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A facile microwave-assisted synthesis of pyrano[2,3- d]pyrimidines derivatives is accomplished via reactions of 4-arylmethylene-2-phenyloxazol-5(4 H)-ones with pyrimidine-4,6-diol in . The reaction is simple to perform and occurs under mild conditions with broad scope of applicability. [ABSTRACT FROM AUTHOR]

Objectives: Elevated lumbar multifidus stiffness has been observed in populations with chronic low back pain (LBP). However, the modulation of deep (DLM) and superficial (SLM) lumbar multifidus stiffness, considering their distinct structural characteristics and functions, remains unaddressed, especially in athletes. This study aimed to compare differences in DLM and SLM stiffness in professional athletes from different sports with and without chronic LBP., Design: Cross-sectional study., Setting: This study was conducted at a provincial sports training centre., Participants: Ninety-nine professional athletes (age: 18-27 years) from weightlifting, badminton, and track and field teams were recruited. Thirty-eight had chronic bilateral LBP., Interventions: Not applicable., Main Outcome Measures: Ultrasound shear wave elastography (SWE) measured Young's modulus (stiffness indicator) of DLM and SLM at the L4/5 facet joint level. Two-way analysis of variance examined the effects of chronic LBP and sport type on DLM and SLM stiffness while considering proper confounders. Significance was set at p < 0.05., Results: Athletes with chronic LBP demonstrated significantly higher DLM stiffness on the dominant (by 17.73%, mean difference (MD) = 2.52kPa, p = 0.001) and non-dominant sides (by 13.54%, MD = 1.83kPa, p = 0.046) compared to pain-free counterparts. SLM stiffness varied significantly among the three athlete groups. Post-hoc analyses revealed greater SLM stiffness on the non-dominant side in weightlifters than in badminton players (by 51.76%, MD = 8.97kPa, p = 0.010) or track and field athletes (by 72.01%, MD = 11.01kPa, p = 0.008)., Conclusions: Chronic LBP and sport type significantly impact multifidus muscle stiffness, suggesting the need for targeted clinical assessments and reconditioning strategies focusing on DLM for chronic LBP and SLM for athletes in trunk extension-intensive sports., (Copyright © 2024. Published by Elsevier Inc.)

Abstract: Zhou, EFM, Wong, AYL, Peng, J, Lin, G, Wen, T, Fang, J, Zhou, C, and Fu, SN. Diaphragm function in elite weightlifters with and without chronic low back pain and its impacts on sports performance. J Strength Cond Res XX(X): 000-000, 2024-The aim of this study was to compare diaphragm function between elite weightlifters with and without chronic low back pain (LBP) and to explore the associations between diaphragm function and sports performance. Forty-nine elite weightlifters aged 16-26 years were recruited, including 29 women (16-25 years, mean ± SD = 19.93 ± 2.70 years) and 20 men (16-26 years, mean ± SD = 20.95 ± 2.68 years). Of these, 23 subjects had chronic LBP. Diaphragm thickness and excursion were assessed using ultrasonography, and maximal inspiratory pressure (MIP), measured with POWERbreathe KH2, served as indicators of diaphragm contractility and strength, respectively. Sports performance was gauged through maximal snatch and clean and jerk lifts. Group differences and performance correlations were analyzed with consideration for confounders. The significance was set at p ≤ 0.05. Weightlifters with chronic LBP demonstrated significantly lower diaphragmatic contractility: diaphragm thickening fraction (by 21%; mean difference [MD] = 0.09, p = 0.04, Cohen's d = 0.69) and diaphragm excursion (by 18%; MD = 0.99, p < 0.01, Cohen's d = 0.89) compared with non-LBP controls. In addition, MIP was positively related to snatch (r = 0.34, p = 0.02) and clean and jerk (r = 0.43, p < 0.01) lifts. This study revealed that elite weightlifters with chronic LBP exhibit reduced diaphragm contractility, and inspiratory muscle force output (primary diaphragm) was associated with lifting performance. Incorporating diaphragm strengthening into training and rehabilitation might enhance performance and aid in LBP management, offering a dual benefit for athletes., (Copyright © 2024 National Strength and Conditioning Association.)

In the title compound, C(14)H(11)N(3)OS·C(2)H(5)OH, the dihedral angle between the pyridine N-C(fused)-C(fused)-C(thio-phene) plane and the plane of the thio-phene ring is 81.9 (3)°, indicating that they are close to perpendicular. The dihedral angle between this pyridine plane and the benzene ring is 1.3 (3)°. The thio-phene ring is disordered over two coplanar orientations with an occupancy ratio of 0.692 (7):0.308 (7), while the ethanol solvent mol-ecule is also disordered over two sets of site in a 0.66 (4):0.34 (4) ratio. In the crystal, chains are formed along the b axis by N-H⋯O and O-H⋯N inter-actions with adjacent chains being connected through C-H⋯N and C-H⋯S inter-actions.

The title compound, C(22)H(18)ClN(3)S, was synthesized by the reaction of 4-chloro-benzaldehyde, tetra-hydro-thio-pyran-4-one and 3-methyl-1-phenyl-1H-pyrazol-5-amine in acetic acid without a catalyst. The pyridine and pyrazole rings are almost coplanar, the dihedral angle between their mean planes being 2.50 (1)°. The thio-pyran ring exhibits an envelope conformation. The crystal packing is stabilized by inter-molecular C-H⋯Cl hydrogen bonds and by C-H⋯π and π-π inter-actions [centroid-centroid distances of 3.825 (2) Å between pyridine rings and 3.557 (2) Å between pyrazole and pyridine rings.

The title compound, C(25)H(22)N(2)O(3), was synthesized by the reaction of 3-nitro-benzaldehyde, dimedone and 2-naphthyl-amine in ethanol. In the mol-ecular structure, the cyclo-hexenone ring adopts an envelope conformation, whereas the piperidine ring has a boat conformation. The crystal packing is stabilized by inter-molecular N-H⋯O hydrogen bonds.

In the mol-ecule of the title compound, C(26)H(22)N(4)S(2), the pyrazole ring is oriented at a dihedral angle of 0.85 (3)° with respect to the adjacent naphthyridine ring, while the other ring of naphthyridine adopts an envelope conformation. The dihedral angle between phenyl and pyrazole rings is 87.65 (3)°. In the crystal structure, weak inter-molecular C-H⋯N inter-actions link the mol-ecules into chains. The π-π contacts between the naphthyridine rings and the naphthyridine and thio-phene rings [centroid-centroid distances = 3.766 (3) and 3.878 (3) Å] may further stabilize the structure. A weak C-H⋯π inter-action is also present.