Nitrogen acquisition strategy shifts with tree age depending on root functional traits and soil properties in Larix principis-rupprechtii plantations.

Introduction: Variation in plant nitrogen uptake rate and substrate preference is complicated due to the combined influence of abiotic and biotic factors. For the same species of tree across different ages, the interactions between root structural traits, nitrogen uptake rate, and soil environment have not been fully characterized, a situation that constrains our understanding of underground resource strategies employed by trees at different ages. Methods: In the present study, we examined the nitrogen uptake rate, mycorrhiza, morphology, architecture, and chemistry of the roots of Larix principis-rupprechtii in a chronosequence (aged 18, 27, 37, 46, and 57 years) in the Saihanba Mechanical Forest Farm in Northern China. Results: L. principis-rupprechtii preferred to absorb ammonium, followed in order by glycine and nitrate. The ammonium uptake rate of L. principis-rupprechtii significantly decreased (aged 18-37 years) and then increased (aged 46-57 years) with tree age. The glycine, nitrate, and total nitrogen uptake rates decreased with tree age. The root resource acquisition strategy appeared to shift from an acquisitive strategy to a conservative strategy associated with increasing tree age. Discussion: Along the root-mycorrhizal collaboration gradient, the younger L. principis-rupprechtii relied more on their own root morphology and physiology to acquire resources, adopting a "do it yourself" strategy comprising increasing the specific root length, the specific root area, and the N uptake rate (nitrate and glycine). Conversely, older trees depended more on mycorrhizal partners to acquire nitrogen resources, an "outsourcing" strategy. The results contribute to our understanding of underground resource-use strategies of plants and the nitrogen cycle in forest ecosystems according to stand age.

[A prospective study of super-thin anterolateral thigh flap harvesting assisted by high-frequency color Doppler ultrasound in detecting perforators in deep adipose layers].

Objective: To investigate the clinical application of high-frequency color Doppler ultrasound (HFCDU) in detecting perforators in the deep adipose layers for harvesting super-thin anterolateral thigh flap (ALTF). Methods: Between August 2019 and January 2023, 45 patients (46 sides) with skin and soft tissue defects in the foot and ankle were treated, including 29 males and 16 females, aged from 22 to 62 years, with an average of 46.7 years. The body mass index ranged from 19.6 to 36.2 kg/m 2, with an average of 23.62 kg/m 2. The causes of injury included traffic accident injury in 15 cases, heavy object crush injury in 20 cases, mechanical injury in 8 cases, heat crush injury in 1 case, and chronic infection in 1 case. There were 20 cases on the left side, 24 cases on the right side, and 1 case on both sides. After thorough debridement, the wound size ranged from 5 cm×4 cm to 17 cm×11 cm. All patients underwent free super-thin ALTF transplantation repair. HFCDU was used to detect the location of the perforators piercing the deep and superficial fascia, as well as the direction and branches of the perforators within the deep adipose layers before operation. According to the preoperative HFCDU findings, the dimensions of the super-thin ALTF ranged from 6 cm×4 cm to 18 cm×12 cm. The donor sites of the flaps were directly sutured. Results: A total of 55 perforators were detected by HFCDU before operation, but 1 was not found during operation. During operation, a total of 56 perforators were found, and 2 perforators were not detected by HFCDU. The positive predictive value of HFCDU for identifying perforator vessels was 98.2%, and the sensitivity was 96.4%. Among the 54 perforators accurately located by HFCDU, the orientation of the perforators in the deep adipose layers was confirmed during operation. There were 21 perforators (38.9%) traveled laterally and inferiorly, 12 (22.2%) traveled medially and inferiorly, 14 (25.9%) traveled laterally and superiorly, 5 (9.3%) traveled medially and superiorly, and 2 (3.7%) ran almost vertically to the body surface. Among the 54 perforators accurately located by HFCDU, 35 were identified as type 1 perforators and 12 as type 2 perforators (HFCDU misidentified 7 type 2 perforators as type 1 perforators). The sensitivity of HFCDU in identifying type 1 perforators was 100%, with a positive predictive value of 83.3%. For type 2 perforators, the sensitivity was 63.2%, and the positive predictive value was 100%. The surgeries were successfully completed. The super-thin ALTF had a thickness ranging from 2 to 6 mm, with an average of 3.56 mm. All super-thin ALTF survived, however, 1 flap experienced a venous crisis at 1 day after operation, but it survived after emergency exploration and re-anastomosis of the veins; 1 flap developed venous crisis at 3 days after operation but survived after bleeding with several small incisions; 3 flaps had necrosis at the distal edge of the epidermis, which healed after undergoing dressing changes. All 45 patients were followed up 6-18 months (mean, 13.6 months). Three flaps required secondary defatting procedures, while the rest had the appropriate thickness, and the overall appearance was satisfactory. Conclusion: Preoperative application of HFCDU to detect the perforator in the deep adipose layers can improve the success and safety of the procedure by facilitating the harvest of super-thin ALTF.

Comparative study of trimming and resection of diseased finger superficial flexor tendons in gouty carpal tunnel syndrome.

BACKGROUND: Hyperuricemia can lead to synovial hyperplasia in the wrist. In severe cases, it can lead to the deposition of gouty stone in the carpal tunnel, resulting in increased pressure in the carpal tunnel and compression of the median nerve to cause carpal tunnel syndrome (CTS), which is called gouty carpal tunnel syndrome (GCTS). As for the surgical treatment of gouty carpal tunnel syndrome, scholars have different opinions on whether it is necessary to remove the superficial flexor tendon. The purpose of this study was to compare the clinical efficacy of trimming and resection of the diseased superficial flexor tendon in the treatment of gouty carpal tunnel syndrome. METHODS: Clinical data were collected from May 2016 to July 2021 from 10 patients (13 affected wrists) diagnosed with gouty carpal tunnel syndrome and classified into two groups according to the surgical modality: the diseased portion of the gout-eroded superficial finger tendon was trimmed in 9 wrists, and the diseased superficial finger flexor tendon was excised in 4 wrists. Values related to flexion and extension functions, 2-PD, DASH, BCTQ, VAS and recurrence in the affected fingers were compared between the two groups as well as before and after surgery in each group. RESULTS: All affected limbs used were cleared of gouty stones, finger numbness improved, no skin necrosis occurred, and all incisions healed at stage I. At follow-up (13.58 ± 5.53 months), there was no significant difference between groups in flexion and extension function, 2-PD, DASH, BCTQ, and VAS with respect to the affected fingers, and patients in both groups improved significantly before and after surgery. Treatment of only one wrist involved trimming to remove lesion-affected portions of tendon, which reappeared 1 year after surgery, and there was one case of poor recovery from greater piriformis muscle atrophy in both procedures. CONCLUSION: Regarding surgical treatment of patients with gouty carpal tunnel syndrome in which the gouty stone has invaded the superficial flexor tendons of the fingers, the diseased superficial flexor tendons can be selectively excised, and the postoperative mobility of the affected fingers may not be impaired.

Bacterial Changes in Boiled Crayfish between Different Storage Periods and Characterizations of the Specific Spoilage Bacteria.

This study investigated changes in the microbial compositions of crayfish tails during storage at 4 °C (for 0-12 days) as measured using high-throughput sequencing (HTS). The specific spoilage organisms (SSOs) in the crayfish tails were isolated using culture-dependent cultivation methods, and they were identified by 16S rRNA and characterized for their enzymatic spoilage potentials (e.g., protease, lipase, phospholipase, and amylase). The spoilage abilities of the selected strains in the crayfish tails were assessed by inoculating them into real food. Moreover, the microbial growth and the volatile basic nitrogen (TVB-N) changes were monitored during the storage period. The results from the HTS showed that the dominant genus of shrimp tails evolved from Streptococcus (D0) to Pseudomonas (D4) and, finally, to Paenisporosarcina (D12) during storage. Seven bacterial species (Acinetobacter lwoffii, Aeromonas veronii, Kurthia gibsonii, Pseudomonas sp., Exiguobacterium aurantiacum, Lelliottia amnigena, and Citrobacter freundii) were screened from the spoiled shrimp tails by the culture-dependent method, among which Aeromonas veronii had the strongest spoilage ability.

The combined effects of ultrasound and plasma-activated water on microbial inactivation and quality attributes of crayfish during refrigerated storage.

In this study, a decontamination technology combining ultrasound (US) and plasma-activated water (PAW) was developed to better preserve crayfish. First, the decontamination efficacy of US, PAW and their combinations (UP) on crayfish was quantified after 0, 20, 40, or 60 min of treatments. The total viable count (TVC) was reduced by 0.27-0.77 Log CFU/g after individual US or PAW treatments, while a TVC reduction of 1.17 Log CFU/g was achieved after 40 min of UP treatment. Besides, the changes in psychrotrophic bacteria, lactic acid bacteria, yeasts and molds followed a similar trend to TVC. UP treatments normally resulted in more significant reductions in the natural microbiota of crayfish than US or PAW treatments. Furthermore, the microbial quality, physicochemical properties and sensory properties of crayfish after different treatments were assessed during storage at 4 °C for 12 days. According to TVC and total volatile basic nitrogen (TVB-N) values, the control group became unacceptable from 4 days, US or PAW groups became unacceptable from 6 days, while UP group extended the storage time to 8-10 days. During storage, thiobarbituric acid reactive substances (TBARS) values of all the groups were maintained below 0.5 mg/kg, among which the control group exhibited the highest value (0.39 mg/kg). Moreover, UP treatment effectively retarded the deterioration in color and texture properties of crayfish. Fourier transform infrared (FTIR) spectroscopy analysis indicated that UP treatment decreased the α-helix contents and increased the ß-sheet contents of crayfish proteins, while the structural changes were not evident at the end of storage. Low-field nuclear magnetic resonance (LF-NMR) analysis revealed that UP treatment reduced the water migration and enhanced the stability of bond water in crayfish. In addition, E-nose analysis revealed the protection of UP treatment on the sensory properties of crayfish during storage. This study demonstrated that the combinations of US and PAW treatments effectively accelerated the decontamination of crayfish and contributed to better storage quality.

Investigating 3D-printed disk compressing against skin for pain relief in intradermal infiltration anesthesia: a randomized controlled trial.

BACKGROUND: Pain intensity may be varied during the needle advancing through different skin layers, injection into the intradermal layer may exclude mixed pain from deeper planes. This study aimed to investigate whether compressing a three-dimensional (3D)-printed disk against the skin may relieve pain associated with intradermal injection of local anesthetic which mimics the skin test procedure. METHODS: After institutional review board approval, 3D-printed disks with projections were designed for this study. Enrolled patients were randomized to receive either a disk compressing against the axillary skin during the intradermal injection of local anesthesia (compressing disk group) or an intradermal injection of local anesthesia without any compression (no compressing disk group). The primary outcomes were pain intensity (100-mm visual analog scale) and satisfaction (5-point Likert scale) as assessed by patients. RESULTS: Ninety patients with American Society of Anesthesiologists I-II physical status receiving intradermal local anesthesia prior to an ultrasound-guided axillary approach were included. Eighty-seven patients completed the study, with 44 and 43 patients in disk and no disk groups, respectively. Pain scores were significantly different (P < 0.001) in compressing disk (median, 10; IQR, 5-20) and no compressing disk (median, 30; IQR, 20-40) groups. The median satisfaction score was 5 in both groups. No complications occurred during follow-up. CONCLUSION: Compressing a 3D-printed disk against the skin may reduce intradermal needle pain and offers an effective alternative for nerve block induction.

Complementary belowground strategies underlie species coexistence in an early successional forest.

Unravelling belowground strategies is critical for understanding species coexistence and successional dynamics; yet, our knowledge of nutrient acquisition strategies of forest species at different successional stages remains limited. We measured morphological (diameter, specific root length, and root tissue density), architectural (branching ratio), physiological (ammonium, nitrate, and glycine uptake rates) root traits, and mycorrhizal colonisation rates of eight coexisting woody species in an early successional plantation forest in subtropical China. By incorporating physiological uptake efficiency, we revealed a bi-dimensional root economics space comprising of an 'amount-efficiency' dimension represented by morphological and physiological traits, and a 'self-symbiosis' dimension dominated by architectural and mycorrhizal traits. The early pioneer species relied on root-fungal symbiosis, developing densely branched roots with high mycorrhizal colonisation rates for foraging mobile soil nitrate. The late pioneer species invested in roots themselves and allocated effort towards improving uptake efficiency of less-mobile ammonium. Within the root economics space, the covariation of axes with soil phosphorus availability also distinguished the strategy preference of the two successional groups. These results demonstrate the importance of incorporating physiological uptake efficiency into root economics space, and reveal a trade-off between expanding soil physical space exploration and improving physiological uptake efficiency for successional species coexistence in forests.

Contrasting effects of nitrogen and phosphorus additions on nitrogen competition between coniferous and broadleaf seedlings.

Nitrogen (N) is a major element limiting plant growth and metabolism. Nitrogen addition can influence plant growth, N uptake, and species interactions, while phosphorus (P) addition may affect N acquisition. However, knowledge of how nutrient availability influences N uptake and species interactions remains limited and controversial. Here, pot experiments were conducted for 14 months, in which conifers (Pinus massoniana and Pinus elliottii) and broadleaved trees (Michelia maudiae and Schima superba) were planted in monoculture or mixture, and provided additional N and P in a full-factorial design. Nitrogen addition increased the biomass, but P addition did not significantly affect the biomass of the four subtropical species. Combined N and P (NP) addition had no additive effect on plant biomass over N addition. Total plant biomass was significantly positively correlated to root traits (branching intensity and root tissue density) and leaf traits (net photosynthetic rate, stomatal conductance, and transpiration rate), but negatively correlated to root diameter in response to nutrient addition. Plant uptake rates of NH4+ or NO3- were not altered by N addition, but P or NP additions decreased NH4+ uptake rates and increased NO3- uptake rates. Neighboring conifers significantly inhibited NH4+ and NO3- uptake rates of the two broadleaf species, but neighboring broadleaves had no effects on the N uptake rates of pine species. The effects of nutrient additions on interspecific interactions differed among species. Nitrogen addition altered the interaction of P. elliottii and M. maudiae from neutral to competition, while P addition altered the interaction of P. massoniana and M. maudiae from neutral to favorable effects. Increasing nutrient availability switched the direction of interspecific interaction in favor of pines. This study provides insights into forest management for productivity improvement and optimizing the selection of broadleaf species regarding differences in soil fertility of subtropical plantations.

Development of self-assembled zein-fucoidan complex nanoparticles as a delivery system for resveratrol.

Resveratrol is a well-studied dietary polyphenol with diverse health-promoting bioactivities. However, the aqueous insolubility and chemical instability of resveratrol hamper its practical application. This study set out to address these limitations by constructing zein-fucoidan composite nanoparticles as a delivery system of resveratrol. The optimized resveratrol-loaded zein-fucoidan particles (RE-ZFP) were obtained at zein-to-fucoidan ratio of 2:1 (w/w) and zein-to-resveratrol ratio of 10:1 (w/w), and RE-ZFP showed evenly distributed and smoothly spherical microstructures, mean particle size of 121 nm, ζ-potential of - 41 mV, encapsulation efficiency for resveratrol of 95.4%. Electrostatic, steric, hydrophobic, and hydrogen-bonding interactions were major forces required to form RE-ZFP. In addition, RE-ZFP exhibited greater photostability and colloidal stability (including pH, ionic, and storage stabilities) than resveratrol-loaded zein particles (RE-ZP). Particularly, RE-ZFP showed fairly good pH stability. Moreover, zein-fucoidan-based delivery system exhibited a controlled release of resveratrol under in vitro digestion. Finally, zein-fucoidan nanocarriers presented extremely low cytotoxicity to HIEC-6 cells. All the findings demonstrate that the zein-fucoidan nanoparticles developed in the current work will be a prospective strategy for loading resveratrol and other hydrophobic bioactive ingredients and thus extending their application in nutraceuticals or pharmaceuticals.

Zein/fucoidan-based composite nanoparticles for the encapsulation of pterostilbene: Preparation, characterization, physicochemical stability, and formation mechanism.

The objective of this work is to fabricate zein/fucoidan composite nanoparticles for the delivery of pterostilbene, a hydrophobic nutraceutical with diverse beneficial biological activities. Pterostilbene-encapsulated zein/fucoidan composite nanoparticles were prepared using an anti-solvent precipitation method. The fucoidan levels affected the physicochemical properties of the composite nanoparticles. When the zein to fucoidan mass ratio was 10:1, 5:1, 2:1, or 1:1, the prepared zein/fucoidan nanoparticles were stable, and these nanoparticles showed higher pterostilbene encapsulation efficiency than did zein nanoparticles. Fucoidan-stabilized zein nanoparticles exhibited globular structure with average diameters of 120-150 nm. Fourier-transform infrared spectroscopy, X-ray diffraction, and fluorescence spectrum analysis confirmed that the formation of composite nanoparticles was mainly driven by electrostatic, hydrogen-bonding, and hydrophobic interactions between pterostilbene, zein, and fucoidan. Furthermore, the photochemical stability of pterostilbene encapsulated in zein/fucoidan nanoparticles was markedly better than that of pterostilbene loaded in zein nanoparticles or unencapsulated pterostilbene. Zein/fucoidan nanoparticles provided a better controlled release of pterostilbene than did zein nanoparticles under simulated gastrointestinal conditions. Moreover, the cytotoxicity assay demonstrated that zein/fucoidan nanoparticles were nontoxic to Caco-2, HK-2, and L-02 cells. Based on our results, the zein/fucoidan nanoparticles may be a promising delivery carrier for the encapsulation, protection, and release of pterostilbene.

Quantifying spatial morphology and connectivity of urban heat islands in a megacity: A radius approach.

Urban heat island (UHI) effect is an important ecological consequence of rapid urbanization. Although the spatio-temporal evolution of urban heat islands (UHIs) and their driving forces have been discussed in previous studies, the accurate identification of the spatial morphology and connectivity of UHIs is currently lacking. Taking Beijing City as an example, the radius approach (RA) was applied to identify the thresholds of UHIs, and multiple indexes were calculated to analyze the changing connectivity of UHIs from 2000 to 2015. The results showed that the UHIs in Beijing City formed archipelagos, which composed of single main heat island that occupied >79.85% of the total area, and small heat islands scattered in the centers of surrounding districts. In 15 years, the total area occupied by UHIs increased by 30.04%, indicating that the UHI effect became worse. As for landscape patterns of UHIs, aggregation index (AI) increased by 1.6%, landscape shape index (LSI) decreased by 4.1%, and probability of connectivity (PC) increased by 69.1%, all indicating that the distribution of UHIs became more compact, and the connectivity between islands increased. Different expansion types had different influences on the landscape patterns of UHIs: the edge-expansion reduced the fragmentation of UHIs and increased connectivity between islands, the infilling expansion made the boundaries of UHIs regular, and the leapfrog expansion made the AI slight decrease. Based on the radius approach, identifying the range of multi-center UHIs and their spatial expansion type can provide an effective planning guideline for mitigating the negative UHI effect.

Encapsulation of pterostilbene in nanoemulsions: influence of lipid composition on physical stability, in vitro digestion, bioaccessibility, and Caco-2 cell monolayer permeability.

Pterostilbene as a functional food ingredient is limited by low water-solubility and low bioaccessibility. Recently, there has been growing interest to use nanoemulsions to encapsulate hydrophobic compounds. In particular, the lipid type plays a critical role in the efficacy of nanoemulsions. In this study, three different lipids (medium chain triglycerides (MCTs), sunflower oil, and olive oil) were each used as carrier lipids to fabricate nanoemulsions for delivery of pterostilbene. The impact of carrier lipid composition on the physical stability and in vitro digestion of each pterostilbene-loaded nanoemulsion was studied. Its effect on pterostilbene bioaccessibility and Caco-2 cell monolayer permeability of pterostilbene was also investigated. The saturation concentrations of pterostilbene in the three lipids were firstly determined. Nanoemulsions were subjected to in vitro digestion using a model simulating the gastrointestinal tract. Mixed micelles were thus obtained and analyzed for intestinal epithelial permeability using a Caco-2 cell monolayer model. The saturation solubility of pterostilbene in the tested lipids was ranked as follows: MCT > sunflower oil ≈ olive oil. The extent of free fatty acid release during lipid digestion decreased as follows: MCT > sunflower oil > olive oil. Bioaccessibility of pterostilbene followed a similar trend. The highest apparent permeability coefficient of pterostilbene was observed in MCT micelles, followed by sunflower oil or olive oil micelles. Our study indicated that nanoemulsions fabricated with MCTs were more effective for delivering pterostilbene than those produced with long chain triglycerides. Moreover, for long chain triglycerides, the higher unsaturation levels of lipids improved the lipid digestibility and pterostilbene bioaccessibility.

Spatial-temporal change of land surface temperature across 285 cities in China: An urban-rural contrast perspective.

As an important theme in global climate change and urban sustainable development, the changes of land surface temperature (LST) and surface urban heat island (SUHI) have been more and more focused by urban ecologists. This study used land-use data to identify the urban-rural areas in 285 cities in China and comparatively analyzed LST in urban-rural areas with the perspective of spatial-temporal dynamics heterogeneity. The results showed that, 98.9% of the cities exhibited SUHI effect in summer nighttime and the effect was stronger in northern cities than that in southern cities. In 2010, the mean SUHI intensity was the largest in summer daytime, with 4.6% of the cities having extreme SUHI of over 4°C. From 2001 to 2010, the nighttime LST of most cities increased more quickly in urban areas compared with rural areas, with an increasing tendency of the urban-rural LST difference. The difference in the urban- rural LST change rate was concentrated in the range of 0-0.1°C/year for 68.0% of cities in winter and 70.8% of cities in summer. For the higher LST increasing in urban areas compared with rural areas, there were more cities in summer than winter, indicating that the summer nighttime was the key temporal period for SUHI management. Based on the change slope of urban-rural LST, cities were clustered into four types and the vital and major zones for urban thermal environment management were identified in China. The vital zone included cities in Hunan, Hubei and other central rising provinces as well as the Beibu Gulf of Guangxi Province. The major zone included most of the cities in Central Plain Urban Agglomeration, Yangtze River Delta and Pearl River Delta. These results can provide scientific basis for SUHI adaptation in China.

Nitrogen acquisition by plants and microorganisms in a temperate grassland.

Nitrogen (N) limitation is common in most terrestrial ecosystems, often leading to strong competition between microorganisms and plants. The mechanisms of niche differentiation to reduce this competition remain unclear. Short-term (15)N experiments with NH4(+), NO3(-), and glycine were conducted in July, August and September in a temperate grassland to evaluate the chemical, spatial and temporal niche differentiation by competition between plants and microorganisms for N. Microorganisms preferred NH4(+) and NO3(-), while plants preferred NO3(-). Both plants and microorganisms acquired more N in August and September than in July. The soil depth had no significant effects on microbial uptake, but significantly affected plant N uptake. Plants acquired 67% of their N from the 0-5 cm soil layer and 33% from the 5-15 cm layer. The amount of N taken up by microorganisms was at least seven times than plants. Although microorganisms efficiently compete for N with plants, the competition is alleviated through chemical partitioning mainly in deeper soil layer. In the upper soil layer, neither chemical nor temporal niche separation is realized leading to strong competition between plants and microorganisms that modifies N dynamics in grasslands.