SpatialSim: Recognizing Spatial Configurations of Objects With Graph Neural Networks.

An embodied, autonomous agent able to set its own goals has to possess geometrical reasoning abilities for judging whether its goals have been achieved, namely it should be able to identify and discriminate classes of configurations of objects, irrespective of its point of view on the scene. However, this problem has received little attention so far in the deep learning literature. In this paper we make two key contributions. First, we propose SpatialSim (Spatial Similarity), a novel geometrical reasoning diagnostic dataset, and argue that progress on this benchmark would allow for diagnosing more principled approaches to this problem. This benchmark is composed of two tasks: "Identification" and "Discrimination," each one instantiated in increasing levels of difficulty. Secondly, we validate that relational inductive biases-exhibited by fully-connected message-passing Graph Neural Networks (MPGNNs)-are instrumental to solve those tasks, and show their advantages over less relational baselines such as Deep Sets and unstructured models such as Multi-Layer Perceptrons. We additionally showcase the failure of high-capacity CNNs on the hard Discrimination task. Finally, we highlight the current limits of GNNs in both tasks.

Does medicine run in the family-evidence from three generations of physicians in Sweden: retrospective observational study.

OBJECTIVE: To examine occupational heritability in medicine and changes in heritability over time, with Swedish population wide administrative data that allowed mapping family trees of physicians spanning up to three generations. DESIGN: Retrospective observational study. SETTING: Individual level administrative registry data from Sweden. PARTICIPANTS: Physicians born in 1950-90 and living in Sweden at some time during 2001-16 (n=47 400). MAIN OUTCOME MEASURES: The proportion of individuals with a completed medical degree with at least one parent who also trained in medicine, and the change in this proportion across birth cohorts. Additional analyses were conducted among other relatives (grandparents, aunts and uncles, and siblings) and for individuals with a law degree. RESULTS: For 27 788 physicians, where the educational background for both parents was known, 14% had a parent who was also a physician and 2% had two parents who were physicians. The proportion of physicians with at least one physician parent increased significantly over time, from 6% for physicians born in 1950-59 to 20% for physicians born in 1980-90 (P<0.001). The same pattern of increasing occupational heritability was not seen for individuals with law degrees. CONCLUSIONS: In recent cohorts of physicians in Sweden, one in five had a parent who was also a physician, more than triple the proportion seen for physicians born three decades earlier. A similar pattern was not seen in lawyers, suggesting that increasing occupational heritability in medicine does not reflect intergenerational persistence of high paying degrees alone. Rather, for physicians in Sweden, medicine might increasingly run in families.

Influence of the boron atom on the solvatochromic properties of 4-nitroaniline-functionalized boronate esters.

Para-nitroaniline derivatives with peripheral 1,2- and 1,3-diol functionalities [O(2)N-C(6)H(4)-NR(1)-CH(2)CH(OH)CH(2)OH; O(2)N-C(6)H(4)-NR(1)-CH(CH(2)OH)(2); R(1) = -H, -CH(3)] covalently bonded to the amino group are esterified with various para-substituted phenylboronic acids [R(2)-C(6)H(4)-B(OH)(2); R(2) = -OCH(3), -CH(3), -H, -Br, -CHO, -NO(2), -B(OH)(2)], and the solvatochromic properties of these esters are investigated in 33 solvents of different polarity. To interpret the solvent effects, the established linear solvation energy (LSE) multiparameter equations of Kamlet-Taft and the improved Catalán scales are used. Although the boron atom is separated by two or three sp(3)-hybridized carbon atoms from the actual chromophore, solvation effects have a significant positive solvatochromic effect on the nitroaniline unit (R(1) = -CH(3)) as result of the solvent acting as a donor at the boron atom. The influence of the substituent R(2) on the coefficient b of the LSE relationship according to Kamlet-Taft and Catalán, which reflects the quantitative influence of the hydrogen-bonding acceptor or the electron-pair donor capacity of the solvent on the position of the UV-vis absorption maximum, can be determined via a linear Hammett relationship [b = f(σ(p))]. The interpretation of the effects is based on the electronic influence of the solvated boronic acid ester unit on the 4-nitroaniline group, predominantly through inductive interactions.

Saponins can perturb biologic membranes and reduce the surface tension of aqueous solutions: a correlation?

Saponins are secondary plant compounds. They have a triterpenoid or steroidal backbone. Sugars are attached to one or more points of this structure, forming chains that can be branched. This appearance leads to amphiphilic properties giving saponins the ability to interact with both lipophilic and hydrophilic structures. The surfactant behavior lets them lower the surface tension in aqueous solutions and form micelles when reaching the critical micelle concentration (cmc). It also lets them interact with biologic membrane layers that usually consist of phospholipids and cholesterol. This action may perturb the membrane and its function leading to membrane perforation or complete lysis. Thus saponins are also known for their cytotoxicity and membranolytic, respectively hemolytic features. In our studies we wanted to answer the question if there is a correlation between the unspecific detergent behavior when lowering the surface tension and the ability to perforate cell membranes and to act cytotoxic. Do saponins showing a considerable reduction in the surface tension also reveal an evident cytotoxicity or/and a marked cell membrane perforation? We tested a variety of saponins with distinct structures. The reduction in the surface tension and the cmc were analyzed on a tensiometer using the Wilhelmy plate method. The general cytotoxicity was determined in a cell model by DNA quantification. The cell membrane toxicity or membrane perforation was explored in a cell model by quantification of the leakage of the intracellular enzyme lactate dehydrogenase (LDH). The experiments revealed a correlation between the membrane toxicity and the reduction in surface tension.

A hospital-based intermittent nocturnal hemodialysis program for children and adolescents.

OBJECTIVE: To establish a hospital-based nocturnal hemodialysis (NHD) program for children and adolescents. STUDY DESIGN: Sixteen patients (age, 0.5 to 17 years) were prospectively included. Uremia-associated measures as well as amount and dosage of medication were enumerated. Quality of life also was evaluated. Results were compared with data of the same patients on conventional hemodialysis and with matched control subjects (conventional HD). RESULTS: NHD was well tolerated. Median Kt/V values increased. Predialytic mean arterial pressure, urea, phosphate, and parathyroid hormone levels decreased. There was an increase in protein catabolic rate. Dietary and fluid restrictions could be lifted. Amount and dosage of phosphate and potassium binders and antihypertensive medication could be reduced. Quality of life improved and days of absence from school decreased in all patients. CONCLUSIONS: In addition to a better control of uremia-associated measures, NHD allows free dietary and fluid intake and improves patient well-being. Given the continuing shortage of donor organs for kidney transplantation and the high morbidity and mortality on conventional HD, intensified dialysis regimens are a much-needed therapeutic option.

Chromo- and fluorophoric water-soluble polymers and silica particles by nucleophilic substitution reaction of poly(vinyl amine).

Novel chromophoric and fluorescent carbonitrile-functionalized poly(vinyl amine) (PVAm) and PVAm/silica particles were synthesized by means of nucleophilic aromatic substitution of 8-oxo-8H-acenaphtho[1,2-b]pyrrol-9-carbonitrile (1) with PVAm in water. The water solubility of 1 has been mediated by 2,6-O-ß-dimethylcyclodextrin or by pre-adsorption onto silica particles. Furthermore, 1 was converted with isopropylamine into the model compound 1-M. All new compounds were characterized by NMR, FTIR, UV-vis and fluorescence spectroscopy. The solvent-dependent UV-vis absorption and fluorescence emission band positions of the model compound and the carbonitrile-functionalized PVAm were studied and interpreted using the empirical Kamlet-Taft solvent parameters π(*) (dipolarity/polarizability), α (hydrogen-bond donating capacity) and ß (hydrogen-accepting ability) in terms of the linear solvation energy relationship (LSER). The solvent-independent regression coefficients a, b and s were determined using multiple linear correlation analysis. It is shown, that the chains of the polymer have a significant influence on the solvatochromic behavior of 1-P. The structure of the carbonitrile 1-Si bound to polymer-modified silica particles was studied by means of X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) measurements. Fluorescent silica particles were obtained as shown by fluorescence spectroscopy with a diffuse reflectance technique.

Electrophilic substituent constant sigma(+) of electron donor substituents in nonpolar media.

The electrophilic substituent constant sigma(+) was derived from the relative rate constants of the solvolysis of substituted alpha-cumyl chlorides in an acetone/water solvent mixture in the original work by Brown and Okamoto (J. Am. Chem. Soc. 1958, 80, 4979). As an extension of this procedure, we were looking for methods to determine sigma(+) values in nonpolar media. We have calculated the exocyclic charges q(R) for alpha-cumyl cations (R-C(6)H(4)CMe(2)(+)) as a measure of the electron-donating capacity of meta and para substituents. The UV-vis absorption nu(max) of the analogously substituted nitrobenzene derivatives has been used for the experimental measurement of the electron donating capacity of substituents R in nonpolar media. A linear relationship between nu(max) and Deltaq(R) (= q(R-C(6)H(4)CMe(2)(+)) - q(C(6)H(5)CMe(2)(+))) was obtained. A description of the electron-donating capacity in nonpolar media can be achieved both for substituents investigated already and for those for which the experimental determination of sigma(+) has previously been difficult. Special interest was directed to boron-based substituents in which the electron-donating ability is dependent on the coordinational environment of the boron atom.

Chiral 1,2- and 1,3-diol-functionalized chromophores as Lego building blocks for coupled structures.

Chiral nitroanilines containing 1,2- or 1,3-diol functionalities have been synthesized by nucleophilic aromatic substitution of fluoronitroanilines with 1-aminopropane-2,3-diols and 2-aminopropane-1,3-diol in the melt. X-ray structure analyses confirm retention of the configuration of the chiral center. The novel chromophores are suitable to link reversibly to various substituted arylboronic acids which allows the construction of new solvatochromic sensor molecules suitable to response to solvent and anion coordination by fluoride. The solvatochromism of the new compounds has been studied using the Kamlet-Taft LSE relationship.