Too Lonely to Help: Early Adolescents' Social Connections and Willingness to Help During COVID-19 Lockdown.

We examined early adolescents' social connections, their emotional state, and their willingness to act prosocially during COVID-19 pandemic lockdown. In two studies-comparing fourth to sixth graders during lockdown with a similar sample in pre-pandemic times, and longitudinally examining the same sample of participants, twice-we found that overall, early adolescents' emotional state during lockdown was significantly worse than in normal times (before the pandemic). This decline was explained by the participants' ratings of their loneliness, which was linked to their social (virtual) connections during lockdown. Importantly, participants with fewer social connections (in the virtual world as well as in face-to-face interactions) were less willing to help a lonely peer-even though they experienced similar pangs of loneliness.

COBRA-LIKE2, a member of the glycosylphosphatidylinositol-anchored COBRA-LIKE family, plays a role in cellulose deposition in arabidopsis seed coat mucilage secretory cells.

Differentiation of the maternally derived seed coat epidermal cells into mucilage secretory cells is a common adaptation in angiosperms. Recent studies identified cellulose as an important component of seed mucilage in various species. Cellulose is deposited as a set of rays that radiate from the seed upon mucilage extrusion, serving to anchor the pectic component of seed mucilage to the seed surface. Using transcriptome data encompassing the course of seed development, we identified COBRA-LIKE2 (COBL2), a member of the glycosylphosphatidylinositol-anchored COBRA-LIKE gene family in Arabidopsis (Arabidopsis thaliana), as coexpressed with other genes involved in cellulose deposition in mucilage secretory cells. Disruption of the COBL2 gene results in substantial reduction in the rays of cellulose present in seed mucilage, along with an increased solubility of the pectic component of the mucilage. Light birefringence demonstrates a substantial decrease in crystalline cellulose deposition into the cellulosic rays of the cobl2 mutants. Moreover, crystalline cellulose deposition into the radial cell walls and the columella appears substantially compromised, as demonstrated by scanning electron microscopy and in situ quantification of light birefringence. Overall, the cobl2 mutants display about 40% reduction in whole-seed crystalline cellulose content compared with the wild type. These data establish that COBL2 plays a role in the deposition of crystalline cellulose into various secondary cell wall structures during seed coat epidermal cell differentiation.

Insights into the microstructures of hygroscopic movement in plant seed dispersal.

As non-motile organisms, plants develop means to spread their progenies. Hygroscopic movement is a very common mechanism employed in seed dispersal. This type of movement is created when the tissue desiccates and the cell walls dry and shrink. A contraction force develops, the direction and strength of which depends on the architecture of the tissue. This force may be utilized for a simple release of seeds, their catapultion, and for pushing seeds along the soil to a germination locus. We review the formation of a bend, a twist and a coil within various dispersal apparatuses as a reaction to the dehydration of the tissue. We compare the microscopic structures of hygroscopic devices supporting slow or fast movement, adaptations to dry or wet climates, and single use versus repeated movement. We discuss the development of the disconnecting tissues in relation to the development of a hygroscopic mechanism. As plant cultivation is dependent on seed dispersal control, we demonstrate that during the domestication of sesame and wheat, seed dispersal is avoided not due to a defective hygroscopic tissue, but rather a missing dehiscence tissue. Seed dispersal is a crucial stage in the life cycle of plants. Thus, hygroscopic movement plays a central part in plant ecology and agriculture.

Hygroscopic movements in Geraniaceae: the structural variations that are responsible for coiling or bending.

The family Geraniaceae is characterized by a beak-like fruit, consisting of five seeds appended by a tapering awn. The awns exhibit coiling or bending hygroscopic movement as part of the seed dispersal strategy. Here we explain the variation in the hygroscopic reaction based on structural principles. We examined five representative species from three genera: Erodium, Geranium, and Pelargonium. Using X-ray diffraction, and electron and polarized light microscopy, we measured the cellulose microfibril angles in relation to the cell and cellulose helix axes. The behavior of separated single cells during dehydration was also examined. A bi-layered structure characterizes all the representative genera studied, with a hygroscopically contracting inner layer, and a stiff outer layer. We found that the cellulose arrangement in the inner layer is responsible for the type of awn deformation (coiling or bending). In three of the five awns examined, we identified an additional coiling outer sublayer, which adds coiling deformation to the awn. We divide the movements into three types: bending, coiling, and coiled-bending. All movement types are found in the Geranium genus. These characteristics are of importance for understanding the evolution of seed dispersal mechanisms in the Geraniaceae family.

Precision of estimating equations for GFR in children with a solitary functioning kidney: the KIMONO study.

BACKGROUND AND OBJECTIVE: Children with a solitary functioning kidney may develop CKD. Although widely used, equations to estimate GFR are not validated in these patients. This study sought to determine the precision of common estimating equations in the KIMONO (KIdney of MONofunctional Origin) cohort. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Two creatinine-based (estimated GFR [eGFR]-Schwartz, urinary creatinine clearance), two cystatin C-based (eGFR-Zappitelli1, eGFR-CKiD [Chronic Kidney Disease in Children] 1), and two cystatin C/creatinine-based (eGFR-Zappitelli2, eGFR-CKiD2) estimates were compared with the gold standard GFR measured by inulin single injection (GFR-inulin) in 77 children with a solitary functioning kidney (time span of assembly, 2005-2012). Included patients were 1.5-19.8 years of age. Kidney Disease Outcomes Quality Initiative (K/DOQI) classification was compared between GFR-inulin and eGFR methods to analyze misclassification by estimating equations. RESULTS: The eGFR-CKiD2 equation performed best in children with a solitary functioning kidney (mean bias, -0.9 ml/min per 1.73 m(2); 95% and 54% of values within ±30% and ±10% of GFR-inulin, respectively). Mean bias for eGFR-Schwartz was 0.4 ml/min per 1.73 m(2), with 90% and 33% of values within ±30% and ±10% of GFR-inulin, respectively. For all estimates, misclassification in K/DOQI stage ranged from 22% (eGFR-Zappitelli1) to 44% (urinary creatinine clearance) of children. CONCLUSIONS: Use of a combined serum cystatin C/creatinine-based equation (eGFR-CKiD2) is recommended to monitor renal function in children with a solitary functioning kidney. When cystatin C is not routinely available, eGFR-Schwartz should be used. Misclassification in K/DOQI-stage remains a caveat for all equations.

Quantification of microfibril angle in secondary cell walls at subcellular resolution by means of polarized light microscopy.

The cell walls constitute the mechanical support of plants. Crystalline cellulose building the walls forms rigid microfibrils that set the stiffness of the cell and the direction in which it expands during growth. Therefore, the determination of the directions of the microfibrils is important in both mechanical and developmental assays. We adapted polarized light microscopy to estimate the cellulose microfibril orientations at subcellular resolution. The optical information supplements X-ray scattering data, Raman microspectroscopy, and electron microscopy. We analyzed samples from three plant tissues: cells from an Araucaria excels branch, in which we revealed lower cellulose density in regions where the cell wall curvature becomes bigger, namely, the cell wall corners; a wheat (Triticum turgidum) awn's hygroscopically active region, which revealed a gradient in the cellulose microfibril angles that spans across four cell rows; and a stork's bill's (Erodium gruinum) coiling awn, which revealed that the cellulose in the cell wall is organized in two orientations seamed together, rather than in a continuous helix. The unique spatial information is easily obtained from microscopic specimens and further illuminates new aspects in the mechanical tissues.

Emergence of spontaneous twist and curvature in non-euclidean rods: application to Erodium plant cells.

We present a limiting model for thin non-euclidean elastic rods. Originating from the three-dimensional (3D) reference metric of the rod, which is determined by its internal material structure, we derive a 1D reduced rod theory. Specifically, we show how the spontaneous twist and curvature of a rod emerge from the reference metric derivatives. Thus, the model allows calculating the unconstrained equilibrium configuration of a thin rod directly from its internal structure. The model is applied to the study of cells from members of the Geraniaceae plant family and their configurational response to dehydration. We show how the geometrical arrangement of cellulose fibrils on the cell walls determines the helical shapes of isolated cells.

Tilted cellulose arrangement as a novel mechanism for hygroscopic coiling in the stork's bill awn.

The sessile nature of plants demands the development of seed-dispersal mechanisms to establish new growing loci. Dispersal strategies of many species involve drying of the dispersal unit, which induces directed contraction and movement based on changing environmental humidity. The majority of researched hygroscopic dispersal mechanisms are based on a bilayered structure. Here, we investigate the motility of the stork's bill (Erodium) seeds that relies on the tightening and loosening of a helical awn to propel itself across the surface into a safe germination place. We show that this movement is based on a specialized single layer consisting of a mechanically uniform tissue. A cell wall structure with cellulose microfibrils arranged in an unusually tilted helix causes each cell to spiral. These cells generate a macroscopic coil by spiralling collectively. A simple model made from a thread embedded in an isotropic foam matrix shows that this cellulose arrangement is indeed sufficient to induce the spiralling of the cells.

Cyclo[2]benzimidazole: luminescence turn-on sensing of anions.

Cyclo[2]benzimidazole is a new host for anions that turns on its luminescence up to 150 fold upon binding. Photoexcited cyclo[2]benzimidazole undergoes an efficient non-radiative deactivation through an excited-state intramolecular proton-transfer (ESIPT) mechanism. Upon binding an anion, the ESIPT pathway is blocked, resulting in an increase in the luminescence efficiency.

Anion-binding properties of the tripyrrolemethane group: a combined experimental and theoretical study.

Tripyrrolemethane- and bistripyrrolemethane-containing systems were recently reported to be efficient and selective hosts for anions. Nevertheless, the basic intrinsic properties of tripyrrolemethane as a ligand for anions have not yet been explored. Here we report the study of the anion-binding properties of the tripyrrolemethane group. We applied a combined experimental and theoretical approach to determine the affinity of the tripyrrolemethane system for different anions in the gas phase, in solution and in the crystalline state. In the crystal, the tripyrrolemethane group forms a number of different complexes with the bromide ion, some involving the participation of more than one ligand species. Despite the very similar basicity of fluoride and dihydrogen phosphate, the tripyrrolemethane ligand exhibits a clear preference for the fluoride anion in solution, which indicates an anion-binding system and not merely deprotonation. Although the affinity of the tripyrrolemethane ligand for other ions was negligible in solution, gas-phase studies show that complexation with larger halide ions is favoured over complexation with fluoride.

Sensitive and selective PET-based diimidazole luminophore for Zn(II) ions: a structure-activity correlation.

3-(3-Ethoxymethyl-1H-imidazol-2-yl)-3-(1-ethoxymethyl-1H-imidazol-2-yl)-3H-benzo[de]isochromen-1-one, 4, is a novel photoinduced electron transfer (PET) chemosensor that becomes fluorescent upon binding metal ions and shows a strong preference toward Zn(II) ions. The new bisimidazol PET sensor and its zinc complex were prepared and characterized in terms of their crystal structures, absorption and emission spectra, and orbital energy diagrams. Free 4 is a weakly luminescent species. On the basis of detailed DFT calculations, we suggest that the poor luminescence yield of free 4 originates from its orbital structure in which two pi-orbitals of the two imidazole rings, HOMO and HOMO-1, are situated between two pi-orbitals of the isochromene-one system, HOMO-2 and LUMO. The absorption and emission processes occur between the two pi-orbitals of the isochromene-one system, HOMO-2 and LUMO, and the two pi-imidazole orbitals serve as quenchers for the excited state of the molecule through nonradiative processes. Upon binding Zn(II) ions, 4 becomes a highly luminescent species having a luminescence maximum peaking at 375 nm (lambda(ex) = 329 nm). The significant 900-fold enhancement in luminescence upon binding of the Zn(II) ions is attributed to the stabilization of the pi-orbitals of the imidazole rings upon their engagement in new bonds with the zinc ion. The affinity of 4 to zinc ions in acetonitrile is found to be very high, Ka > 3 x 10(6) M(-1), while with other metals ions, the association constants are considerably weaker.

Sensitive and selective photoinduced-electron-transfer-based sensing of alkylating agents.

Photoinduced-electron-transfer (PET)-based chemosensing is a very elegant way of reporting the presence of a guest species in solution. This method was successfully applied for the detection of different ionic species, such as cations, anions, and protons. Herein, we report on the application of the PET chemosensing concept for the efficient and selective detection of different alkylating agents. 2-(2-Dimethylaminoethyl)benzo[de]isoquinoline-1,3-dione (1) was found to be a highly selective and effective PET chemosensor that turns luminescent upon reacting with different alkylating agents. This PET-based system detected even rather weak alkylating agents, such as dichloromethane. A PET-based sensor that consists of 1 as the active component could detect rather low concentrations of alkylating agents in solution and in the gas phase.