Lily viruses regulate the viral community of the Lanzhou lily rhizosphere and indirectly affect rhizosphere carbon and nitrogen cycling.

The rhizosphere, where plant roots interact intensely with the soil, is a crucial but understudied area in terms of the impact of virus infection. In this study, we investigated the effects of lily symptomless virus (LSV) and cucumber mosaic virus (CMV) on the Lanzhou lily (Lilium davidii var. unicolor) rhizosphere using metagenomics and bioinformatics analysis. We found that virus infection significantly altered soil pH, inorganic carbon, nitrate nitrogen, and total sulfur. Co-infection with LSV and CMV had a greater influence than single infections on the α- and ß-diversity of the rhizosphere viral community in which the absolute abundance of certain virus families (Siphoviridae, Podoviridae, and Myoviridae) increased significantly, whereas bacteria, fungi, and archaea remained relatively unaffected. These altered virus populations influenced the rhizosphere microbial carbon and nitrogen cycles by exerting top-down control on bacteria. Co-infection potentially weakened rhizosphere carbon fixation and promoted processes such as methane oxidation, nitrification, and denitrification. In addition, the co-occurrence network of bacteria and viruses in the rhizosphere revealed substantial changes in microbial community composition under co-infection. Our partial-least-squares path model confirmed that the diversity of the rhizosphere viral community indirectly regulated the carbon and nitrogen cycling functions of the microbial community, thus affecting the accumulation of carbon and nitrogen nutrients in the soil. Our results are the first report of the effects of virus infection on the lily rhizosphere, particularly for co-infection; they therefore complement research on the plant virus pathogenic mechanisms, and increase our understanding of the ecological role of rhizosphere soil viruses.

Quantitative Evaluation of Human Lens and Lens Capsule Elasticity by Optical Coherence Elastography Based on a Rayleigh Wave Model.

Evaluating the biomechanical properties of the lens and lens capsule is important for the clinical diagnosis and treatment of age-related cataracts and presbyopia. In this study, we developed an optical coherent elastography technique to assess the elasticity of the lens and lens capsule in the human eye. With age, the mean Young's modulus of the lens increased from 12.28 ± 0.87 kPa to 18.59 ± 1.45 kPa, and the lens capsule increased from 6.33 ± 0.36 kPa to 13.33 ± 0.74 kPa. The results showed that the Young's modulus of the lens capsule and lens increased with age, with the Young's modulus of the lens significantly higher than that of the lens capsule. This study reports the assessment of the elasticity of the human lens and lens capsule by the OCE technique, indicating that it may provide a potential clinical tool for advancing research on diseases affecting the lens.

In Vivo Imaging and Evaluation of Corneal Biomechanics After Corneal Transplantation by Optical Coherence Elastography.

Postoperative corneal biomechanical evaluation is of great significance in clinical monitoring and management since corneal transplantation is one of the main methods to improve visual function. In this paper, we propose an OCE system based on a small ultrasound transducer to realize the in vivo detection of postoperative corneal elasticity in different directions. It was first validated and analyzed by different agar, and then the elasticity changes in normal cornea and post-transplant corneal implants and implant beds were further investigated. Compared with normal corneas, the shear wave velocity of the postoperative cornea decreased from 7.42 ± 1.71 m/s to 4.95 ± 0.35 m/s. Meanwhile, the shear wave velocity of the corneal implant bed was lower than that of the implanted sheet. Therefore, this study reports the first biomechanical measurement of corneal grafts based on the OCE technique, which might provide a potential tool for the postoperative evaluation of clinical patients.

Characterization of Limbus Biomechanical Properties Using Optical Coherence Elastography.

The elasticity of the limbus is crucial for ocular health, yet it remains inadequately explored. This study employs acoustic radiation force optical coherence elastography (ARF-OCE) to evaluate the biomechanical properties of the limbus under varying intraocular pressures. The method was validated using a heterogeneous phantom and subsequently applied to ex vivo porcine limbus samples. Elastic wave velocity at specific locations within the limbus was calculated, and the corresponding Young's modulus values were obtained. Spatial elasticity distribution maps were generated by correlating Young's modulus values with their respective locations in the two-dimensional structural images. The results indicate that ARF-OCE enhances the understanding of limbus biomechanical behavior and holds potential for diagnosing regional variations caused by ocular diseases.

Investigating the properties of ortho-positronium in liquid scintillators under oxygen quenching.

Investigating the mechanism of positron annihilation in liquid-scintillator based neutrino experiments could be helpful for positron reconstruction algorithms and positron-electron discrimination analysis. Based on this, we utilize a novel positron annihilation lifetime spectrometer to characterize a series of liquid scintillator samples without direct contact with the positron source by applying the anti-coincidence method, which facilitates the measurement of liquids with high accuracy and low background. We obtain an ortho-positronium (o-Ps) lifetime value of 3.02 ns for liquid scintillators composed of linear alkylbenzene and two solutes, and we also measure liquid scintillator samples by bubbling different gases to study the interaction of oxygen dissolved with positronium. The discussion of the annihilation behavior of o-Ps in liquid scintillators further clarify the factors affecting the lifetime and intensity of o-Ps, and the calculation of annihilation rate and free volume radius within the samples has potential applications in characterizing gas solubility and free volume in liquids with o-Ps as probe.

First Report of Fusarium avenaceum Causing Root Rot of Raspberry (Rubus corchorifolius) in China.

Raspberry (Rubus corchorifolius) plants hold historical, economic, and medicinal importance in China (Yang et al. 2022). Raspberries are cultivated to generate income for local farmers in Lintao County, Dingxi City, Gansu Province. However, farmers encountered challenges due to raspberry plants exhibiting root rot disease, resulting in plant death. During a thorough field survey conducted in June 2022, symptoms ranging from leaf yellowing and wilting to necrotic lesions and root rots were observed, where approximately 30% of raspberry plants were affected. Five diseased and healthy plants were collected from the farmers' fields in Lintao (35.53oN, 103.84oE) for pathogen identification. Symptomatic and asymptomatic root tissues were surface sterilized with 75% ethanol for 30 s and 3% NaOCl for 5 min, followed by three rinses in sterile water. Small pieces (0.5 × 0.5 cm) were cut and incubated on potato dextrose agar (PDA) plates at 25°C for 7-10 days. Twenty-two pure Fusarium isolates, which displayed four distinct colony groups morphologically, were obtained. Pathogenicity tests on isolates RB10, RB1, RB30, and RB23, representing each colony group, revealed that RB10 exhibited symptoms similar to those observed in the field. The RB10 strain produced yellowish-white to greyish-white colonies on PDA and was then cultured in a carboxymethylcellulose (CMC) broth for enhanced conidia production (Zhang et al. 2020). Macroconidia were sickle-shaped or slightly curved, with three to five septa (19.2 to 38.5 x 3.1 to 5.8 µm, n =40). Microconidia were oval to ellipsoidal, non-septate or featuring 1 to 2 septa (4.8 to 10.5 x 2.1 to 5.2 µm, n=20). These morphological features indicated the isolate was similar to Fusarium avenaceum (Leslie and Summerell, 2006). For further identification of the strains, genomic regions (ITS-rDNA, TEF-1α, and RPB2) were amplified and sequenced using specific primers ITS1/ITS4, EF-1/EF-2, and 5f2/7cr, respectively (O'Donnell et al. 2010; Uwaremwe et al. 2021; Zarrin et al. 2016). PCR BLASTn queries of NCBI GenBank revealed a 99.8% (522 bp), 99.4% (355 bp) and 99.6% (985 bp) homology with F. avenaceum (MZ724839.1, MN271631.1, and MK185026.1), respectively. Sequences were deposited in GenBank (ITS, OR735571; TEF-1α, PP216660; RPB2, PP857820). One-year-old raspberry seedlings were planted in pots with a sterile soil mix (2:2:1 v/v ratio of soil, peat, and vermiculite) under controlled greenhouse conditions (23-26°C, 16h light/8h dark). A month post-planting, taproots were wounded in six pots and inoculated with 20 ml of conidia suspension (106 conidia/ml), while the other six pots were maintained as controls. After 14 days, RB10-infected plants showed symptoms similar to field observations, while controls remained healthy. The experiment was conducted twice, and re-isolation confirmed both the pathogenicity and identity of the pathogen. In the concatenated phylogenetic tree of ITS, TEF-1α and RPB2, strain RB10 was clustered with the F. avenaceum representative strains KG502, KG431 and F094. Studies revealed F. avenaceum varied pathogenicity across plants (Bugingo, 2022; Moparthi et al. 2020& 2024; Yli-Mattila et al. 2018), and it has been reported to induce raspberry fruit rot (Wang et al. 2017). However, no previous reports linked this fungus to raspberry root rot. This report is crucial for understanding the impact of root rot disease on raspberry cultivation and developing effective management strategies.

Age-period-cohort analysis of global, regional, and national pancreatic cancer incidence, mortality, and disability-adjusted life years, 1990-2019.

BACKGROUND: Pancreatic cancer is one of the deadliest cancers in the world. In recent years, the incidence and mortality rates of pancreatic cancer have shown an increasing trend year by year. This study investigates the independent effects of age, period, and cohort on the global incidence, mortality, and disability-adjusted life years (DALYs) of pancreatic cancer from 1990 to 2019, and evaluates the differences in the burden of pancreatic cancer across regions with different Sociodemographic Index (SDI) levels. METHODS: Estimating the impact of age, period, and cohort on pancreatic cancer disease burden in different SDI regions using age-period-cohort modeling with data (with 95% uncertainty intervals [UI]) from the Global Burden of Disease (GBD) Study 2019 and net drift of age-standardized incidence rates (ASIR), age-standardized mortality rates (ASMR), and age-standardized DALY rates (ASDR) for pancreatic cancer in 120 countries. RESULTS: The number of new cases of pancreatic cancer worldwide increased from 197,348 (95% UI: 188,604,203,971) in 1990 to 530,297 (486,175,573,635) in 2019, the number of deaths increased from 198,051 (189,329 to 204,763) in 1990 to 531,107 (491,948 to 566,537) in 2019, and the number of DALY increased from 4,647,207 (4,465,440 to 4,812,129) in 1990 to 11,549,016 (10,777,405 to 1,238,912) in 2019. The ASIR of the average levels in global pancreatic cancer increased from 5.22 (4.97 to 5.40) per 100,000 population to 6.57 (6.00 to 7.09) per 100,000 population, the ASMR increased from 5.34 (5.07 to 5.52) per 100,000 population to 6.62 (6.11 to 7.06) per 100,000 population, and the ASDR increased from 115.47 (110.82 to 119.60) per 100,000 population to 139.61 (130.18 to 149.14) per 100,000 population. The incidence, mortality, and DALY rates of pancreatic cancer increase with age globally and across all SDI regions, peaking in the 85-89 age group. In high and high-middle SDI regions, the growth rate for males is higher than for females before the age of 85, while females have a higher growth rate after 85. The 75-79 age group exhibits the highest DALY rate in high and high-middle SDI regions, significantly higher than the global and other SDI regions. From 1990 to 2019, the period effects of pancreatic cancer incidence, mortality, and DALY rates have increased significantly worldwide, while remaining almost unchanged in high and high-middle SDI regions. In contrast, period effects have significantly increased in middle, low-middle, and low SDI regions. Cohort effects are more pronounced in middle, low-middle, and low SDI regions. CONCLUSIONS: With the aggravation of population aging, the incidence and mortality rates of pancreatic cancer in the world are increasing, and effective prevention and control measures can be achieved by reducing the exposure of risk factors. The APC model used in our analysis provides a novel approach to understanding the complex trends in the incidence, mortality, and disability-adjusted life years of pancreatic cancer. It can inform the development of targeted interventions to reduce the severe disease burden caused by pancreatic cancer.

Multi-omics analysis reveals the effects of three application modes of plant growth promoting microbes biofertilizer on potato (Solanum tuberosum L.) growth under alkaline loess conditions.

Potato is an important crop due to its high contents of starch, protein, and various vitamins and minerals. Biofertilizers are composed of plant growth promoting microbes (PGPMs) which are essential for improving the growth and resistance of potato. However, little information has focused on the modes of inoculation of biofertilizers on plant growth and microecology. This study aims to reveal the response mechanism of the potato to three modes of inoculation of biofertilizers all containing PGPM Bacillus amyloliquefaciens EZ99, i.e. scattered mode of 5 kg/ha biofertilizer (M5), soaking seed tubers with dissolved 5 kg/ha biofertilizer (MZG), and scattered mode of 3 kg/ha biofertilizer + 2 kg/ha sucrose (MY34) in alkaline loess field through multi-omics analysis of transcriptome, metabolome and microbiome. The physiological result revealed that two application modes of equal amount of biofertilizer M5 and MZG significantly improved the growth and yield of potatoes. Furthermore, the transcriptome of potato exhibited sets of differentially expressed genes enriched in photosynthesis, sugar metabolism, and phenylpropanoid biosynthesis among the three modes, with the M5 mode exhibiting overall up-regulation of 828 genes. Based on the untargeted metabolomic analysis of potato tuber, M5 mode significantly accumulated sucrose, while MZG and MY34 mode significantly accumulated the stress metabolites euchrenone b6 and mannobiose, respectively. Besides, the microbial structure of potato rhizosphere showed that the diversity of bacteria and fungi was similar in all soils, but their abundances varied significantly. Specifically, beneficial Penicillium was enriched in M5 and MZG soils, whereas MY34 soil accumulated potential pathogens Plectosphaerella and saccharophilic Mortierella. Collectively, these e findings highlight that MZG is the most effective mode to promote potato growth and stimulate rhizosphere effect. The present study not only encourages sustainable agriculture through agroecological practices, but also provides broad prospects for the application of PGPM biofertilizer in staple foods.

Viscoelasticity quantification of cancerous tongue using intraoral optical coherence elastography: a preliminary study.

Quantifying the biomechanical properties of the tongue is significant for early diagnosis of tongue carcinoma. Therefore, an intraoral optical coherence elastography system based on a miniature probe was proposed here to evaluate the viscoelasticity of in vivo tongue for the first time. Results of experiments with Sprague-Dawley rats indicate that considerable elasticity diversity occurred between cancerous and normal tongues, and the corresponding ratio of their Young's modulus was evaluated to be 3.74. It is also found that, viscosity in diseased tissue is smaller than that in normal tissue. Additionally, healthy, transitional and cancerous regions in the cancerous tongue can be distinguished easily by calculating viscoelasticity characteristics. Based on this preliminary attempt, our method with advantages of noninvasive, high-resolution, high-sensitivity and real-time detection and convenient operation may have good potential to become a useful tool for tongue carcinoma assessment after further optimization.

Paris saponin VII inhibits triple-negative breast cancer by targeting the MEK/ERK/STMN1 signaling axis.

BACKGROUND: Triple-negative breast cancer (TNBC) is a category of breast cancer characterized with high molecular heterogeneity. Owing to the lack of effective therapeutic strategies, patients with TNBC have a poor prognosis. Paris saponin VII (PSⅦ), a steroidal saponin extracted from the rhizome of Trichillium tschonoskii Maxim, exhibits excellent anti-cancer activity in a variety of solid tumors. However, the role and potential mechanism of PSⅦ against TNBC remain unexplored. PURPOSE: This study aimed to elucidate the therapeutic effects of PSⅦ against TNBC and explore the potential mechanism of action. METHODS: We combined the analysis of public single-cell sequencing data with weighted gene co-expression network analysis (WGCNA) to identity differentially expressed genes (DEGs) that distinguished malignant and normal epithelial cells in TNBC. Subsequently, the biological features of DEGs in TNBC were evaluated. Gene set enrichment analysis (GSEA) was used to define potential pathways associated with the DEGs. The pharmacological activity of PSⅦ for TNBC was evidenced via in vitro and in vivo experiments, and molecular docking, molecular dynamics (MD), surface plasmon resonance (SPR) assay and western blotting were employed to confirm the relative mechanisms. RESULTS: Single-cell sequencing and WGCNA revealed STMN1 as a pivotal biomarker of TNBC. STMN1 overexpression in TNBC was associated with poor patient prognosis. GSEA revealed a significant accumulation of STMN1 within the MAPK signaling pathway. Furthermore, In vitro experiments showed that PSⅦ showed significantly suppressive actions on the proliferation, migration and invasion abilities for TNBC cells, while inducing apoptosis. Molecular docking, MD analysis and SPR assay indicated a robust interaction between PSⅦ and the MEK protein. Western blotting revealed that PSⅦ may inhibit tumor progression by suppressing the phosphorylation of MEK1/2 and the downstream phosphorylation of ERK1/2 and STMN1. Intraperitoneal injection of PSⅦ (10 mg/kg) notably reduced tumor growth by 71.26 % in a 4T1 xenograft model. CONCLUSION: In our study, the systems biology method was used to identify potential therapeutic targets for TNBC. In vitro and in vivo experiments demonstrated PSⅦ suppresses cancer progression by targeting the MEK/ERK/STMN1 signaling axis. For the first time, the inhibition of STMN1 phosphorylation has been indicated as a possible mechanism for the anticancer effects of PSⅦ. These results emphasize the potential value of PSⅦ as a promising anti-cancer drug candidate for further development in the field of TNBC therapeutics.

Impacts of continuous cropping on the rhizospheric and endospheric microbial communities and root exudates of Astragalus mongholicus.

Astragalus mongholicus is a medicinal plant that is known to decrease in quality in response to continuous cropping. However, the differences in the root-associated microbiome and root exudates in the rhizosphere soil that may lead to these decreases are barely under studies. We investigated the plant biomass production, root-associated microbiota, and root exudates of A. mongholicus grown in two different fields: virgin soil (Field I) and in a long-term continuous cropping field (Field II). Virgin soil is soil that has never been cultivated for A. mongholicus. Plant physiological measurements showed reduced fresh and dry weight of A. mongholicus under continuous cropping conditions (i.e. Field II). High-throughput sequencing of the fungal and bacterial communities revealed differences in fungal diversity between samples from the two fields, including enrichment of potentially pathogenic fungi in the roots of A. mongholicus grown in Field II. Metabolomic analysis yielded 20 compounds in A. mongholicus root exudates that differed in relative abundance between rhizosphere samples from the two fields. Four of these metabolites (2-aminophenol, quinic acid, tartaric acid, and maleamate) inhibited the growth of A. mongholicus, the soil-borne pathogen Fusarium oxysporum, or both. This comprehensive analysis enhances our understanding of the A. mongholicus microbiome, root exudates, and interactions between the two in response to continuous cropping. These results offer new information for future design of effective, economical approaches to achieving food security.

Real-time imaging and quantitative analysis of internal gap formation in bulk-fill and conventional resin composites: An OCT evaluation.

BACKGROUND: This study used optical coherence tomography (OCT) to observe real-time internal gap formation in both bulk-fill and conventional resin composites. It aimed to provide a quantitative analysis of variations, addressing the inconclusive nature of microleakage assessment caused by differences in testing methods. METHODS: Fifty extracted third molars prepared with Class I cavities, were divided into five groups (n = 10). Conventional resin Filtek Z350 XT (FZX) was applied with a double-layer filling of 2 mm per layer. Bulk-fill resins X-tra fil (XTF), Filtek Bulk Fill Posterior Restorative (FBP), Surefil SDR Flow + (SDR), and Filtek Flowable Restorative (FFR) were applied with a single-layer filling of 4 mm. Real-time OCT imaging was conducted during light curing. Post-curing, the entire sample was OCT-scanned. Following this, ImageJ software was used to measure the gap (G1 %). Subsequently, thermal cycling (TC) (5000 times, 5 °C-55 °C) was applied, followed by OCT scanning to calculate the gap (G2 %) and ΔG%. Data were analyzed using two-way repeated measures ANOVA, Kruskal-Wallis test, and Duncan's test (α=0.05). RESULTS: There was no significant difference in G1 % among the groups (p > 0.05). Following TC, FZX exhibited the highest G2 %, succeeded by FFR, FBP, XTF, and SDR, with SDR demonstrating the lowest G2 % (p < 0.05). FZX showed the highest ΔG% (p < 0.05), while SDR exhibited the lowest ΔG% (p < 0.05). CONCLUSION: OCT proves to be a promising tool for detecting microleakage. TC exerted a more significant negative impact on conventional resin. Surefil SDR Flow + displayed the least microleakage, both before and after TC.

Impact of electron irradiation on semi-insulating and conductive ß-Ga2O3 single crystals.

The damage behavior and defect evolution in Si-doped and Fe-doped ß-Ga2O3 crystals were investigated using an electron irradiation of 1 MeV at a dose of 1 × 1016 cm-2 in conjunction with structural and optoelectronic characterizations. Distinct decline in electron spin resonance (ESR) signal with g = 1.96 and a UV luminesce of 375 nm were observed in Si-doped ß-Ga2O3 due to the capture of free carriers by irradiation defects. As for the Fe-doped sample, both defect-related blue emission and Cr3+ impurity-related red luminescence underwent prominent suppression after electron irradiation, which can be correlated to the creation of VO and VGa defects and the formation of non-radiative recombination. Noticeably, neither VO- nor VGa-related ESR signals were detected in Fe-doped and Si-doped ß-Ga2O3 irrespective of irradiation; g = 2.003 resonance was observed in Mg-doped ß-Ga2O3 and it experienced remarkable augmentation after electron irradiation. We assigned the g = 2.003 peak to the VGa acceptor. Besides, although the Raman mode of 258 cm-1 in Si-doped ß-Ga2O3 has been suggested to be electron concentration dependent, no obvious change in peak intensity was observed before and after electron irradiation.

Quantitative assessment of corneal elasticity distribution after FS-LASIK using optical coherence elastography.

Quantifying corneal elasticity after femtosecond laser-assisted in situ keratomileusis (FS-LASIK) procedure plays an important role in improving surgical safety and quality, since some latent complications may occur ascribing to changes in postoperative corneal biomechanics. Nevertheless, it is suggested that current research has been severely constrained due to the lack of an accurate quantification method to obtain postoperative corneal elasticity distribution. In this paper, an acoustic radiation force optical coherence elastography system combined with the improved phase velocity algorithm was utilized to realize elasticity distribution images of the in vivo rabbit cornea after FS-LASIK under various intraocular pressure levels. As a result, elasticity variations within and between the regions of interest could be identified precisely. This is the first time that elasticity imaging of in vivo cornea after FS-LASIK surgery was demonstrated, and the results suggested that this technology may hold promise in further exploring corneal biomechanical properties after refractive surgery.

[Retracted] MicroRNA­378 regulates cell proliferation and migration by repressing RNF31 in pituitary adenoma.

[This retracts the article DOI: 10.3892/ol.2017.7431.].

Two-dimensional elastic distribution imaging of the sclera using acoustic radiation force optical coherence elastography.

The scleral elasticity is closely related with many ocular diseases, but the relevant research is still insufficient. Here, we utilized optical coherence elastography to carefully study biomechanical properties of the sclera at different positions and under different intraocular pressures. Meanwhile, elastic wave velocity and Young's modulus of each position were obtained using a phase velocity algorithm. Accordingly, the two-dimensional elasticity distribution image was achieved by mapping the Young's modulus values to the corresponding structure based on the relationship between the position and its Young's modulus. Therefore, elastic information in regions-of-interest can be read and compared directly from the scleral structure, indicating that our method may be a very useful tool to evaluate the elasticity of sclera and provide intuitive and reliable proof for diagnosis and research.

Granular bacterial inoculant alters the rhizosphere microbiome and soil aggregate fractionation to affect phosphorus fractions and maize growth.

The constraint of phosphorus (P) fixation on crop production in alkaline calcareous soils can be alleviated by applying bioinoculants. However, the impact of bacterial inoculants on this process remains inadequately understood. Here, a field study was conducted to investigate the effect of a high-concentration, cost-effective, and slow-release granular bacterial inoculant (GBI) on maize (Zea mays L.) plant growth. Additionally, we explored the effects of GBI on rhizosphere soil aggregate physicochemical properties, rhizosphere soil P fraction, and microbial communities within aggregates. The outcomes showed a considerable improvement in plant growth and P uptake upon application of the GBI. The application of GBI significantly enhanced the AP, phoD gene abundance, alkaline phosphatase activity, inorganic P fractions, and organic P fractions in large macroaggregates. Furthermore, GBI impacted soil aggregate fractionation, leading to substantial alterations in the composition of fungal and bacterial communities. Notably, key microbial taxa involved in P-cycling, such as Saccharimonadales and Mortierella, exhibited enrichment in the rhizosphere soil of plants treated with GBI. Overall, our study provides valuable insight into the impact of GBI application on microbial distributions and P fractions within aggregates of alkaline calcareous soils, crucial for fostering healthy root development and optimal crop growth potential. Subsequent research endeavors should delve into exploring the effects of diverse GBIs and specific aggregate types on P fraction and community composition across various soil profiles.

Quantitative evaluation of biomechanical properties of optic nerve head by using acoustic radiation force optical coherence elastography.

Significance: Previous studies have demonstrated that the biomechanical properties of the optic nerve head (ONH) are associated with a variety of ophthalmic diseases; however, they have not been adequately studied. Aim: We aimed to obtain a two-dimensional (2D) velocity distribution image based on the one-to-one correspondence between velocity values and position using the acoustic radiation force optical coherence elastography (ARF-OCE) technique combined with a 2D phase velocity algorithm. Approach: An ARF-OCE system has the advantages of non-invasive detection, high resolution, high sensitivity, and high-speed imaging for quantifying the biomechanical properties of the ONH at different intraocular pressures (IOPs) and detection directions. The 2D phase velocity algorithm is used to calculate the phase velocity values at each position within the imaging region, and then the 2D velocity distribution image is realized by mapping the velocity values to the corresponding structure based on the one-to-one relationship between velocity and position. The elasticity changes can be read directly according to the quantitative relationship between Lamb wave velocity and Young's modulus. Results: Our quantitative results show that the phase velocity and Young's modulus of the ONH increase by 32.50% and 129.44%, respectively, with increasing IOP, which is in general agreement with the results of previous studies, but they did not produce large fluctuations with the constant change of the ONH direction. These results are consistent with the changes of elastic information in the 2D velocity distribution image. Conclusions: The results suggest that the ARF-OCE technology has great potential in detecting the biomechanical properties of the ONH at different IOPs and directions, and thus may offer the possibility of clinical applications.

What drives soil degradation after gravel mulching for 6 years in northwest China?

Gravel mulch is an agricultural water conservation practice that has been widely used in the semi-arid region of northwest China, but its effectiveness is now lessening due to soil degradation caused by long-term gravel mulching. In this study, we report on a 6-year-long gravel mulch experiment conducted in the northwestern Loess Plateau to evaluate the impact of gravel mulch on soil physicochemical properties and microbial communities, with the objective of clarifying the causes of long-term gravel mulching-induced land degradation. After 6 years mulching, we found that gravel mulched soil contained significantly higher concentrations of total carbon and total organic carbon than non-mulched soil (control). Long-term gravel mulching significantly changed the soil microbial diversity and abundance distribution of bacterial and fungal communities. Notably, the relative abundance of Acidobacteria was significantly higher under gravel mulching than the control (no mulching), being significantly greater in the AG treatment (small-sized gravel, 2-5 mm) than all other treatments. Conversely, the relative abundance of Actinobacteria was significantly lower under gravel mulching than the control, being the lowest in the BG treatment (large-sized gravel, 40-60 mm). At the same time, the relative abundance of Bacteroidetes was significantly lower in AG yet higher in BG vis-à-vis the other treatments. Of the various factors examined, on a 6-year scale, the capture of dust by gravel mulch and altered carbon and nitrogen components in soil play major contributing roles in the compositional change of soil microorganisms. These results suggest that modified soil material input from gravel mulching may be the key factor leading to soil degradation. More long-term experimental studies at different sites are now needed to elucidate the mechanisms responsible for soil degradation under gravel mulching.

Changes in Soil Properties, Microbial Quantity and Enzyme Activities in Four Castanopsis hystrix Forest Types in Subtropical China.

It is well established that forest type can have a profound impact on soil physicochemical properties but the associated changes in soil microbial communities and the mechanisms by which soil quality is improved by various plantations are not fully understood. In this study, soil physicochemical properties and microbial and enzyme activities were investigated in four forest types-Castanopsis hystrix pure forests (CHPF), C. hystrix-Pinus elliottii mixed forests (CHPEF), C. hystrix-Michelia macclurei mixed forests (CHMMF), and C. hystrix-Mytilaria laosensis mixed forests (CHMLF) in the subtropical region of China. The purpose of this study was to assess the effects of afforestation types on characteristics of soil-its physical, chemical, and biological properties. The results showed that the contents of soil total organic carbon (TOC), soil total nitrogen (TN), microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN) were significantly improved in both CHMMF and CHMLF mixed forest stands when compared to the CHPF pure stand. Soil enzyme activities were enhanced in the mixed forests. In particular, high phosphatase activity was observed in CHMLF stands, leading to the transformation of soil phosphorus to available phosphorus in this forest type. Our study demonstrated that the broad-leaved mixed forests, but not coniferous mixed forests, could significantly improve soil quality in the study region. Our research provides a scientific insight into the promotion of vegetation restoration and plantation forest management in plantation regions of subtropical areas.