Employing neural density functionals to generate potential energy surfaces.

CONTEXT: With the union of machine learning (ML) and quantum chemistry, amid the debate between machine-learned functionals and human-designed functionals in density functional theory (DFT), this paper aims to demonstrate the generation of potential energy surfaces using computations with machine-learned density functional approximation (ML-DFA). A recent research trend is the application of ML in quantum sciences in the design of density functionals such as DeepMind's Deep Learning model (DeepMind21, DM21). Though science reported the state-of-the-art performance of DM21, the opportunity to utilize DeepMind's pretrained DM21 neural networks in computations in quantum chemistry has not yet been tapped. So far in the literature, the Deep Learning density functionals (DM21) have not been applied to generate potential energy surfaces. While the superior accuracy of DM21 has been reported, there is still a scarcity of publications that apply DM21 in calculations in the field. In this context, for the first time in literature, neural density functionals inferring 2D potential energy surfaces (ML-DFA-PES) based on machine-learned DFA-based computational method is contributed in this paper. This paper reports the ML-DFA-generated PES for C4H8, H2O, H2, and H2+ by employing a pretrained DM21m TensorFlow model with cc-pVDZ basis set. In addition, we also analyze the long-range behavior of DM21 based PES to investigate the ability to describe a system at long ranges. Furthermore, we compare PES diagrams from DM21 with popular DFT functionals (b3lyp/ PW6B95) and CCSD(T). METHODS: In this method, 2D potential energy surfaces are obtained using a method that relies upon the neural network's ability to accurately learn the mapping between 3D electron density and exchange-correlation potential. By inserting Deep Learning inference in DFT with a pretrained neural network, self-consistent field (SCF) energy at different geometries along the coordinates of interest is computed, and then, potential energy surfaces are plotted. In this method, first, the electron density is computed mathematically, and this computed 3D electron density is used as a ML feature vector to predict the exchange correlation potential as a ML inference computed by a forward pass of pre-trained DM21 TensorFlow computational graph, followed by the computation of self-consistent field energy at multiple geometries, and then, SCF energies at different bond lengths/angles are plotted as 2D PES. We implement this in a python source code using frameworks such as PySCF and DM21. This paper contributes this implementation in open source. The source code and DM21-DFA-based PES are contributed at https://sites.google.com/view/MLfunctionals-DeepMind-PES .

Effect of Isothermic Dialysis on Intradialytic Hypertension.

The primary outcome was incidence of intradialytic hypertension (IDH) during standard and cooler isothermic dialysate temperatures. Two pair of haemodialysis sessions were done at 37°C (SHD) and at isothermic temperature (IHD). All the four dialysis were done on the same time of the day to negate the changes due to circadian variation in body temperature. Axillary and tympanic temperatures were measured before start of the dialysis and dialysis temperature was adjusted as per axillary temperature. Sixty patients were enrolled and completed the study. The mean delivered dialysate temperature in the intervention group was 36.5 ± 0.2 achieving a 0.5 ± 0.2°C between-group separation. The incidence of IDH and intradialytic hypotension while on SHD and IHD were 79/120 (66%) vs 44/120 (37%), odds ratio (OR) 3.3, 95% confidence interval (CI) (1.96-5.65) and 45/120 (38%) vs 14/120 (12%), OR 4.5, 95% CI (2.3-8.7), respectively. The 4 h time averaged mean systolic blood pressure (SBP) at IHD and SHD were 154 ± 1.7 and 157.2 ± 1.1 mmHg, respectively, the mean difference in SBP being -3.4 mmHg to -3.1 mmHg, 95% CI, P < 0.001. The standard deviation, a measure of BP variability was lower at IHD than at SHD (P < 0.001). In a subgroup analysis during IHD there was a significant reduction of both SBP and diastolic BP during the entire duration of dialysis in 35 out of 60 patients (systolic 4 h mean 154.96 ± 2.22 vs 164.32 ± 1.99 mmHg), (diastolic 4 h mean 79.24 ± 0.82 vs 82.54 ± 0.68 mmHg) - (rANOVA for systolic and diastolic <0.001). This phenomenon of cooler dialysis causing reduction of BP was reproduced in the same group of patients when the IHD was repeated another time (systolic 4 h mean 157.95 ± 1.88 vs 160.65 ± 1.47), (diastolic 4 h mean 79.27 ± 0.74 vs 82.03 ± 1.07) rANOVA for systolic and diastolic <0.001. The incidence of IDH can be reduced significantly by reducing the dialysate temperature to patients' body temperature. Hypertension during dialysis is related to heat gain during dialysis.

Quantum Rényi relative entropies affirm universality of thermodynamics.

We formulate a complete theory of quantum thermodynamics in the Rényi entropic formalism exploiting the Rényi relative entropies, starting from the maximum entropy principle. In establishing the first and second laws of quantum thermodynamics, we have correctly identified accessible work and heat exchange in both equilibrium and nonequilibrium cases. The free energy (internal energy minus temperature times entropy) remains unaltered, when all the entities entering this relation are suitably defined. Exploiting Rényi relative entropies we have shown that this "form invariance" holds even beyond equilibrium and has profound operational significance in isothermal process. These results reduce to the Gibbs-von Neumann results when the Rényi entropic parameter α approaches 1. Moreover, it is shown that the universality of the Carnot statement of the second law is the consequence of the form invariance of the free energy, which is in turn the consequence of maximum entropy principle. Further, the Clausius inequality, which is the precursor to the Carnot statement, is also shown to hold based on the data processing inequalities for the traditional and sandwiched Rényi relative entropies. Thus, we find that the thermodynamics of nonequilibrium state and its deviation from equilibrium together determine the thermodynamic laws. This is another important manifestation of the concepts of information theory in thermodynamics when they are extended to the quantum realm. Our work is a substantial step towards formulating a complete theory of quantum thermodynamics and corresponding resource theory.

A putative low-molecular-mass penicillin-binding protein (PBP) of Mycobacterium smegmatis exhibits prominent physiological characteristics of DD-carboxypeptidase and beta-lactamase.

DD-carboxypeptidases (DD-CPases) are low-molecular-mass (LMM) penicillin-binding proteins (PBPs) that are mainly involved in peptidoglycan remodelling, but little is known about the dd-CPases of mycobacteria. In this study, a putative DD-CPase of Mycobacterium smegmatis, MSMEG_2433 is characterized. The gene for the membrane-bound form of MSMEG_2433 was cloned and expressed in Escherichia coli in its active form, as revealed by its ability to bind to the Bocillin-FL (fluorescent penicillin). Interestingly, in vivo expression of MSMEG_2433 could restore the cell shape oddities of the septuple PBP mutant of E. coli, which was a prominent physiological characteristic of DD-CPases. Moreover, expression of MSMEG_2433 in trans elevated beta-lactam resistance in PBP deletion mutants (ΔdacAdacC) of E. coli, strengthening its physiology as a dd-CPase. To confirm the biochemical reason behind such physiological behaviours, a soluble form of MSMEG_2433 (sMSMEG_2433) was created, expressed and purified. In agreement with the observed physiological phenomena, sMSMEG_2433 exhibited DD-CPase activity against artificial and peptidoglycan-mimetic DD-CPase substrates. To our surprise, enzymic analyses of MSMEG_2433 revealed efficient deacylation for beta-lactam substrates at physiological pH, which is a unique characteristic of beta-lactamases. In addition to the MSMEG_2433 active site that favours dd-CPase activity, in silico analyses also predicted the presence of an omega-loop-like region in MSMEG_2433, which is an important determinant of its beta-lactamase activity. Based on the in vitro, in vivo and in silico studies, we conclude that MSMEG_2433 is a dual enzyme, possessing both DD-CPase and beta-lactamase activities.

Success rates for functional MR imaging in children.

BACKGROUND AND PURPOSE: Functional MR imaging is widely used for research in functional brain development in healthy children. However, obtaining high-quality brain imaging data from pediatric research participants requires cooperation that is challenging for young children. In this study, we examined success rates for fMRI in typically developing children in both longitudinal and cross-sectional research study designs to inform the recruitment needs of future pediatric brain imaging studies. MATERIALS AND METHODS: In the cross-sectional study, 459 healthy children (5-18 years of age, 215 girls) were recruited. A subset of 30 healthy children 5-7 years of age from the cross-sectional cohort were selected and scanned for 10 consecutive years in the longitudinal arm of the study. Following anatomic scans, each participant attempted 4 functional MR imaging tasks. Success rate was defined as the proportion of fMRI tasks completed. Differences in success rates across sexes and in cross-sectional-versus-longitudinal cohorts were evaluated by using the Fischer exact test. RESULTS: In the cross-sectional study, 74% of the children completed all tasks. Success rates for individual tasks ranged from 34% to 67% for children 5-7 years of age and 76%-100% for those 8-18 years of age. In the longitudinal study, 89% of children completed all tasks in all 10 years. We established significance (P < .0001) between the cross-sectional and longitudinal cohorts for both 0% and 100% task completion rates. There was no significance between sexes. CONCLUSIONS: When designing pediatric fMRI studies in children, the sample sizes indicated by power analysis should be scaled up according to age (ie, 33% for ages 8-18 years, 50% for ages 5-7 years).

White matter microstructural abnormality in children with hydrocephalus detected by probabilistic diffusion tractography.

BACKGROUND AND PURPOSE: Hydrocephalus is a severe pathologic condition in which WM damage is a major factor associated with poor outcomes. The goal of the study was to investigate tract-based WM connectivity and DTI measurements in children with hydrocephalus by using the probabilistic diffusion tractography method. MATERIALS AND METHODS: Twelve children with hydrocephalus and 16 age-matched controls were included in the study. Probabilistic diffusion tractography was conducted to generate tract-based connectivity distribution and DTI measures for the genu of the corpus callosum and the connectivity index. Tract-based summary measurements, including the connectivity index and DTI measures (fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity), were calculated and compared between the 2 study groups. RESULTS: Tract-based summary measurement showed a higher percentage of voxels with lower normalized connectivity index values in the WM tracts in children with hydrocephalus. In the genu of the corpus callosum, the left midsegment of the corticospinal tract, and the right midsegment of the corticospinal tract, the normalized connectivity index value in children with hydrocephalus was found to be significantly lower (P < .05, corrected). The tract-based DTI measures showed that the children with hydrocephalus had significantly higher mean diffusivity, axial diffusivity, and radial diffusivity in the genu of the corpus callosum, left midsegment of the corticospinal tract, and right midsegment of corticospinal tract and lower fractional anisotropy in the genu of the corpus callosum (P < .05, corrected). CONCLUSIONS: The analysis of WM connectivity showed that the probabilistic diffusion tractography method is a sensitive tool to detect the decreased continuity in WM tracts that are under the direct influence of mechanical distortion and increased intracranial pressure in hydrocephalus. This voxel-based connectivity method can provide quantitative information complementary to the standard DTI summary measures.

DTI values in key white matter tracts from infancy through adolescence.

BACKGROUND AND PURPOSE: DTI is an advanced neuroimaging technique that allows in vivo quantification of water diffusion properties as surrogate markers of the integrity of WM microstructure. In our study, we investigated normative data from a large number of pediatric and adolescent participants to examine the developmental trends in DTI during this conspicuous WM maturation period. MATERIALS AND METHODS: DTI data in 202 healthy pediatric and adolescent participants were analyzed retrospectively. Fractional anisotropy and mean diffusivity values in the corpus callosum and internal capsule were fitted to an exponential regression model to delineate age-dependent maturational changes across the WM structures. RESULTS: The DTI metrics demonstrated characteristic exponential patterns of progression during development and conspicuous age-dependent changes in the first 36 months, with rostral WM tracts experiencing the highest slope of the exponential function. In contrast, the highest final FA and lowest MD values were detected in the splenium of the corpus callosum and the posterior limb of the internal capsule. CONCLUSIONS: Our analysis shows that the more caudal portions of the corpus callosum and internal capsule begin the maturation process earlier than the rostral regions, but the rostral regions develop at a more accelerated pace, which may suggest that rostral regions rely on development of more caudal brain regions to instigate their development. Our normative DTI can be used as a reference to study normal spatiotemporal developmental profiles in the WM and help identify abnormal WM structures in patient populations.

Diffusion tensor imaging properties and neurobehavioral outcomes in children with hydrocephalus.

BACKGROUND AND PURPOSE: White matter structural alterations and the correlation with neuropsychological deficits in children with hydrocephalus have not been well investigated. In this prospective study, the objectives were the following: 1) to apply DTI to detect in vivo white matter alterations based on diffusion properties in children with acute hydrocephalus, 2) to quantify early neuropsychological deficits, and 3) to explore the correlation between potential neuropsychological deficits and abnormalities in functionally related white matter. MATERIALS AND METHODS: A total of 44 children, 24 with hydrocephalus and 20 controls, were enrolled in the study. DTI indices, FA, MD, AD, and RD, were evaluated in the gCC, sCC, PLIC, and ALIC. The ABAS-II was used as a broad screener of development, including conceptual, social, practical, and motor skills. The correlation between the Motor Scale and DTI indices in the PLIC was analyzed. RESULTS: DTI analyses showed that the gCC and sCC in children with hydrocephalus had lower FA and higher MD, driven by the increased RD with statistical significance (P < .05) or trend-level significance (P = .06). The PLIC and ALIC had significantly higher AD in children with hydrocephalus (P < .05). On the ABAS-II, parent ratings of general adaptive skills, conceptual skills, and motor skills were significantly lower in children with hydrocephalus (all at P < .05). The MD and RD values in the PLIC were found to have trend-level or significant correlation with the Motor Scale (P = .057, .041, respectively). CONCLUSIONS: DTI reveals alterations in the white matter structure in children with hydrocephalus with preliminary findings suggesting correlation with clinical motor deficits.

Dynamical evolution of quantum oscillators toward equilibrium.

A pure quantum state of large number N of oscillators, interacting via harmonic coupling, evolves such that any small subsystem n<

Generalized information theoretic measure to discern the quantumness of correlations.

A novel measure, quantumness of correlations Q_AB is introduced here for bipartite states, by incorporating the required measurement scheme crucial in defining any such quantity. Quantumness coincides with the previously proposed measures in special cases and it vanishes for separable states--a feature not captured by the measures proposed earlier. It is found that an optimal generalized measurement on one of the parts leaves the overall state in its closest separable form, which shares the same marginal for the other part, implying that Q_AB is nonzero for all entangled bipartite states and it serves as an upper bound to the relative entropy of entanglement.

Positive-operator-valued-measure view of the ensemble approach to polarization optics.

The statistical ensemble formalism of Kim et al [J. Opt. Soc. Am. A4, 433 (1987)] offers a realistic model for characterizing the effect of stochastic nonimage-forming optical media on the state of polarization of transmitted light. With suitable choice of the Jones ensemble, various Mueller transformations-some of which are hitherto unknown-are deduced. It is observed that the ensemble approach is formally identical to the positive-operator-valued measures (POVMs) on the quantum density matrix. This observation, in combination with the recent suggestion by Ahnert and Payne [Phys. Rev. A71, 012330-1 (2005)]-in the context of generalized quantum measurement on single photon polarization states-that linear optics elements can be employed in setting up all possible POVMs enables us to propose a way of realizing different types of Mueller devices.

Characterizing multiparticle entanglement in symmetric N-qubit states via negativity of covariance matrices.

We show that higher order intergroup covariances involving even number of qubits are necessarily positive semidefinite for N-qubit separable states, which are completely symmetric under permutations of the qubits. This identification leads to a family of sufficient conditions of inseparability based on the negativity of 2kth order intergroup covariance matrices (2k

[False acute large bowel obstruction]. / Falesná akutní pseudoobstrukce tlustého streva.

Acute pseudobstruction of the large intestine is also termed the "Ogilvie" syndrome. The life- threatening condition without obvious mecha nical obstruction of the intestine, results from a major enlargement of the large intestine, which, if no therapy is initiated on time, may result in perforation of the right- sided colon, most commonly of the caecum. In this case study, the patient underwent urgent surgery for incipient caecal perforation. Nor the preoperative plain abdominal x- ray examination, abdominal CT, nor the laparotomy procedure detected any mechanical bowel obstruction. The condition was diagnosed as the Ogilvie syndrome in a chronic renal disorder of the patient. The procedure included transversostomy, drainage of the peritoneal cavity and complex management, and the patient was discharged to homecare on the ninth postoperative day. However, two weeks later, the patient was rehospitalized for bleeding from the stoma site. Colonoscopy detected a small stenosing tumor in the lienal flexure of the large intestine. The case study highlights failure of both the CT and x-ray abdominal examinations (air up to the sigmoid), as well as of the surgical exploration. Therefore, it may be concluded that not all pseudoobstructions are truely "pseudo".

Validity of the second law in nonextensive quantum thermodynamics.

The second law of thermodynamics in nonextensive statistical mechanics is discussed in the quantum regime. Making use of the convexity property of the generalized relative entropy associated with the Tsallis entropy indexed by q, Clausius' inequality is shown to hold in the range q in (0, 2]. This restriction on the range of the entropic index, q, is purely quantum mechanical and there exists no upper bound of q for validity of the second law in classical theory.

Acute myeloid leukemia presenting as splenic rupture.

We describe a rare case of acute myeloid leukemia presenting primarily as an acute abdomen due to spontaneous splenic rupture in a 19 years male patient. He was treated with splenectomy after failure of conservative management for splenic preservation but later succumbed to an intracerebral haemorrhage.

Hepatic abscess complicating paratyphoid infection.

Salmonellosis is ubiquitous and is a world-wide public health concern. Liver abscesses are occasionally reported in Salmonella typhi infections, they are a very rare complication of Salmonella paratyphi infections. A 28 year old male patient without any prior medical history presented with fever, abdominal pain and a tender hepatomegaly. The imaging studies revealed multiple liver abscesses and an ultrasound (US) guided aspiration of the abscess yielded heavy growth of Salmonella paratyphi A. He was treated successfully by percutaneous drainage of the abscesses and appropriate antibiotics.

Ingested needles in a 3-month-old infant.

This case describes a 3-month-old infant who swallowed multiple straight sewing needles that were removed at laparotomy. A motherhood psychiatric disorder was suspected.