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Ninfeo della Villa Massei a Capannori, loc. Massa Macinaia
No full textScheda sul ninfeo ottocentesco della Villa Massei a Massa Macinaia, Capannor
Use of Raman spectroscopy and PLS for the quantification of critical quality attributes in biopharmaceutical products
No full textThe pharmaceutical industry continually seeks innovative ways to streamline process development and ensure that the products meet stringent quality standards and regulatory requirements. In this context, a cutting-edge approach that is increasingly being used is Process Analytical Technology (PAT), a systematic methodology which provides real-time insights into the production process by timely in-line, online or at-line measurements of critical quality and performance attributes of raw and in-process materials and processes.
In this framework, this paper deals with the application of Raman spectroscopy, a rapid and non-destructive analytical tool, and chemometric techniques, namely Partial Least Squares (PLS), for the quantification of multiple Critical Quality Attributes (CQAs) of biopharmaceutical products.
Specifically, the protein/excipient quantification, protein oxidation, protein aggregation, and protein fragmentation were evaluated. In fact, the monitoring of these product quality attributes at different process development stages and process steps allows a better understanding of the impact of the process parameters on the product quality. As an example, the quantification of protein/excipients composition is fundamental during the compounding and filtration step. Instead, the HMW (High Molecular Weight) and LMW (Low Molecular Weight) species and the oxidation level can be affected during manual or automated visual inspection step as the product is exposed to the light source as well as to the ambient temperature for some time. A monoclonal antibody (mAb) was used as model protein, with different excipients such as Methionine and Polysorbate 20. Dilutions were performed to get samples with different concentrations. Thermal stress was applied to investigate changes in protein aggregation (HMW) and protein fragmentation (LMW), while an oxidative stress was performed to obtain samples characterized by different oxidation levels.
The present study shows that the combination of Raman spectroscopy and PLS turned out in excellent performances as far as it concerns the quantification of HMW, LMW and the product composition, when compared to the conventional analytical techniques. However, Raman spectroscopy was not able to discern the oxidation levels in the samples, probably due to the low sensitivity of the tool or due to the intrinsic difficulty of sample preparations for model calibration
NIR-based real-time monitoring of freeze-drying processes: Application to fault and endpoint detection
Full text linkIn the pharmaceutical industry, freeze-drying is crucial for the stability of active pharmaceutical ingredients (APIs). Monitoring this complex process presents challenges as traditional methods often lack real-time insights, potentially leading to quality issues and batch rejections. Effective monitoring is then essential for optimizing process parameters and minimizing waste, thus saving costs and resources. This study evaluated the application of Near-Infrared (NIR) spectroscopy for the real-time monitoring of the freeze-drying process: NIR spectra were acquired in-line via a specially designed flange in the freeze-dryer. Two approaches were investigated. The first involved freeze-drying monitoring using control charts, thus creating a reference model based on cycles under normal
conditions. A PCA model was developed using these reference cycles, and an intentional fault cycle was performed to test the system’s ability to detect deviations. Multivariate control charts, utilizing Hotelling’s T2 and DModX metrics, were shown to effectively monitor process deviations, enhancing the understanding of freeze-drying dynamics. The second approach was based on the use of NIR spectroscopy for assessing residual moisture during lyophilization. By integrating Partial Least Squares (PLS) regression with inline NIR spectra, we estimated endpoints and detected faults in both reference and faulty cycles. The results showed strong correlations between PLS estimates and the Pirani–Baratron method, highlighting NIR’s applicability for monitoring drying phases. This research
advocates for broader NIR implementation in pharmaceutical development, emphasizing its potential to monitor the process, ensure quality, and reduce out-of-specification product
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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