be the most typical structure of cortical bone in large mammals including humans. This type of tissue provides a good combination of strength and fracture toughness. As has been shown by John D Currey and other researchers, large deformations are associated with the appearance of microdamage that optically whitens the tissue, a process that has been identified as a contribution to bone toughness. Using finite-element modelling, we study crack propagation in a material with periodic variation of mechanical parameters, such as elastic modulus and strength, chosen to represent lamellar bone. We show that a multitude of microcracks appears in the region ahead of the initial crack tip, thus dissipating energy even without a progression of the initial crack tip. Strength and toughness are shown to be both larger for the (notched) lamellar material than for a homogeneous material with the same average properties and the same initial notch. The length of the microcracks typically corresponds to the width of a lamella, that is, to several microns. This simultaneous improvement of strength and toughness may explain the ubiquity of lamellar plywood structures not just in bone but also in plants and in chitin-based cuticles of insects and arthropods.


Assuntos
Osso e Ossos , Fraturas Ósseas , Animais , Osso Cortical , Módulo de Elasticidade , Humanos , Estresse Mecânico
7.
Beilstein J Nanotechnol ; 9: 2265-2276, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30202695

RESUMO

The surface energy, particularly for nanoparticles, is one of the most important quantities in understanding the thermodynamics of particles. Therefore, it is astonishing that there is still great uncertainty about its value. The uncertainty increases if one questions its dependence on particle size. Different approaches, such as classical thermodynamics calculations, molecular dynamics simulations, and ab initio calculations, exist to predict this quantity. Generally, considerations based on classical thermodynamics lead to the prediction of decreasing values of the surface energy with decreasing particle size. This phenomenon is caused by the reduced number of next neighbors of surface atoms with decreasing particle size, a phenomenon that is partly compensated by the reduction of the binding energy between the atoms with decreasing particle size. Furthermore, this compensating effect may be expected by the formation of a disordered or quasi-liquid layer at the surface. The atomistic approach, based either on molecular dynamics simulations or ab initio calculations, generally leads to values with an opposite tendency. However, it is shown that this result is based on an insufficient definition of the particle size. A more realistic definition of the particle size is possible only by a detailed analysis of the electronic structure obtained from initio calculations. Except for minor variations caused by changes in the structure, only a minor dependence of the surface energy on the particle size is found. The main conclusion of this work is that surface energy values for the equivalent bulk materials should be used if detailed data for nanoparticles are not available.

8.
Beilstein J Nanotechnol ; 8: 2221-2229, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29114449

RESUMO

Structure and properties of small nanoparticles are still under discussion. Moreover, some thermodynamic properties and the structural behavior still remain partially unknown. One of the best investigated nanoparticles is the Au55 cluster, which has been analyzed experimentally and theoretically. However, up to now, the results of these studies are still inconsistent. Consequently, we have carried out the present ab initio study of the Au55 cluster, using up-to-date computational concepts, in order to clarify these issues. Our calculations have confirmed the experimental result that the thermodynamically most stable structure is not crystalline, but it is glassy. The non-crystalline structure of this cluster was validated by comparison of the coordination numbers with those of a crystalline cluster. It was found that, in contrast to bulk materials, glass formation is connected to an energy release that is close to the melting enthalpy of bulk gold. Additionally, the surface energy of this cluster was calculated using two different theoretical approaches resulting in values close to the surface energy for bulk gold. It shall be emphasized that it is now possible to give a confidence interval for the value of the surface energy.

9.
PLoS One ; 10(9): e0138550, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26397113

RESUMO

BACKGROUND: Low vitamin D levels have been associated with depressive symptoms in population-based studies and non-clinical samples as well as with clinical depression. This study aimed to examine the association of vitamin D levels with the severity and dimensions of depressive symptoms in hospitalized patients with a current episode of depression taking into account confounding variables. METHODS: We investigated 380 patients (mean age 47 ± 12 years, 70% women) who were consecutively hospitalized with a main diagnosis of an ICD-10 depressive episode. All patients self-rated depressive symptom severity with the Hospital Anxiety and Depression Scale (HADS-D), the Beck Depression Inventory-II (BDI-II), and the Brief Symptom Inventory. A principal component analysis was performed with all 34 items of these questionnaires and serum levels of 25-hydroxyvitamin D3 (25-OH D) were measured. RESULTS: Vitamin D deficiency (< 50 nmol/l), insufficiency (50-75 nmol/l), and sufficiency (> 75 nmol/l) were present in 55.5%, 31.8% and 12.6%, respectively, of patients. Patients with vitamin D deficiency scored higher on the HADS-D scale and on an anhedonia symptom factor than those with insufficient (p-values ≤ 0.023) or sufficient (p-values ≤ 0.008) vitamin D. Vitamin D deficient patients also scored higher on the BDI-II scale than those with sufficient vitamin D (p = 0.007); BDI-II cognitive/affective symptoms, but not somatic/affective symptoms, were higher in patients with vitamin D deficiency (p = 0.005) and insufficiency (p = 0.041) relative to those with sufficient vitamin D. Effect sizes suggested clinically relevant findings. CONCLUSIONS: Low vitamin D levels are frequent in hospitalized patients with a current episode of depression. Especially 25-OH D levels < 50 nmol/l were associated with cognitive/affective depressive symptoms, and anhedonia symptoms in particular.


Assuntos
Depressão/sangue , Depressão/complicações , Hospitalização , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/complicações , Análise Fatorial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada
10.
Acta Mater ; 89: 278-289, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25937805

RESUMO

Thin metal films deposited on polymer substrates are used in flexible electronic devices such as flexible displays or printed memories. They are often fabricated as complicated multilayer structures. Understanding the mechanical behavior of the interface between the metal film and the substrate as well as the process of crack formation under global tension is important for producing reliable devices. In the present work, the deformation behavior of copper films (50-200 nm thick), bonded to polyimide directly or via a 10 nm chromium interlayer, is investigated by experimental analysis and computational simulations. The influence of the various copper film thicknesses and the usage of a brittle interlayer on the crack density as well as on the stress magnitude in the copper after saturation of the cracking process are studied with in situ tensile tests in a synchrotron and under an atomic force microscope. From the computational point of view, the evolution of the crack pattern is modeled as a stochastic process via finite element based cohesive zone simulations. Both, experiments and simulations show that the chromium interlayer dominates the deformation behavior. The interlayer forms cracks that induce a stress concentration in the overlying copper film. This behavior is more pronounced in the 50 nm than in the 200 nm copper films.

11.
Rev Sci Instrum ; 82(11): 113709, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22128986

RESUMO

We describe the design and performance of a quasi in situ scanning force microscope with an automatic operated reaction chamber. The design provides a repetitive hermetically sealed sample environment for successive processing. The reaction chamber is based on a combination of a flexure-guided cover, a piezo-positioning system and a force applicator system. An axial force seals the cover against the reactor enabling flow-through applications at low pressure, ambient pressure, or elevated pressure. The position stability of the sample relative to the probe is characterized and a full automated operation of the instrument is explored by the alignment of an ABC terblock copolymer thin film undergoing solvent vapor annealing in the presence of a high electric field. Due to the high electric field strength and the sharp scanning force microscope tip it is impossible to perform in situ scanning in the presence of the electric field.

12.
Acta Biomater ; 6(3): 1001-5, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19735744

RESUMO

Biogenic single crystals with complex shapes are believed to be generated by the crystallization of an amorphous precursor. Recent biomimetic experiments on the crystallization of calcite via amorphous-to-crystalline transition point to the fact that the transformation kinetics may be controlled by the micropattern and the macroscopic shape of the amorphous precursor phase. Here we analyse a simple kinetic model, based on thermodynamic considerations, showing that the presence of cavities in the micropatterned precursor phase might interfere with the transformation process and control its kinetics. The size of the cavities couples to the total surface energy and, hence, to crystal nucleation and growth, while the spacing of the cavities, as compared to the typical diffusion path, controls the possible nucleation of competing crystals.


Assuntos
Materiais Biocompatíveis/química , Carbonato de Cálcio/química , Modelos Químicos , Modelos Moleculares , Simulação por Computador , Cristalização/métodos , Cinética , Conformação Molecular , Porosidade
13.
Phys Rev Lett ; 97(1): 018106, 2006 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-16907415

RESUMO

Bilayer structures in catanionic systems experimentally showed peculiar mechanical behavior. The observed increase in the bending stiffness is supposedly connected to additional hydrogen bonds forming between anionic headgroups. With a simple model, we can explain the extreme sensitivity of the bending stiffness of the membrane on the molar ratio of the charged molecules. This effect is further amplified by the sandwichlike structure of the membrane, where the apolar core separating the headgroups acts via a kind of lever-arm principle. As a consequence of these combined effects, the model membrane changes from a soft behavior with bending rigidities on the order of 10k(B)T to an extremely stiff membrane with a bending stiffness more than 2 orders of magnitude larger where most of this change occurs within a molar ratio interval smaller than 0.1.


Assuntos
Cristalização/métodos , Bicamadas Lipídicas , Fluidez de Membrana , Lipídeos de Membrana/química , Modelos Químicos , Modelos Moleculares , Simulação por Computador , Elasticidade , Interações Hidrofóbicas e Hidrofílicas , Mecânica , Conformação Molecular , Estresse Mecânico
14.
Langmuir ; 21(25): 11974-80, 2005 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-16316141

RESUMO

We investigate the mechanism of microdomain orientation in concentrated block copolymer solutions exposed to a dc electric field by in situ synchrotron small-angle X-ray scattering (SAXS). As a model system, we use concentrated solutions of a lamellar polystyrene-b-polyisoprene block copolymer in toluene. We find that both the microscopic mechanism of reorientation and the kinetics of the process strongly depend on the initial degree of order in the system. In a highly ordered lamellar system with the lamellae being aligned perpendicular to the electric field vector, only nucleation and growth of domains is possible as a pathway to reorientation and the process proceeds rather slowly. In less ordered samples, grain rotation becomes possible as an alternative pathway, and the process proceeds considerably faster. The interpretation of our finding is strongly corroborated by dynamic self-consistent field simulations.


Assuntos
Espalhamento a Baixo Ângulo , Difração de Raios X , Eletricidade , Cinética , Polímeros
15.
Phys Rev Lett ; 95(19): 195702, 2005 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-16383995

RESUMO

Thermodynamic equilibrium states are given by the minimum of a convex free energy function with suitable boundary conditions. Nonconvexity may lead to the coexistence of several phases and the classical Gibbs phase rule allows constructing their equilibrium properties (e.g., density or pressure). Within the framework of nonequilibrium thermodynamics, the maximization of energy dissipation (under suitable boundary conditions) can be used as an extremal principle to find stationary states. We show that stationary states generally exist for convex energy dissipation functions and that nonconvexity leads to metastable and unstable states. A geometric argument, similar in spirit to Gibbs' double-tangent construction, yields the stability limits of stationary states. This argument is applied to study a classical problem of materials science, namely the motion of a grain boundary under the influence of solute drag.

16.
Phys Rev E Stat Nonlin Soft Matter Phys ; 65(6 Pt 2): 067102, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12188868

RESUMO

The fit of fracture strength data of brittle materials (Si(3)N(4), SiC, and ZnO) to the Weibull and normal distributions is compared in terms of the Akaike information criterion. For Si(3)N(4), the Weibull distribution fits the data better than the normal distribution, but for ZnO the result is just the opposite. In the case of SiC, the difference is not large enough to make a clear distinction between the two distributions. There is not sufficient evidence to show that the Weibull distribution is always preferred to other distributions, and the uncritical use of the Weibull distribution for strength data is questioned.

17.
J Morphol ; 213(2): 225-240, 1992 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29865594

RESUMO

The starling cochlea was studied with TEM at four locations along the basilar papilla to investigate gradients in morphological features over the papilla's length and width. Hair cell shape changes continuously from neural to abneural and from basal to apical. Unlike the situation in mammals, there are no distinct populations of hair cells; the previously described types (tall hair cells and short hair cells) are merely extremes in a continuum. Contacts between THC are a normal feature. Except at the base of the papilla, SHC have very large cuticular plates, suggesting a micromechanical function for these cells. In contrast to the THC, the SHC normally completely lack afferent innervation; this indicates that their function is restricted to within the basilar papilla itself. © 1992 Wiley-Liss, Inc.

18.
J Morphol ; 204(1): 75-87, 1990 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29865709

RESUMO

Gills of Chiton olivaceus, a primitive mollusc, are relatively simple in their structure and ultrastructure but are well adapted to a life in the intertidal zone. In contrast to some other molluscs, there is no differentiation of the gill epithelium into functional regions other than respiratory ones. Ciliation of the epithelium in certain areas may optimize water flow from the outer to the inner part of the mantle cavity. The hemolymph sinuses are oriented so that hemolymph flows in the opposite direction. Interstitial cells link epithelial cells with nerve endings. Muscle cells as well as the collagenous matrix in the connective tissue differ within the main gill axis and the lateral lamellae. The life cycle of immunoactive cells within the connective tissue and the hemolymph is described.

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