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Moiré effects in vertical stacks of two-dimensional crystals give rise to new quantum materials with rich transport and optical phenomena that originate from modulations of atomic registries within moiré supercells. Due to finite elasticity, however, the superlattices can transform from moiré-type to periodically reconstructed patterns. Here we expand the notion of such nanoscale lattice reconstruction to the mesoscopic scale of laterally extended samples and demonstrate rich consequences in optical studies of excitons in MoSe 2 -WSe 2 heterostructures with parallel and antiparallel alignments. Our results provide a unified perspective on moiré excitons in near-commensurate semiconductor heterostructures with small twist angles by identifying domains with exciton properties of distinct effective dimensionality, and establish mesoscopic reconstruction as a compelling feature of real samples and devices with inherent finite size effects and disorder. Generalized to stacks of other two-dimensional materials, this notion of mesoscale domain formation with emergent topological defects and percolation networks will instructively expand the understanding of fundamental electronic, optical and magnetic properties of van der Waals heterostructures., (© 2023. The Author(s).)

Vertical van der Waals heterostructures of semiconducting transition metal dichalcogenides realize moiré systems with rich correlated electron phases and moiré exciton phenomena. For material combinations with small lattice mismatch and twist angles as in MoSe 2 -WSe 2 , however, lattice reconstruction eliminates the canonical moiré pattern and instead gives rise to arrays of periodically reconstructed nanoscale domains and mesoscopically extended areas of one atomic registry. Here, we elucidate the role of atomic reconstruction in MoSe 2 -WSe 2 heterostructures synthesized by chemical vapor deposition. With complementary imaging down to the atomic scale, simulations, and optical spectroscopy methods, we identify the coexistence of moiré-type cores and extended moiré-free regions in heterostacks with parallel and antiparallel alignment. Our work highlights the potential of chemical vapor deposition for applications requiring laterally extended heterosystems of one atomic registry or exciton-confining heterostack arrays.

Objectives: Suicidal ideation is a pervasive and painful experience that varies considerably in its phenomenology. Here, we consider how one key risk variable might inform our understanding of variation in suicidal ideation: emotion-related impulsivity, the trait-like tendency towards unconstrained speech, behaviour, and cognition in the face of intense emotions. We hypothesized that emotion-related impulsivity would be tied to specific features, including severity, perceived lack of controllability, more rapidly fluctuating course, higher scores on a measure of acute suicidal affective disturbance, and more emotional and cognitive disturbance as antecedents., Methods: We recruited two samples of adults (Ns = 421, 221) through Amazon Mechanical Turk (MTurk), with oversampling of those with suicidal ideation. Both samples completed psychometrically sound self-report measures online to assess emotion- and non-emotion-related dimensions of impulsivity and characteristics of suicidal ideation., Results: One form of emotion-related impulsivity related to the severity, uncontrollability, dynamic course, and affective and cognitive precursors of ideation., Conclusions: Despite limitations of the cross-sectional design and self-report measures, the current findings highlight the importance of specificity in considering key dimensions of impulsivity and suicidal ideation., (© 2022 British Psychological Society.)

Introduction: Rumination and emotion-related impulsivity predict suicidal ideation, suicide attempts, and nonsuicidal self-injury (NSSI). Because rumination and emotion-related impulsivity, though, are highly correlated, we consider their unique vs. conjoint influence on suicidal ideation and self-harm., Method: Across two samples of adults (N's = 171 and 191), we examined how rumination and emotion-related impulsivity relate to suicidal ideation, suicide attempts, and NSSI. We assess the more general process of repetitive negative thinking and the more specific process of suicide-related rumination. Participants completed the Three-Factor Impulsivity Index and the self-report Columbia-Suicide Severity Rating Scale. Those in sample 1 completed the Perseverative Thinking Questionnaire and the Deliberate Self-Harm Inventory, and those in Sample 2 completed the Suicide Rumination Scale., Results: Emotion-related impulsivity and both forms of rumination showed robust bivariate correlations with suicidal ideation, suicide attempts, and NSSI. Neither rumination or impulsivity related to suicide attempts controlling for ideation or to NSSI. In multivariable analyses, emotion-related impulsivity but not general rumination was tied to suicidal ideation. In contrast, suicide-related rumination was more directly tied to suicidal ideation than was impulsivity., Conclusions: Findings provide support for a more nuanced approach to the forms of impulsivity and rumination related to suicidal ideation., (© 2022 The American Association of Suicidology.)

The control of wheat diseases using bioagents is not well studied under field conditions. The present study was aimed at investigating, during four consecutive growing seasons (2017-2020), the efficacy of two integrated crop protection (ICP) systems to control the common wheat diseases for enhancing the productivity and profitability of winter wheat crops and ensuring nutritional and food security. Two environmental-friendly treatments were tested, biological (T1), which contained bioagents and fertilizers, and combined (T2), which included fertilizers and bioagents coupled with lower doses of fungicides. The chemical treatment (T3) was used for comparison with (T1) and (T2). Furthermore, two Russian winter wheat varieties (Nemchinovskaya 17 (V1) and Moscovskaya 40 (V2)) were studied. A randomized complete block design was used with four replicates. Diseases infestation rates for snow mold (SM), root rot (RR), powdery mildew (PM), and Fusarium (Fus), yield performances, and grain quality (measured through protein content) were determined according to the tested treatments, and the economic efficiency was calculated for each treatment. The combined treatment (T2) was the most effective against fungal diseases with 1.8% (SM), 1.2% (RR), 0.9% (PM), and 0.9% (Fus). The highest grain yield (6.8 t·ha -1 ), protein content (15.2%), and 1000-grain weight (43.7%) were observed for winter wheat variety Moscovskaya 40 with the combined treatment (T2). The highest number of productive stems (N.P.S) (556 stems/m 2 ) was attained for combined treatment (T2), followed by biological treatment (T1) (552 stems/m 2 ) with the variety Nemchinovskaya 17. The profitability (cost-benefit ratio) of the combined treatment (T2) was 2.38 with the Moscovskaya 40 variety (V2), while 2.03 was recorded for the biological treatment. Applying environmentally friendly combined and biological treatments resulted in high wheat yield and net income, as well as healthy products.

The occurrence and mechanisms underlying non-local or crossover muscle fatigue is an ongoing issue. This study aimed to investigate crossover fatigue of the plantar flexor muscles. Sixteen recreationally active males (n = 6) and females (n = 10) visited the laboratory for four sessions and performed a single 5-s pre-test maximal voluntary isometric contraction (MVIC) with each plantar flexors muscle. Thereafter, the fatigue intervention involved two 100-s MVICs (60-s recovery) with their dominant plantar flexors or rested for 260-s (control). Subsequently, in two separate sessions, Hoffman reflexes (H-reflex) were evoked in the non-dominant, non-exercised, leg before and following the dominant leg fatigue or control intervention (Fatigue-Reflex and Control-Reflex conditions). MVIC forces and volitional (V)-waves were monitored in the non-dominant leg in the other two sessions (Fatigue-MVIC and Control-MVIC) before and after the intervention (fatigue or control) as well as during 12 repeated MVICs and immediately thereafter. Despite the force reduction in the dominant leg (42.4%, p = 0.002), no crossover force deficit with single (F (1,9) = 0.02, p = 0.88, pƞ 2 = 0.003) or repeated (F (1,9) = 0.006, p = 0.93, pƞ 2 = 0.001 ) MVIC testing were observed. The H-reflex did not change after the fatigue (F (1,7) = 0.51; p = 0.49; pƞ 2 = 0.06) or repeated MVICs (F (1,8) = 0.27; p = 0.61; pƞ 2 = 0.03). There were also no crossover effects of fatigue on the V-wave with single (F (1,8) = 3.71, p = 0.09, pƞ 2 = 0.31 ) or repeated MVICs (F (1,6) = 1.45, p = 0.27, pƞ 2 = 0.19 ). Crossover fatigue was not evident with the plantar flexors nor any significant changes in H-reflex and V-waves in the soleus muscle. This finding suggests that crossover fatigue may not necessarily occur in slow-twitch predominant muscle groups., (© Journal of Sports Science and Medicine.)

Layered two-dimensional materials exhibit rich transport and optical phenomena in twisted or lattice-incommensurate heterostructures with spatial variations of interlayer hybridization arising from moiré interference effects. Here, we report experimental and theoretical studies of excitons in twisted heterobilayers and heterotrilayers of transition metal dichalcogenides. Using MoSe 2 -WSe 2 stacks as representative realizations of twisted van der Waals bilayer and trilayer heterostructures, we observe contrasting optical signatures and interpret them in the theoretical framework of interlayer moiré excitons in different spin and valley configurations. We conclude that the photoluminescence of MoSe 2 -WSe 2 heterobilayer is consistent with joint contributions from radiatively decaying valley-direct interlayer excitons and phonon-assisted emission from momentum-indirect reservoirs that reside in spatially distinct regions of moiré supercells, whereas the heterotrilayer emission is entirely due to momentum-dark interlayer excitons of hybrid-layer valleys. Our results highlight the profound role of interlayer hybridization for transition metal dichalcogenide heterostacks and other realizations of multi-layered semiconductor van der Waals heterostructures.

Behm, DG, Alizadeh, S, Hadjizadeh Anvar, S, Mahmoud, MMI, Ramsay, E, Hanlon, C, and Cheatham, S. Foam rolling prescription: a clinical commentary. J Strength Cond Res 34(11): 3301-3308, 2020-Although the foam rolling and roller massage literature generally reports acute increases in range of motion (ROM) with either trivial or small performance improvements, there is little information regarding appropriate rolling prescription. The objective of this literature review was to appraise the evidence and provide the best prescriptive recommendations for rolling to improve ROM and performance. The recommendations represent studies with the greatest magnitude effect size increases in ROM and performance. A systematic search of the rolling-related literature found in PubMed, ScienceDirect, Web of Science, and Google Scholar was conducted using related terms such as foam rolling, roller massage, ROM, flexibility, performance, and others. From the measures within articles that monitored ROM (25), strength (41), jump (41), fatigue (67), and sprint (62) variables; regression correlations and predictive quadratic equations were formulated for number of rolling sets, repetition frequency, set duration, and rolling intensity. The analysis revealed the following conclusions. To achieve the greatest ROM, the regression equations predicted rolling prescriptions involving 1-3 sets of 2-4-second repetition duration (time for a single roll in one direction over the length of a body part) with a total rolling duration of 30-120-second per set. Based on the fewer performance measures, there were generally trivial to small magnitude decreases in strength and jump measures. In addition, there was insufficient evidence to generalize on the effects of rolling on fatigue and sprint measures. In summary, relatively small volumes of rolling can improve ROM with generally trivial to small effects on strength and jump performance.

The optical properties of monolayer and bilayer transition metal dichalcogenide semiconductors are governed by excitons in different spin and valley configurations, providing versatile aspects for van der Waals heterostructures and devices. Here, we present experimental and theoretical studies of exciton energy splittings in external magnetic field in neutral and charged WSe 2 monolayer and bilayer crystals embedded in a field effect device for active doping control. We develop theoretical methods to calculate the exciton g-factors from first principles for all possible spin-valley configurations of excitons in monolayer and bilayer WSe 2 including valley-indirect excitons. Our theoretical and experimental findings shed light on some of the characteristic photoluminescence peaks observed for monolayer and bilayer WSe 2 . In more general terms, the theoretical aspects of our work provide additional means for the characterization of single and few-layer transition metal dichalcogenides, as well as their heterostructures, in the presence of external magnetic fields.

Background: This study aimed to determine the magnitude of volume reduction of the latissimus dorsi (LD) muscle after treatment using only postoperative radiotherapy (PORTx) in patients who underwent immediate breast reconstruction using an extended LD musculocutaneous (eLDMC) flap after partial mastectomy., Methods: We retrospectively reviewed 28 patients who underwent partial mastectomy and an eLDMC flap, received only PORTx, and underwent chest computed tomography (CT) 7 to 10 days after surgery and 18±4 months after the end of radiotherapy, from March 2011 to June 2016. The motor nerve to the LD was resected in all patients. One plastic surgeon performed the procedures, and the follow-up period was at least 36 months (mean, 46.6 months). The author obtained LD measurements from axial CT views, and the measurements were verified by an experienced radiologist. The threshold for statistical significance was set at P<0.05., Results: A statistically significant decrease in the LD volume was found after the end of PORTx (range, 61.19%-80.82%; mean, 69.04%) in comparison to the measurements obtained 7 to 10 days postoperatively (P<0.05). All cases were observed clinically for over 3 years., Conclusions: The size of an eLDMC flap should be determined considering an average LD reduction of 69% after PORTx. Particular care should be taken in determining the size of an eLDMC flap if the LD is thick or if it occupies a large portion of the flap.

In this Letter, we analyze circular dichroism (CD) enhancement of a helical semiconductor nanoribbon exposed to a weak homogenous electric field. By creating a periodic superlattice for the confined electrons, the electric field splits the electronic sub-bands into minibands and gives rise to critical points in the electronic density of states. We show that the modification of the electronic energy spectrum results in the appearance of new optically active transitions in the CD and absorption spectra, and that the CD signal of the nanoribbon is significantly enhanced at the critical points. The ability to dynamically control the chiroptical response of semiconductor nanoribbons by an external electric field makes them promising for the next-generation nanophotonic devices.

In the present study, we tried to evaluate the relationship between Fascin molecule expression and other histopathologic parameters, especially tumor grade and hormone profile. Sixty-one malignant breast tumors were enrolled in this study. Fascin marker staining was performed on paraffin blocks of breast samples using immunohistochemistry (IHC) method. The age range of patients was 26-87 years, with an average of 48.41 ±1.68. Our results showed that fascin expression was significantly higher in tumors with high grade histology, lymph node involvement and larger tumor size (p = 0.04, 0.04, 0.04, respectively). Also fascin expression in triple negative tumors was significantly higher than other molecular subtypes (p = 0.001). fascin can be used as an important marker in evaluating breast cancer especially in triple negative tumors.

Quantum confinement and collective excitations in perovskite quantum-dot (QD) supercrystals offer multiple benefits to the light emitting and solar energy harvesting devices of modern photovoltaics. Recent advances in the fabrication technology of low dimensional perovskites has made the production of such supercrystals a reality and created a high demand for the modelling of excitonic phenomena inside them. Here we present a rigorous theory of Frenkel excitons in lead halide perovskite QD supercrystals with a square Bravais lattice. The theory shows that such supercrystals support three bright exciton modes whose dispersion and polarization properties are controlled by the symmetry of the perovskite lattice and the orientations of QDs. The effective masses of excitons are found to scale with the ratio of the superlattice period and the number of QDs along the supercrystal edge, allowing one to fine-tune the electro-optical response of the supercrystals as desired for applications. We also calculate the conductivity of perovskite QD supercrystals and analyze how it is affected by the optical generation of the three types of excitons. This paper provides a solid theoretical basis for the modelling of two- and three-dimensional supercrystals made of perovskite QDs and the engineering of photovoltaic devices with superior optoelectronic properties.

The search for the optimal geometry of optically active semiconductor nanostructures is making steady progress and has far-reaching benefits. Yet the helical springlike shape, which is very likely to provide a highly dissymmetric optical response, remains somewhat understudied theoretically. Here we comprehensively analyze the optical activity of semiconductor nanosprings using a fully quantum-mechanical model of their electronic subsystem and taking into account the anisotropy of their interaction with light. We show that the circular dichroism of semiconductor nanosprings can exceed that of ordinary semiconductor nanocrystals by a factor of 100 and be comparable to the circular dichroism of metallic nanosprings. It is also demonstrated that nanosprings can feature a total dissymmetry of optical response for certain ratios between their length and coil height. The magnitude and sign of the circular dichroism signal can be controlled by stretching or compressing the nanosprings, which makes them a promising material base for optomechanical sensors, polarization controllers, and other types of optically active nanophotonic devices.

We present rigorous analysis of optical activity of chiral semiconductor gammadions whose chirality in three dimensions is caused by the nonuniformity of thickness in the transverse plane. It is shown that such gammadions not only distinguish between the two circular polarizations upon scattering and reflection of light, like all two-dimensional semiconductor nanostructures with planar chirality do, but also exhibit circular dichroism and circularly polarized luminescence. Chiral semiconductor gammadions whose charge carriers are mostly confined to the arms are found to feature both high dissymmetry of optical response and a constant-sign circular dichroism signal over a wide frequency range. It is also shown that the strength of the gammadion's chiroptical response is determined solely by two geometric factors: the variation range of the gammadion's thickness and the arms' curvature. Our seminal theoretical study is intended to lay the foundation for future applications of semiconductor gammadions in chiral nanophotonics and nanotechnology.

Two-dimensional (2D) nanomaterials have been intensively investigated due to their interesting properties and range of potential applications. Although most research has focused on graphene, atomic layered transition metal dichalcogenides (TMDs) and particularly MoS 2 have gathered much deserved attention recently. Here, we report the induction of chirality into 2D chiral nanomaterials by carrying out liquid exfoliation of MoS 2 in the presence of chiral ligands (cysteine and penicillamine) in water. This processing resulted in exfoliated chiral 2D MoS 2 nanosheets showing strong circular dichroism signals, which were far past the onset of the original chiral ligand signals. Using theoretical modeling, we demonstrated that the chiral nature of MoS 2 nanosheets is related to the presence of chiral ligands causing preferential folding of the MoS 2 sheets. There was an excellent match between the theoretically calculated and experimental spectra. We believe that, due to their high aspect ratio planar morphology, chiral 2D nanomaterials could offer great opportunities for the development of chiroptical sensors, materials, and devices for valleytronics and other potential applications. In addition, chirality plays a key role in many chemical and biological systems, with chiral molecules and materials critical for the further development of biopharmaceuticals and fine chemicals, and this research therefore should have a strong impact on relevant areas of science and technology such as nanobiotechnology, nanomedicine, and nanotoxicology.

Large variation exists in mitochondrial DNA (mtDNA) not only between but also within individuals. Also in human cancer, tumor-specific mtDNA variation exists. In this work, we describe the comparison of four methods to extract mtDNA as pure as possible from frozen tumor tissue. Also, three state-of-the-art methods for sensitive detection of mtDNA variants were evaluated. The main aim was to develop a procedure to detect low-frequent single-nucleotide mtDNA-specific variants in frozen tumor tissue. We show that of the methods evaluated, DNA extracted from cytosol fractions following exonuclease treatment results in highest mtDNA yield and purity from frozen tumor tissue (270-fold mtDNA enrichment). Next, we demonstrate the sensitivity of detection of low-frequent single-nucleotide mtDNA variants (≤1% allele frequency) in breast cancer cell lines MDA-MB-231 and MCF-7 by single-molecule real-time (SMRT) sequencing, UltraSEEK chemistry based mass spectrometry, and digital PCR. We also show de novo detection and allelic phasing of variants by SMRT sequencing. We conclude that our sensitive procedure to detect low-frequent single-nucleotide mtDNA variants from frozen tumor tissue is based on extraction of DNA from cytosol fractions followed by exonuclease treatment to obtain high mtDNA purity, and subsequent SMRT sequencing for (de novo) detection and allelic phasing of variants.

Engineering nanostructured optical materials via the purposeful distortion of their constituent nanocrystals requires the knowledge of how various distortions affect the nanocrystals' electronic subsystem and its interaction with light. We use the geometric theory of defects in solids to calculate the linear permittivity tensor of semiconductor nanocrystals whose crystal lattice is arbitrarily distorted by imperfections or strains. The result is then employed to systematically analyze the optical properties of nanocrystals with spatial dispersion caused by screw dislocations and Eshelby twists. We demonstrate that Eshelby twists create gyrotropy in nanocrystals made of isotropic semiconductors whereas screw dislocations can produce it only if the nanocrystal material itself is inherently anisotropic. We also show that the dependence of circular dichroism spectrum on the aspect ratio of dislocation-distorted semiconductor nanorods allows resonant enhancing their optical activity (at least by a factor of 2) and creating highly optically active nanomaterials.

Large surface-to-volume ratio, one-dimensional quantum confinement, and strong optical activity make chiral nanoscrolls ideal for the detection and sensing of small chiral molecules. Here, we present a simple physical model of chiroptical phenomena in multilayered tapered semiconductor nanoscrolls. Our model is based on a linear transformation of coordinates, which converts nanoscrolls into flat but topologically distorted nanoplatelets whose optical properties can then be treated analytically. As an illustrative application example, we analyze absorption and circular dichroism spectra of CdSe nanoscrolls using an eight-band model of CdSe. We show that the optical activity of the nanoscrolls originates from the chiral distortion of their crystal lattice and determine selection rules for the optically active interband transitions. The results of our study may prove useful for the modeling and design of semiconductor nanoscrolls and nanoscroll-based materials.

We use quantum theory of molecular crystals to study collective excitations (excitons) of gyrotropic quantum-dot (QD) supercrystals with complex lattices consisting of two or more sublattices of semiconductor QDs. We illustrate the potentials of our approach by applying it to analytically calculate the linear permittivity tensor of supercrystals with two QDs per unit cell. The spatial dispersions of exciton energy bands and permittivity tensor components are examined in detail for two-dimensional supercrystals with a square lattice, which are relatively easy to fabricate in practice. Our results provide a systematic and versatile framework for the engineering of dispersion properties of gyrotropic QD supercrystals and for the analysis of their absorption and circular dichroism spectra.

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The arthropod-borne Zika virus (ZIKV) is currently causing a major international public health threat in the Americas. This study describes the isolation of ZIKV from the plasma of a 29-year-old female traveler that developed typical symptoms, like rash, fever and headache upon return from Suriname. The complete genome sequence including the 5' and 3' untranslated regions was determined and phylogenetic analysis showed the isolate clustering within the Asian lineage, close to other viruses that have recently been isolated in the Americas. In addition, the viral quasispecies composition was analyzed by single molecule real time sequencing, which suggested a mutation frequency of 1.4 × 10 -4 for this ZIKV isolate. Continued passaging of the virus in cell culture led to the selection of variants with mutations in NS1 and the E protein. The latter might influence virus binding to cell surface heparan sulfate.

Here we review our three recently developed analytical models describing the intraband optical activity of semiconductor nanocrystals, which is induced by screw dislocations, ionic impurities, or irregularities of the nanocrystal surface. The models predict that semiconductor nanocrystals can exhibit strong optical activity upon intraband transitions and have large dissymmetry of magnetic-dipole absorption. The developed models can be used to interpret experimental circular dichroism spectra of nanocrystals and to advance the existing techniques of enantioseparation, biosensing, and chiral chemistry., (© 2017 Wiley Periodicals, Inc.)

The studying of how twisted light interacts with chiral matter on the nanoscale is paramount for tackling the challenging task of optomechanical separation of nanoparticle enantiomers, whose solution can revolutionize the entire pharmaceutical industry. Here we calculate optical forces and torques exerted on chiral nanoparticles by Laguerre-Gaussian beams carrying a topological charge. We show that regardless of the beam polarization, the nanoparticles are exposed to both chiral and achiral forces with nonzero reactive and dissipative components. Longitudinally polarized beams are found to produce chirality densities that can be 10 9 times higher than those of transversely polarized beams and that are comparable to the chirality densities of beams polarized circularly. Our results and analytical expressions prove useful in designing new strategies for mechanical separation of chiral nanoobjects with the help of highly focussed beams.

Chiral molecules made of coupled achiral semiconductor nanocrystals, also known as quantum dots, show great promise for photonic applications owing to their prospective uses as configurable building blocks for optically active structures, materials, and devices. Here we present a simple model of optically active quantum-dot molecules, in which each of the quantum dots is assigned a dipole moment associated with the fundamental interband transition between the size-quantized states of its confined charge carriers. This model is used to analytically calculate the rotatory strengths of optical transitions occurring upon the excitation of chiral dimers, trimers, and tetramers of general configurations. The rotatory strengths of such quantum-dot molecules are found to exceed the typical rotatory strengths of chiral molecules by five to six orders of magnitude. We also study how the optical activity of quantum-dot molecules shows up in their circular dichroism spectra when the energy gap between the molecular states is much smaller than the states' lifetime, and maximize the strengths of the circular dichroism peaks by optimizing orientations of the quantum dots in the molecules. Our analytical results provide clear design guidelines for quantum-dot molecules and can prove useful in engineering optically active quantum-dot supercrystals and photonic devices.

The ability to induce optical activity in nanoparticles and dynamically control its strength is of great practical importance due to potential applications in various areas, including biochemistry, toxicology, and pharmaceutical science. Here we propose a new method of creating optical activity in originally achiral quantum nanostructures based on the mixing of their energy states of different parities. The mixing can be achieved by selective excitation of specific states or via perturbing all the states in a controllable fashion. We analyze the general features of the so produced optical activity and elucidate the conditions required to realize the total dissymmetry of optical response. The proposed approach is applicable to a broad variety of real systems that can be used to advance chiroptical devices and methods.

Here we report anisotropy of intrinsic chiroptical response in CdSe/CdS quantum dot-in-rod systems. These nanostructures being oriented in an external electric field demonstrate dependence of circular dichroism signal on the orientation of the nanocrystals. The type of circular polarization in these nanostructures correlates with preferential direction of linear polarization, and the degree of circular polarization is the maximal for the first circular dichroism band corresponding to the absorption band edge. We also support our experimental data with a theoretical model. Using this model, we show a direct connection between theoretically derived morphological parameters of twisting in nanocrystals lattices and calculated from experimental data parameters of circular dichroism anisotropy.

We present a general approach to analyzing the optical activity of semiconductor nanocrystals of chiral shapes. By using a coordinate transformation that turns a chiral nanocrystal into a nanocuboid, we calculate the rotatory strengths, dissymmetry factors, and peak values of the circular dichroism (CD) signal upon intraband transitions inside the nanocrystal. It is shown that the atomic roughness of the nanocrystal surface can result in rotatory strengths as high as 10 -36   erg×cm 3 and in peak CD signals of about 0.1  cm -1 for typical nanocrystal densities of 10 16   cm -3 . The developed approach may prove useful for other nanocrystal shapes whereas the derived expressions apply directly for the modeling and interpretation of experimental CD spectra of quantum dots, nanorods, and nanoplatelets.

Optical activity is a common natural phenomenon, which occurs in individual molecules, biomolecules, biological species, crystalline solids, liquid crystals, and various nanosized objects, leading to numerous important applications in almost every field of modern science and technology. Because this activity can hardly be altered, creation of artificial active media with controllable optical properties is of paramount importance. Here, for the first time to the best of our knowledge, we theoretically demonstrate that optical activity can be inherent to many semiconductor nanowires, as it is induced by chiral dislocations naturally developing during their growth. By assembling such nanowires in two- or three-dimensional periodic lattices, one can create optically active quantum supercrystals whose activity can be varied in many ways owing to the size quantization of the nanowires' energy spectra. We believe that this research is of particular importance for the future development of semiconducting nanomaterials and their applications in nanotechnology, chemistry, biology, and medicine.

The size dependence of the quantized energies of elementary excitations is an essential feature of quantum nanostructures, underlying most of their applications in science and technology. Here we report on a fundamental property of impurity states in semiconductor nanocrystals that appears to have been overlooked--the anticrossing of energy levels exhibiting different size dependencies. We show that this property is inherent to the energy spectra of charge carriers whose spatial motion is simultaneously affected by the Coulomb potential of the impurity ion and the confining potential of the nanocrystal. The coupling of impurity states, which leads to the anticrossing, can be induced by interactions with elementary excitations residing inside the nanocrystal or an external electromagnetic field. We formulate physical conditions that allow a straightforward interpretation of level anticrossings in the nanocrystal energy spectrum and an accurate estimation of the states' coupling strength.

We present a theory of phonon-assisted photoluminescence from a semiconductor quantum dot (QD) whose electron and phonon subsystems are resonantly coupled via the polar electron-phonon interaction. We show that the resonance-induced renormalization of the QD energy spectrum, leading to the formation of the polaron-like states, can be performed exactly in terms of the arbitrarily degenerate states of electron-hole pairs and the phonon modes of equal energies. Using the model of QDs with finite potential barriers for electron and holes leads to new selection rules of interband optical transitions and the three-particle interaction describing simultaneous absorption and/or emission of a photon and a phonon. We also derive a simple expression for the differential cross section of the stationary, low-temperature photoluminescence, which allows the fundamental parameters of the polaron-like excitations to be readily extracted from the frequency-resolved experimental spectra. In particular, the energies of the excitations and the coherence relaxation rates of the optical transitions resulting in their generation and recombination are shown to be directly given by the positions and widths of the photoluminescence peaks. The developed theory complements the existing experimental techniques of studying the phonon-assisted photoluminescence from individual nanocrystals.

The synthesis of a variety of 2,3-disubstituted quinolines has been achieved successfully via a one-pot three-component reaction of arylamines, arylaldehydes and aliphatic aldehydes in the presence of butylpyridinium tetrachloroindate(III), [bpy][InCl4], ionic liquid as a green catalyst and solvent. Mild conditions with excellent conversions, and simple product isolation procedure are noteworthy advantages of this method. The recyclability of the ionic liquid makes this protocol environmentally benign.

The deep ocean is the largest and least known ecosystem on Earth. It hosts numerous pelagic organisms, most of which are able to emit light. Here we present a unique data set consisting of a 2.5-year long record of light emission by deep-sea pelagic organisms, measured from December 2007 to June 2010 at the ANTARES underwater neutrino telescope in the deep NW Mediterranean Sea, jointly with synchronous hydrological records. This is the longest continuous time-series of deep-sea bioluminescence ever recorded. Our record reveals several weeks long, seasonal bioluminescence blooms with light intensity up to two orders of magnitude higher than background values, which correlate to changes in the properties of deep waters. Such changes are triggered by the winter cooling and evaporation experienced by the upper ocean layer in the Gulf of Lion that leads to the formation and subsequent sinking of dense water through a process known as "open-sea convection". It episodically renews the deep water of the study area and conveys fresh organic matter that fuels the deep ecosystems. Luminous bacteria most likely are the main contributors to the observed deep-sea bioluminescence blooms. Our observations demonstrate a consistent and rapid connection between deep open-sea convection and bathypelagic biological activity, as expressed by bioluminescence. In a setting where dense water formation events are likely to decline under global warming scenarios enhancing ocean stratification, in situ observatories become essential as environmental sentinels for the monitoring and understanding of deep-sea ecosystem shifts.

Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant disease caused by an alanine tract expansion mutation in poly(A) binding protein nuclear 1 (expPABPN1). To model OPMD in a myogenic and physiological context, we generated mouse myoblast cell clones stably expressing either human wild type (WT) or expPABPN1 at low levels. Transgene expression is induced on myotube differentiation and results in formation of insoluble nuclear PABPN1 aggregates that are similar to those observed in patients with OPMD. Quantitative analysis of PABPN1 in myotube cultures revealed that expPABPN1 accumulation and aggregation is greater than that of the WT protein. We found that aggregation of expPABPN1 is more affected than WT PABPN1 by inhibition of proteasome activity. Consistent with this, in myotube cultures expressing expPABPN1, deregulation of the proteasome was identified as the most significantly perturbed pathway. Differences in the accumulation of soluble WT and expPABPN1 were consistent with differences in ubiquitination and rate of protein turnover. This study demonstrates, for the first time to our knowledge, that, in myotubes, the ratio of soluble/insoluble expPABPN1 is significantly lower compared with that of the WT protein. We suggest that this difference can contribute to muscle weakness in OPMD., (Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

A patient without prior history of renal failure or hemodialysis presented with weakness of the extremities. On magnetic resonance imaging (MRI), a peri-odontoid soft-tissue mass hypointense to muscle on both T1- and T2-weighted images was noted without obvious bony destruction. Pathological examination revealed degenerated fibrocartilage which stained for amyloid. Further, peroxidase staining for beta-2 microglobulin was positive. We describe the first case of a beta-2 microglobulin peri-odontoid amyloidoma without preceding history of hemodialysis and a review of literature is performed.