Narrow Vessels Research Articles

Vascular Tissues Distribution Affects Calcium and Calcium Oxalate Crystals in Fruits of Wild Tomato (Lycopersicon pimpinellifolium (L.) Mill.).

Tomato fruit is an excellent model for evaluating calcium regulation in plants since it expresses symptoms of either calcium deficiency or calcium excess. Aiming to evaluate the structure of the vascular system and its interactions with calcium and calcium oxalate crystals (CaOx), fruits of Lycopersicon pimpinellifolium were studied. Calcium levels were evaluated in basal, median, and distal pericarp portions, which were also analyzed under a light microscope to describe the structure. The L. pimpinellifolium pericarp shows idioblasts with calcium oxalate crystals. Vascular bundles of the basal pericarp show large transverse sections and abundant xylem vessels. The vascular bundles were smaller in the distal pericarp, and the xylem showed fewer and narrower vessels. The terminal bundles often consisted exclusively of phloem. Despite the differences observed in vascular bundle composition, the density of the vascular system was uniform in the pericarp as a consequence of bundle ramifications that occur at distal portions. The calcium concentration and crystal idioblasts decrease towards the apex of the fruit. The reduction in the xylem:phloem ratio seems to determine the low calcium concentration in the distal fruit portion.

Divergences in stem and leaf traits between lianas and coexisting trees in a subtropical montane forest

Abstract Patterns in functional trait variation associated with the ecological strategies of lianas and trees in subtropical montane forests remain poorly understood due to lack of trait comparisons. Here, we filled this gap by investigating trait divergence between lianas and trees with different leaf habits for 13 traits of 33 species (7 deciduous and 4 evergreen liana species, and 10 deciduous and 12 evergreen tree species) in a subtropical montane forest in southwestern China. We found that lianas had significantly larger stem xylem vessel diameter, higher theoretical hydraulic conductivity, specific leaf area, leaf nitrogen, and phosphorus concentrations, but lower leaf dry-matter content and N/P ratio than sympatric trees, indicating that lianas employ an acquisitive ecological strategy, with a more efficient stem hydraulic system and more productive leaves. In contrast to trees, lianas exhibited a larger variation in vessel diameter, with a few wide and many narrow vessels in the xylem, indicating a greater vessel dimorphism. Growth form explained 48.7% of the total trait variation, while leaf habit only explained 3.8% of trait variation, without significant interaction between growth form and leaf habit. In addition, significant stem–leaf trait relationships were only found in trees, but not in lianas, indicating decoupling of stem hydraulic function and leaf traits in subtropical lianas. These results suggest that subtropical montane lianas and trees differ strikingly in stem and leaf functional traits. Further studies are warranted to strengthen our understanding of the mechanisms underlying the strong divergence in ecological strategies between lianas and trees in subtropical forest ecosystems.

Pharmacokinetics and Pharmacodynamics of Topical Decongestants Xylometazoline and Oxymetazoline: A Literature Review

Introduction: This article provides a review and detailed analysis of scientific publications on the pharmacokinetic and pharmacodynamic characteristics of xylometazoline and oxymetazoline. Xylometazoline and oxymetazoline are two commonly used nasal decongestants used to temporarily relieve nasal congestion caused by colds, allergies, and sinusitis. Both drugs narrow blood vessels in the nasal passages, reducing edema and rhinorrhea.
 Aims: The aim of the study is to evaluate the pharmacokinetic and pharmacodynamic characteristics of xylometazoline and oxymetazoline based on a literature review.
 Material and Methods: A retrospective review of literature data was performed using Scopus, Web of Science, PubMed, and ScienceDirect databases. Different keyword combinations, such as "topical decongestants", "xylometazoline", "oxymetazoline", "pharmacokinetics" and "pharmacodynamics", were used to search for information on the problem addressed. When processing search results, either the most recent publications (over the last 10 years) or the latest publications for this topic (regardless of their release) were chosen.
 Results: After reviewing abstracts and getting acquainted with their full-text articles, 47 scientific sources that met the eligibility criteria were selected. Although there are minor differences between pharmacokinetics and pharmacodynamics of xylometazoline and oxymetazoline according to available literature sources, both drugs exhibit very low systemic exposure, thus reducing the number of side effects due to the lack of systemic action and producing a high local concentration of the drugs in areas of inflammation. Besides, because of its pharmacokinetic properties, xylometazoline has a faster onset of action and a shorter duration of therapeutic effect compared to oxymetazoline.

Comparative anatomy vs mechanistic understanding: how to interpret the diameter-vulnerability link

Summary Results from comparative and ecological wood anatomy combined with a number of experimental studies on plant hydraulics have led to a pervasive and longstanding assumption that wider-diameter vessels are more vulnerable to drought-induced embolism than narrower vessels. Although we agree that wider vessels tend to be more vulnerable than narrower vessels within stems and within roots across most species, our current understanding of the diameter-vulnerability link does not offer a mechanistic explanation for why increased vessel diameter should consistently lead to greater vulnerability or vice versa. Causes of drought-induced embolism formation and spread likely operate at the nano-level, especially at gas-liquid-surfactant interfaces inside intervessel pit membranes. We evaluate here new perspectives on drought-induced embolism and its key anatomical and physico-chemical drivers, of which vessel diameter is one of the parameters involved, although its linkage to embolism vulnerability is likely indirect. As such, the diameter-vulnerability link does not imply that species with on average wider vessels are consistently more susceptible to drought-induced embolism compared to species with narrower vessels. Scientific priorities for future progress should focus on more accurate predictions of how water transport in plants is affected by drought, which requires a better mechanistic understanding of xylem network topology and biophysical processes at the nano-scale level in individual vessels that determine embolism formation and spread.

THU350 Rapid Decrease Of Glycemic Levels In Three Patients With Severe Insulin Resistance Associated With Bell’s Palsy.

Abstract Disclosure: E. Chuki: None. M. Lightbourne: None. B. Abel: None. R.J. Brown: None. Bell’s palsy (BP) is associated with diabetic angiopathy and facial nerve ischemia and may be the first sign of diabetic mononeuropathy. Specific risk factors for diabetic mononeuropathy have not been well established. Rapid tightening of glycemic control has been associated with worsening diabetic retinopathy. However, this association has not been reported previously in the development of diabetic mononeuropathy or BP. We describe three patients with extreme insulin resistance, in whom rapid correction of hyperglycemia was temporally associated with development of BP. Case 1: A 63 year-old African American male with history of type 2 diabetes (T2D) and peripheral neuropathy was admitted with sudden onset severe insulin resistance and DKA, leading to a diagnosis of type B insulin resistance. Serum glucose was >600 mg/dl and A1c was 13.4%. He was treated with an insulin drip, then transitioned to subcutaneous insulin U-500 at a total daily dose of ∼3000 units, resulting in blood glucose between 140 and 180 mg/dl. On Day 5 after initiating U-500 and achieving tight control of glycemia, the patient developed bilateral Bell’s Palsy, which resolved after 4 years. Case 2: A 25 year-old African American female with history of T2D was admitted with sudden onset severe insulin resistance and DKA requiring an insulin drip of ∼3,000 units per day, leading to a diagnosis of type B insulin resistance. A1c on admission was 14%. After ∼5 days, she transitioned to U-500 that was titrated over 2 weeks to a total daily dose of 3,000 units with blood glucose between 98 and 177 mg/dL. She developed bilateral BP approximately 43 days from onset of DKA and 36 days after starting U-500 insulin with improved glycemic control. At last follow up 5 years later she still had residual facial weakness. Case 3: A 25 year-old Caucasian male with history of diabetes due to type A insulin resistance (Rabson-Mendenhall Syndrome) and recurrent ketosis on U500 insulin >1,000 units daily had poor adherence to insulin and diet with A1c of 14.3%. 3 weeks after A1c measurement he was started on a Continuous Glucose Monitor (CGM), leading to dramatic change in diet and medication adherence, with reduction in the estimated A1c based on glucose management indictor (GMI) to 7.7% within 3 weeks. 3 weeks after starting CGM use with improved compliance and glycemic control, he developed unilateral BP, which fully recovered after 1 month.We report 3 cases in which onset of BP was observed in rapid temporal correlation with massive increases in insulin dose and/or improvement in glycemia. Severe insulin resistance and rapid decrease of glycemic levels may lower intravascular volume and narrow vessels, leading to microvascular disruption of the vasa nervorum, ultimately causing mononeuropathy. A more gradual approach to glycemia management in patients with severe insulin resistance may be warranted to mitigate this risk. Presentation: Thursday, June 15, 2023

THU614 Neurofibromatosis Type 1 Presenting With Pheochromocytoma And Severe Vascular And Hematological Manifestations Due To A Novel NF1 Mutation

Abstract Disclosure: L.A. Alobaid: None. O. Alsagheir: None. M. Alswailem: None. B. Alghamdi: None. A.S. Alzahrani: None. Neurofibromatosis (NF) type 1 is an autosomal dominant condition caused by germline mutations in NF1, a tumor suppressor gene encoding neurofibromin. Pheochromocytomas (PCC) and paragangliomas can develop in up to 8% of patients with NF type 1. Vasculopathy leading to vascular narrowing and malformations are also well described manifestations of NF. Finally, a number of hematological manifestations have been described including thrombocytosis, leukocytosis, myelodysplastic syndrome, acute myeloid leukemia, and lymphoma. We present a young woman who has NF type 1 and presented with all of these unusual manifestations including PCC, leukemoid reaction, severe thrombocytosis, vascular malformations and narrowing, extensive skin freckling and café au lait spots. She was found to have a novel truncating NF1 mutation, which explains the severity of her disease. Case description: A 21-year-old lady referred to our hospital with a 4-year history of episodic headaches, blurred vision, on/off palpitations, sweating, and facial redness. She was found to be severely hypertensive at 200-230/95-140 mm Hg. Family history was positive for skin freckling, nodules and café au let spots in her father, two aunts and four siblings. On examination, BP 195/100 mmHg, Pulse 120 bpm. She has widespread skin freckling, and cafe au lait spots of different sizes and shapes. Systemic examination was otherwise normal. Urine metanaphrine was 9.34 umol/day (0-1.49) and normetanephrine 42.16 umol/day (0-3.43). A CT scan of the abdomen showed an 8-cm left adrenal heterogeneously enhancing hypervascular mass and narrowing of the infrarenal abdominal aorta with sever stenosis of celiac artery origin and severe diffuse narrowing of the left external iliac artery. Gallium 68 PET CT scan revealed an uptake at the same mass without other foci of uptake. Laboratory investigations: HbA1c 11.9%, WBC 18-24x109/L, Platelets 850-1,350x109/L. Bone marrow examination was refused by the patient so the exact underlying hematological disorder could not be accurately diagnosed. She was prepared with phenoxybenzamine and labetalol and underwent an open left adrenalectomy. Post operatively, she developed a large right anterior cerebral artery ischemic stroke as a complication of narrow cerebral vessels and the severe thrombocytosis. Histopathological examination confirmed the diagnosis of PCC with Ki67∼20%. Molecular testing revealed a novel truncating NF1 mutation (c.7606C>T, p.Gln2536X). Conclusion: We describe unusually severe haematological and vascular manifestations of NF type 1 in a young girl who presented with a large PCC. These severe manifestations reflect the broad manifestations of NF type 1 due to the important role of neurofibromin in different organs and the significant effects of the underlying NF1 truncating mutation in this patient. Presentation: Thursday, June 15, 2023

Petiole XLA (xylem to leaf area ratio) integrates hydraulic safety and efficiency across a diverse group of eucalypt leaves.

A theoretical trade-off between the efficiency and safety of water transport systems in plants is used to explain diverse ecological patterns, from tree size to community structure. Despite its pervasive influence, this theory has marginal empirical support. This may be partially due to obfuscation of associations by wide phylogenetic sampling or non-standard sampling between studies. To address this, we examine the coordination of structural and anatomical traits linked to hydraulic safety and efficiency in the leaves of an ecologically diverse group of eucalypts. We introduce a new trait for characterising leaf water transport function measured as the cross-sectional XA at the petiole divided by the downstream leaf area (XLApetiole ). Variation in XLApetiole revealed support for a safety-efficiency trade-off in eucalypt leaves. XLApetiole was negatively correlated with theoretical petiole xylem conductivity (Ks_petiole ) and strongly negatively correlated with leaf cavitation vulnerability (Ψ50leaf ). Species with lower Ψ50leaf exhibited petiole xylem with narrower vessels and greater fibre wall area fractions. Our findings highlight XLApetiole as a novel integrative trait that provides insights into the evolution of leaf form and function in eucalypts and holds promise for wider use among diverse species.

Biodegradable Polymeric Stent: Poly(lactic acid) Variation

Stenting is a treatment procedure to insert an implant-like needle into the blood vessel for the purpose of removing plaque and thrombosis while supporting the weak blood vessel. This procedure will enlarge the narrow blood vessel and restore blood circulation. Specifically, stent implantation is being combined with coronary angioplasty procedure to be known as percutaneous coronary intervention (PCI), which is an approach to treat cardiovascular diseases (CVD). There are three main variations of commercialized stents: Bare metal stent, drug-eluting stent and biodegradable stent. These three variations are focusing on the utilization of metal as the base material. Biodegradable metallic stent is a metallic stent which can be degraded into the physiological environment following an implantation. Even though forthcoming complications of permanent stent can be overcome with this type of stent, the degradation products often trigger inflammation and disturb the cascaded physiological processes. Therefore, researchers are moving towards biodegradable polymeric stents that are able to degrade while not harming the implanted lesion and surrounding tissues. This review article is intended to expose the information on biodegradable polymeric stent specifically to the implementation of poly(lactic acid) (PLA) and its variation as the polymeric materials.

Xylem structure and hydraulic function in roots and stems of chaparral shrub species from high and low elevation in the Sierra Nevada, California.

Xylem structure and hydraulics were compared between individuals at lower and upper elevation distribution limits for five chaparral shrub species along a steep transect in the southern Sierra Nevada, California, USA. Higher-elevation plants experienced frequent winter freeze-thaw events and increased precipitation. We hypothesized that environmental differences would lead to xylem trait differences between high and low elevations, but predictions were complicated because both water stress (low elevation) and freeze-thaw events (high elevation) may select for similar traits, such as narrow vessel diameter. We found significant changes in the ratio of stem xylem area to leaf area (Huber value) between elevations, with more xylem area required to support leaves at low elevations. Co-occurring species significantly differed in their xylem traits, suggesting diverse strategies to cope with the highly seasonal environment of this Mediterranean-type climate region. Roots were more hydraulically efficient and more vulnerable to embolism relative to stems, potentially due to roots being buffered from freeze-thaw stress, which allows them to maintain wider diameter vessels. Knowledge of the structure and function of both roots and stems is likely important in understanding whole-plant response to environmental gradients.

Analysis and prediction of hematocrit in microvascular networks

Hematocrit, defined as the volume percentage of red blood cells in blood, is an important indicator of human health status because it involves the capability of blood to deliver oxygen. The present work aims to analyze and predict the hematocrit distribution in microvascular networks from the direct simulations of cellular blood flow. The networks are geometrically complex, composed of bifurcations, confluences and winding vessels, while the cells exhibit multiple dynamic behaviors, including deformation and aggregation. Hence, our simulations can not only capture the behaviors of each cell in a single vessel, but also characterize the hematocrit of the cell population in a complex network. The results showed that the hematocrit is spatially and temporally heterogeneous in the microvascular network, which is largely attributed to the existence of bifurcations. The more complex the network, the more pronounced the heterogeneity, and it varies steadily over time in wide vessels but periodically fluctuates in narrow vessels. Based on a certain number of data samples, we predicted the hematocrit distribution in a microvascular network, by using the deep learning technique, instead of carrying out the direct simulation. This provides a fast and efficient way to measure the hematocrit distribution in a microvascular network. After that, we examined the effects of other cell types on the hematocrit, which are quite different from the case with the red blood cells only, due to the vascular blockage caused by the cell clusters. In such a case, it becomes very difficult to predict the hematocrit distribution by the deep learning technique, and its heterogeneity becomes more obvious.

A Novel Electromagnetic Positioning Prototype System With Simplified Receiver for Interventional Surgery Application

To meet the need of 3D positioning of surgical instru-ment in interventional surgery and the requirement of smaller size sensor for the narrow blood vessels, a new electromagnetic posi-tioning model is proposed with simplified receiver. Based on the electromagnetic theory and geometry principle, the electromag-netic field transmitter with groups of three orthogonal coils and the simplified receiver with smaller size than existing sensors are designed. Then, using Biot-Savart Law, the distance between re-ceiving end and geometric center of orthogonal coils is calculated, and the spatial coordinate of receiving end is computed with the spherical intersection formula. To further reduce the positioning error, a two-round accuracy improvement algorithm is designed for selecting the optimal topology of coil groups at the transmitter end and fitting correction of the calculated distance. We imple-ment the prototype system and perform both simulation experi-ments and actual experiments. The results show that our proposed new electromagnetic positioning method with simplified receiver has higher accuracy and stronger stability, compared with the tra-ditional positioning approach of three-coil transmitter and three-coil receiver.

Toward a better understanding of angiosperm xylogenesis: a new method for a cellular approach.

The kinetics of wood formation in angiosperms are largely unknown because their complex xylem anatomy precludes using the radial position of vessels and fibers to infer their time of differentiation. We analyzed xylogenesis in ring-porous ash (Fraxinus angustifolia) and diffuse-porous beech (Fagus sylvatica) over 1 yr and proposed a novel procedure to assess the period of vessel and fiber enlargement using a referential radial file (RRF). Our approach captured the dynamics of wood formation and provided a robust estimation of the kinetics of vessel and fiber enlargement. In beech, fibers and vessels had a similar duration of enlargement, decreasing from 14 to 5 d between April and July. In ash, wide vessels formed in April enlarged at a rate of 27 × 103 μm2 d-1 , requiring half the time of contemporary fibers (6 vs 12 d), and less time than the narrower vessels (14 d) formed in May. These findings reveal distinct cell-type-dependent mechanisms for differentiation in diffuse-porous and ring-porous trees, enhancing our understanding of angiosperm wood cell kinetics. Our approach presents an effective method for investigating angiosperm wood formation and provides a more accurate representation of vessel and fiber morphogenesis in wood formation models.

The vulnerability to drought-induced embolism-conduit diameter link: breaching the anatomy-physiology divide

Summary The best explanations of the relationship between organismal form and function-those regarded by scientists as the most solid — always account for both comparative, across-species, patterns, as well as experimental results. This is true in all of biology, as it is for the study of xylem structure-function relations, where there is still a need for xylem physiology and functional comparative wood anatomy to mutually complement each other. To illustrate the magnitude and urgency of this need, we discuss Sherwin Carlquist’s postulate of a link between vulnerability to drought-induced embolism and conduit diameter, summarizing some of the major global patterns of xylem trait variation that are currently explained by postulating a vulnerability–diameter link. These include wider community mean and maximum vessel diameters in wetter vs drier vegetation types; that vessels can be >700 μm in diameter but plants virtually always produce much narrower ones; that dryland plants with wider vessels drop their leaves earlier; wide-to-narrow vessels across growth rings; and the wide vessels of lianas surrounded by narrow vessels. These patterns are global, and we are aware of no anatomical evidence contradicting a vulnerability–diameter link. Despite the pervasiveness of these patterns, many xylem biologists do not regard the patterns as providing guidance for research in functional xylem biology. Instead, proposing and testing hypotheses to account for all of the data — xylem physiology experiments and comparative anatomical patterns in all their complexity and with all of their contradictions — provides the best way forward for the field. This effort requires proposing and testing hypotheses that are consistent with both experimental as well as comparative data. Crucially, it also requires not rejecting the vulnerability–diameter link without providing an alternative explanation that better explains the patterns currently explained by appeal to the link.

Unveiling resilience mechanisms of Quercus ilex seedlings to severe water stress: Changes in non-structural carbohydrates, xylem hydraulic functionality and wood anatomy

Over the last few decades, extensive dieback and mortality episodes of Quercus ilex L. have been documented after severe drought events in many Mediterranean forests. However, the underlying physiological, anatomical, and biochemical mechanisms remain poorly understood. We investigated the physiological and biochemical processes linked to embolism formation and non-structural carbohydrates (NSCs) dynamics in Q. ilex seedlings exposed to severe water stress and rewatering. Measurements of leaf gas exchange, water relations, non-structural carbohydrates, drought-related gene expression, and anatomical changes in wood parenchyma were assessed. Under water stress, the midday stem water potential dropped below - 4.5 MPa corresponding to a ~ 50 % loss of hydraulic conductivity. A 70 % reduction in stomatal conductance led to a strong depletion of wood NSCs. Starch consumption, resulting from the upregulation of the β-amylase gene BAM3, together with the downregulation of glucose (GPT1) and sucrose (SUC27) transport genes, suggests glucose utilization to sustain cellular metabolism in the wood parenchyma. After rewatering, the presence of residual xylem embolism led to an incomplete recovery of leaf gas exchanges. However, the partial restoration of photosynthesis allowed the accumulation of new starch reserves in the wood parenchyma and the production of new narrower vessels. In addition, changes in the cell wall composition of the wood parenchyma fibers were observed. Our findings indicate that thirty days of rewatering were sufficient to restore the NSCs reserves and growth rates of Q. ilex seedlings and that the carryover effects of water stress were primarily caused by hydraulic dysfunction.

Wood and bark anatomy of the charismatic Wisteria vines (Leguminosae)

Summary Wisteria is a legume genus composed of lianas with a disjunct distribution, occurring in temperate zones of eastern Asia and the eastern United States, being also introduced in numerous countries as an ornamental. The anatomy of the wood has been previously studied for W. sinensis and only some characteristics of the phloem have been reported for this species. Here we describe the overall wood and bark anatomy of four Wisteria species and identify diagnostic, informative anatomical features to sort them for identification purposes among the species of the genus. Samples were collected from natural, naturalized, and introduced populations and processed using traditional anatomical techniques, while a few samples were analyzed from photos available online. Wisteria species show conserved wood anatomy, even if species occur as far apart as Asia and North America. The presence of a cambial variant, vessel dimorphism, G-fibers, non-lignified axial, and ray parenchyma is common and is here interpreted as part of the lianescent syndrome. The subepidermal origin of the periderm is taxonomically informative within the subfamily. The few variable features that vary among species are the arrangement of narrow vessels: radial to dendritic pattern in the specie W. frutescens and arranged in clusters in the species distributed in Eastern Asia. Also, the ray cell composition: procumbent, square, and upright cells mixed through the body in the specie W. sinensis and procumbent to square cells in the body and upright in the margins in the species W. brachybotrys and W. frutescens.

The role of imperforate tracheary elements and narrow vessels in wood capacitance of angiosperm trees

Summary There is a broad diversity of imperforate tracheary elements (ITEs) — libriform fibers, fiber-tracheids, true tracheids and vasicentric/vascular tracheids — described thoroughly by Sherwin Carlquist. However, in a quantitative sense, the functional meaning of different ITE types present in the wood of vessel-bearing angiosperms remains unclear because very few structure–function studies measure ITEs’ properties. ITEs with abundant pits and wide pit borders — vascular tracheids, vasicentric tracheids, and true tracheids sensu Carlquist — have been shown to conduct water and, thanks to this conductive ability and the multitude of pits, they could also contribute to wood capacitance. A dataset of 30 temperate angiosperm tree species was reanalysed to record the presence/absence of true, vasicentric, and vascular tracheids including data on conduits15 fraction and vessel-conduit15 contact fraction (conduits15 were defined as cells resembling vessels and with a maximum lumen diameter of 15 μm. They encompassed narrow vessels, vasicentric tracheids, and vessel tails). The presence of tracheids, conduits15 fraction, and contact fraction had no effect on wood capacitance, except, per given wood volumetric lumen water content, species with true tracheids tended to have lower capacitance. These results suggest that the presence of tracheids or conduits15 properties do not limit wood capacitance, but the results do not exclude the potential role these cells may play in internal water dynamics.

Vessel diameter polymorphism determines vulnerability-to-embolism curve shape

Summary Sherwin Carlquist proposed several functional interpretations for vessel diameter, including that narrow vessels were hydraulically “safe” while wide diameter vessels were more vulnerable to embolism. He applied these ideas both across species and biomes, and within xylem tissue, where function of growth ring types was inferred from vessel diameter polymorphisms (occurrence of differing vessel diameter classes within a tissue). Following on Carlquist’s ideas, we were interested in evaluating if vessel diameter polymorphism could be linked to vulnerability-to-embolism curve shape. Vulnerability curves were fit with a model that included a continuous shape term (alpha). We predicted that high variation in vessel diameter would result in lower alpha (more r-shaped) curves whereas low variation would produce higher alpha (more s-shaped) curves, with potential for intermediate curve types. Our findings support Carlquist’s functional interpretations of vessel diameter. Vessel diameter polymorphism was strongly correlated to vulnerability curve shape. Homogeneous vessel diameters were associated with more s-shaped curves. As vessel diameter polymorphism increased, alpha declined and curves became more linear. High polymorphism was associated with r-shaped curves. There was no relationship between vessel length and curve shape. Vessel diameter was strongly correlated with a common estimate of embolism resistance (P50), with wider diameter vessels associated with increased vulnerability. Vulnerability curves show enormous variety in shape and scale, and both parameters are likely critical in understanding and predicting plant function. Carlquist’s ecological anatomy data, predictions, and functional inferences will continue to be valuable as we expand our understanding of structure–function links in plant anatomy.

Lossless temporal contrast analysis of laser speckle images from periodic signals.

Laser speckle contrast imaging is a technique that provides valuable physiological information about vascular topology and blood flow dynamics. When using contrast analysis, it is possible to obtain detailed spatial information at the cost of sacrificing temporal resolution and vice versa. Such a trade-off becomes problematic when assessing blood dynamics in narrow vessels. This study presents a new contrast calculation method that preserves fine temporal dynamics and structural features when applied to periodic blood flow changes, such as cardiac pulsatility. We use simulations and in vivo experiments to compare our method with the standard spatial and temporal contrast calculations and demonstrate that the proposed method retains the spatial and temporal resolutions, resulting in the improved estimation of the blood flow dynamics.

Xylem anatomical and hydraulic traits vary within crown but not respond to water and nitrogen addition in Populus tomentosa

Nitrogen (N) and water availability are the two crucial factors confining tree growth and forest productivity. Irrigation, fertilization, and combined fertigation are commonly applied to plantation forests for improving productivity. However, how xylem vasculature responds to these management practices remains poorly understood. Here we investigated the responses of tree growth, xylem anatomical structure, and hydraulics of the upper, middle, and lower canopy branches in a 6-year-old Populus tomentosa plantation subjected to four years of irrigation and fertigation treatments. The results showed that an improvement in tree growth only occurred in the irrigation treatment while the addition of N in fertigation treatments did not have a cumulative effect on tree growth. Most of the xylem anatomical traits, including vessel hydraulic diameter (Dh), vessel density (VD), vessel fraction (VF), double vessel wall thickness (t), potential specific sapwood hydraulic conductivity (Kp), fiber wall to lumen ratio (Tf/Df), vessel wall reinforcement (t/b)2, and wood density (WD) all showed conserved plasticity to long-term irrigation and fertigation, despite different tree growth rate, implying that aboveground biomass accumulation may have decoupled from the branch-level xylem traits. Besides, the alterations of other factors, including stomatal regulation strategy and crown structure with soil water and N availabilities, might better explain the variation in tree growth. In contrast, greater variations in branch xylem traits were detected across canopy layers. The upper canopy showed greater hydraulic safety characterized by narrower and denser vessels, higher cell wall to lumen ratio, and higher wood density compared to the lower canopy, while hydraulic efficiency (Kp) remained constant across the crown, thus highlighting the priority of hydraulic safety over efficiency in the construction of branch xylem. Overall, our study revealed the response pattern of P. tomentosa xylem structure to long-term water and N management, which facilitates a comprehensive understanding on the mechanisms underpinning the influence of water and nutrients regulation on the performance of fast-growing tree species’ plantations.

Identification of a novel NF1 deletion variant in a Taiwanese boy with neurofibromatosis type 1-associated Moyamoya syndrome.

The clinical significance of vasculopathy in patients with neurofibromatosis type 1 (NF1) has not been clearly elucidate due to its asymptomatic presentation and undetermined frequency.1 Compared with frequently affected renal arteries, NF1-associated Moyamoya syndrome (MMS), which is characterized by progressive intracranial artery narrowing and small telangiectatic vessel development, accounts for merely 0.6% of cases.2 Nevertheless, undiagnosed MMS results in markedly high risk of ischemic and hemorrhagic stroke in young adults.