Two-Dimensional Metal Halide Perovskites Created by Binary Conjugated Organic Cations for High-Performance Perovskite Photovoltaics.

Studies indicated that two-dimensional (2D) metal halide perovskites (MHPs) embodied with three-dimensional (3D) MHPs were a facile way to realize efficient and stable perovskite solar cells (PSCs) and perovskite photodetectors (PPDs). Here, high-performance PSCs and PPDs, which are based on 2D/3D MHPs bilayer thin films, where the 2D MHPs are created by binary conjugated organic cations, are reported. Systemically studies reveal that the above novel 2D/3D MHPs bilayer thin films possess an enlarged crystal size, balanced charge transport, reduced charge carrier recombination, smaller charge-transfer resistance, and accelerated charge-extraction process compared to the 2D/3D MHPs bilayer thin films, where the 2D MHPs are created by a single conjugated organic cation. As a result, the PSCs based on the above novel 2D/3D MHPs bilayer thin film exhibit a power conversion efficiency of 22.76%. Moreover, unencapsulated PSCs possess dramatically enhanced stability compared with those based on the 2D/3D MHPs bilayer thin films, where the 2D MHPs are created by a single conjugated organic cation. In addition, the PPDs based on the above novel 2D/3D MHPs bilayer thin film exhibit a projected detectivity of 1016 cm Hz1/2/W and a linear dynamic range of 108 dB at room temperature. Our studies indicate that the development of binary conjugated organic cation-based 2D MHPs incorporated with 3D MHPs is a simple method to realize high-performance PSCs and PPDs.

Manipulating Nucleation and Crystal Growth of Inorganic Perovskite Solar Cells.

Inorganic metal halide perovskite materials as sunlight absorbers for solar cells exhibit better thermal stability than organic-inorganic hybrid counterparts. Pure cesium lead triiodide (CsPbI3), with the most suitable band gap, suffers phase instability under an ambient environment. Nucleation and crystal growth are two crucial steps in fabricating a solution-processed perovskite film. A high-quality perovskite film with good morphology makes a significant impact on the efficiency and stability of perovskite solar cells. Dimethylformamide (DMF) is a commonly used aprotic solvent. However, it is difficult to obtain a high-quality inorganic perovskite film using DMF as a single solvent due to its slow evaporation and strong coordination with Pb2+. Here, we investigate dimethylacetamide (DMAc)/DMF as a cosolvent to prompt nucleation during the spin-coating process, leading to higher nucleation density and better surface coverage. In addition, we introduce CsBr in dimethylammonium lead triiodide (DMAPbI3)/CsI precursors to slow down the crystal growth process. CsBr does not increase the film band gap but leads to a pinhole-free film with better crystallinity. Through nucleation and crystal growth engineering, the power conversion efficiency of inorganic perovskite devices is improved to 17.67%, and ambient environment stability is significantly enhanced.

Cross-seeding enables repurposing of aurein antimicrobial peptides as a promoter of human islet amyloid polypeptide (hIAPP).

Since hIAPP (human islet amyloid polypeptide) aggregation and microbial infection are recognized as significant risk factors that contribute to the pathogenesis of type II diabetes (T2D), targeting these catastrophic processes simultaneously may have a greater impact on the prevention and treatment of T2D. Different from the well-studied hIAPP inhibitors, here we propose and demonstrate a repurposing strategy for an antimicrobial peptide, aurein, which can simultaneously modulate hIAPP aggregation and inhibit microbial infection. Collective data from protein, cell, and bacteria assays revealed multiple functions of aurein including (i) promotion of hIAPP aggregation at a low molar ratio of aurein:hIAPP = 0.5 : 1-2 : 1, (ii) reduction of hIAPP-induced cytotoxicity in RIN-m5F cells, and (iii) preservation of original antimicrobial activity against E. coli., S.A., and S.E. strains in the presence of hIAPP. These functions of aurein are mainly derived from its strong binding to different hIAPP seeds through conformationally similar ß-sheet association. Our study provides a promising avenue for the repurposing of antimicrobial peptides (such as aurein) as amyloid modulators for blocking at least two pathological pathways in T2D.

The Role of Introgression During the Radiation of Endemic Fishes Adapted to Living at Extreme Altitudes in the Tibetan Plateau.

Recent genomic analyses of evolutionary radiations suggest that ancient introgression may facilitate rapid diversification and adaptive radiation. The loach genus Triplophysa, a genus with most species endemic to Tibetan Plateau, shows ecological diversity and rapid evolution and represents a potential example of adaptive radiation linked to the uplift of the Tibetan Plateau. Here, we interrogate the complex evolutionary history of Triplophysa fishes through the analysis of whole-genome sequences. By reconstructing the phylogeny of Triplophysa, quantifying introgression across this clade, and simulating speciation and migration processes, we confirm that extensive gene flow events occurred across disparate Triplophysa species. Our results suggest that introgression plays a more substantial role than incomplete lineage sorting in underpinning phylogenetic discordance in Triplophysa. The results also indicate that genomic regions affected by ancient gene flow exhibit characteristics of lower recombination rates and nucleotide diversity and may associate with selection. Simulation analysis of Triplophysa tibetana suggests that the species may have been affected by the Gonghe Movement in the third uplift of the Tibetan Plateau, resulting in founder effects and a subsequent reduction in Ne.

Effect of External Magnetic Field on Bulk Heterojunction Polymer Solar Cells.

Polymer solar cells (PSCs) with a bulk heterojunction (BHJ) device structure have incredible advantages, such as low-cost fabrication and flexibility. However, the power conversion efficiency (PCE) of BHJ PSCs needs to be further improved to realize their practical applications. In this study, boosted PCEs from PSCs based on BHJ composites incorporated with Fe3 O4 magnetic nanoparticles (MNPs), aligned by an external magnetic field (EMF), are reported. It is found that the coercive electric field within the Fe3 O4 MNPs generated by the EMF has a strong and positive influence on the charge generation, which results in a more than 10% increase in free charge carriers. Moreover, the coercive electric field speeds up the charge carrier transport and suppresses charge carrier recombination within PSCs. In addition, a shortened extraction time makes charge carriers more likely to make it to the electrodes. As a result, more than 15% enhancement in PCE is observed from the PSCs based on the BHJ composite incorporated with the Fe3 O4 MNPs and the EMF as compared with that based on the BHJ composite thin film. This work indicates that the incorporation of MNPs and the EMF is a facile way to enhance the PCEs of PSCs.

Origins of the Photocurrent Multiplication Effect in the Polythiophene-Based Photodetectors.

The photocurrent multiplication (PM) effect has been used to boost the device performance of polymer-based photodetectors (PDs), but its origin is rarely addressed. In this study, the origins of the PM effect in polymer PDs based on the P3HT:PC71 BM bulk heterojunction (BHJ) composite thin film, where P3HT is poly(3-hexylthiophene), and PC71 BM is [6,6]phenyl-C71 -butyric acid methyl ester, through both computational simulation and experimental investigation are reported. Systematic studies indicate that two key factors play an important role in the realization of the PM effect in polymer PDs. One factor is the work function of the metal electrode, and the other is the PC71 BM aggregations at the interface between the P3HT:PC71 BM BHJ composite thin film and the metal electrode. Moreover, the results from both experimental and computational simulation indicate that the values of the current density under light illumination minus the current density in the dark of polymer PDs are increased simultaneously along with the reduction of the thickness of the P3HT:PC71 BM BHJ composite thin film. The results provide an understanding of the PM effect in polymer PDs and guidance for the development of high-performance polymer PDs based on BHJ composite thin film.

Formulating Zwitterionic, Responsive Polymers for Designing Smart Soils.

The design of new remediation strategies and materials for treating saline-alkaline soils is of fundamental and practical importantance for many applications. Conventional soil remediation strategies mainly focus on the development of fertilizers or additives for water, nutrient, and heavy metal managements in soils, but they often overlook a soil sensing function for early detection of salinization/alkalization levels toward optimal and timely soil remediation. Here, new smart soils, structurally consisting of the upper signal soil and the bottom hygroscopic bed and chemically including zwitterionic, thermo-responsive poly(NIPAM-co-VPES) and poly(NIPAM-co-SBAA) aerogels in each soil layer are formulated. Upon salinization, the resultant smart soils exhibit multiple superior capacities for reducing the soil salinity and alkalinity through ion exchange, controlling the water cycling, modulating the degradation of pyridine-base ligands into water-soluble, nitrogenous salts-rich ingredients for soil fertility, and real-time monitoring salinized soils via pH-induced allochroic color changes. Further studies of plant growth in smart soils with or without salinization treatments confirm a synergy effect of soil remediation and soil sensing on facilitating the growth of plants and increasing the saline-alkaline tolerance of plants. The esign concept of smart soils can be further expanded for soil remediation and assessment.

Repurposing of intestinal defensins as multi-target, dual-function amyloid inhibitors via cross-seeding.

Amyloid formation and microbial infection are the two common pathological causes of neurogenerative diseases, including Alzheimer's disease (AD), type II diabetes (T2D), and medullary thyroid carcinoma (MTC). While significant efforts have been made to develop different prevention strategies and preclinical hits for these diseases, conventional design strategies of amyloid inhibitors are mostly limited to either a single prevention mechanism (amyloid cascade vs. microbial infection) or a single amyloid protein (Aß, hIAPP, or hCT), which has prevented the launch of any successful drug on the market. Here, we propose and demonstrate a new "anti-amyloid and anti-bacteria" strategy to repurpose two intestinal defensins, human α-defensin 6 (HD-6) and human ß-defensin 1 (HBD-1), as multiple-target, dual-function, amyloid inhibitors. Both HD-6 and HBD-1 can cross-seed with three amyloid peptides, Aß (associated with AD), hIAPP (associated with T2D), and hCT (associated with MTC), to prevent their aggregation towards amyloid fibrils from monomers and oligomers, rescue SH-SY5Y and RIN-m5F cells from amyloid-induced cytotoxicity, and retain their original antimicrobial activity against four common bacterial strains at sub-stoichiometric concentrations. Such sequence-independent anti-amyloid and anti-bacterial functions of intestinal defensins mainly stem from their cross-interactions with amyloid proteins through amyloid-like mimicry of ß-sheet associations. In a broader view, this work provides a new out-of-the-box thinking to search and repurpose a huge source of antimicrobial peptides as amyloid inhibitors, allowing the blocking of the two interlinked pathological pathways and bidirectional communication between the central nervous system and intestines via the gut-brain axis associated with neurodegenerative diseases.

Efficient and Stable Perovskite Solar Cells by B-Site Compositional Engineered All-Inorganic Perovskites and Interface Passivation.

Perovskite solar cells (PSCs) have emerged as a cost-effective solar technology in the past years. PSCs by three-dimensional hybrid inorganic-organic perovskites exhibited decent power conversion efficiencies (PCEs); however, their stabilities were poor. On the other hand, PSCs by all-inorganic perovskites indeed exhibited good stability, but their PCEs were low. Here, the development of novel all-inorganic perovskites CsPbI2Br:xNd3+, where Pb2+ at the B-site is partially heterovalently substituted by Nd3+, is reported. The CsPbI2Br:xNd3+ thin films possess enlarged crystal sizes, enhanced charge carrier mobilities, and superior crystallinity. Thus, the PSCs by the CsPbI2Br:xNd3+ thin films exhibit more than 20% enhanced PCEs and dramatically boosted stability compared to those based on pristine CsPbI2Br thin films. To further boost the device performance of PSCs, solution-processed 4-lithium styrenesulfonic acid/styrene copolymer (LiSPS) is utilized to passivate the surface defect and suppress surface charge carrier recombination. The PSCs based on the CsPbI2Br:xNd3+/LiSPS bilayer thin film possess reduced charge extraction lifetime and suppressed charge carrier recombination, resulting in 14% enhanced PCEs and significantly boosted stability compared to those without incorporation of the LiSPS interface passivation layer. All these results indicate that we developed a facile way to approach high-performance PSCs by all-inorganic perovskites.

Solution-Processed Ternary Perovskite-Organic Broadband Photodetectors with Ultrahigh Detectivity.

Room temperature operated, solution-processed ultrasensitive broadband photodetectors are widely used in various industrial companies in the scientific and medical sectors. Herein, we report solution-processed ultrahigh detectivity broadband photodetectors based on the ternary perovskite-organic composites. To ensure the photodetector based on perovskites has a photoresponse from the ultraviolet-visible to the near-infrared (NIR) region, low optical gap n-type conjugated organic molecules are incorporated with the three-dimensional (3D) perovskites mixed with the two-dimensional (2D) perovskites to form the ternary perovskite-organic composites, which possess an extended spectral response up to the NIR region and superior film characteristics compared to the 2D-3D mixed perovskite composites. Moreover, the photodetectors based on the ternary perovskite-organic composites exhibit enhanced photocurrent and suppressed dark current compared to those based on the 2D/3D mixed perovskite composites. As a result, at room temperature, the photodetectors based on the ternary perovskite-organic composites exhibit a spectral response from 375 to 1000 nm, whereas the photodetectors based on the 2D-3D mixed perovskite composites exhibit a spectral response from 375 to 800 nm. Furthermore, the photodetectors based on the ternary perovskite-organic composites have a photodetectivity over 1015 cm Hz1/2 W-1 (Jones) in the ultraviolet-visible region and over 1013 Jones in the NIR region, a linear dynamic range over 110 dB, and a fast response time. All these results demonstrate that we developed a facile way to realize uncooled solution-processed ultrahigh detectivity broadband photodetectors based on the ternary perovskite-organic composites.

[Historical Changes and Responses to Human Activities of Polycyclic Aromatic Hydrocarbons in Lake Sediments from Northern China During the Past 100 Years].

Polycyclic aromatic hydrocarbons (PAHs) are of concern globally because of their carcinogenic, teratogenic, mutagenic, and bio-accumulative effects. Northern China is one of the regions in China with a high density of lakes; however, the lake aquatic environment is becoming seriously deteriorated, especially from PAH pollution due to the intensification of human activities during the past 100 years. Therefore, the spatial distribution and historical changes in PAHs in lake sediments from northern China were analyzed to indicate their response to anthropogenic emissions and pollution reduction actions. The ω(PAHs) in lake sediments ranged from 18.2 to 1205.0 ng·g-1, and low molecular weight PAHs were the dominant compounds. PAH concentrations increased from the 1950s to a peak level in the 2000s, which was induced mainly by increased energy consumption and rapid economy development, with PAH levels decreasing subsequently in the last 10 years due to craft improvement of wastewater treatment plants and the promotion of new energy policies. Spatially, PAHs pollution in Northeast and North China was more serious than that in Northwest China due to the higher level of economic development and energy consumption. Source apportionment results revealed that historical PAH emissions transferred from biomass combustion to a mixture of coal and petroleum combustion. In addition, the results of ecological risk assessment showed that the synthetic sediment quality index (SeQI) of northern China ranged from 36 to 75, and North and Northeast China posed higher ecological risk than that in Northwest China, with phenanthrene (Phe), acenaphthylene (Ace), acenaphthylene (Acy), and dibenzo(a,h)anthracene (DahA) as the main risk contributors.

High-Performance Ternary Perovskite-Organic Solar Cells.

Perovskite solar cells in which 2D perovskites are incorporated within a 3D perovskite network exhibit improved stability with respect to purely 3D systems, but lower record power conversion efficiencies (PCEs). Here, a breakthrough is reported in achieving enhanced PCEs, increased stability, and suppressed photocurrent hysteresis by incorporating n-type, low-optical-gap conjugated organic molecules into 2D:3D mixed perovskite composites. The resulting ternary perovskite-organic composites display extended absorption in the near-infrared region, improved film morphology, enlarged crystallinity, balanced charge transport, efficient photoinduced charge transfer, and suppressed counter-ion movement. As a result, the ternary perovskite-organic solar cells exhibit PCEs over 23%, which are among the best PCEs for perovskite solar cells with p-i-n device structure. Moreover, the ternary perovskite-organic solar cells possess dramatically enhanced stability and diminished photocurrent hysteresis. All these results demonstrate that the strategy of exploiting ternary perovskite-organic composite thin films provides a facile way to realize high-performance perovskite solar cells.

A mechanistic survey of Alzheimer's disease.

Alzheimer's disease (AD) is the most common, age-dependent neurodegenerative disorder. While AD has been intensively studied from different aspects, there is no effective cure for AD, largely due to a lack of a clear mechanistic understanding of AD. In this mini-review, we mainly focus on the discussion and summary of mechanistic causes of Alzheimer's disease (AD). While different AD mechanisms illustrate different molecular and cellular pathways in AD pathogenesis, they do not necessarily exclude each other. Instead, some of them could work together to initiate, trigger, and promote the onset and development of AD. In a broader viewpoint, some AD mechanisms (e.g., amyloid aggregation mechanism, microbial infection/neuroinflammation mechanism, and amyloid cross-seeding mechanism) could also be applicable to other amyloid diseases including type II diabetes, Parkinson's disease, and prion disease. Such common mechanisms for AD and other amyloid diseases explain not only the pathogenesis of individual amyloid diseases, but also the spreading of pathologies between these diseases, which will inspire new strategies for therapeutic intervention and prevention for AD.

Two-/Three-Dimensional Perovskite Bilayer Thin Films Post-Treated with Solvent Vapor for High-Performance Perovskite Photovoltaics.

Perovskite photovoltaics (PPVs) using three-dimensional (3D) perovskites incorporated with two-dimensional (2D) perovskites have drawn great concentration in both academic and industrial sectors. Here, we report high performance of PPVs based on the 2D/3D perovskite bilayer thin film post-annealed with solvent vapor. The 2D/3D perovskite bilayer thin film post-annealed with solvent vapor possesses enlarged crystal size and crystallinity and blue-shifted photoluminescence compared to a 3D MAPbI3 thin film. Moreover, compared to the PPVs based on a 3D perovskite thin film, enlarged built-in potential, suppressed charge carrier recombination, boosted charge transport, and reduced charge carrier extraction time are observed from the PPVs based on the 2D/3D perovskite bilayer thin film post-annealed with solvent vapor. As a result, perovskite solar cells exhibit a power conversion efficiency of 22.13% and dramatically enhanced stability, and perovskite photodetectors show a photoresponsivity of 1.38 AW-1, detectivity of 6.52 × 1014 cm Hz1/2 W-1, and linear dynamic range of over 167 dB at room temperature. These results demonstrate that we develop a simple method to approach high-performance PPVs by the 2D/3D perovskite bilayer thin film.

[Screening of Priority Pollutants and Risk Assessment for Surface Water from Shengjin Lake].

Shengjin Lake, which serves as an important National Nature Reserve, is suffering from chemical pollution due to rapid industrial and agricultural development in the circumjacent basin. Therefore, 168 anthropogenic toxic chemicals were determined to examine their spatial distribution and identify priority pollutants using a ranking system based on occurrence(O), persistence(P), bioaccumulation(B), ecological risk(E), and human health risk(H). Ecosystem and human health risks were also assessed. The spatial distribution of pollutants indicated that higher concentrations occur in the upper lake area compared to the middle and lower lake areas because of Jiang Dam. According to the derived priority pollutant list, phthalate esters(PAEs), organochlorine pesticides(OCPs), and heavy metals(HMs) are high-priority pollutants; polychlorinated biphenyls(PCBs), polycyclic aromatic hydrocarbons(PAHs), and volatile organic compounds(VOCs) are medium-priority pollutants; and antibiotics(ANTs) are low-priority pollutants. The ecology risk quotient(RQ) of the high-priority pollutants ranged from 4.3 to 15.9, indicating severe ecology risk to the aquatic organism, and higher risks were found in the upper lake areas. Additionally, the human health risk assessment revealed negligible carcinogenic risks associated with high-priority pollutants. The comprehensive ranking system established in this study can be applied to other lake basins by altering the measured concentrations to screen for priority pollutants, offering a scientific foundation for identifying priority control pollutants for watershed management.

A General Crosslinker Strategy to Realize Intrinsic Frozen Resistance of Hydrogels.

Development and understanding of antifreezing materials are fundamentally and practically important for materials design and delivery. However, almost all of antifreezing materials are either organic/icephobic materials containing no water or hydrophilic hydrogels containing antifreezing additives. Here, a general crosslinking strategy to fabricate a family of EGINA-crosslinked double-network hydrogels with intrinsic, built-in antifreezing and mechanical properties, but without any antifreezing additives is proposed and demonstrated. The resultant hydrogels, despite large structural and compositional variations of hydrophilies, electrolytes, zwitterions, and macromolecules of polymer chains, achieved strong antifreezing and mechanical properties in different environments including solution state, gel state, and hydrogel/solid interfaces. Such general antifreezing property of EGINA-crosslinked hydrogels, regardless network compositions, is likely stemmed from their highly hydrophilic and tightly crosslinked DN structures for inducing strong water-network bindings to prevent ice crystal formation from free waters in hydrogel networks. EGINA-crosslinked hydrogels can also serve as a key component to be fabricated into smart windows with high optical transmittance and supercapacitors with excellent electrochemical stability at subzero temperatures. This work provides a simple, blueprint antifreezing design concept and a family of antifreezing hydrogels for the better understanding of the composite-structure-property relationship of antifreezing materials and the fundamentals of confined water in wet soft materials.

A negative piezo-conductive effect from doped semiconducting polymer thin films.

In the past years, piezo-conductive sensors have drawn great attention in both academic and industrial sectors. The piezo-conductive sensors made by inorganic semiconductors exhibited poor mechanical flexibility, restricting their further practical applications. In this study, we report the piezo-conductive sensors by a semiconducting polymer, poly(3,4-ethylenedioxythiophene) doped with tosylate ions (PEDOT:Tos) thin films. Systemically studies indicate that the piezo-conductive response of the PEDOT:Tos thin films is originated from the deformation of the PEDOT crystal cells and the stretched π-π distances induced by Tos. Moreover, the negative piezo-conductive effect, for the first time, is observed from PEDOT:Tos thin film under the pressure. A working mechanism is further proposed to interpret the transient from a positive to a negative piezo-conductive response within the PEDOT:Tos thin films. Our studies offer a facile route to approach effective piezo-conductive sensors based on conjugated polymers.

Solid-State Double-Network Hydrogel Redox Electrolytes for High-Performance Flexible Supercapacitors.

Flexible supercapacitors have great potential applications in wearable and portable electronics, but their practical applications were limited due to the low energy density and mechanical flexibility of solid-state electrolytes used for the construction of flexible supercapacitors. In this study, we first report the solid-state double-network (DN) hydrogel electrolytes (HEs) incorporated with Na2MoO4 redox additives. It is found that the solid-state DN HEs with Na2MoO4 redox additives exhibit high electrochemical performance, excellent mechanical properties, and fast self-recovery features. We then demonstrate novel symmetric supercapacitors (SSCs) incorporated with the solid-state Na2MoO4 DN HEs and the active carbon cloths as the electrodes. The SSCs exhibit a specific capacitance of 84 mF/cm2 at a current density of 1 mA/cm2 and an energy density of 70 µWh/cm2 at a power density of 3800 µWh/cm2. Moreover, the SSCs retain approximately 80% capacitance retention after 7000 charge/discharge cycles, which indicates that the SSCs possess excellent flexibility and stability. All of these results demonstrate that the SSCs incorporated with the solid-state Na2MoO4 DN HEs as energy-storage devices have great practical applications in wearable and portable electronics.

Does the Dzungarian racerunner ( Eremias dzungarica Orlova, Poyarkov, Chirikova, Nazarov, Munkhbaatar, Munkhbayar & Terbish, 2017) occur in China? Species delimitation and identification with DNA barcoding and morphometric analyses.

The Eremias multiocellata-przewalskii species complex is a viviparous group in the genus Eremias, and a well-known representative of taxonomically complicated taxa. Within this complex, a new species - E. dzungarica (Orlova et al., 2017) - has been described recently from western Mongolia and eastern Kazakhstan, with an apparent distribution gap in northwestern China. In this study, we used an integrative taxonomic framework to address whether E. dzungarica indeed occurs in China. Thirty specimens previously classified as E. multiocellata were collected in eastern Kazakhstan and the adjacent Altay region in China. The cytochrome c oxidase I ( COI) barcodes were sequenced and compiled with those from Orlova et al. (2017) and analyzed with the standard and diverse barcoding techniques. We detected an absence of a barcoding gap in this complex, which indicates potential cryptic species in Eremias sp. 3 with high intraspecific diversity and multiple recently evolved species in Clade A. Both BIN and GMYC suggested an unrealistically large number of species (23 and 26, respectively), while ABGD, mPTP and BPP indicated a more conservative number of species (10, 12, and 15, respectively), largely concordant with the previously defined species-level lineages according to phylogenetic trees. Based on molecular phylogeny and morphological examination, all 30 individuals collected in this study were reliably identified as E. dzungarica - a distinct species - confirming the occurrence of this species in the Altay region, Xinjiang, China. Potentially owing to the larger sample size in this study, our morphological analyses revealed many inconsistencies with the original descriptions of E. dzungarica, which were primarily associated with sexual dimorphism and a broader range of values for various traits.

Records of three mammal tick species parasitizing an atypical host, the multi-ocellated racerunner lizard, in arid regions of Xinjiang, China.

BACKGROUND: Ticks are ectoparasites that feed on blood of a broad taxonomical range of terrestrial and flying vertebrates and are distributed across a wide range of environmental settings. To date, the species identity, diversity, and relationships among the ticks on lizards in China have been poorly understood. METHODS: In this study, 30 ticks, collected from the multi-ocellated racerunner (Eremias multiocellata) lizard in the Tarim Basin and adjacent Yanqi Basin of the Xinjiang Uygur Autonomous Region in China, were identified by morphological observation and confirmed by DNA-based techniques. The mitochondrially encoded 12S rRNA, 16S rRNA, and COI gene fragments of ticks were amplified and sequenced. To understand the genetic polymorphisms, 47 ticks collected from hedgehogs and 1 from brushwood in the Tarim Basin were also included. Species identification was based on both morphological and molecular characters. The median-joining network approach was used to evaluate the intraspecific genealogies of the ticks and their relatedness with the geographical origin or hosts. RESULTS: The sequence similarity analysis confirmed that the 30 ticks belong to three genera and three species including 11 individuals of Hyalomma asiaticum, 3 of Rhipicephalus turanicus, and 16 of Haemaphysalis sulcata. A network approach revealed paraphyletic populations of R. turanicus and Hy. asiaticum at the intraspecies level regarding geographical origin and low host specificity. For R. turanicus and Hy. asiaticum, common ancestry was observed between COI sequences from lizards and other sequence types from different hosts and countries. CONCLUSIONS: To our knowledge, our study is the first to conduct a molecular survey of ticks from lizards in the arid regions of Xinjiang, China. Eremias multiocellata is an atypical host of the three tick species. Notably, two species of ticks, Hy. asiaticum and R. turanicus, have been collected and identified from lizards in China for the first time. Star-like networks suggest both of them might have experienced recent population expansion. The discoveries are closely related to the geographical environments in Xinjiang and will provide information for the control of ticks and tick-borne pathogens in Northwest China.