33 research outputs found
Some empirical results on nearest-neighbour pseudo-populations for resampling from spatial populations
In finite populations, pseudo-population bootstrap is the sole method preserving the spirit of the original bootstrap performed from iid observations. In spatial sampling, theoretical results about the convergence of bootstrap distributions to the actual distributions of estimators are lacking, owing to the failure of spatially balanced sampling designs to converge to the maximum entropy design. In addition, the issue of creating pseudo-populations able to mimic the characteristics of real populations is challenging in spatial frameworks where spatial trends, relationships, and similarities among neighbouring locations are invariably present. In this paper, we propose the use of the nearest-neighbour interpolation of spatial populations for constructing pseudo-populations that converge to real populations under mild conditions. The effectiveness of these proposals with respect to traditional pseudo-populations is empirically checked by a simulation stud
Primary Drying Optimization in Pharmaceutical Freeze-Drying: A Multivial Stochastic Modeling Framework
Primary drying is the most time-consuming and energy-intensive step in pharmaceutical freeze-drying. Minimizing the duration of this stage is of paramount importance to speed up process development..
Addressing charge‐transfer and locally‐excited states in a twisted biphenyl push‐pull chromophore
We present the synthesis and spectroscopic characterization of a twisted push‐pull biphenyl molecule undergoing photoinduced electron transfer. Steady‐state and transient absorption spectra suggest, in this rigid molecular structure, a subtle interplay between locally‐excited and charge‐transfer states, whose equilibrium and dynamics is only driven by solvation. A theoretical model is presented for the solvation dynamics and, with the support of quantum chemical calculations, we demonstrate the existence of two sets of states, having either local or charge‐transfer character, that only “communicate” thanks to solvation, which is the sole driving force for the charge‐separation process
Time-Resolved and Steady-State Spectroscopy of Native and Mutated Thermobifida Fusca Hemoglobins
General anesthesia impairs muscle microvascular compliance
Introduction Drugs used to induce and maintain general
anesthesia have deep effects on the cardiovascular system. To our knowledge there are no studies investigating microvascular
compliance during general anesthesia with a noninvasive approach
based on near-infrared spectroscopy (NIRS) technology.
Methods We randomized 36 healthy subjects undergoing maxillofacial surgery to receive general anesthesia with a sevofluorane–remifentanil (Group S) or a propofol–remifentanil association (Group P). We collected noninvasive measures of hemoglobin concentration from the gastrocnemius muscle of the subjects using a NIRS device (NIMO, NIROX srl, Italy), which performs quantitative assessments of the [HbO2] and [Hb] exploiting precise absorption measurements close to the absorption peak of the water. Data were collected during a series of venous occlusions at different cuff pressures, before and after 30 minutes from induction of general anesthesia. The muscle blood volume and microvascular compliance were obtained with a process previously described elsewhere [1]. Data were analyzed with a one-way analysis of variance test.
Results Demographic data of the 36 subjects were similar in both
Groups S and P. General anesthesia reduced the heart rate and
mean arterial pressure and increased the total muscle blood
volume in both groups (Group S: from 2.4 ± 0.9 to 3.2 ± 1.2 ml/
100 ml; Group P: from 2.4 ± 1.2 to 3.5 ± 1.8 ml/100 ml;
P < 0.05). During general anesthesia, despite no differences in
muscle blood volume between the two groups, sevofluorane–
remifentanil significantly decreased microvascular compliance
(from 0.15 ± 0.08 to 0.09 ± 0.04 ml/mmHg/100 ml; P = 0.001)
whereas propofol–remifentanil did not (from 0.15 ± 0.08 to
0.16 ± 0.11 ml/mmHg/100 ml; P = 0.39)
Excited-State Absorption and Ultrafast Relaxation Dynamics of Porphyrin, Diprotonated Porphyrin, and Tetraoxaporphyrin Dication
Maturation of Aluminium Adsorbed Antigens Contributes to the Creation of Homogeneous Vaccine Formulations
Although aluminium-based vaccines have been used for almost over a century, their mechanism of action remains unclear. It is established that antigen adsorption to the adjuvant facilitates delivery of the antigen to immune cells at the injection site. To further increase our understanding of aluminium-based vaccines, it is important to gain additional insights on the interactions between the aluminium and antigens, including antigen distribution over the adjuvant particles. Immuno-assays can further help in this regard. In this paper, we evaluated how established formulation strategies (i.e., sequential, competitive, and separate antigen addition) applied to four different antigens and aluminium oxyhydroxide, lead to formulation changes over time. Results showed that all formulation samples were stable, and that no significant changes were observed in terms of physical-chemical properties. Antigen distribution across the bulk aluminium population, however, did show a maturation effect, with some initial dependence on the formulation approach and the antigen adsorption strength. Sequential and competitive approaches displayed similar results in terms of the homogeneity of antigen distribution across aluminium particles, while separately adsorbed antigens were initially more highly poly-dispersed. Nevertheless, the formulation sample prepared via separate adsorption also reached homogeneity according to each antigen adsorption strength. This study indicated that antigen distribution across aluminium particles is a dynamic feature that evolves over time, which is initially influenced by the formulation approach and the specific adsorption strength, but ultimately leads to homogeneous formulations