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Parotidectomy specimens: cytological and histological correlation
(Medpharm Publications, 2026) Opperman Johan; Afrogheh A.; Grobbelaar J.
Background: There are few descriptive studies from South Africa of parotid gland tumours. This is a descriptive study of parotid pathology managed surgically, and to ascertain the accuracy and concordance of preoperative cytological diagnosis compared with final pathology. Methods: A retrospective chart review of all parotidectomies performed between January 2016 and September 2024 was done. Incomplete and duplicate files were excluded. Results: A total of 179 specimens were included and confirmed benign tumours in 125 (69.83%), malignant tumours in 51 (28.749%), and non-neoplastic disease in 3 (1.68%). Pleomorphic adenoma was the most common benign tumour accounting for 38.07% (67/176), while squamous cell carcinoma was the most common malignant tumour representing 5.68% (10/176). Of the 179 parotidectomy cases, a 158 had at least one fine needle aspiration biopsy (FNAB) performed. A further 16 patients had other diagnostic tests and were excluded. The remaining 142 cases had a parotid FNAB as the only preoperative investigation. In 113 of these 142 cases FNAB results could be correlated with benign or malignant final histology results. The sensitivity and specificity for identifying malignant tumours were 60% and 96.77% respectively, with an overall accuracy of 90.27%. Our concordance rate for malignant tumours was 80% and 91.84% for benign tumours. Conclusion: The pattern of parotid pathology is consistent with previous regional data. FNAB is reliable for identifying benign tumours but less sensitive for malignancy. Where preoperative histology will influence management, core needle biopsy should be considered, rather than repeating FNAB which provides limited additional value.
Evolution of health policy and systems research (HPSR) capacity in West Africa and authorship pattern: a bibliometric analysis from 2015 to 2024
(Elsevier B.V., 2026) Defor, Selina; Gnamon Abe, Juliana F.; Agyepong, Irene A.; Lehmann, Uta
Background The generation of HPSR evidence in West Africa has historically been driven by external institutions, with limited leadership from local researchers. Recent investments, including the establishment of the West African Network of Emerging Leaders in Health Policy and Systems Research (WANEL), aimed to strengthen local research capacity. The objective of this study was to assess how authorship patterns and publication outputs have evolved over the past decade. Methods We conducted a bibliometric analysis using PubMed to identify peer-reviewed publications authored by 103 WANEL members between 2015 and 2024. We analysed the frequency of publication overtime by study type, research domain, authorship order, institutional affiliation, and collaboration patterns. Results Overall, WANEL members produced 1027 publications during the study period, of which 617 (60.1%) were HPSR-related. Of these, 62.9% (388) had West African first authors, mostly from Nigeria (47.0%) and Ghana (17.5%), while contributions from Francophone countries remained limited (6%). First-author institutions were predominantly in West Africa (62.9%), indicating a remarkable shift toward southern-led research. However, intra-network collaboration appeared quite low: only 62 (10%) of HPSR publications were co-authored by multiple WANEL members. Thematic analysis showed service delivery (49.1%) dominated research focus, followed by financing (12.6%) and information systems (11.2%). Conclusion A growing regional research capacity and ownership is observed; this is depicted by the increased West African leadership in HPSR publication. Persistent disparities call for more persistence, increasing targeted investments in underrepresented contexts and stronger cross-country partnerships, for a more equitable and sustainable HPSR ecosystem in West Africa.
The effects of methylprednisolone on non-inflamed and inflamed In vitro brain endothelial cells
(Taylor and Francis Ltd., 2026) Siebrits, Michaela Nicole; Fisher, David; Willemse, Chontrelle; Makhathini, Khayelihle Brian
The blood-brain barrier (BBB) is primarily regulated by highly selective endothelial cells. Inflammation of the brain capillaries can compromise the BBB’s functioning. Methylprednisolone (M-Pred), a synthetic glucocorticoid, is clinically prescribed to treat systemic inflammation; however, little is known about its effect on both non-inflamed and inflamed brain capillaries. This study evaluated the effectiveness of M-Pred in ameliorating the lipopolysaccharide (LPS)-induced inflammatory response using the in vitro BBB model (bEnd.3). Cultured brain endothelial cells (BECs) were exposed to LPS (500, 1000, 2000 ng/ml) and co-treated with selected concentrations of M-Pred (10, 20, 40 µM). Cell proliferation, quantification of pro-inflammatory cytokines TNF-α and IL-1β (ELISA), and monolayer permeability (Transendothelial Electrical Resistance) were investigated. LPS decreased live cell number, increased dead cell number, and increased cell monolayer permeability; LPS increased pro-inflammatory cytokine secretion. These data confirmed the experimental functionality of the in vitro inflammatory BBB model. In the absence of inflammation, M-Pred decreased bEnd.3 cell monolayer permeability and pro-inflammatory cytokine secretion. M-Pred failed to alleviate LPS-induced inflammation across all tested concentrations. Chronic M-Pred treatment in the absence of inflammation proved detrimental to bEnd.3 cells’ physiology.
Regulating local phosphoric acid environment via HDTMPA-modified catalyst layers for enhanced high-temperature proton exchange membrane fuel cells
(Elsevier B.V., 2026) Tian, Zihao; Khotseng, Lindiwe; Pasupathi, Sivakumar
Managing phosphoric acid (PA) distribution within the catalyst layers is a critical challenge for the development of high-performance high-temperature proton exchange membrane fuel cells (HT-PEMFCs). This work introduces a novel strategy using hexamethylenediamine tetra(methylenephosphonic acid) (HDTMPA) as a functional additive in the cathode to precisely regulate the local PA environment. HDTMPA performs a dual function: its strong hydrogen-bonding interactions with PA effectively anchor the acid, which prevents the excessive flooding and poisoning of Pt catalyst sites, while its electron-rich nitrogen atoms help establish a robust proton-conduction network. Consequently, a membrane electrode assembly (MEA) with an HDTMPA-modified cathode (0.5 mgPt cm−2) achieves a peak power density of 715 mW cm−2 at 150 °C, a 42% enhancement over the unmodified baseline (503 mW cm−2). Furthermore, the modified MEA demonstrates exceptional durability, exhibiting only a 5.0% performance decay after an accelerated durability test of 10,000 cycles, compared to a 17.5% decay for the control. In-situ electrochemical analysis confirms the enhanced kinetics, validating this molecular design approach as a new avenue for developing highly stable and efficient HT-PEMFCs.
Zero-divisor graphs of semirings with no S-vertices
(University of Guilan, 2026) Mehdi-Nezhad, Elham; Hassan, Khalid O.E.
Let R be a commutative semiring (ring) with identity 1 ≠ 0. A vertex a in a simple graph G is said to be a Smarandache vertex (or S-vertex for short) provided that there exist three distinct vertices x, y, and b (all different from a) in G such that x—a, a—b, and b—y are edges in G, but there is no edge between x and y. In this interdisciplinary subject, we investigate the interplay between the algebraic properties of the commutative semirings and their associated zero-divisor graphs, denoted by Γ(R), using the notion of the S-vertices in connection with the nonexistence of S-vertices in Γ(R). We discuss when Γ(R) is a complete bipartite graph together with some of its other graph-theoretic properties and their relation to the nonexistence of S-vertices of Γ(R).