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Human pluripotent stem cells (hPSCs) are a powerful tool for modelling human development. In recent years, hPSCs have become central in cell-based therapies for neurodegenerative diseases given their potential to replace affected neurons. However, directing hPSCs into specific neuronal types is complex and requires an accurate protocol that mimics endogenous neuronal development. Here we describe step-by-step a fast feeder-free neuronal differentiation protocol to direct hPSCs to mature forebrain neurons in 37 days in vitro (DIV). The protocol is based upon a combination of specific morphogens, trophic and growth factors, ions, neurotransmitters and extracellular matrix elements. A human-induced PSC line (Ctr-Q33) and a human embryonic stem cell line (GEN-Q18) were used to reinforce the potential of the protocol. Neuronal activity was analysed by single-cell calcium imaging. At 8 DIV, we obtained a homogeneous population of hPSC-derived neuroectodermal progenitors which self-arranged in bi-dimensional neural tube-like structures. At 16 DIV, we generated hPSC-derived neural progenitor cells (NPCs) with mostly a subpallial identity along with a subpopulation of pallial NPCs. Terminal in vitro neuronal differentiation was confirmed by the expression of microtubule associated protein 2b (Map 2b) by almost 100% of hPSC-derived neurons and the expression of specific-striatal neuronal markers including GABA, CTIP2 and DARPP-32. HPSC-derived neurons showed mature and functional phenotypes as they expressed synaptic markers, voltage-gated ion channels and neurotransmitter receptors. Neurons displayed diverse spontaneous activity patterns that were classified into three major groups, namely “high”, “intermediate” and “low” firing neurons. Finally, transplantation experiments showed that the NPCs survived and differentiated within mouse striatum for at least 3 months. NPCs integrated host environmental cues and differentiated into striatal medium-sized spiny neurons (MSNs), which successfully integrated into the endogenous circuitry without teratoma formation. Altogether, these findings demonstrate the potential of this robust human neuronal differentiation protocol, which will bring new opportunities for the study of human neurodevelopment and neurodegeneration, and will open new avenues in cell-based therapies, pharmacological studies and alternative in vitro toxicology. Electronic supplementary material The online version of this article (10.1007/s12035-020-01907-4) contains supplementary material, which is available to authorized users.

Background Network alterations underlying neurodegenerative diseases often precede symptoms and functional deficits. Thus, their early identification is central for improved prognosis. In Huntington’s disease (HD), the cortico-striatal networks, involved in motor function processing, are the most compromised neural substrate. However, whether the network alterations are intrinsic of the striatum or the cortex is not fully understood. Results In order to identify early HD neural deficits, we characterized neuronal ensemble calcium activity and network topology of HD striatal and cortical cultures. We used large-scale calcium imaging combined with activity-based network inference analysis. We extracted collective activity events and inferred the topology of the neuronal network in cortical and striatal primary cultures from wild-type and R6/1 mouse model of HD. Striatal, but not cortical, HD networks displayed lower activity and a lessened ability to integrate information. GABAA receptor blockade in healthy and HD striatal cultures generated similar coordinated ensemble activity and network topology, highlighting that the excitatory component of striatal system is spared in HD. Conversely, NMDA receptor activation increased individual neuronal activity while coordinated activity became highly variable and undefined. Interestingly, by boosting NMDA activity, we rectified striatal HD network alterations. Conclusions Overall, our integrative approach highlights striatal defective network integration capacity as a major contributor of basal ganglia dysfunction in HD and suggests that increased excitatory drive may serve as a potential intervention. In addition, our work provides a valuable tool to evaluate in vitro network recovery after treatment intervention in basal ganglia disorders.

To predict patients who would benefit from adaptive radiotherapy (ART) and re-planning intervention based on machine learning from anatomical and dosimetric variations in a retrospective dataset.90 patients (pts) treated for head-neck cancer (HN) formed a multicenter data-set. 41 HN pts (45.6%) were considered for learning; 49 pts (54.4%) were used to test the tool. A homemade machine-learning classifier was developed to analyze volume and dose variations of parotid glands (PG). Using deformable image registration (DIR) and GPU, patients' conditions were analyzed automatically. Support Vector Machines (SVM) was used for time-series evaluation. "Inadequate" class identified patients that might benefit from replanning. Double-blind evaluation by two radiation oncologists (ROs) was carried out to validate day/week selected for re-planning by the classifier.The cohort was affected by PG mean reduction of 23.7±8.8%. During the first 3weeks, 86.7% cases show PG deformation aligned with predefined tolerance, thus not requiring re-planning. From 4th week, an increased number of pts would potentially benefit from re-planning: a mean of 58% of cases, with an inter-center variability of 8.3%, showed "inadequate" conditions. 11% of cases showed "bias" due to DIR and script failure; 6% showed "warning" output due to potential positioning issues. Comparing re-planning suggested by tool with recommended by ROs, the 4th week seems the most favorable time in 70% cases.SVM and decision-making tool was applied to overcome ART challenges. Pts would benefit from ART and ideal time for re-planning intervention was identified in this retrospective analysis.

Neuronal networks can spontaneously exhibit periodic bursts of collective activity. High-resolution calcium imaging and computer modelling of in vitro cultures now reveal that this behaviour is a consequence of noise focusing—an implosive concentration of spontaneous activity due to the interplay between network topology and intrinsic neuronal dynamics.

Purpose To investigate the accuracy and robustness of commercial algorithms for Deformable Image Registration (DIR) to propagate regions of interest (ROIs), against image quality typical of Cone Beam CT (CBCT) and Megavoltage Cone-beam CT (MVCT) images, using computational phantoms based on real head and neck (HN) patient images. Methods Eleven institutions joined the study with five commercial DIR solutions. Three real patient data-sets from different on board imaging devices (OBI by Varian, XVI by Elekta, and MVCT by Tomotherapy) were used with different image quality. Two specific Deformation Vector Fields (DVF) with realistic level of deformations, were generated with a dedicated software and then applied to each data-set. The accuracy of the algorithms was assessed by comparing the DIR-mapped ROIs from each center with those of reference, using the Dice Similarity Coefficient (DSC) and Mean Distance to Conformity (MDC) metrics. Prognostic factors of DIR performances were carried out. Results Based on more than 700 DIR-mapped ROIs the 4-way ANOVA analysis states that DIR algorithm, image quality and organ type are significant predictors of DIR performances. A slightly dependence from applied DVF is detected (p = 0.035) with a post hoc test. Putting together all CI data of all institutions for the first DVF, the mean CI was 0.88 ± 0.05 (1 SD), and the mean MDC is 0.38 ± 0.96 (1 SD); for the second DVF, the mean CI was 0.86 ± 0.11 (1 SD), and the mean MDC is 0.43 ± 1.08 (1 SD). The thyroid, located near the FOV border, was the underperformer organ with large errors (unacceptable). All other organs were mapped with an acceptable accuracy (at voxel size level). One imaging system performs statistically better than the others, and one algorithm produced unsatisfactory results respect all the others. Conclusions This work studies the impact of CBCT and MVCT image quality on DIR performance in a ground truth provided scenario. Clinical issues like Adaptive Radiation Therapy (ART) need accurate and robust DIR software. The reported result highlight that in HN district the image quality and the implemented algorithm are strictly related to DIR performances.

In a multicenter evaluation the precision and stability of single slice peripheral Quantitative Computed Tomography (pQCT) systems were assessed. Compared to central Europe the peripheral QCT device is also widely used in the Italian health care system. Phantoms were measured frequently on each machine in four pQCT scanners over a two-year period using an identical automated software program. Intrasite and intersite phantom mineral densities, expressed in units of mg/cm^3, were analyzed and examined. The short and long term precision were estimated from the consistency of these measurements using the root mean square error and expressed as coefficient of variation in percent (% CV). Short term precision was good (mean intrasite coefficient of variation (CV) 0.21\pm 0.056 standard deviation (SD)). Intersite measurements of a single phantom revealed differences between machines of the same type of not more than 2.9 mg/cm^3. At four sites frequent phantom measurements revealed a mean CV of 0.18% (range 0.12-0.28). No significant changes in the regression slopes (drift of the machine versus time) were observed. We conclude that the in vitro precision and stability of the single slice pQCT systems are sufficiently high and unlikely to negatively affect the in vivo precision.

Introduction The European Federation of Organisations in Medical Physics (EFOMP) has recently released a protocol for quality control (QC) in digital mammography with the intent of harmonizing and simplifying the QC procedures across the European countries. Purpose The aim of this work was to report our experience regarding the implementation of the EFOMP protocol for QC in digital mammography in a multi-hospital/vendor context. Materials and methods QC tests suggested by the EFOMP protocol were merged with mandatory tests by national (Italian) regulations in order to build a local QC protocol. The protocol was applied to one DR and three CR mammography systems developed by different vendors. Time needed for routine QCs was measured. A fast weekly test was implemented to assess the long term reproducibility of relevant quantities (dose and SNR). Results By employing one physicist and one technologist, the time needed for routine QC was: 4.5 h ± 0.5 h (annual tests), 2.5 h ± 0.5 h (semiannual tests), 0.2 h ± 0.1 h (weekly tests). For weekly tests, coefficients of variation of dose and SNR were below 6.0% (four-months period evaluated). By applying the developed protocol, two major and five minor anomalies were identified and corrected. Conclusions The EFOMP protocol could be adapted to local (Italian) regulations with minor modifications. Flexibility and simplification of routine QCs were advantageous in a busy multi-hospital/vendor context. Disclosure None.

It is known that RNS VLSI processors can parallelize fixed-point addition and multiplication operations by the use of the Chinese remainder theorem (CRT). The required modular operations, however, must use specialized hardware whose design and implementation can create several problems. In this paper a modified residue arithmetic, called pseudo-RNS is introduced in order to alleviate some of the RNS problems when digital signal processing (DSP) structures are implemented. Pseudo-RNS requires only the use of modified binary processors and exhibits a speed performance comparable with other RNS traditional approaches. Some applications of the pseudo-RNS to common DSP architectures, such as multipliers and filters, are also presented in this paper. They are compared in terms of the area-time square product versus other RNS and weighted binary structures. It is proven that existing combinatorial or look-up table approaches for RNS are tailored to small designs or special applications, while the pseudo-RNS approach remains competitive also for complex systems. >

In highly integrated processors, a concurrent fault tolerance capability is particularly important, especially for real-time applications. In fact, in these systems, transient errors are often present, but are difficult to correct online. Error recovery procedures applied for each processing or memory element require large amount of hardware and can reduce throughput. Residue arithmetic has intrinsic fault tolerance capability and requires less complex hardware. A single error correction procedure based on the use of a redundant residue number system (RRNS) and the base extension operation is proposed. The method uses a very small decision table and works in parallel mode; therefore it is suitable for high speed VLSI circuit realization. A parallel systolic architecture which realizes the algorithm is introduced. >

Multilayer perceptrons (MLPs) with weight values restricted to powers of two or sums of powers of two are introduced. In a digital implementation, these neural networks do not need multipliers but only shift registers when computing in forward mode, thus saving chip area and computation time. A learning procedure, based on backpropagation, is presented for such neural networks. This learning procedure requires full real arithmetic and therefore must be performed offline. Some test cases are presented, concerning MLPs with hidden layers of different sizes, on pattern recognition problems. Such tests demonstrate the validity and the generalization capability of the method and give some insight into the behavior of the learning algorithm. >

The phosphorescence spectra of triphenylene and truxene, recorded in glassy solvents at 77 K, are presented. Their vibronic structure is interpreted on the basis of intensities computed with the help of quantum-chemical calculations. The agreement between observed and simulated intensities is very satisfactory and contributes to improve and complete the assignment of ground state frequencies of the two disk-like molecules.

The N70 and P100 components of transient pattern visual evoked potentials (P-VEPs) were measured in migraine patients, with and without aura, and in normal subjects in order to evaluate their latency, amplitude and occipital scalp distribution. The aim was to find any typical electrophysiological abnormalities in migraine. P-VEP N70 and P100 were analyzed in 59 patients without any known visual field defect. Mean latency and amplitude values were within normal ranges for either N70 and P100 all over the occipital scalp; the only significant abnormality we found was related to the absolute right-left amplitude ratio either for N70 and P100 waves, providing an asymmetry in P-VEP scalp distribution; this finding was detected in 78.9% of patients with aura and 72.5% without aura. Our results show that in migraine patients, both P-VEP waves N70 and P100, have an asymmetric topographic distribution, even during interictal phases, that can be explained by a cortical disturbance in agreement with the neural hypothesis of headache.

Forty-four patients suffering a stroke for the first time were examined within 10 h of the onset of symptoms; the tests performed on their admission to hospital, and thereafter on the third and seventh day, were 24-h Holter EKG with spectral analysis of heart rate variability, evaluation of arterial blood pressure and the levels of catecholamine in the blood and 24-h urine. The dynamic EKG on admission revealed that 31 (70.5%) out of the 44 patients already had arrhythmia. These alterations were observed in 9 (75%) out of 12 haemorrhagic patients with a significant (P0.05) prevalence compared to 22 (68.8%) of the 32 ischaemic ones. Arrhythmia showed up in 16 (76.2%) out of 21 cases with right hemisphere lesions and in 12 (63.2%) out of 19 cases of left hemisphere lesions; this difference was also significant (P0.05). Arrhythmia was still present in 19 (43.2%) patients after 3 days and only in 2 (6.5%) patients after 7 days. The spectral analysis parameters on admission and after 3 days were significantly (P0.05) modified in patients with stroke plus arrhythmia, compared to patients with stroke alone and to control subjects, whereas no further differences were observed on the seventh day. Moreover, the percentage of patients with arterial hypertension and high levels of catecholamine greatly decreased from the third day onwards. A transient autonomic nervous system imbalance with prevalent sympathetic activity may justify this cardiovascular impairment during the hyperacute phase of stroke.

Singlet-triplet spin-orbit matrix elements, which govern the lowest 3B1u 1Ag transition in typical aromatic molecules like naphtalene and anthracene, are calculated with INDO molecular orbitals and the conventional spin-orbit one-electron hamiltonian. The correct order of magnitude of the triplet radiative lifetimes is obtained for the two molecules, when INDO MO coefficients are referred to a symmetrically orthogonalized basis. The possibility of using the semiempirical Hamiltonian is explored using ab initio wave-functions for a few test cases. Reasonably accurate doublet-doublet and singlet-triplet matrix elements have been computed.

The mechanism of photochemical interconversion of cisand trans-stilbene involves the crossing to an excited intermediate with a potential-energy minimum at the twisted geometry (∝=90°). The lifetime of such an intermediate has been theoretically estimated and found to be long enough (0.1 ns ≤τ≤1 ns) to be monitored experimentally. The calculation is based on the theory of radiationless transitions and involves the estimate of the vibronic coupling by the torsional co-ordinate due to the avoided crossing at ∝=90°.

A method is proposed for synthesizing very low-sensitivity recursive digital filters on the basis of three techniques: 1) delay replacement; 2) transformation of resistance-terminated reactive ladders into digital structures; 3) multiplier scaling. The method applies to the case where the poles of the transfer function of the filter are near z = 1 , as is the case when the sampling rate is increased. The low-sensitivity property of the resulting schemes is proved and illustrated by examples.

The Herzberg‐Teller theory of vibronic intensity borrowing is reinvestigated. A potentially serious deficiency is found in the conventional approximation scheme based on neglecting vibronic perturbation of the ground state relative to that of the excited state. Simple theoretical models are studied and show systematic cancellation of the lowest‐order induced transition dipole moment if both vibronic perturbations are included. As a result the vibronic coupling between Born‐Oppenheimer states via nuclear momenta, for which such a cancellation does not occur, tends to contribute measurably to the induced transition moment, contrary to what usually is assumed. Two methods to distinguish between Herzberg‐Teller‐type (HT) and Born‐Oppenheimer‐type (BO) contributions are discussed, namely the absorption‐emission asymmetry and the isotope effect. The former results from interference between HT and BO terms, which is usually constructive in absorption and destructive in emission; the latter is due to the fact tha...

The electronic matrix elements governing intersystem crossing in aromatic hydrocarbons are derived and evaluated. The derivation is equivalent to Fano's treatment of resonance scattering. It is shown that the best first‐order description for crossings that show simple unimolecular behavior involves molecular states that are both spin contaminated and vibronically contaminated, but can be adequately represented by an expansion to second order in pure‐spin adiabatic Born‐Oppenheimer states. The corresponding first‐ and second‐order matrix elements are expanded about a nuclear equilibrium configuration and the expansions are terminated through the application of a symmetry argument. This yields five different types of matrix elements with small or vanishing cross terms; these matrix elements are associated with five experimentally distinguishable mechanisms, namely (1) direct spin‐orbit coupling, (2) vibronically induced spin‐orbit coupling, (3) mixed vibronic and spin‐orbit coupling, (4) resonant spin‐orbit coupling, and (5) vibronically induced resonant spin‐orbit coupling. To distinguish these mechanisms use is made of isotope effects, spin polarization and vibrational selection. The available experimental data on singlet‐to‐triplet crossing in naphthalene and anthracene are analyzed in detail and compared with qualitative and quantitative theoretical predictions. It is concluded that at low temperature singlet‐to‐triplet crossing in naphthalene is dominated by crossing to the third‐lowest triplet state via the third mechanism. At high temperature the dominant process involves either resonant crossing to the fourth‐lowest triplet state via the fifth mechanism or resonant crossing to the fifth‐lowest triplet state via the fourth mechanism. In an appendix spin‐rotational and orbital‐rotational coupling are shown to be too small to contribute measurably to these crossings.

It is shown that a simple expression, differing from the one currently used, must be adopted when calculating π electron spin densities from unrestricted H.F. wave functions in connection with the prediction of proton hyperfine couplings in aromatic free radicals. The proposed formula gives results which are almost identical to those one obtains after complete projection of the unwanted parts of the unrestricted function.

A network interpretation of the Yule-Walker equations is proposed. In terms of the resulting network two results are derived, particularly useful in the case of low-order systems.

A method is proposed for synthesizing a recursive digital filter based on the lattice scheme. The resulting new structure has consequently the optimal properties of the lattice. In particular, the low sensitivity with respect to multiplier coefficients is illustrated by an example.

Examination of IgE serum levels in 37 patients with psoriasis showed statistically significant values higher than normal when the extent of skin involved was more than 50%.

Time-varying models can be identified by lattice predictors with time-dependent reflection coefficients. The main defect of these predictors is that the magnitude of their coefficients cannot be controlled. In the present work a method is presented for removing such inconvenience based on linear programming.

A method is proposed for realising FIR digital filters with a very low computational cost by applying a modular arithmetic. The basis of the method is the choice of the two submoduli 2B and 2B + 1, with 2B + 1 equal to a prime, and the use of the isomorphism between multiplicative groups and additive groups both in the case of the modulus 2B and 2B + 1.

We propose a coaxial-cable equalising structure based on the use of active networks containing RC distributed lines. A numerical example proves the validity of the approach.

An approach to design easily a receiver for digital fibre-optic communication systems is given. In particular, a 34.368 Mbit/s communication system is analysed, where little or no avalanche-detector gain is used.

Singlet–triplet spin–orbit matrix elements have been estimated for pyrazine using molecular wavefunctions obtained by an ab initio configuration‐interaction method and minimal basis sets of Gaussian atomic orbitals. The computed radiative lifetime (10.2 ms) of the short lived component of the lowest 3B3u state is in good agreement with the experimental value. For the next excited triplet state (3B1u) a radiative lifetime is found similar to that of azine molecules in which the lowest triplet state is of ππ* nature. The spin–orbit matrix elements governing the rate constants of the T1→S0 and S1→T1 nonradiative processes have been evaluated.