Nematic elastomers with aligned carbon nanotubes: new electromechanical actuators

We demonstrate, for the first time, the large electromechanical response in nematic liquid crystalline elastomers filled with a very low (~0.01%) concentration of carbon nanotubes, aligned along the nematic director at preparation. The nanotubes create a very large effective dielectric anisotropy of the composite. Their local field-induced torque is transmitted to the rubber-elastic network and is registered as the exerted uniaxial stress of order ~1kPa in response to a constant field of order ~1MV/m. We investigate the dependence of the effect on field strength, nanotube concentration and reproducibility under multiple field-on and -off cycles. The results indicate the potential of the nanotube-nematic elastomer composites as electrically driven actuators

Condition for the Existence of Complex Modes in a Trapped Bose--Einstein Condensate with a Highly Quantized Vortex

We consider a trapped Bose--Einstein condensate (BEC) with a highly quantized vortex. For the BEC with a doubly, triply or quadruply quantized vortex, the numerical calculations have shown that the Bogoliubov--de Gennes equations, which describe the fluctuation of the condensate, have complex eigenvalues. In this paper, we obtain the analytic expression of the condition for the existence of complex modes, using the method developed by Rossignoli and Kowalski [R. Rossignoli and A. M. Kowalski, Phys. Rev. A 72, 032101 (2005)] for the small coupling constant. To derive it, we make the two-mode approximation. With the derived analytic formula, we can identify the quantum number of the complex modes for each winding number of the vortex. Our result is consistent with those obtained by the numerical calculation in the case that the winding number is two, three or four. We prove that the complex modes always exist when the condensate has a highly quantized vortex

Historical Perspectives on Trade and Risk on the Silk Road, Middle East and China

In this paper we examine historical trends in the Silk Road where we discuss historical trade risks, Chinese dynasties and trade. We examine trade risks along the land and sea routes through Central Asia and Middle East. We discuss Chinese balance of payments during different dynasties and the changes in the land and the sea routes. We examine how the trade patterns and routes shifted with the discovery of the New World and when the Dutch and the British formed pooled risk trade associations

An optimal stopping problem for spectrally negative Markov additive processes

Previous authors have considered optimal stopping problems driven by the running maximum of a spectrally negative L\'evy process $X$, as well as of a one-dimensional diffusion. Many of the aforementioned results are either implicitly or explicitly dependent on Peskir's maximality principle. In this article, we are interested in understanding how some of the main ideas from these previous works can be brought into the setting of problems driven by the maximum of a class of Markov additive processes (more precisely Markov modulated L\'evy processes). Similarly to previous works in the L\'evy setting, the optimal stopping boundary is characterised by a system of ordinary first-order differential equations, one for each state of the modulating component of the Markov additive process. Moreover, whereas scale functions played an important role in the previously mentioned work, we work instead with scale matrices for Markov additive processes here. We exemplify our calculations in the setting of the Shepp-Shiryaev optimal stopping problem, as well as a family of capped maximum optimal stopping problems.Comment: 31 page

CHARACTERIZATION OF CYLINDROCARPON-LIKE ANAMORPHS CAUSING ROOT AND BASAL ROT OF APRICOT AND IN VITRO ACTIVITIES OF SOME FUNGICIDES

Four apricot nurseries were surveyed in Hatay province in Turkey to evaluate the phytosanitary status of the nursery plant material. Endophytic and potential pathogenic fungi were identified in plants and 12 Cylindrocarpon-like anamorph isolates were detected in the root system and basal stems of analyzed rootstocks. Based on partial sequencing ITS, three different  Cylindrocarpon-like anamorph species were identified as Dactylonectria torresensis (6 isolates), Dactylonectria novozelandica (3 isolates) and Neonectria candida (3 isolates). Pathogenicity tests were conducted under greenhouse conditions which showed that all three Cylindrocarpon-like anamorph species, were identified as pathogens. ADt12 (D. torresensis) isolate, obtained from the survey area, have been tested in vitro for its sensitivity to several fungicides (thiophanate-methyl (70%), fluazinam (500g/L), fludioxonil (230g/L), and boscalid (26.7%)+pyraclostrobin (6.7%)). It was determined that ADt12 isolate was highly sensitive to fludioxonil and fluazinam, and sensitive to thiophanate-methyl and boscalid+pyraclostrobin as a result of probit analysis of EC50 values

Haptic Feedback Relocation from the Fingertips to the Wrist for Two-Finger Manipulation in Virtual Reality

Relocation of haptic feedback from the fingertips to the wrist has been considered as a way to enable haptic interaction with mixed reality virtual environments while leaving the fingers free for other tasks. We present a pair of wrist-worn tactile haptic devices and a virtual environment to study how various mappings between fingers and tactors affect task performance. The haptic feedback rendered to the wrist reflects the interaction forces occurring between a virtual object and virtual avatars controlled by the index finger and thumb. We performed a user study comparing four different finger-to-tactor haptic feedback mappings and one no-feedback condition as a control. We evaluated users' ability to perform a simple pick-and-place task via the metrics of task completion time, path length of the fingers and virtual cube, and magnitudes of normal and shear forces at the fingertips. We found that multiple mappings were effective, and there was a greater impact when visual cues were limited. We discuss the limitations of our approach and describe next steps toward multi-degree-of-freedom haptic rendering for wrist-worn devices to improve task performance in virtual environments.Comment: 6 pages, 9 figures, 1 table, submitted and accepted to the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 2022 Conferenc

Gamma Irradiation on Growth and Development of Amorphophallus Muelleri Blume.

Iles-iles (Amorphophallus muelleri Blume) produces apomictic seeds lead to low genetic variation. In order to induce genetic variation, germinated seeds were exposed to Gamma irradiation (Co-60) at doses of 10 to 100 Gy. Seed irradiation was conducted at Center for the Application of Isotope and Irradiation Technology -National Nuclear Energy Agency (CAIRT), Indonesia. Morphology and yield of M1 generation were observed. Results showed that irradiation at a dose of 10 Gy close to LD50 with survival rate 56%. Gamma irradiation at a dose of 10 Gy delayed seeds germination. Germination rates gradually increased and reached maximum at 4 weeks after planting (WAP) for control plants, and 14 WAP of irradiated plants. At 16 WAP, germination rate of 10 Gy irradiated plants was 56% and 84% for those of control plants. Irradiation induced chimera as indicated by short petiole, variegated and abnornal shape of leaflets. Some irradiated plants entered dormancy at 8-10 weeks later than control ones. Prolong vegetative periode lead the plants to produce heavier corms. This study revealed the possibility to induce variation of A. muelleri by using gamma irradition. Keywords: Amorphophallus muelleri, gamma irradiation (Co-60), morphological variation, mutation breedin

Cognitive functions in neurofibromatosis type 1 patients and unaffected siblings

Attention, learning, and perceptual problems have been reported at various degrees and rates in neurofibromatosis type 1 (NF1). We aimed to define the cognitive profiles frequently associated with NF1. Children and adolescents with NF1 (n=58) were tested using Wechsler Intelligence Scales for Children-Revised (WISC-R), Judgment of Line Orientation, and Bender Visual-Motor Gestalt tests. Comparison groups were unaffected siblings of NF1 patients (n=20), children with attention deficit and hyperactivity disorder (ADHD, n=40), and normal children (n=40). No difference was found between familial or sporadic NF1 cases. Seventeen/58 (29%) of NF1 cases had a full scale IQ 80 (n=27) scored lower in WISC-R subtests measuring visual perception when compared to a healthy control group of similar intelligence, and lower in arithmetic but better in Bender-Gestalt and Judgment of Line Orientation tests when compared to an ADHD group of similar intelligence. These results indicate a high prevalence of mental retardation in a clinical NF1 series. NF1 patients who have normal intelligence may have impaired visual perception, but their visual perceptual problems are less than in ADHD. The tendency of unaffected siblings of NF1 patients to have mildly but consistently low test scores compared to healthy controls needs to be studied further for underlying genetic or environmental factors

Investigating cation binding properties of crown ethers with DFT methods

Benzopiran kumarinleri doğal bitkilerden sentezlenen ve pek çok özellik gösteren önemli bileşiklerdir. Bu moleküller, kromofor özelliklerinden dolayı en çok boya kimyasında kullanılmaktadırlar. Kuvvetli oksijen köprüleri içeren bu makro halkalı bileşikler, alkali ve toprak alkali metaller ile (+) yüklü kompleksler oluşturmaktadırlar. Pedersen, yüksek seçiciliği olan taç eter moleküllerin keşfi ve kullanımı ile ilgili olarak yaptığı çalışmalardan ötürü 1987 Nobel Kimya ödülünü almıştır. Kumarin türevlerinin optik özellikleri ile makro halkalı taç eterlerin katyon bağlama özelliklerini bir araya getirerek uygulama alanlarını genişletmek üzere Tiftikçi ve Erk tarafından bir seri molekül sentezlenmiştir (Tiftikçi ve Erk,2004). Literatüre son yıllarda kazandırılan bu moleküllerin elektronik ve optik özelliklerinin bilinmesi daha sonra yapılacak olan sentezlere de ışık tutacaktır. Bu özelliklerin teorik yöntemlerle anlaşılmasına yönelik yapılan bu çalışmada ayrıca kumarin halkasının makro halkaya bağlanma pozisyonuna, kumarin halkası üzerindeki sübstitüsyona, makro halka büyüklüğüne ve katyonun büyüklüğüne bağlı olarak moleküllerin UV soğurma spektrumlarındaki ve katyon bağlama enerjilerindeki değişiklikler de incelenmiştir. Bağlanma enerjileri ya da moleküllerin iyon seçiciliği Li+, Na+, ve K+ iyonları için Yoğunluk Fonksiyoneli Teorisi (YFT) yöntemiyle B3LYP/6-31g(d) seviyesinde gaz fazında, su ve asetonitril için ortamın dielektrik sabiti değiştirilerek çözücü ortamında hesaplanmıştır. Elde edilen sonuçlar mevcut olan deneysel sonuçlarla karşılaştırılmıştır. Katyonlu ve katyonsuz moleküllerin 0 Kelvin’deki gaz fazı ve çözücüye göre düzeltilmiş elektronik enerjileri, sıfır enerjisi göz önüne alınarak hesaplanmıştır. Katyon bağlama reaksiyonunun entalpisi ve serbest enerjisi ise baz fonksiyonundan gelen hatalara göre düzeltilerek rapor edilmiştir. Bağlanma enerjilerinin daha yüksek bazda tekrarlanan hesaplarla baz fonksiyonuna bağlı olarak nasıl değiştiği incelenmiştir. Anahtar Kelimeler: Kumarin, Taç Eterler, DFT, BSSE.The coumarins of benzopyran are important compounds which are synthesized from natural plants and have a good number of features. These molecules are mostly used at dye chemistry-because of their chromophoric features. Macrocyclic ether molecules which are known as good cation binding compounds, are first discovered in 1967 by Charles J. Pedersen who won 1/3 of the Chemistry Nobel Prize for the development and use of molecules with structure-specific interactions of high selectivity These molecules contain strong oxygen bridges and have a tendency to form positively charged complexes with alkaline and soil alkaline metals in solution. Being aware of the electronic and optical features of these molecules, which have been shown recent literatures, will illuminate the forthcoming syntheses. To bring optical features of the coumarin derivatives and the cation binding features of macrocyclic crown ethers together, a series of new molecules are synthesized by Tiftikçi and Erk to expand the application areas of both type of molecules (Tiftikçi; Erk, 2004). In this study which is done to understand these features with theoretical methods, the binding position of the coumarin to the macrocyclic,  the substitution on the coumarin, the magnitude of macrocyclic and according to the magnitude of the cation, the changes on the UV absorption spectrums of molecules and the cation binding energy are also analyzed. The energy of binding or the ion selectivity of the molecules are calculated with the following methods; for Li+, Na+, ve K+ ions with the method of DFT (Density Functional Theory) at the B3LYP/6-31g(d) level at gas phase, for water and asetonitril, by changing the constant dielectric at the solvent medium. The outcomes which are yield are compared with the existing experimental outcomes. The gas phase at the 0 Kelvin of the molecules with and without cations and their corrected electronic energy according to the solvent are calculated by regarding the zero energy. Also, the enthalpies and free energy of the cation binding reaction are reported by correcting according to the errors coming from the base function (BSSE). Depending on the base function, how the binding energies change with repeated calculations at a higher base is examined. In this study cationic recognition of the computerized form of crown ethers, which were synthesized before, has been investigated. For that reason optimization of the molecules has been carried out. Geometries of the studied molecules optimized using Density Functional Theory method (Devlin vd, 1994,1996) B3LYP (Becke 3 Parameter Lee-Yang-Parr) functional (Lee vd, 1998), and 6-31g(d) bases functional. Using optimized molecules with Time Dependent Density Functional Theory methods Exited states were optimized. Using exited states values which were computed by TDDFT method, UV graphics drawn with a computer software written in Fortran. The attained values are normalized to 1 and graphs are plotted according to wave lengths. UV spectra peaks are analyzed to find source and reasons of the peak it could happen is investigated (Erk vd., 1998). To investigate interactions with Na+ cation, BSSE correlation energy method used for calculation of reaction energies. To investigate effect of solvent water and asetonitril used as solvent. Reaction energies of water and asetonitril were also calculated. Attained results are compared with the experimental results. To confirm optimized geometries, experimental X-ray results of   18crown6 Na+ molecules compared with results of the study. There is a concordant between experimental X-Ray data and theoretical optimized geometry. So the method applied in this study has been chosen correctly for those molecules?. For studies carried out in asetonitril, when UV peaks are compared with experimental data, it has been understood that there is accommodation between them. With comparing experimental and theoretical data It has been tried to proof the correctness of the applied methods. These evidences could be used in further studies as basis. The UV absorption is shifted to visible region when coumarin ring is added to alone crown ethers. For that reason the optical properties of crown ethers can be investigated. Moreover if coumarin rings are added to aromatic groups like phenyl, the maximum UV peaks are shifted to red region. If more functional groups are added to the crown ether ring, the cation binding energy of the crown ether will decrease. For that reason cation binding also decreases. Keywords: Coumarin, Crown Ethers, DFT, COMPASS, BSSE