Converting non-Mesogenic to Mesogenic Stacking of Amino-s-Triazine-Based Dendrons with p-CN Phenyl Unit by Eliminating Peripheral Dipole

Three new amino-s-triazine-based dendrons, 1a, 1b, and 1c, containing an aryl-CN moiety in the dendritic skeleton were prepared in 72–81% yields (1a: R1 = − N(n-C8H17)2, R2 = n-OC8H17, 1b: R1 = R2 = − N(n-C8H17)2, 1c: R1 = − N(n-C8H17)2, R2 = − N(n-C4H9)2). Dendrons 1a with N(n-C8H17)2 and n-OC8H17 peripheral substituents, surprisingly, did not show any mesogenic phase during the thermal process. However, non-mesogenic 1a can be converted to mesogenic 1b or 1c by eliminating the peripheral dipole arising from the alkoxy substituent; dendron 1b only comprising the same N(n-C8H17)2 peripheral groups showed a ~25 °C mesogenic range on heating and ~108 °C mesogenic range on cooling. In contrast, dendron 1c possessing different N(n-CmH2m+1)2 (m = 8 versus m = 4) peripheral units, having similar stacking as 1b, exhibited a columnar phase on thermal treatment, but its mesogenic range (~9 and ~66 °C on heating and cooling, respectively) was much narrower than that of 1b, attributed to 1c’s less flexible alkyl chains in the peripheral part of dendron. Dendron 1a with the alkoxy substituent in the peripheral skeleton, creating additional dipole correspondingly, thus, leads to the dendritic molecules having a non-mesogenic stacking. Without the peripheral dipole for intermolecular side-by-side interaction, dendrons 1b and 1c exhibit a columnar phase on thermal treatment because of the vibration from the peripheral alkyl chain.

Improving diagnostics of periodontal diseases in children with connective tissue dysplasia based on X-ray morphometric and densitometric data

Relevance. Detection of maxillofacial pathomorphological changes in children with connective tissue dysplasia (CTD) allows identifying the nature and severity of disorders, as well as it serves the basis for selecting the best treatment options in view of the pathogenetic features. The purpose is to improve the diagnosis of periodontal diseases in children with CTD based on x-ray morphometric indices of the lower jaw and peripheral skeleton ultrasound osteodensitometry.Materials and methods. 92 children with varying CTD severity, and 43 healthy children, underwent cone-beam computed tomogram examination with a further analysis of their X-ray morphometric (quantitative, qualitative) values and the lower jaw optical density indices. Besides, the status of the peripheral skeleton bone tissue was also determined through quantitative ultrasonic densitometry.Results. Quantitative X-ray morphometric indices in healthy children and children with CTD revealed strong positive correlation with the Z-criterion of osteodensitometry, offering an objective reflection of the bone tissue status in the peripheral skeleton.Conclusion. CTD progression in children correlates with the bone structure destruction intensity in the maxillofacial area, an increase in chronic productive inflammation, a decrease in the bone density, bone tissue fibrous transformation, a decrease in the thickness of cortical, and fiber-dissociation in closing, plates, of the lower jaw, prevalence of mid- and fine-meshed bone pattern, disturbed spatial orientation and thinning of bone trabeculae, as well as the development of pathologies in the periodontium.

Bone Metabolism in Adolescents Undergoing Bariatric Surgery

Purpose The prevalence of childhood obesity has increased over past decades with a concomitant increase in metabolic and bariatric surgery (MBS). While MBS in adults is associated with bone loss, only a few studies have examined the effect of MBS on the growing skeleton in adolescents. Methods This mini-review summarizes available data on the effects of the most commonly performed MBS (sleeve gastrectomy and gastric bypass) on bone in adolescents. A literature review was performed using PubMed for English-language articles. Results Dual-energy x-ray absorptiometry (DXA) measures of areal bone mineral density (aBMD) and BMD Z scores decreased following all MBS. Volumetric BMD (vBMD) by quantitative computed tomography (QCT) decreased at the lumbar spine while cortical vBMD of the distal radius and tibia increased over a year following sleeve gastrectomy (total vBMD did not change). Reductions in narrow neck and intertrochanteric cross-sectional area and cortical thickness were observed over this duration, and hip strength estimates were deleteriously impacted. Marrow adipose tissue (MAT) of the lumbar spine increased while MAT of the peripheral skeleton decreased a year following sleeve gastrectomy. The amount of weight loss and reductions in lean and fat mass correlated with bone loss at all sites, and with changes in bone microarchitecture at peripheral sites. Conclusion MBS in adolescents is associated with aBMD reductions, and increases in MAT of the axial skeleton, while sleeve gastrectomy is associated with an increase in cortical vBMD and decrease in MAT of the peripheral skeleton. No reductions have been reported in peripheral strength estimates.

Beating the Limitation of Energy Gap Law Utilizing Deep Red MR-TADF Emitter with Narrow Energy-Bandwidth

<p><b>The development of high-performance deep red/near-infrared organic light-emitting diodes is hindered by strong non-radiative processes as governed by the energy gap law. </b><b>Herein, a novel BN-containing skeleton featuring linear N-π-N and B-π-B structure is developed, establishing partial </b><b>bonding/antibonding character on phenyl core for enhanced electronics coupling of para-positioned B atoms as well as N atoms to narrow energy gaps. Also, the remained MR effect on the peripheral skeleton to maintain the MR effect to minimize the bonding/ antibonding character and suppress vibrational coupling between S₀ and S₁, thereby </b><b>fundamentally</b><b> overcoming the luminescent boundary set by the energy gap law. The target</b><b> molecules </b><b>R-BN and R-TBN exhibited extremely high</b><b> PLQYs of 100% with </b><b>emission wavelengths at 666 and 686 nm,</b><b> respectively. The narrow FWMHs of 38 nm observed also testify the effectiveness of vibronic suppression. The corresponding OLEDs afford</b><b> </b><b>record-high</b><b> EQEs over 28% with emission wavelength over 664 nm</b><b>. </b><b></b></p>

Beating the Limitation of Energy Gap Law Utilizing Deep Red MR-TADF Emitter with Narrow Energy-Bandwidth

<p><b>The development of high-performance deep red/near-infrared organic light-emitting diodes is hindered by strong non-radiative processes as governed by the energy gap law. </b><b>Herein, a novel BN-containing skeleton featuring linear N-π-N and B-π-B structure is developed, establishing partial </b><b>bonding/antibonding character on phenyl core for enhanced electronics coupling of para-positioned B atoms as well as N atoms to narrow energy gaps. Also, the remained MR effect on the peripheral skeleton to maintain the MR effect to minimize the bonding/ antibonding character and suppress vibrational coupling between S₀ and S₁, thereby </b><b>fundamentally</b><b> overcoming the luminescent boundary set by the energy gap law. The target</b><b> molecules </b><b>R-BN and R-TBN exhibited extremely high</b><b> PLQYs of 100% with </b><b>emission wavelengths at 666 and 686 nm,</b><b> respectively. The narrow FWMHs of 38 nm observed also testify the effectiveness of vibronic suppression. The corresponding OLEDs afford</b><b> </b><b>record-high</b><b> EQEs over 28% with emission wavelength over 664 nm</b><b>. </b><b></b></p>

Proton MR spectroscopy in characterization of focal bone lesions of peripheral skeleton

Background The aim of our study was to determine the value of single-voxel proton MR spectroscopy (1HMRS) in distinguishing benign from malignant focal bone lesions in the peripheral skeleton. MRI and 1HMRS was performed in 50 focal lesions (> 1 cm size) detected on radiographs of peripheral skeleton.1HMRS was performed at 1.5 T with TE of 144 ms with automatic shimming and water suppression. Qualitative analysis for a discrete choline peak at 3.2 ppm was done. Significance of the presence of choline peak on 1HMRS in distinguishing benign from malignant lesions was calculated using histopathology as a gold standard. Chi-square test was used and p value < 0.05 was considered significant. Results Forty-one benign and 9 malignant lesions were confirmed by histopathological results. Amongst malignant lesions, choline peak was positive in all but 1 case of low-grade lymphoma. MR spectra of 11 benign lesions showed the presence of choline peak. All 7 benign giant cell tumors (GCT) were positive for choline peak. The sensitivity, specificity, PPV, NPV of proton MR spectroscopy in differentiating benign from malignant lesions were 87.5%,71%,38.8%, and 96.4% respectively. p value was significant (< 0.05). Conclusion 1HMRS in focal bone lesions can help in the differentiation of malignant from benign musculoskeletal tumors. Although some benign lesions may show false-positive result, absence of choline peak is a reliable reassurance against malignancy. GCT is an exception amongst benign bone tumors as it consistently shows the presence of choline peak on 1HMRS.

Study of local and generalized bone loss in patients with rheumatoid arthritis

Chronic inflammation in rheumatoid arthritis (RA) is accompanied by local (periarticular osteoporosis) and generalized loss of bone mineral density in the axial and peripheral skeleton. The paper discusses the relationship between local and generalized bone loss and the contribution of various factors to bone changes. Information about the contribution of age at the onset of RA to the progression of destructive changes in the hands and feet and the rate of generalized bone loss in the axial and peripheral skeleton are contradictory.