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Heteroatom doping is a powerful strategy to alter the electronic structure of polycyclic aromatic hydrocarbons (PAHs). Especially boron doping endows PAH scaffolds with electron-accepting character and Lewis acidic centers. Herein, we report that embedding a five-membered borole ring into a polycyclic skeleton imparts the π-system with antiaromatic character and thereby induces unique properties and behavior. A series of borole-embedded π-conjugated compounds were synthesized from teraryl precursors via a borylation/intramolecular electrophilic C–H borylation sequence. The obtained compounds exhibit planar structures with distorted geometries around the boron center and form columnar slipped face-to-face π-stacked structures. Among these compounds, a pyrene-fused derivative shows an intense emission with a high quantum yield in solution. This compound also exhibits high Lewis acidity, which reflects the antiaromatic character and strained structure of the borole substructure. This compound forms a Lewis acid–base adduct even with weakly Lewis basic phosphorus-containing polycyclic π-systems. Analyzing the crystal structure of the thus-obtained adduct revealed a complex between the boron- and phosphorus-embedded π-systems with a direct B–P dative bond. This complex undergoes photodissociation in the excited state and exhibits an emission exclusively from the base-free borole-embedded π-system.

We report the kinetically controlled supramolecular polymerization of boron-containing π-conjugated molecules, which was enabled by a seeding method based on dual trapping of a metastable state by synergistic intramolecular hydrogen bonding and Lewis acid-based complexation. Planarized triarylborane-based 1, which bears a diamide chain with chiral alkyl groups, was synthesized. Upon cooling, the solution of monomer 1afforded a supramolecular polymerization in a cooperative manner to form helical supramolecular nanostructures with intense J-type aggregate emission. In the presence of pyridine, the triarylborane moiety formed a Lewis acid–base complex, which enhances the stabilization of the metastable monomeric state. An assembly incompetent structure with a folded diamide chain conformation and a pyridine moiety axially coordinated to the boron atom is responsible for slowing the spontaneous aggregation. The seeding method was successfully applied to the solution to produce homogeneous nanofibers even at a high (millimolar-level) concentration. This unprecedented kinetic control via dual trapping provides an effective method to achieve seed-initiated polymerization under concentrated conditions.

BackgroundVariants in the type IV collagen gene (COL4A1/2) cause early-onset cerebrovascular diseases. Most individuals are diagnosed postnatally, and the prenatal features of individuals with COL4A1/2variants remain unclear.MethodsWe examined COL4A1/2in 218 individuals with suspected COL4A1/2-related brain defects. Among those arising from COL4A1/2variants, we focused on individuals showing prenatal abnormal ultrasound findings and validated their prenatal and postnatal clinical features in detail.ResultsPathogenic COL4A1/2variants were detected in 56 individuals (n=56/218, 25.7%) showing porencephaly (n=29), schizencephaly (n=12) and others (n=15). Thirty-four variants occurred de novo (n=34/56, 60.7%). Foetal information was available in 47 of 56 individuals, 32 of whom (n=32/47, 68.1%) had one or more foetal abnormalities. The median gestational age at the detection of initial prenatal abnormal features was 31 weeks of gestation. Only 14 individuals had specific prenatal findings that were strongly suggestive of features associated with COL4A1/2variants. Foetal ventriculomegaly was the most common initial feature (n=20/32, 62.5%). Posterior fossa abnormalities, including Dandy-Walker malformation, were observed prenatally in four individuals. Regarding extrabrain features, foetal growth restriction was present in 16 individuals, including eight individuals with comorbid ventriculomegaly.ConclusionsPrenatal observation of ventriculomegaly with comorbid foetal growth restriction should prompt a thorough ultrasound examination and COL4A1/2gene testing should be considered when pathogenic variants are strongly suspected.

Dimesitylboron-functionalized stilbene derivatives have been found to undergo an unusual regioselective photoisomerization upon irradiation at 365 nm. Using NMR to follow the photoreaction, the structures of key reaction intermediates and the final products were established. This photoisomerization occurs in four steps: trans–cisisomerization, Diels–Alder reaction, di-π-methane rearrangement, and ring opening with [1,3]-H migration. This results in the formation of a rare structure with three fused five-membered rings and a six-membered one.

Microcephaly-capillary malformation syndrome is a congenital and neurodevelopmental disorder caused by biallelic mutations in the STAMBPgene. Here we identify the novel homozygous mutation located in the SH3 binding motif of STAMBP(NM_006463.4) (c.707C>T: p.Ser236Phe) through whole-exome sequencing. The case patient was a 2-year-old boy showing severe global developmental delay, progressive microcephaly, refractory seizures, dysmorphic facial features, and multiple capillary malformations. Immunoblot analysis of patient-derived lymphoblastoid cell lines (LCLs) revealed a severe reduction in STAMBP expression, indicating that Ser236Phe induces protein instability. STAMBP interacts with the SH3 domain of STAM and transduces downstream signals from the Jaks-STAM complex. The substitution of Ser236Phe found in the case patient was located in the SH3-binding motif, and we propose the mutation may block STAM binding and subsequently induce STAMBP degradation. Contrary to previously reported STAMBPmutations, the Ser236Phe mutation did not lead to constitutive activation of the PI3K-AKT-mTOR pathway in patient-derived LCLs, as indicated by the expression of phosphorylated S6 ribosomal protein, suggesting that it is not the major pathomechanism underlying the disorder in this patient.

When a firm undertakes foreign direct investment, it must determine the level of ownership in its foreign subsidiary. This study examines the determinants of the ownership strategy of a Japanese logistics firm from the perspective of international business studies (IB). The study focuses on firm-level factors, including “contributed assets” for shaping firm-specific advantage which a parent firm possesses, “complementary assets” which such firm may need to acquire in a foreign country, and international experience. It also analyzes country-level factors including the institutional difference between a home country and a host country. The study conducts a Tobit regression analysis on the relationship between such factors and the equity ownership level in a foreign subsidiary based on the data-sets of Japanese logistics firms.

We performed whole-exome sequencing analysis of patients with genetically unsolved hypomyelinating leukoencephalopathies, identifying 8 patients with TUBB4Amutations and allowing the phenotypic spectrum of TUBB4Amutations to be investigated.

This study explores how managerial ties between foreign firms and local firms and those between foreign firms and local government officials affect the performance of firms operating in transition economies. Using survey data collected from Japanese firms operating in China, this study finds that managerial ties between foreign firms and both local firms and local government officials are positively associated with the performance of Japanese firms in China. The study also examines how attributes specific to foreign firms operating in transition economies moderate the positive effect of managerial ties on the performance of foreign firms. Three significant moderators: host country experience, strategic orientation, and local market knowledge of foreign firms, are highlighted in the analysis.

This paper investigates vehicle routing and scheduling which includes dynamic and stochastic elements of travel time on links. In order to consider the characteristics of travel time, three shortest path models were used. In the first model, the path is based on average travel time determined using Dijkstra's method (1959). The second model is the adaptive least-expected time path model developed by Miller-Hooks (2001)and the third one is the expected shortest path presented by Fu and Rilett (1998). Vehicle routes and schedules were calculated based on link costs by the three shortest path models. Deliveries using the vehicle routes and schedules were simulated and total costs of deliveries were compared. On a test road network, the dynamic and stochastic shortest paths showed good performance in delivery simulations. However, in the road network of the central area of Osaka, average costs in delivery simulations are at the same level for all the shortest path models considered. Therefore, it can be said that the performance of vehicle routing and scheduling in delivery simulations is influenced by characteristics of travel time information, and it is observed that low-cost and stable vehicle routing and scheduling are obtained using dynamic and stochastic shortest path models.

Excited-state conformation capture methodology was proposed for the construction of different types of triplet-involved emission materials (TADF, RTP, heavy-atom-free RTP and ultra RTP).

Vitamin B12 deficiency in infants often presents with nonspecific hematological, gastrointestinal, and neurological manifestations. It is usually caused by inadequate intake, abnormal absorption, or congenital disorders of vitamin B12 metabolism, including transport disorders. We describe a vitamin B12-deficient infant with severe anemia who was breastfed. His mother had undiagnosed vitamin B12 deficiency having undergone total gastrectomy 18 years earlier. The infant developed normally after taking vitamin B12. It is important to suspect vitamin B12 deficiency in mothers who have undergone gastrectomy. Early diagnosis and treatment of vitamin B12 deficiency in infants is important and will help improve long-term prognosis.

Thirtyseven ageladine A analogues are synthesized by employing a previously explored total synthetic route to natural ageladine A.

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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.