A Multidomain Survivable Virtual Network Mapping Algorithm

Although the existing networks are more often deployed in the multidomain environment, most of existing researches focus on single-domain networks and there are no appropriate solutions for the multidomain virtual network mapping problem. In fact, most studies assume that the underlying network can operate without any interruption. However, physical networks cannot ensure the normal provision of network services for external reasons and traditional single-domain networks have difficulties to meet user needs, especially for the high security requirements of the network transmission. In order to solve the above problems, this paper proposes a survivable virtual network mapping algorithm (IntD-GRC-SVNE) that implements multidomain mapping in network virtualization. IntD-GRC-SVNE maps the virtual communication networks onto different domain networks and provides backup resources for virtual links which improve the survivability of the special networks. Simulation results show that IntD-GRC-SVNE can not only improve the survivability of multidomain communications network but also render the network load more balanced and greatly improve the network acceptance rate due to employment of GRC (global resource capacity)

Prevalence and factors associated with post-traumatic stress disorder in healthcare workers exposed to COVID-19 in Wuhan, China: a cross-sectional survey

BackgroundThe COVID-19 pandemic has posed significant threats to both the physical and psychological health of healthcare workers working in the front-line combating COVID-19. However, studies regarding the medium to long term impact of COVID-19 on mental health among healthcare workers are limited. Therefore, we conducted this cross-sectional survey to investigate the prevalence, factors and impact of post-traumatic stress disorder (PTSD) in healthcare workers exposed to COVID-19 8 months after the end of the outbreak in Wuhan, China.MethodsA web-based questionnaire was delivered as a link via the communication application WeChat to those healthcare workers who worked at several COVID-19 units during the outbreak (from December 2019 to April 2020) in Wuhan, China. The questionnaire included questions on social-demographic data, the post-traumatic stress disorder checklist-5 (PCL-5), the family care index questionnaire (Adaptation, Partnership, Growth, Affection and Resolve, APGAR), and the quality-of-life scale (QOL). The prevalence, risk and protective factors, and impact of PTSD on healthcare workers were subsequently analyzed.ResultsAmong the 659 participants, 90 healthcare workers were still suffering from PTSD 8 months after the end of the outbreak of COVID-19 in Wuhan, in which avoidance and negative impact were the most affected dimensions. Suffering from chronic disease, experiencing social isolation, and job dissatisfaction came up as independent risk factors for PTSD, while obtaining COVID-19 related information at an appropriate frequency, good family function, and working in well-prepared mobile cabin hospitals served as protective factors. The impact of PTSD on COVID-19 exposed healthcare workers was apparent by shortened sleeping time, feeling of loneliness, poorer quality of life and intention to resign.ConclusionsEight months after the end of the COVID-19 outbreak in Wuhan, the level of PTSD in healthcare workers exposed to COVID-19 was still high. Apart from the commonly recognized risk factors, comorbid chronic disease was identified as a new independent risk factor for developing PTSD. For countries where the pandemic is still ongoing or in case of future outbreaks of new communicable diseases, this study may contribute to preventing cases of PTSD in healthcare workers exposed to infectious diseases under such circumstances

Diversity and Functional Roles of the Gut Microbiota in Lepidopteran Insects

Lepidopteran insects are one of the most widespread and speciose lineages on Earth, with many common pests and beneficial insect species. The evolutionary success of their diversification depends on the essential functions of gut microorganisms. This diverse gut microbiota of lepidopteran insects provides benefits in nutrition and reproductive regulation and plays an important role in the defence against pathogens, enhancing host immune homeostasis. In addition, gut symbionts have shown promising applications in the development of novel tools for biological control, biodegradation of waste, and blocking the transmission of insect-borne diseases. Even though most microbial symbionts are unculturable, the rapidly expanding catalogue of microbial genomes and the application of modern genetic techniques offer a viable alternative for studying these microbes. Here, we discuss the gut structure and microbial diversity of lepidopteran insects, as well as advances in the understanding of symbiotic relationships and interactions between hosts and symbionts. Furthermore, we provide an overview of the function of the gut microbiota, including in host nutrition and metabolism, immune defence, and potential mechanisms of detoxification. Due to the relevance of lepidopteran pests in agricultural production, it can be expected that the research on the interactions between lepidopteran insects and their gut microbiota will be used for biological pest control and protection of beneficial insects in the future

Passively Mode-Locked Solid-State Laser with Absorption Tunable Graphene Saturable Absorber Mirror

| openaire: EC/H2020/820423/EU//S2QUIPTwo-dimensional layered materials have attracted huge interest in the generation of ultrafast laser for their excellent saturable absorption properties. However, it is still challenging to precisely control their saturable absorption properties. Here, by alternatively changing the electric field intensity on the surface of high-reflection mirror, we successfully control the nonlinear absorption properties (e.g., saturable fluence, modulation depth) of graphene-based saturable absorber mirrors (GSAM) at the optical telecommunication wavelength of 1.3 mu m and their applications in solid-state lasers for the first time. Modulation depth of 1.2% is obtained from a GSAM with deposition of a lambda/8 ( = 1.3 mu m) thick SiO2 layer between the monolayer graphene and a high-reflection mirror, while modulation depth is increased to 4.3% with a lambda/4 thick SiO2 layer insertion in another GSAM. Pulses with the duration of 20 ps (lambda/8 thick SiO2 insertion) and 7.4 ps (lambda/4 thick SiO2 insertion) are achieved, respectively, based on the two mirrors. Our results indicate that this method is easy and reliable to versatility modulate the saturable absorption properties of other two-dimensional layered materials beyond graphene for the generation of ultrafast solid-state lasers.Peer reviewe

Reactivity of 3‑Imino-Functionalized Indoles with Rare-Earth-Metal Amides: Unexpected Substituent Effects on C–H Activation Pathways and Assembly of Rare-Earth-Metal Complexes

The reactivities of different 3-imino-functionalized indoles with rare-earth-metal amides [(Me₃Si)₂N]₃RE­(μ-Cl)­Li­(THF)₃ were studied to reveal unexpected substituent effects on C–H bond activation pathways, leading to the formation of unusual rare-earth-metal complexes. The reactions of 3-(<i>tert-</i>butylimino)­indole with [(Me₃Si)₂N]₃RE­(μ-Cl)­Li­(THF)₃ produced tetranuclear rare-earth-metal complexes {[η¹:(μ₂-η¹:η¹):η¹-3-(<i>t</i>BuNCH)­C₈H₄N]­RE₂­(μ₂-Cl)₂(THF)­[N­(SiMe₃)₂]­(η¹:η¹-[μ-η⁵:η²<i>-</i>3-(<i>t</i>BuNCH)­C₈H₅N]₂Li)}₂ (RE = Ho (<b>1a</b>), Er (<b>1b</b>)), incorporating a unique indolyl-1,2-dianion through sp² C–H activation bonded with the central metal in η¹:(μ₂-η¹:η¹) mode. The reactions of 3-(phenylimino)­indole with [(Me₃Si)₂N]₃RE­(μ-Cl)­Li­(THF)₃ afforded novel binuclear complexes formulated as {3-[PhNCH­(CH₂SiMe₂)­N­(SiMe₃)]­C₈H₅NRE­(THF)­(μ₂-Cl)­Li­(THF)₂}₂ (RE = Y (<b>2a</b>), Sm (<b>2b</b>), Dy (<b>2c</b>), Yb (<b>2d</b>)) through an unexpected sp³ C–H bond activation with subsequent C–C bond coupling reactions. Treatment of 3-(2-methylphenylimino)­indole or 3-(4-methylphenylimino)­indole with [(Me₃Si)₂N]₃­Yb­(μ-Cl)­Li­(THF)₃ generated the corresponding dinuclear rare-earth-metal amido complexes {3-[(2-MePh)­NCH­(CH₂SiMe₂)­N­(SiMe₃)]­C₈H₅NYb­(THF)­(μ₂-Cl)­Li­(THF)₂}₂ (<b>3</b>) and {3-[(4-MePh)­NCH­(CH₂SiMe₂)­N­(SiMe₃)]­C₈H₅NYb­(THF)­(μ₂-Cl)­Li­(THF)₂}₂ (<b>4</b>), following the same pathway for the formation of complexes <b>2a</b>–<b>d</b>. Treatment of 3-(4-<i>tert</i>-butylphenylimino)­indole with [(Me₃Si)₂N]₃RE­(μ-Cl)­Li­(THF)₃ afforded new hexanuclear rare-earth-metal complexes {3-[(4-^<i>t</i>Bu-Ph)­NHCH­(CH₂SiMe₂)­N­(SiMe₃)]­C₈H₅NREN­(SiMe₃)₂}₆ (RE = Dy (<b>5a</b>), Ho (<b>5b</b>), Er (<b>5c</b>)) via sp³ C–H bond activation followed by C–C bond coupling reactions. In contrast, under the same conditions as those for the preparation of <b>5</b>, the reaction with the corresponding yttrium complex provided the new heterohexayttrium complex {3-[(4-<i>t</i>Bu-Ph)­NCH­(CH₂SiMe₂)­N­(SiMe₃)]­C₈H₅NYN­(SiMe₃)₂­Li­(THF)}₆ (<b>6</b>), having a 4-<i>t</i>Bu-anilido moiety. All of these complexes were fully characterized by elemental analysis, spectroscopic methods, and X-ray structure analysis. Plausible pathways for the formation of these different rare-earth-metal complexes were proposed

Flexible Method for Generating Arbitrary Vector Beams Based on Modified Off-Axis Interference-Type Hologram Encoding

A novel experimental setup for the generation of arbitrary vector beams is proposed. The system major includes two reflective liquid crystal spatial light modulators (RLC-SLM) and a polarizing beam splitting prism. Moreover, this method is not limited by the wavelength of light wave and the pixel size of SLM. Theoretical analysis shows that when Gaussian beam or a plane beam is illuminated on a computer-generated hologram (CGH) specially designed in this work, the complex amplitudes of the vector field’s two orthogonal polarization components may be changed by modifying the encoding parameters, resulting in a vector beam with arbitrary complex amplitude and polarization in the output field. The experimental results also show that the two independent coding channels of the device have good polarization-selective imaging ability, which greatly improves the flexibility of generating arbitrary vector beams

CNC-Pincer Rare-Earth Metal Amido Complexes with a Diarylamido Linked Biscarbene Ligand: Synthesis, Characterization, and Catalytic Activity

In preparation of CNC-pincer rare-earth metal amido complexes with a diarylamido linked biscarbene ligand, it is found that conditions have a key influence on final products. Reaction of a THF suspension of bis­[2-(3-benzyl­imidazolium)-4-methyl­phenyl]­amine dichlorides (H₃<b>L</b>Cl₂) with [(Me₃Si)₂­N]₃­RE­(μ-Cl)­Li­(THF)₃ (RE = Yb, Eu, Sm) in THF at room temperature afforded the only unexpected fused-heterocyclic compound 8,9-dibenzyl-3,14-dimethyl-8<i>a</i>,9-dihydro-8<i>H</i>-benzo­[4,5]­imidazo­[2′,1′:2,3]­imidazo­[1,2-<i>a</i>]­imidazo­[2,1-<i>c</i>]­quinoxaline (<b>1</b>) containing an imidazolyl ring and a piperidyl ring, which formed through carbene C–C and C–N coupling. However, the reaction of H₃<b>L</b>Cl₂ with [(Me₃Si)₂­N]₃­Er­(μ-Cl)­Li­(THF)₃ in toluene afforded the CNC-pincer erbium amido complex incorporating a diarylamido linked biscarbene ligand <b>L</b>Er­[N­(SiMe₃)₂]₂ (<b>2</b>) in low yield and the above fused-heterocyclic compound <b>1</b>. The stepwise reaction of H₃<b>L</b>Cl₂ with strong bases (<i>n</i>-BuLi or LiCH₂SiMe₃) in THF for 4 h, followed by treatment with [(Me₃Si)₂­N]₃­RE­(μ-Cl)­Li­(THF)₃, generated zwitterion complexes [<b>L</b>₂RE]­[RECl­{N­(SiMe₃)₂}₃] (<b>L</b> = [4-CH₃-2-{(C₆H₄CH₂-[N­(CH)₂­CN]}­C₆H₃]₂N; RE = Y (<b>3</b>), Er (<b>4</b>), Yb (<b>5</b>)) in less than 20% yields together with fused-heterocyclic compound <b>1</b>. Additionally, the reaction of H₃<b>L</b>Cl₂ with 6 equiv of NaN­(SiMe₃)₂ in THF for 4 h, followed by treatment with YbCl₃, generated a novel discrete complex [<b>L</b>₂Yb]­[{Na­(μ-N­(SiMe₃)₂)}₅­(μ₅-Cl)] (<b>6</b>). The one-pot reaction of H₃<b>L</b>Cl₂ with <i>n</i>-BuLi, followed by reaction with [(Me₃Si)₂­N]₃­RE­(μ-Cl)­Li­(THF)₃ in THF at −78 °C, generated the CNC-pincer lanthanide bisamido complexes <b>L</b>RE­[N­(SiMe₃)₂]₂ (RE = Er (<b>2</b>), Y (<b>7</b>), Sm (<b>8</b>), Eu (<b>9</b>)) in moderate yields. These kinds of biscarbene supported pincer bisamido complexes could also be prepared by a one-pot reaction of bis­(imidazolium) salt (H₃<b>L</b>Cl₂) with 5 equiv of NaN­(SiMe₃)₂, followed by treatment with RECl₃, in good yields at −78 °C. Investigation of the catalytic activity of complexes <b>2</b> and <b>7</b>–<b>9</b> indicated that all complexes showed a high activity toward the addition of terminal alkynes to carbodiimides producing propiolimidines, which represents the first example of rare-earth metal CNC-pincer-type catalysts applied for catalytic C–H bond addition of terminal alkynes to carbodiimides at room temperature

Synthesis and Reactivity of Rare-Earth-Metal Monoalkyl Complexes Supported by Bidentate Indolyl Ligands and Their High Performance in Isoprene 1,4-cis Polymerization

A series of novel rare-earth-metal monoalkyl complexes incorporating partially rotation restricted [N,N]-bidentate indolyl ligands were synthesized and characterized, and their reactivities and catalytic activities were investigated. Treatment of [RE­(CH₂SiMe₃)₃(thf)₂] with 1 equiv of 2-[(<i>N</i>-2,6-diisopropylphenyl)­iminomethyl)]­indole (2-(2,6-^<i>i</i>Pr₂C₆H₃NCH)­C₈H₅NH) in toluene at room temperature afforded the rare-earth-metal monoalkyl complexes [η¹:η¹-2-(2,6-^<i>i</i>Pr₂C₆H₃NCH)­Ind]₂RE­(CH₂SiMe₃)­(thf) (Ind = indolyl; RE = Yb (<b>1</b>), Er (<b>2</b>), Y (<b>3</b>), Dy (<b>4</b>), Gd (<b>5</b>)) and the samarium complex [η¹:η¹-2-(2,6-^<i>i</i>Pr₂C₆H₃NCH)­Ind]₃Sm (<b>6</b>) via alkane elimination in good yields. Treatment of complex <b>2</b> or <b>3</b> with 1 equiv of PhSiH₃ in toluene at 80 °C for 12 h afforded the dinuclear complexes {[μ-η⁶:η¹:η¹-2-(2,6-^<i>i</i>Pr₂C₆H₃NCH₂)­Ind]­RE­[2-(2,6-^<i>i</i>Pr₂C₆H₃NCH)­Ind]}₂ (Ind = indolyl, RE = Er (<b>7</b>), Y (<b>8</b>)) in good isolated yields. Treatment of complex <b>2</b> or <b>3</b> with 1 equiv of amidine (2,6-^<i>i</i>Pr₂C₆H₃)­NCHNH­(2,6-^<i>i</i>Pr₂C₆H₃) in toluene produced the corresponding complexes [η¹:η¹-2-(2,6-^<i>i</i>Pr₂C₆H₃NCH)­C₈H₅N]₂RE­[(2,6-^<i>i</i>Pr₂C₆H₃)­NCHN­(2,6-^<i>i</i>Pr₂C₆H₃)] (RE = Er (<b>9</b>), Y (<b>10</b>)) possessing the amidinate ligand [(2,6-^<i>i</i>Pr₂C₆H₃N)₂CH]⁻. The molecular structures of all complexes were determined by X-ray crystallography. The monoalkyl complexes <b>1</b>–<b>5</b> were tested as isoprene polymerization initiators. Among the complexes investigated, the optimum combination <b>5</b>/Al^<i>i</i>Bu₃/[Ph₃C]­[B­(C₆F₅)₄] displayed a high catalytic activity in isoprene polymerization, producing polymers with an extremely high 1,4-cis selectivity (up to 99%), a high number-average molecular weight (<i>M</i>_n = 7.2 × 10⁵), and a narrow molecular weight distribution (PDI = 1.34) at an isoprene to initiator molar ratio of 6000:1

De Novo Design of Peptidic Positive Allosteric Modulators Targeting TRPV1 with Analgesic Effects.

Transient receptor potential vanilloid 1 (TRPV1) ion channel is a nociceptor critically involved in pain sensation. Direct blockade of TRPV1 exhibits significant analgesic effects but also incurs severe side effects such as hyperthermia, causing failures of TRPV1 inhibitors in clinical trials. In order to selectively target TRPV1 channels that are actively involved in pain-sensing, peptidic positive allosteric modulators (PAMs) based on the high-resolution structure of the TRPV1 intracellular ankyrin-repeat like domain are de novo designed. The hotspot centric approach is optimized for protein design; its usage in Rosetta increases the success rate in protein binder design. It is demonstrated experimentally, with a combination of fluorescence resonance energy transfer (FRET) imaging, surface plasmon resonance, and patch-clamp recording, that the designed PAMs bind to TRPV1 with nanomolar affinity and allosterically enhance its response to ligand activation as it is designed. It is further demonstrated that the designed PAM exhibits long-lasting in vivo analgesic effects in rats without changing their body temperature, suggesting that they have potentials for developing into novel analgesics