Evidence for the h_b(1P) meson in the decay Upsilon(3S) --> pi0 h_b(1P)

Using a sample of 122 million Upsilon(3S) events recorded with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC, we search for the $h_b(1P)$ spin-singlet partner of the P-wave chi_{bJ}(1P) states in the sequential decay Upsilon(3S) --> pi0 h_b(1P), h_b(1P) --> gamma eta_b(1S). We observe an excess of events above background in the distribution of the recoil mass against the pi0 at mass 9902 +/- 4(stat.) +/- 2(syst.) MeV/c^2. The width of the observed signal is consistent with experimental resolution, and its significance is 3.1sigma, including systematic uncertainties. We obtain the value (4.3 +/- 1.1(stat.) +/- 0.9(syst.)) x 10^{-4} for the product branching fraction BF(Upsilon(3S)-->pi0 h_b) x BF(h_b-->gamma eta_b).Comment: 8 pages, 4 postscript figures, submitted to Phys. Rev. D (Rapid Communications

Relationship between subscapularis tears and injuries to the biceps pulley

The purpose of this study was to analyse the relationship between long head of the biceps brachii (LHBT) lesions and subscapularis tears. The hypothesis was that a bicipital pulley might remain intact, even in the case of a subscapularis tear

Bipolar transfer of the pectoralis major muscle for restoration of elbow

International audienceBACKGROUND:This study evaluated the functional outcomes of bipolar pedicled pectoralis major (PM) transfer to restore elbow flexion.METHODS:We retrospectively reviewed 29 transfers in 28 patients with a mean age of 31.2 years (range, 5-65 years). The loss of elbow flexion was due to brachial plexus palsy in 24 patients, elbow flexors necrosis in 4, and poliomyelitis in 1. The entire PM muscle was mobilized and fixed proximally to the coracoid process. Intraoperative positioning and postoperative immobilization of the shoulder and the elbow flexed at 60° and 120°, respectively, allowed direct distal fixation of the muscle to the biceps brachii tendon.RESULTS:At the last follow-up (mean, 13 months; range, 4-37 months), 41% of the transfers (n = 12) recovered grade 4 elbow flexion strength and were able to lift 2.2 kg on average (range, 0.5-5 kg), 52% (n = 15) recovered grade 3 strength, and 7% (n = 2) had a poor result (ie, grade 2 elbow flexion). The mean active elbow flexion was 100° (ranging, 30°-150°), and the patients had 0° to 10° elbow flexion contracture.CONCLUSIONS:Our results indicate that bipolar PM transfer is a reliable and effective procedure to restore elbow flexion. Flexion of the shoulder and elbow allowed the transfer to reach the elbow fold and avoided an interposition graft between the distal PM and the biceps brachii tendon

Humeral head size predicts baseplate lateralization in reverse shoulder arthroplasty: a comparative computer model study

Background: In reverse shoulder arthroplasty (RSA), the ideal combination of baseplate lateralization (BL), glenosphere size (GS), and glenosphere overhang (GOH) with a commonly used 145° neck shaft angle (NSA) is unclear. This is the first study evaluating correlations of body height (BH), humeral head size (HS), glenoid height (GH), and association of gender with best glenoid configurations for range of motion (ROM) maintaining anatomic lateralization (aLAT) for optimized muscle length in 145° and less distalized 135° RSA. Methods: In this computer model study, 22 computed tomographies without joint narrowing were analyzed (11 male/female). A standardized semi-inlay 145° platform stem was combined with 20 glenoid configurations (baseplate [B] 25, 25 + 3/+6 lateralized [l], 29, 29 + 3/6l combined with glenosphere 36, 36 + 2 eccentric [e], 36 + 3l, 39, 39 + 3e, 39 + 3l , 42, 42 + 4e). Abduction-adduction, flexion-extension, external rotation-internal rotation, total ROM (TROM), and total notching relevant (TNR) ROM were computed, best TROM models respecting aLAT (-1 mm to +1 mm) and HS/GH recorded. Second, the 145° models (Ascend Flex stem; Stryker, Kalamazoo, MI, USA) were converted and compared to a 135° inlay RSA (New Perform stem; Stryker, Kalamazoo, MI, USA) maintaining GOH (6.5-7 mm) and aLAT. Results: Best 145° models had eccentric glenospheres (mean BL: 3.5 mm, GOH 8.8 mm, GS 38.1 mm, distalization 23 mm). The 135° models had concentric glenospheres, mean BL 3.8 mm, GOH 6.9 mm, GS 39.7 mm, and distalization 14.1 mm. HS showed the strongest positive correlation with BL in 145° and 135° models (0.65/0.79). Despite reduced GOH in smaller females with a 135° NSA, adduction, external rotation, extension, TNR ROM, and TROM were significantly increased (P = .02, P = .005, P = .005, P = .004, P = .003), abduction however reduced (P = .02). The same trends were seen for males. Conclusion: HS is a practical measure in surgery or preoperatively, and the strong positive correlation with BL is a useful planning aid. Despite reduction of GOH, conversion to a less distalized 135° NSAinlay design is powerful to maintain and even significantly increase all components of TNR ROM (extension/external rotation/adduction) in small females with the drawback of reduced abduction which may however be compensated by scapula motion. Lateralization with a less distalized 135° RSA optimizes muscle length, may facilitate subscapularis repair, and maintains highest rigid body motion

Protonation thermochemistry of aminoacetonitrile

International audienc

Strategies for determining heteroaggregation attachment efficiencies of engineered nanoparticles in aquatic environments

Heteroaggregation of engineered nanoparticles (ENPs) with suspended particulate matter (SPM) ubiquitous in natural waters often dominates the transport behaviour and overall fate of ENPs in aquatic environments. In order to provide meaningful exposure predictions and support risk assessment for ENPs, environmental fate and transport models require quantitative information about this process, typically in the form of the so-called attachment efficiency for heteroaggregation αhetero. The inherent complexity of heteroaggregation—encompassing at least two different particle populations, various aggregation pathways and several possible attachment efficiencies (α values)—makes its theoretical and experimental determination challenging. In this frontier review we assess the current state of knowledge on heteroaggregation of ENPs with a focus on natural surface waters. A theoretical analysis presents relevant equations, outlines the possible aggregation pathways and highlights different types of α. In a second part, experimental approaches to study heteroaggregation and derive α values are reviewed and three possible strategies are identified: i) monitoring changes in size, ii) monitoring number or mass distribution and iii) studying indirect effects, such as sedimentation. It becomes apparent that the complexity of heteroaggregation creates various challenges and no single best method for its assessment has been developed yet. Nevertheless, many promising strategies have been identified and meaningful data can be derived from carefully designed experiments when accounting for the different concurrent aggregation pathways and clearly stating the type of α reported. For future method development a closer connection between experiments and models is encourage

Radical formation of amino acid precursors in interstellar regions? Ser, Cys and Asp

It is proposed that the glycine precursor NH(2)CH(2)CN may be synthesised in interstellar dust clouds by the radical combination reactions NH(2)˙ + ˙CH(2)CN → NH(2)CH(2)CN (ΔG = -302 kJ mol(-1)) and/or NH(2)CH(2)˙ + ˙CN → NH(2)CH(2)CN (ΔG = -414 kJ mol(-1)). All calculations at the CCSD(T)/aug-cc-pVDZ//B3LYP/6-31+G(d) level of theory. This paper extends that concept to radical/radical coupling reactions to form Ser, Cys and Asp precursor nitriles. The hydrogen abstraction process NH(2)CH(2)CN + HO˙→ NH(2)˙CHCN + H(2)O (ΔG = -130 kJ mol(-1)) is suggested to precede the radical coupling reactions NH(2)˙CHCN + R˙→ NH(2)CHRCN (R˙ = ˙CH(2)OH, ˙CH(2)SH and ˙CH(2)CN) to form nitrile precursors of the amino acids Ser, Cys and Asp. These three reactions are all favourable (ΔG = -240, -227 and -223 kJ mol(-1)). The radical species ˙CH(2)NH(2), ˙CH(2)OH, ˙CH(2)SH and ˙CH(2)CN are shown to be stable for the microsecond timeframe by a combination of theoretical calculations and the experimental mass spectrometric neutralization/reionization procedure.Daniel J. Knowles, Tianfang Wang and John H. Bowi