On the Microscopic Origin of Cholesteric Pitch

We present a microscopic analysis of the instability of the nematic phase to chirality when molecular chirality is introduced perturbatively. We show that previously neglected short-range biaxial correlations play a crucial role in determining the cholesteric pitch. We propose an order parameter which quantifies the chirality of a molecule.Comment: RevTeX 3.0, 4 pages, one included eps figure. Published versio

Effects of miRNA-15 and miRNA-16 expression replacement in chronic lymphocytic leukemia : implication for therapy

This work was supported by: Associazione Italiana Ricerca sul Cancro (AIRC) Grant 5 x mille n.9980, (to M.F., F.M. A. N., P.T. and M.N.) ; AIRC I.G. n. 14326 (to M.F.), n.10136 and 16722 (A.N.), n.15426 (to F.F.). AIRC and Fondazione CaRiCal co-financed Multi Unit Regional Grant 2014 n.16695 (to F.M.). Italian Ministry of Health 5x1000 funds (to S.Z. and F.F). A.G R. was supported by Associazione Italiana contro le Leucemie-Linfomi-Mielomi (AIL) Cosenza - Fondazione Amelia Scorza (FAS). S.M. C.M., M.C., L.E., S.B. were supported by AIRC.Peer reviewedPostprin

Mesoscopic organization reveals the constraints governing C. elegans nervous system

One of the biggest challenges in biology is to understand how activity at the cellular level of neurons, as a result of their mutual interactions, leads to the observed behavior of an organism responding to a variety of environmental stimuli. Investigating the intermediate or mesoscopic level of organization in the nervous system is a vital step towards understanding how the integration of micro-level dynamics results in macro-level functioning. In this paper, we have considered the somatic nervous system of the nematode Caenorhabditis elegans, for which the entire neuronal connectivity diagram is known. We focus on the organization of the system into modules, i.e., neuronal groups having relatively higher connection density compared to that of the overall network. We show that this mesoscopic feature cannot be explained exclusively in terms of considerations, such as optimizing for resource constraints (viz., total wiring cost) and communication efficiency (i.e., network path length). Comparison with other complex networks designed for efficient transport (of signals or resources) implies that neuronal networks form a distinct class. This suggests that the principal function of the network, viz., processing of sensory information resulting in appropriate motor response, may be playing a vital role in determining the connection topology. Using modular spectral analysis, we make explicit the intimate relation between function and structure in the nervous system. This is further brought out by identifying functionally critical neurons purely on the basis of patterns of intra- and inter-modular connections. Our study reveals how the design of the nervous system reflects several constraints, including its key functional role as a processor of information.Comment: Published version, Minor modifications, 16 pages, 9 figure

A comparison of the response of PADC neutron dosemeters in high-energy neutron fields

Within the framework of the EURADOS Working Group 11, a comparison of passive neutron dosemeters in high-energy neutron fields was organised in 2011. The aim of the exercise was to evaluate the response of poly-allyl-glycol-carbonate neutron dosemeters from various European dosimetry laboratories to high-energy neutron fields. Irradiations were performed at the iThemba LABS facility in South Africa with neutrons having energies up to 66 and 100 Me

Whole brain resting-state analysis reveals decreased functional connectivity in major depression

Recently, both increases and decreases in resting-state functional connectivity have been found in major depression. However, these studies only assessed functional connectivity within a specific network or between a few regions of interest, while comorbidity and use of medication was not always controlled for. Therefore, the aim of the current study was to investigate whole-brain functional connectivity, unbiased by a priori definition of regions or networks of interest, in medication-free depressive patients without comorbidity. We analyzed resting-state fMRI data of 19 medication-free patients with a recent diagnosis of major depression (within six months before inclusion) and no comorbidity, and 19 age- and gender-matched controls. Independent component analysis was employed on the concatenated data sets of all participants. Thirteen functionally relevant networks were identified, describing the entire study sample. Next, individual representations of the networks were created using a dual regression method. Statistical inference was subsequently done on these spatial maps using voxelwise permutation tests. Abnormal functional connectivity was found within three resting-state networks in depression: 1) decreased bilateral amygdala and left anterior insula connectivity in an affective network, 2) reduced connectivity of the left frontal pole in a network associated with attention and working memory, and 3) decreased bilateral lingual gyrus connectivity within ventromedial visual regions. None of these effects were associated with symptom severity or grey matter density. We found abnormal resting-state functional connectivity not previously associated with major depression, which might relate to abnormal affect regulation and mild cognitive deficits, both associated with the symptomatology of the disorder

miR-29b sensitizes multiple myeloma cells to bortezomib-induced apoptosis through the activation of a feedback loop with the transcription factor Sp1

MicroRNAs (miRNAs) with tumor-suppressor potential might have therapeutic applications in multiple myeloma (MM) through the modulation of still undiscovered molecular pathways. Here, we investigated the effects of enforced expression of miR-29b on the apoptotic occurrence in MM and highlighted its role in the context of a new transcriptional loop that is finely tuned by the proteasome inhibitor bortezomib. In details, in vitro growth inhibition and apoptosis of MM cells was induced by either transient expression of synthetic miR-29b or its stable lentivirus-enforced expression. We identified Sp1, a transcription factor endowed with oncogenic activity, as a negative regulator of miR-29b expression in MM cells. Since Sp1 expression and functions are regulated via the 26S proteasome, we investigated the effects of bortezomib on miR-29b-Sp1 loop, showing that miR-29b levels were indeed upregulated by the drug. At the same time, the bortezomib/miR-29b combination produced significant pro-apoptotic effects. We also demonstrated that the PI3K/AKT pathway plays a major role in the regulation of miR-29b-Sp1 loop and induction of apoptosis in MM cells. Finally, MM xenografts constitutively expressing miR-29b showed significant reduction of their tumorigenic potential. Our findings indicate that miR-29b is involved in a regulatory loop amenable of pharmacologic intervention and modulates the anti-MM activity of bortezomib in MM cells

A method for the assessment and compensation of positioning errors in industrial robots

Industrial Robots (IR) are currently employed in several production areas as they enable flexible automation and high productivity on a wide range of operations. The IR low positioning performance, however, has limited their use in high precision applications, namely where positioning errors assume importance for the process and directly affect the quality of the final products. Common approaches to increase the IR accuracy rely on empirical relations which are valid for a single IR model. Also, existing works show no uniformity regarding the experimental procedures followed during the IR performance assessment and identification phases. With the aim to overcome these restrictions and further extend the IR usability, this paper presents a general method for the evaluation of IR pose and path accuracy, primarily focusing on instrumentation and testing procedures. After a detailed description of the experimental campaign carried out on a KUKA KR210 R2700 Prime robot under different operating conditions (speed, payload and temperature state), a novel online compensation approach is presented and validated. The position corrections are processed with an industrial PC by means of a purposely developed application which receives as input the position feedback from a laser tracker. Experiments conducted on straight paths confirmed the validity of the proposed approach, which allows remarkable reductions (in the order of 90%) of the orthogonal deviations and in-line errors during the robot movements

Understanding the twist-bend nematic phase: the characterisation of 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'-yl) hexane (CB6OCB) and comparison with CB7CB

Acknowledgements The FFTEM data were obtained at the (Cryo) TEM facility at the Liquid Crystal Institute, Kent State University, supported by the Ohio Research Scholars Program Research Cluster on Surfaces in Advanced Materials. ODL acknowledges the support of NSF DMR-1410378 grant. The authors are grateful for financial support from MINECO/FEDER MAT2015-66208-C3-2-P and from the Gobierno Vasco (GI/IT-449-10) OA via RSC Gold4GoldPeer reviewedPublisher PD

A chromosome-anchored eggplant genome sequence reveals key events in Solanaceae evolution

With approximately 450 species, spiny Solanum species constitute the largest monophyletic group in the Solanaceae family, but a high-quality genome assembly from this group is presently missing. We obtained a chromosome-anchored genome assembly of eggplant (Solanum melongena), containing 34,916 genes, confirming that the diploid gene number in the Solanaceae is around 35,000. Comparative genomic studies with tomato (S. lycopersicum), potato (S. tuberosum) and pepper (Capsicum annuum) highlighted the rapid evolution of miRNA:mRNA regulatory pairs and R-type defense genes in the Solanaceae, and provided a genomic basis for the lack of steroidal glycoalkaloid compounds in the Capsicum genus. Using parsimony methods, we reconstructed the putative chromosomal complements of the key founders of the main Solanaceae clades and the rearrangements that led to the karyotypes of extant species and their ancestors. From 10% to 15% of the genes present in the four genomes were syntenic paralogs (ohnologs) generated by the pre-γ, γ and T paleopolyploidy events, and were enriched in transcription factors. Our data suggest that the basic gene network controlling fruit ripening is conserved in different Solanaceae clades, and that climacteric fruit ripening involves a differential regulation of relatively few components of this network, including CNR and ethylene biosynthetic genes

High prevalence of patent foramen ovale in migraine with aura

In this study we evaluated the presence of patent foramen ovale (PFO) in a cohort of 25 consecutive patients suffering from migraine with aura (MA) during an attack presenting to the emergency ward of an Italian hospital. Patients underwent brain magnetic resonance imaging (MRI) with contrast medium, routine coagulation tests, contrast transcranial echocolour–coded sonography (c–TCCS) and transoesophageal echocardiography (TEE). Of the enrolled patients, 88.7% showed a PFO according to the c–TCCS test, whereas only in 72% TEE confirmed the presence of PFO. This discordance could be due to the fact that c–TCCS is more sensitive even with shunts with minimal capacity also located in the pulmonary vasculature. After surgical treatment of the PFO, MA disappeared within two months. Also, the treatment with warfarin as well as with acetylsalicylic acid and flunarizine was able to dramatically reduce the frequency of migraine attacks. These data indicate a higher prevalence of PFO in MA vs. normal population (OR=2.92) and could suggest that the presence of arteriovenous (AV) shunts could represent a trigger for MA attacks as well as for stroke, but more studies are needed to confirm this preliminary hypothesis