Synthesis of Network Biobased Aliphatic Polyesters Exhibiting Better Tensile Properties than the Linear Polymers by ADMET Polymerization in the Presence of Glycerol Tris(undec-10-enoate).

Development of biobased aliphatic polyesters with better mechanical (tensile) properties in film has attracted considerable attention. This report presents the synthesis of soluble network biobased aliphatic polyesters by acyclic diene metathesis (ADMET) polymerization of bis(undec-10-enyl)isosorbide diester [M1, dianhydro-D-glucityl bis(undec-10-enoate)] in the presence of a tri-arm crosslinker [CL, glycerol tris(undec-10-enoate)] using a ruthenium-carbene catalyst, and subsequent olefin hydrogenation using RhCl(PPh3)3. The resultant polymers, after hydrogenation (expressed as HCP1) and prepared in the presence of 1.0 mol% CL, showed better tensile properties than the linear polymer (HP1) with similar molecular weight [tensile strength (elongation at break): 20.8 MPa (282%) in HP1 vs. 35.4 MPa (572%) in HCP1]. It turned out that the polymer films prepared by the addition of CL during the polymerization (expressed as a 2-step approach) showed better tensile properties. The resultant polymer film also shows better tensile properties than the conventional polyolefins such as linear high density polyethylene, polypropylene, and low density polyethylene.

Synthesis of High Molecular Weight Biobased Aliphatic Polyesters Exhibiting Tensile Properties Beyond Polyethylene.

Synthesis of high molecular weight polyesters prepared by acyclic diene metathesis (ADMET) polymerization of bis(undec-10-enoate) with isosorbide (M1), isomannide (M2), and 1,3-propanediol (M3) and the subsequent hydrogenation have been achieved by using a molybdenum-alkylidene catalyst. The resultant polymers (P1) prepared by the ADMET polymerization of M1 (in toluene at 25 °C) possessed high Mn values (Mn = 44400-49400 g/mol), and no significant differences in the Mn values and the PDI (Mw/Mn) values were observed in the samples after the hydrogenation. Both the tensile strength and the elongation at break in the hydrogenated polymers from M1 (HP1) increased upon increasing the molar mass, and the sample with an Mn value of 48200 exhibited better tensile properties (tensile strength of 39.7 MPa, elongation at break of 436%) than conventional polyethylene, polypropylene, as well as polyester containing C18 alkyl chains. The tensile properties were affected by the diol segment employed, whereas HP2 showed a similar property to HP1.

Risk factors for shoulder osteoarthritis with rotator cuff tear in the elderly general population.

HYPOTHESIS AND/OR BACKGROUND: The relationship between shoulder osteoarthritis (OA) and rotator cuff tear (RCT) is unclear. We hypothesized that there is a difference between the pathogenesis of OA complicating RCT and that of RCT complicating OA. In this study, our primary objective was to determine the prevalence of shoulder OA without RCT, RCT without OA, and OA with RCT in the general older population. Our secondary objective was to identify risk factors for the association with OA+RCT in shoulder OA alone or RCT alone, respectively. METHODS: We enrolled patients from the public health checkup conducted in Gunma prefecture (Japan) in 2014. Subjects' shoulder pain at rest, during motion, and at night was evaluated using a questionnaire. Moreover, active and passive range of motions (ROMs) in flexion, abduction, and external rotation were measured. For RCT parameters, we evaluated as no tear, partial-thickness supraspinatus (SSP) tear, full-thickness SSP tear, and SSP-infraspinatus tears. For further analysis, the shoulders were divided into three groups according to the presence of RCT and/or OA: OA, RCT, and OA + RCT groups. Risk factors for OA + RCT were identified in a logistic regression analysis. RESULTS: Overall, 944 of 1148 shoulders were eligible for inclusion. The prevalence rates of shoulder OA, RCT, and OA + RCT were 5.8%, 21.1%, and 4.2%, respectively. Furthermore, 650 shoulders were excluded, and 55, 199, and 40 shoulders had OA, RCT, and OA + RCT, respectively. There were significant differences for age, ROM of active external rotation, strength of abduction, external rotation, and morphology of the rotator tears. However, there were no significant differences for pain visual analog scale score, passive ROM, Simple Shoulder Test, and grades of OA. Older age decreased active ROM in external rotation, and the presence of both subscapularis and SSP-infraspinatus tears was a risk factor for the association of OA with an RCT shoulder. Older age, weaker power in external rotation, and affected dominant side were risk factors for the association of RCT with an OA shoulder. DISCUSSION AND/OR CONCLUSION: This study is the first to report risk factors by considering both shoulder OA and RCT in the general population. Our findings will be useful for the treatment and management of OA and RCT as well as for the prevention of these conditions in the older adults.

A New Platform of B/N-Doped Cyclophanes: Access to a π-Conjugated Block-Type B3 N3 Macrocycle with Strong Dipole Moment and Unique Optoelectronic Properties.

We herein describe a new design principle to achieve B/N-doped cyclophane where an electron-donor block of three triarylamines (Ar3 N) and an acceptor block of three triarylboranes (Ar3 B) are spatially separated on opposite sides of the π-extended ring system. DFT computations revealed the distinct electronic structure of the block-type macrocycle MC-b-B3N3 with a greatly enhanced dipole moment and reduced HOMO-LUMO energy gap in comparison to its analogue with alternating B and N sites, MC-alt-B3N3. The unique arrangement of borane acceptor Ar3 B and amine donor Ar3 N components in MC-b-B3N3 induces exceptionally strong intramolecular charge transfer in the excited state, which is reflected in a largely red-shifted luminescence at 612 nm in solution. The respective linear open-chain oligomer L-b-B3N3 was also synthesized for comparison. Our new approach to donor-acceptor macrocycles offers important fundamental insights and opens up a new avenue to unique optoelectronic materials.

Electrophilic and nucleophilic displacement reactions at the bridgehead borons of tris(pyridyl)borate scorpionate complexes.

Although a wide variety of boron-based "scorpionate" ligands have been implemented, a modular route that offers facile access to different substitution patterns at boron has yet to be developed. Here, we demonstrate new reactivity patterns at the bridgehead positions of a ruthenium tris(pyrid-2-yl)borate complex that allow for facile tuning of steric and electronic properties.

Neuroplasticity Caused by Peripheral Proprioceptive Deficits.

PURPOSE: Proprioceptive feedback is crucial for motor control and stabilization of the shoulder joint in everyday life and sports. Shoulder dislocation causes anatomical and proprioceptive feedback damage that contributes to subsequent dislocations. Previous recurrent anterior shoulder instability (RSI) studies did not investigate functional neuroplasticity related to proprioception of the injured shoulder. Thus, we aimed to study the differences in neuroplasticity related to motor control between patients with RSI and healthy individuals, using functional magnetic resonance imaging, and assess the effects of peripheral proprioceptive deficits due to RSI on CNS activity. METHODS: Using passive shoulder motion and voluntary shoulder muscles contraction tasks, we compared the CNS correlates of proprioceptive activity between patients having RSI (n = 13) and healthy controls (n = 12) to clarify RSI pathophysiology and the effects of RSI-related peripheral proprioceptive deficits on CNS activity. RESULTS: Decreased proprioception-related brain activity indicated a deficient passive proprioception in patients with RSI (P < 0.05 family-wise error, cluster level). Proprioceptive afferent-related right cerebellar activity significantly negatively correlated with the extent of shoulder damage (P = 0.001, r = -0.79). Functional magnetic resonance imaging demonstrated abnormal motor control in the CNS during voluntary shoulder muscles contraction. CONCLUSION: Our integrated analysis of peripheral anatomical information and brain activity during motion tasks can be used to investigate other orthopedic diseases.

Reciprocal inhibition improves posterior shoulder tightness and shoulder range of motion in youth baseball players.

BACKGROUND: The aim of this study was to evaluate the efficacy of reciprocal inhibition for posterior shoulder tightness (PST), internal rotation at 90° abduction (ABIR) limitation, and subacromial impingement in elementary and junior high school baseball players. METHODS: The present study included 290 elementary school and junior high school baseball players who were members of an organized baseball team and attended a medical checkup in 2014. Seventeen participants were excluded because they were left-handed. We applied a sit-up exercise as a tool of reciprocal inhibition to all participants. Before and after the sit-up exercise, we evaluated the shoulder range of motion (ROM) in external rotation at 90° abduction (ABER), ABIR, and horizontal flexion (HF) in both shoulders and the prevalence of subacromial impingement in the dominant shoulder. We defined PST as a ≧15°decrease in the HF angle of the dominant shoulder in comparison to the nondominant shoulder before the sit-up exercise and divided participants into two groups (the PST group and the non-PST groups). An independent t-test was performed to compare the shoulder ROM, and a chi-squared test was performed to compare the prevalence of subacromial impingement between the two groups. A dependent t-test was performed to compare intragroup changes in the shoulder ROM. The McNemar test was performed to compare intragroup changes in the prevalence of subacromial impingement. RESULTS: Fifty-six of 273 participants had PST in the initial examination. The initial examination revealed that the ROM of ABIR and HF in the dominant shoulder were significantly lower in the PST group than those in the non-PST group, whereas the ROM of ABER and total arc were significantly higher in the PST group. The prevalence of subacromial impingement in the PST group was significantly higher than that in the non-PST group. The sit-up exercise improved ABER, ABIR, total arc, HF, and the prevalence of subacromial impingement in both groups. However, the amount of ROM change did not differ between the two groups for any parameter with the exception of HF. CONCLUSION: The presence of PST affects the prevalence of subacromial impingement but was not related to the loss of ABIR or the prevalence of pathological glenohumeral internal rotation deficit. The sit-up exercise, as reciprocal inhibition, can transiently improve the prevalence of subacromial impingement via the improvement of PST.

Risk Factors for Throwing-Related Shoulder and Elbow Pain in Adolescent Baseball Players: A Prospective Study of Physical and Developmental Factors.

BACKGROUND: Throwing-related shoulder and elbow pain continues to be reported among adolescent baseball players. Few prospective studies have specifically examined the association between throwing-related shoulder and elbow pain and physical and developmental changes. PURPOSE: To evaluate the changes in physical and developmental characteristics during 1 year with respect to throwing-related shoulder and elbow pain in adolescent baseball players. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: This 1-year prospective follow-up study investigated 164 baseball players aged 7 to 13 years. Player data (age, height, weight, field position, and pitch count), lower extremity muscle tightness, and range of motion (ROM) of the shoulder, elbow, and hip joints were assessed during the 2016 and 2017 preseason medical examinations. After the 2016 season, the participants completed questionnaires related to throwing-related shoulder and elbow pain, defined as an inability to play for ≥1 week because of elbow or shoulder difficulties. For study participants with and without throwing-related shoulder or elbow pain during the 2016 season, we conducted univariate and multivariate logistic regression analysis to identify risk factors for throwing-related shoulder or elbow pain. RESULTS: Overall, 21 players (12.8%) reported a shoulder pain episode, 56 players (34.1%) had an elbow pain episode, and 70 players (42.7%) reported having experienced shoulder and/or elbow pain during the 2016 season. In multivariate logistic regression analysis, (1) shoulder pain was associated with 2016 preseason height (odds ratio [OR], 1.06; 95% CI, 1.01-1.11; P = .01) and change in dominant-side elbow extension ROM from 2016 to 2017 (OR, 1.12; 95% CI, 1.02-1.24; P = .02); (2) elbow pain was associated with change in weight from 2016 to 2017 (OR, 1.21; 95% CI, 1.04-1.41; P = .014); and (3) throwing-related shoulder and/or elbow pain was associated with greater 2016 preseason height (OR, 1.04; 95% CI, 1.003-1.68; P = .03) and an increase in height from 2016 to 2017 (OR, 1.17; 95% CI, 1.01-1.35; P = .03). CONCLUSION: Our results indicated that adolescent baseball players who were taller in the preseason and those with an increase in height over the 1-year study period faced significant risks for developing throwing-related shoulder and/or elbow pain.

Four-year trend in shoulder and elbow injuries in competitive-level high school baseball pitchers: a repeated cross-sectional survey.

BACKGROUND: Shoulder and elbow injuries are the main cause of throwing disability among high school baseball pitchers. However, longitudinal studies on shoulder and elbow injuries among competitive-level high school baseball pitchers have been insufficient. This study aimed to investigate shoulder and elbow injuries in competitive-level high school baseball pitchers over a four-year period and elucidate the effects of implementing medical checkups on the incidence of shoulder and elbow injuries. METHODS: Five hundred fifty-two high school baseball pitchers, who received preseason medical checkups from February 2012 to February 2015, were enrolled in this study. Shoulder and elbow injuries occurring during the season after medical checkups were prospectively evaluated by a postseason questionnaire. Pitchers who were not able to pitch for >7 days owing to shoulder or elbow pain were defined as having shoulder and elbow injuries during the season. The incidence rates of shoulder and elbow injuries during the seasons were calculated and compared over the 4-year period. RESULTS: Ninety-six percent of medical checkup participants were included in the study. The mean questionnaire collection rate of the prospective study was 71.6% (range: 67.7-78.9%). The incidence of shoulder and elbow injuries significantly decreased from 20.0% in 2012 to 7.7% in 2015 (P = .013). CONCLUSION: The four-year trend in the incidence of shoulder and elbow injuries in competitive-level high school baseball pitchers was evaluated. The incidence of shoulder and elbow injuries during the season significantly decreased with a linear downward trend during the survey period after the implementation of medical checkups.

Negative Cooperativity in Guest Binding of a Ditopic Self-Folding Biscavitand.

A brand-new self-folding biscavitand was synthesized from a feet-to-feet-connected bisresorcinarene. The X-ray crystal structure of the biscaivtand showed that the two cavities are tightly connected with four butylene linkages. The conformationally coupled two cavities accommodated two cationic guests, showing a homotropic negative cooperativity in nonpolar solvents (toluene and chloroform). A polar tetrahydrofuran solvent weakened the cyclic hydrogen bonding interactions of the biscavitand, which resulted in noncooperative guest binding.

Electrochromic Polycationic Organoboronium Macrocycles with Multiple Redox States.

Polycationic macrocycles are attractive as they display unique molecular switching capabilities arising from their redox properties. Although diverse polycationic macrocycles have been developed, those based on cationic boron systems remain very limited. We present herein the development of novel polycationic macrocycles by introducing organoboronium moieties into a conjugated organoboron macrocyclic framework. These macrocycles consist of four bipyridylboronium units that are connected by fluorene and either electron-deficient arylborane or electron-rich arylamine moieties. Electrochemical studies reveal that the macrocycles undergo reversible multi-step redox processes with transfer of up to 10 electrons. Switchable electrochromic behavior is demonstrated via spectroelectrochemical studies and the observed color changes are rationalized by correlation with computed electronic transitions using DFT methods.

Relationship between the Lower Limb Function and Shoulder and Elbow Injuries in Elementary School Baseball Pitchers.

OBJECTIVES: We aimed to examine the relationship between the hip range of motion (ROM) and ankle ROM and throwing-related shoulder and elbow injuries in elementary school baseball pitchers. METHODS: This retrospective comparative study (Level of evidence: Level III) included 195 baseball pitchers (mean age 10.8±1.0 years, range 8-12 years). All pitchers underwent physical function measurements, including height, weight, shoulder strength, and hip and ankle ROM. Shoulder and elbow injury was defined as shoulder and elbow pain that the pitchers had been aware of in the past or at the time of medical checkups. The results for the injured and non-injured groups were then compared. RESULTS: The shoulder ROM and strength in the injured and non-injured groups did not differ to a statistically significant extent. The hip external rotation on the dominant side (injured vs. non-injured: 48.9±11.1° vs. 53.3±9.7°, P<0.01), the hip internal rotation on the non-dominant side (injured vs. non-injured: 36.6±12.0° vs. 40.9±11.0°, P=0.01), and ankle plantar flexion on the non-dominant side (injured vs. non-injured: 52.0±6.8° vs. 54.3±6.7°, P=0.02) were significantly smaller in the injured group than in the non-injured group. CONCLUSIONS: The hip external rotation ROM on the dominant side and the hip internal rotation and ankle plantar flexion on the non-dominant side were significantly lower in the injured group than in the non-injured group. These results may suggest measures to reduce the incidence of elbow and shoulder injuries in elementary school baseball pitchers.

Relationship between upper limb injuries and hip range of motion and strength in high school baseball pitchers.

We aimed to examine the relationship between hip range of motion (ROM) and abduction strength and throwing-related shoulder/elbow injuries in high school baseball pitchers. The study included 135 baseball pitchers. We asked them to fill out a questionnaire at the checkups, that included the dominant arm and the years of baseball experience. To avoid a confirmation bias, the examiners were blinded to the participants' hand dominance. All players underwent physical function measurements, such as height, weight, shoulder and hip strength, and shoulder and hip ROM. Shoulder and elbow injury was defined as shoulder and elbow pain that the patient had been aware of in the past 3 years. The results of injured and non-injured pitchers were compared. Eighty-five pitchers had experienced a shoulder or elbow injury in the past 3 years. The shoulder ROM and strength in the injured and non-injured groups did not differ to a statistically significant extent. The hip external rotation ROM on the dominant side, the hip abduction strength on the non-dominant side, and the hip abduction strength on the dominant side were significantly lower in the injured group than in the non-injured group. The results may contribute to reducing the incidence of these injuries.

Relationship Between Upper Limb Injuries and Hip Range of Motion in Elementary and Junior High School Baseball Players.

BACKGROUND: Shoulder and elbow injuries are major problems in baseball players. Tightness of the upper extremities has been reported as a risk factor for shoulder and elbow injuries in elementary and junior high school baseball players. However, few studies have been conducted on the relationship between decreased hip range of motion (ROM) and shoulder and elbow injuries. PURPOSE/HYPOTHESIS: This study aimed to prospectively examine the relationship between hip ROM and throwing-related shoulder and elbow injuries in elementary and junior high school baseball players. The hypothesis was that players with unrestricted ROM in the hip would have a reduced risk of upper extremity injuries. METHODS: The study included 263 baseball players (mean ± SD age, 10.5 ± 1.3 years; range, 7-14 years). The following physical parameters were assessed: (1) hip flexion ROM measured in the supine position and (2) hip internal and external rotation in the prone position. After the season, players completed questionnaires regarding shoulder and/or elbow injuries. For comparison, the players were classified as injured (not able to play for ≥8 days because of shoulder and/or elbow problems) or noninjured. RESULTS: During the season, 52 players had shoulder and/or elbow injuries. When the injured and noninjured groups were compared, hip flexion on the dominant side (121.5° ± 12.0° vs 126.7° ± 9.8°, respectively; P < .01), hip flexion on the nondominant side (119.6° ± 11.7° vs 126.0° ± 9.9°, respectively; P < .01), and internal rotation on the dominant side (52.5° ± 11.3° vs 56.8° ± 10.8°, respectively; P = .01) were significantly reduced in the injured group. CONCLUSION: We identified preseason decreases in flexion bilaterally and internal rotation on the dominant side as risk factors for shoulder and elbow injuries in elementary and junior high school baseball players. Further studies are required to prevent disabilities in elementary and junior high school baseball players through development of prevention and intervention programs.

Factors affecting the onset and progression of rotator cuff tears in the general population.

While previous studies have revealed factors affecting the progression of rotator cuff tear (RCT), none have yet described factors affecting its onset. The purpose of this longitudinal observational study was to analyze factors affecting the RCT onset and progression in the general population. The present study included 185 shoulders from 93 participants who completed all the examinations in both 2012 and 2017. Participants received a questionnaire with age, gender, arm dominance, and presence of pain at rest, in motion, and at night. The range of motion (ROM), simple shoulder test (SST) were also examined. Anteroposterior radiograph of the shoulder joint was performed to evaluate the degree of osteoarthritic changes by the Samilson-Prieto (S-P) classification. The degree of RCT was examined by ultrasonography. There were 132 shoulders without RCT and 53 with RCT in 2012. RCT occurred in 21 of 132 shoulders, and the factor affecting the RCT onset was S-P grade 2 osteoarthritic change in 2012 (odds ratio [OR] 10.10). RCT progressed in 22 of 53 shoulders, and the factor affecting RCT progression was the presence of motion pain in 2012 (OR 13.76). These results added new knowledge regarding the natural course of RCT onset and progression.

Reliability of shoulder muscle stiffness measurement using strain ultrasound elastography and an acoustic coupler.

PURPOSE: Abnormal increases in muscle tone can be caused by various musculoskeletal disorders. The objective of this study was to evaluate intratester and intertester reliabilities in measuring the stiffness of the shoulder muscles using strain ultrasound elastography (USE) and an acoustic coupler. METHOD: Tissue stiffness was measured in the trapezius muscle and in the supraspinatus muscle of healthy young volunteers. RESULTS: The mean strain ratios measured by two experienced shoulder surgeons were significantly higher in the trapezius muscle than in the supraspinatus muscle (P < 0.001). Intratester reliability was rated as moderate to substantial for the trapezius muscle and substantial for the supraspinatus muscle. Intertester reliability was substantial for both muscles, with an intraclass correlation coefficient (2,1) of 0.62 [95% confidence interval (CI) 0.28-0.82] for the trapezius muscle and 0.69 (95% CI 0.40-0.86) for the supraspinatus muscle. CONCLUSIONS: We found substantial intratester and intertester reliabilities for the trapezius and supraspinatus muscles, suggesting that USE represents a promising modality for measuring the stiffness of shoulder muscles. However, the clinical application of this method will require the development of a device that can standardize the scanning technique to further increase the reliability.

Conformation of K+(Crown Ether) Complexes Revealed by Ion Mobility-Mass Spectrometry and Ultraviolet Spectroscopy.

The conformation and electronic structure of dibenzo-24-crown-8 (DB24C8) complexes with K+ ion were examined by ion mobility-mass spectrometry (IM-MS), ultraviolet (UV) photodissociation (UVPD) spectroscopy in the gas phase, and fluorescence spectroscopy in solution. Three structural isomers of DB24C8 (SymDB24C8, Asym1DB24C8, and Asym2DB24C8) in which the relative positions of the two benzene rings were different from each other were investigated. The IM-MS results at 86 K revealed a clear separation of two sets of conformers for the K+(SymDB24C8) and K+(Asym1DB24C8) complexes whereas the K+(Asym2DB24C8) complex revealed only one set. The two sets of conformers were attributed to the open and closed forms in which the benzene-benzene distances in the complexes were long (>6 Å) and short (<6 Å), respectively. IM-MS at 300 K could not separate the two conformer sets of the K+(SymDB24C8) complex because the interconversion between the open and closed conformations occurred at 300 K and not at 86 K. The crown cavity of DB24C8 was wrapped around the K+ ion in the complex, although the IM-MS results availed direct evidence of rapid cavity deformation and the reconstruction of stable conformers at 300 K. The UVPD spectra of the K+(SymDB24C8) and K+(Asym1DB24C8) complexes at ∼10 K displayed broad features that were accompanied by a few sharp vibronic bands, which were attributable to the coexistence of multiple conformers. The fluorescence spectra obtained in a methanol solution suggested that the intramolecular excimer was formed only in K+(SymDB24C8) among the three complexes because only SymDB24C8 could possibly assume a parallel configuration between the two benzene rings upon K+ encapsulation. The encapsulation methods for K+ ion (the "wraparound" arrangement) are similar in the three structural isomers of DB24C8, although the difference in the relative positions of the two benzene rings affected the overall cross-section. This study demonstrated that temperature-controlled IM-MS coupled with the introduction of appropriate bulky groups, such as aromatic rings to host molecules, could reveal the dynamic aspects of encapsulation in host-guest systems.

Absorption of chemicals in amorphous trisresorcinarene.

Trisresorcinarene is an interesting class of macrocyclic host. Its insoluble nature and conformationally flexible structure allow its application as a solid absorbent. Various aromatic and aliphatic hydrocarbons are absorbed into the amorphous solid of the trisresorcinarene, demonstrating the versatile absorption capability of trisresorcinarene.

Flexor pronator muscles' contribution to elbow joint valgus stability: ultrasonographic analysis in high school pitchers with and without symptoms.

BACKGROUND: Few researchers have examined the different contributions of flexor-pronator muscles to valgus stress in high school baseball pitchers with and without elbow symptoms. This study used ultrasonography to assess these muscles' dynamic contributions to elbow valgus joint stability in high school pitchers. METHODS: A self-administered questionnaire on throwing-related elbow joint pain sustained during the prior year was completed by 89 high school baseball pitchers. Gravity stress ultrasonographic elbow examinations with 30° of flexion were done before and after isometric contraction of the flexor-pronator muscles. For study participants with and without a history of elbow symptoms, we compared differences of ulnohumeral joint space without gravity stress and isometric contraction of the flexor-pronator muscles and with gravity stress only and with isometric contraction of the flexor-pronator muscles under gravity stress. RESULTS: For each pitcher, the ulnohumeral joint space in the condition with valgus stress was significantly larger than in the condition without valgus stress. Also, the ulnohumeral joint space in the condition with valgus stress was significantly larger than in the condition with valgus stress and flexor-pronator isometric muscle contraction. Participants with and without elbow symptom history showed no differences of ulnohumeral joint space in the unloaded and loaded flexor-pronator muscle contracted conditions. CONCLUSION: Ultrasonographic assessment demonstrated that flexor-pronator muscles contribute to elbow valgus stability. No difference was found in the flexor-pronator muscle contribution in high school baseball pitchers with and without elbow symptom history.

Upper-rim functionalization and supramolecular polymerization of a feet-to-feet-connected biscavitand.

An octaiodobiscavitand was synthesized via an aromatic Finkelstein iodination reaction in good yield. Sonogashira and Suzuki coupling reactions of the octaiodobiscavitand gave rise to upper-rim-functionalized biscavitands that self-assembled to form a supramolecular polymer in the solid state.