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We measured the exciton dynamics in van der Waals heterojunctions of transition metal dichalcogenides (TMDCs) and organic semiconductors (OSs). TMDCs and OSs are semiconducting materials with rich and highly diverse optical and electronic properties. Their heterostructures, exhibiting van der Waals bonding at their interfaces, can be utilized in the field of optoelectronics and photovoltaics. Two types of heterojunctions, MoS2-pentacene and WSe2-pentacene, were prepared by layer transfer of 20 nm pentacene thin films as well as MoS2and WSe2monolayer crystals onto Au surfaces. The samples were studied by means of transient absorption spectroscopy in the reflectance mode. We found that A-exciton decay by hole transfer from MoS2to pentacene occurs with a characteristic time of 21 ± 3 ps. This is slow compared to previously reported hole transfer times of 6.7 ps in MoS2-pentacene junctions formed by vapor deposition of pentacene molecules onto MoS2on SiO2. The B-exciton decay in WSe2shows faster hole transfer rates for WSe2-pentacene heterojunctions, with a characteristic time of 7 ± 1 ps. The A-exciton in WSe2also decays faster due to the presence of a pentacene overlayer; however, fitting the decay traces did not allow for the unambiguous assignment of the associated decay time. Our work provides important insights into excitonic dynamics in the growing field of TMDC-OS heterojunctions.

We report for the first time the direct growth of molybdenum disulfide (MoS2) monolayers on nanostructured silicon-on-insulator waveguides. Our results indicate the possibility of utilizing the Chemical Vapour Deposition (CVD) on nanostructured photonic devices in a scalable process. Direct growth of 2D material on nanostructures rectifies many drawbacks of the transfer-based approaches. We show that the van der Waals material grow conformally across the curves, edges, and the silicon–SiO2interface of the waveguide structure. Here, the waveguide structure used as a growth substrate is complex not just in terms of its geometry but also due to the two materials (Si and SiO2) involved. A transfer-free method like this yields a novel approach for functionalizing nanostructured, integrated optical architectures with an optically active direct semiconductor.

Silica-based optical fibres are a workhorse of nonlinear optics, providing ready access to a range of nonlinear phenomena including solitons and self-phase modulation. However, they have one fundamental limitation: due to the amorphous nature of silica, they do not exhibit second-order nonlinearity, except for negligible contributions from surfaces. Here we demonstrate second-harmonic generation in functionalized optical fibres by using a monolayer of highly nonlinear MoS2directly grown on the fibre’s core. The MoS2-functionalized fibre exhibits a second-order susceptibility (χ(2)) value of 44 pm V–1and a second-harmonic generation conversion efficiency of 0.2 × 10–3m−2W−1. This approach is scalable and can be generalized to other transition metal dichalcogenides and a wide range of waveguide systems. Our results demonstrate a new approach towards efficient in-fibre second-harmonic generation sources and may establish a platform for χ(2)-based nonlinear fibre optics, optoelectronics, photonics platforms, integrated optical architectures and active fibre networks.

Second-harmonic generation is of paramount importance in several fields of science and technology, including frequency conversion, self-referencing of frequency combs, nonlinear spectroscopy and pulse characterization. Advanced functionalities are enabled by modulation of the harmonic generation efficiency, which can be achieved with electrical or all-optical triggers. Electrical control of the harmonic generation efficiency offers large modulation depth at the cost of low switching speed, by contrast to all-optical nonlinear devices, which provide high speed and low modulation depth. Here we demonstrate all-optical modulation of second-harmonic generation in MoS2with a modulation depth of close to 100% and speed limited only by the fundamental pulse duration. This result arises from a combination of D3hcrystal symmetry and the deep subwavelength thickness of the sample, it can therefore be extended to the whole family of transition metal dichalcogenides to provide great flexibility in the design of advanced nonlinear optical devices such as high-speed integrated frequency converters, broadband autocorrelators for ultrashort pulse characterization, and tunable nanoscale holograms.

We studied the energy-level alignment at interfaces between various transition-metal dichalcogenide (TMD) monolayers, MoS2, MoSe2, WS2, and WSe2, and metal electrodes with different work functions (WFs). TMDs were deposited on SiO2/silicon wafers by chemical vapor deposition and transferred to Al and Au substrates, with significantly different WFs to identify the metal–semiconductor junction behavior: oxide-terminated Al (natural oxidation) and Au (UV–ozone oxidation) with a WF difference of 0.8 eV. Kelvin probe force microscopy was employed for this study, based on which electronic band diagrams for each case were determined. We observed the Fermi-level pinning for MoS2, while WSe2/metal junctions behaved according to the Schottky–Mott limit. WS2and MoSe2exhibited intermediate behavior.

AbstractObjective:Percutaneous electrical nerve stimulation is a nonpharmacologic modality of analgesia. This study was conducted to evaluate such a technology (ANSiStim™, DyAnsys Inc., San Mateo, CA) prospectively, in conjunction with standard analgesia per patient demand, for managing postoperative pain following lower-segment cesarean section.Materials and Methods:One hundred parturients were randomized into 2 equal groups (controls and study cases). The latter cohort consisted of parturients for whom nerve stimulation was exerted on the pinna. Pain scores were compared across subjects at corresponding time points with 17 intervals in 48 hours, and, in totality, using estimated area under the curves of numerical scores. Conditional inference analysis was also performed.Results:Ninety-six parturients were finally included. The device was well-tolerated by a majority of parturients. Pain scores were significantly lower in the study group, both at corresponding time intervals and in totality. (H − 15)*(0.74 − H)*(H2− 17H + 110)/440, where H was the corresponding hour, fit the pain scores in the control group. Controls could be detected at the 11 hour with greater pain scores (≥ 4), whereas smaller scores (≤ 2) at the 42nd hour mostly revealed that electrical stimulation was performed (p< 0.001). Requirements for supplementary analgesics were lower for subjects who were given the electroanalgesia.Conclusions:Neurostimulation via the ANSiStim™ is a safe and reasonably effective ambulatory analgesic adjuvant following abdominal delivery. There are no serious adverse effects.

Soft lithography using PDMS molds is shown to be a novel promising method to prepare 3D micro Li-ion electrodes, demonstrated by the synthesis of nano-meter TiO2 anatase in the molds via a TiO2 sol. With this approach the 3D electrode morphology can be controlled to a large degree which allows optimisation of the ionic and electronic wiring. The resulting 3D micro shaped nano-TiO2 electrodes, with no conducting or other additives, show very high rate performance in combination with high electrode densities (energy densities) and long cycle life. These results demonstrate the potential application of soft lithography techniques for high performance electrode preparation which, in addition to the large degree of control on the 3D electrode design, is relatively cheap and easy to scale up.

Background:Preoperative fasting is a requirement to be made by anesthesiologists, but they generally depend on nurses to ensure it is carried out by patients. Lack of updated knowledge among nurses may cause complications.Method:The objective of this study was to understand the knowledge of nurses about preoperative fasting. The multi-unit study was conducted in the units of our hospitals using an Internet-based survey. The responders were anonymous to the authors.Results:The survey was sent to approximately 5,000 nurses, with more than 600 responding to the survey. Most of the respondents were aware of the preoperative fasting guidelines. The understanding regarding preoperative fasting appeared to be insufficient among nurses. The nurses appreciated the concern of the anesthesiologists about fasting. The nurses opined that additional training regarding preoperative fasting might benefit them.Conclusion:This survey conveyed to the authors that the nurses of our hospitals were knowledgeable but required further training to update them.2018;49(3):127–131.J Contin Educ Nurs.2018;49(3):127–131.

Well aligned nanowires of ZnO have been made with an electrospinning technique using zinc acetate precursor solutions. Employment of two connected parallel collector plates with a separating gap of 4 cm resulted in a very high degree of nanowire alignment. By adjusting the process parameters, the deposition density of the wires could be controlled. Field effect transistors were prepared by depositing wires between two gold electrodes on top of a heavily doped Si substrate covered with a 300 nm oxide layer. These devices showed good FET characteristics and photosensitivity under UV-illumination. The method provides a fast and scalable fabrication route for functional nanowire arrays with a high degree of alignment and control over nanowire spacing.

Precise control of the electronic surface states of two-dimensional (2D) materials could improve their versatility and widen their applicability in electronics and sensing. To this end, chemical surface functionalization has been used to adjust the electronic properties of 2D materials. So far, however, chemical functionalization has relied on lattice defects and physisorption methods that inevitably modify the topological characteristics of the atomic layers. Here we make use of the lone pair electrons found in most of 2D metal chalcogenides and report a functionalization method via a Lewis acid–base reaction that does not alter the host structure. Atomic layers of n-type InSe react with Ti4+to form planar p-type [Ti4+n(InSe)] coordination complexes. Using this strategy, we fabricate planar p–n junctions on 2D InSe with improved rectification and photovoltaic properties, without requiring heterostructure growth procedures or device fabrication processes. We also show that this functionalization approach works with other Lewis acids (such as B3+, Al3+and Sn4+) and can be applied to other 2D materials (for example MoS2, MoSe2). Finally, we show that it is possible to use Lewis acid–base chemistry as a bridge to connect molecules to 2D atomic layers and fabricate a proof-of-principle dye-sensitized photosensing device.

Atomic layers of two-dimensional (2D) materials have recently been the focus of extensive research. This follows from the footsteps of graphene, which has shown great potential for ultrathin optoelectronic devices. In this paper, we present a comprehensive study on the synthesis, characterization, and thin film photodetector application of atomic layers of InSe. Correlation between resonance Raman spectroscopy and photoconductivity measurements allows us to systematically track the evolution of the electronic band structure of 2D InSe as its thickness approaches few atomic layers. Analysis of photoconductivity spectra suggests that few-layered InSe has an indirect band gap of 1.4 eV, which is 200 meV higher than bulk InSe due to the suppressed interlayer electron orbital coupling. Temperature-dependent photocurrent measurements reveal that the suppressed interlayer interaction also results in more localized pz-like orbitals, and these orbitals couple strongly with the in-plane E′ and E″ phonons. Finally, we measured a strong photoresponse of 34.7 mA/W and fast response time of 488 μs for a few layered InSe, suggesting that it is a good material for thin film optoelectronic applications.

ABSTRACT.Background:Tobacco in any form (smoking or chewing), arecanut chewing, and alcohol are considered to be the major extrinsic etiological factors for potentially malignant disorders of the oral cavity and for squamous cell carcinoma, the most common oral malignancy in India. An increase in nuclear diameter (ND) and nucleus-cell ratio (NCR) with a reduction in cell diameter (CD) are early cytological indicators of dysplastic change. The authors sought to identify cytomorphometric changes in ND, CD, and NCR of oral buccal cells in tobacco and arecanut chewers who chewed with or without betel leaf. Methods:Participants represented 3 groups. Group I consisted of 30 individuals who chewed tobacco and arecanut with betel leaf (BQT chewers). Group II consisted of 30 individuals who chewed tobacco and arecanut without betel leaf (Gutka chewers). Group III comprised 30 apparently healthy nonabusers. Cytological smears were prepared and stained with modified-Papanicolaou stain. Results:Comparisons between Groups I and II and Groups II and III showed that ND was increased, with Pvalues of .054 and .008, respectively, whereas a comparison of Groups I and III showed no statistical significance. Comparisons between Groups I and II and Groups II and III showed that CD was statistically reduced, with Pvalues of .037 and <.000, respectively, whereas comparison of Groups I and III showed no statistical significance. Comparisons between Groups I and II and groups II and III showed that NCR was statistically increased, with Pvalues of <.000, whereas a comparison of Groups I and III showed no statistical significance. Conclusions:CD, ND, and NCR showed statistically significant changes in Group II in comparison with Group I, which could indicate larger and earlier risk of carcinoma for Gutka chewers than in BQT chewers.

Background Tobacco in any form (smoking or chewing), arecanut chewing, and alcohol are considered to be the major extrinsic etiological factors for potentially malignant disorders of the oral cavity and for squamous cell carcinoma, the most common oral malignancy in India. An increase in nuclear diameter (ND) and nucleus-cell ratio (NCR) with a reduction in cell diameter (CD) are early cytological indicators of dysplastic change. The authors sought to identify cytomorphometric changes in ND, CD, and NCR of oral buccal cells in tobacco and arecanut chewers who chewed with or without betel leaf.Methods Participants represented 3 groups. Group I consisted of 30 individuals who chewed tobacco and arecanut with betel leaf (BQT chewers). Group II consisted of 30 individuals who chewed tobacco and arecanut without betel leaf (Gutka chewers). Group III comprised 30 apparently healthy nonabusers. Cytological smears were prepared and stained with modified-Papanicolaou stain.Results Comparisons between Groups I and II and Groups II and III showed that ND was increased, with Pvalues of .054 and .008, respectively, whereas a comparison of Groups I and III showed no statistical significance. Comparisons between Groups I and II and Groups II and III showed that CD was statistically reduced, with Pvalues of .037 and <.000, respectively, whereas comparison of Groups I and III showed no statistical significance. Comparisons between Groups I and II and groups II and III showed that NCR was statistically increased, with Pvalues of <.000, whereas a comparison of Groups I and III showed no statistical significance.Conclusions CD, ND, and NCR showed statistically significant changes in Group II in comparison with Group I, which could indicate larger and earlier risk of carcinoma for Gutka chewers than in BQT chewers.

A cost-effective and versatile methodology for bottom-up patterned growth of inorganic and metallic materials on the micro- and nanoscale is presented. Pulsed electrodeposition was employed to deposit arbitrary patterns of Ni, ZnO, and FeO(OH) of high quality, with lateral feature sizes down to 200–290 nm. The pattern was defined by an oxygen plasma-treated patterned PDMS mold in conformal contact with a conducting substrate and immersed in an electrolyte solution, so that the solid phases were deposited from the solution in the channels of the patterned mold. It is important that the distance between the entrance of the channels, and the location where deposition is needed, is kept limited. The as-formed patterns were characterized by high resolution scanning electron microscope, energy-dispersive X-ray analysis, atomic force microscopy, and X-ray diffraction.

Objective:To present a new treatment method for internal derangement of the temporomandibular joint.

Objective:To evaluate the efficacy of ‘extended lateral sliding genioplasty’ in improving facial balance, symmetry, and aesthetics for patients with facial asymmetry due to unilateral mandibular deficiency.

In this report, we utilize the heterostructures of monolayer MoS2and self-assembled monolayers (SAMs) of organic molecules as a platform to understand how carrier density of nanomaterials affects their friction behaviors. Previous studies on the friction of two-dimensional materials have explored the effect of lattice structures and morphologies. Given the same normal force and scanning speed of the AFM tip, we observe the sliding friction of high-quality n-type monolayer MoS2could be reduced by SAMs. The friction tunability is attributed to the charge transfer from MoS2to SAMs, which modulated the carrier density and hence the carrier-mediated friction behaviors in 2D MoS2. ab initiosimulations and nanoscale mapping of work functions support this hypothesis. These SAMs-based heterostructures provide a potential tool to control friction in low-dimensional materials, and also an original perspective on the effect of electron–phonon coupling on friction at nanoscale.