Tuning the Solubility of Copper Complex in Atom Transfer Radical Self-Condensing Vinyl Polymerizations to Control Polymer Topology via One-Pot to the Synthesis of Hyperbranched Core Star Polymers

In this paper, we propose a simple one-pot methodology for proceeding from atom transfer reaction-induced conventional free radical polymerization (AT-FRP) to atom transfer self-condensing vinyl polymerization (AT-SCVP) through manipulation of the catalyst phase homogeneity (i.e., CuBr/2,2'-bipyridine (CuBr/Bpy)) in a mixture of styrene (St), 4-vinyl benzyl chloride (VBC), and ethyl 2-bromoisobutyrate. Tests of the solubilities of CuBr/Bpy and CuBr2/Bpy under various conditions revealed that both temperature and solvent polarity were factors affecting the solubility of these copper complexes. Accordingly, we obtained different polymer topologies when performing AT-SCVP in different single solvents. We investigated two different strategies to control the polymer topology in one-pot: varying temperature and varying solvent polarity. In both cases, different fractions of branching revealed the efficacy of varying the polymer topology. To diversify the functionality of the peripheral space, we performed chain extensions of the resulting hyperbranched poly(St-co-VBC) macroinitiator (name as: hbPSt MI) with either St or tBA (tert-butyl acrylate). The resulting hyperbranched core star polymer had high molecular weights (hbPSt-g-PSt: Mn = 25,000, Đ = 1.77; hbPSt-g-PtBA: Mn = 27,000, Đ = 1.98); hydrolysis of the tert-butyl groups of the later provided a hyperbranched core star polymer featuring hydrophilic poly(acrylic acid) segments

Submandibular Cavernous Hemangiomas with Multiple Phleboliths Masquerading as Sialolithiasis

Vasoformative tumors (almost exclusively hemangiomas) are the most common lesions of the major salivary glands during infancy and early childhood. They are more common in the parotid gland but are particularly rare in the submandibular gland. Changes in blood flow dynamics within hemangiomas result in thrombus formation and phleboliths. Hemangiomas of the salivary glands in adults are histologically unlike those in infants, the former being characteristically of the cavernous variant. Most cavernous hemangiomas require surgery since they do not show a tendency to regress. A case of an adult man with cavernous hemangioma affecting the submandibular salivary gland that clinically simulated sialolithiasis is presented to alert surgeons to the possibility of such a lesion. We describe the clinical course and review the literature

Is Taiwan's R&D productivity in decline? A microeconometric analysis

Innovation is widely recognized as the main stimulus of economic growth. Considering that Taiwan has devoted increasingly more efforts to R&D since the late 1980s, a crucial question is posed: did the R&D productivity of firms begin to decline in Taiwan during the post-Asian Financial Crisis period when Taiwan's economic growth began to decelerate? This study investigates changes in R&D productivity for Taiwan's manufacturing firms from 1990 to 2003. By employing various approaches to obtain robust results, findings from firm-level microeconometric analysis suggests that overall R&D productivity in Taiwan appears to have been ascendant, particularly during the post-crisis period. This result is also evidenced by segmenting the sample into industry groups, whereby electronics firms have a significantly high R&D productivity growth relative to firms outside the electronics industry. Therefore, the slowdown of Taiwan's economic growth in the past decade is attributed to other influences rather than a slowdown in R&D productivity

DNA oxidation after exercise: a systematic review and meta-analysis

Purpose: 8-Hydroxy-2′-deoxyguanosine (8-OHdG) is a byproduct of DNA oxidation resulting from free radical attacks. Paradoxically, treatment with 8-OHdG accelerates tissue healing. The aim of this study is to quantify the 8-OHdG response after a single session of exercise in both trained and untrained adults.Methods: A systematic review and meta-analysis of exercise intervention studies measuring changes in blood 8-OHdG following resistance exercise and aerobic exercise were conducted. The literature search included Web of Science, PubMed, BASE, and Scopus, with publications up to February 2023 included. Subgroup analysis of training status was also conducted.Results: Sixteen studies involving 431 participants met the eligibility criteria. Resistance exercise showed a medium effect on increasing circulating 8-OHdG levels (SMD = 0.66, p < 0.001), which was similar for both trained and untrained participants. However, studies on aerobic exercise presented mixed results. For trained participants, a small effect of aerobic exercise on increasing circulating 8-OHdG levels was observed (SMD = 0.42; p < 0.001). In contrast, for untrained participants, a large effect of decreasing circulating 8-OHdG levels was observed, mostly after long-duration aerobic exercise (SMD = −1.16; p < 0.05). Similar to resistance exercise, high-intensity aerobic exercise (5–45 min, ≥75% VO2max) significantly increased circulating 8-OHdG levels, primarily in trained participants.Conclusion: Pooled results from the studies confirm an increase in circulating 8-OHdG levels after resistance exercise. However, further studies are needed to fully confirm the circulating 8-OHdG response to aerobic exercise. Increases in 8-OHdG after high-intensity aerobic exercise are observed only in trained individuals, implicating its role in training adaptation.Systematic Review Registration: [https://Systematicreview.gov/], identifier [CRD42022324180