Impact of the future liver remnant volume before major hepatectomy.

INTRODUCTION: Following major liver resection, posthepatectomy liver failure (PHLF) is associated with a high mortality rate. As there is no therapy for PHLF available, avoidance remains the main goal. A sufficient future liver remnant (FLR) is one of the most important factors to reduce the risk for PHLF; however, it is not known which patients benefit of volumetric assessment prior to major surgery. METHODS: A retrospective, bi-institutional cohort study was conducted including all patients who underwent major hepatectomy (extended right hepatectomy, right hepatectomy, extended left hepatectomy and left hepatectomy) between 2010 and 2023. RESULTS: A total of 1511 major hepatectomies were included, with 29.4 % of patients undergoing FLR volume assessment preoperatively. Overall, PHLF B/C occurred in 9.8 % of cases. Multivariate analysis identified diabetes mellitus, extended right hepatectomy, perihilar cholangiocarcinoma (pCCA), gallbladder cancer (GBC) and cirrhosis as significant risk factors for PHLF B/C. High-risk patients (with one or more risk factors) had a 15 % overall incidence of PHLF, increasing to 32 % with a FLR <30 %, and 13 % with an FLR of 30-40 %. Low-risk patients with a FLR <30 % had a PHLF rate of 21 %, which decreased to 8 % and 5 % for FLRs of 30-40 % and >40 %, respectively. For right hepatectomy, the PHLF rate was 23 % in low-risk and 38 % in high-risk patients with FLR <30 %. CONCLUSION: Patients scheduled for right hepatectomy and extended right hepatectomy should undergo volumetric assessment of the FLR. Volumetry should always be considered before major hepatectomy in patients with risk factors such as diabetes, cirrhosis, GBC and pCCA. In high-risk patients, a FLR cut-off of 30 % may be insufficient to prevent PHLF, and additional liver function assessment should be considered.

Prion diseases disrupt glutamate/glutamine metabolism in skeletal muscle.

In prion diseases (PrDs), aggregates of misfolded prion protein (PrPSc) accumulate not only in the brain but also in extraneural organs. This raises the question whether prion-specific pathologies arise also extraneurally. Here we sequenced mRNA transcripts in skeletal muscle, spleen and blood of prion-inoculated mice at eight timepoints during disease progression. We detected gene-expression changes in all three organs, with skeletal muscle showing the most consistent alterations. The glutamate-ammonia ligase (GLUL) gene exhibited uniform upregulation in skeletal muscles of mice infected with three distinct scrapie prion strains (RML, ME7, and 22L) and in victims of human sporadic Creutzfeldt-Jakob disease. GLUL dysregulation was accompanied by changes in glutamate/glutamine metabolism, leading to reduced glutamate levels in skeletal muscle. None of these changes were observed in skeletal muscle of humans with amyotrophic lateral sclerosis, Alzheimer's disease, or dementia with Lewy bodies, suggesting that they are specific to prion diseases. These findings reveal an unexpected metabolic dimension of prion infections and point to a potential role for GLUL dysregulation in the glutamate/glutamine metabolism in prion-affected skeletal muscle.

Using the Montgomery-Koyama-Smith equation to calculate the stomatal area per unit lamina area for 12 Magnoliaceae species.

BACKGROUND AND AIMS: The Montgomery-Koyama-Smith (MKS) equation predicts that total leaf area per shoot is proportional to the product of the sum of individual leaf widths and maximum individual leaf length, which has been validated for some herbaceous and woody plants. The equation is also predicted to be valid in describing the relationship between the total stomatal area per micrograph (AT) and the product of the sum of individual stomatal widths (denoted as LKS) and maximum individual stomatal length (denoted by WKS) in any particular micrograph. METHODS: To test the validity of the MKS equation, 69,931 stomata (from 720 stomatal micrographs from 12 Magnoliaceae species) were examined. The area of each stoma was calculated using empirical measurements of stomatal length and width multiplied by a constant. Six equations describing the relationships among AT, LKS, and WKS were compared. The root-mean-square (RMSE) and the Akaike information criterion (AIC) were used to measure the goodness of fit, and the trade-off between the goodness of fit and the structural complexity of each model, respectively. KEY RESULTS: Analyses supported the validity of the MKS equation and the power-law equation AT ∝ (LKS∙WKS)α, where a is a scaling exponent. The estimated values of α at the species level and for the pooled data were all statistically smaller than unity, which did not support the hypothesis that AT ∝ LTS∙WTS. The power-law equation had smaller RMSE and AIC values than the MKS equation for the data from the 12 individual species and the pooled data. CONCLUSIONS: These results indicate that AT tends to allometrically scale with LKS∙WKS, and that increases in AT do not keep pace with increases in LTS∙WTS. In addition, using the product of LKS and WKS is better than using only one of the two variables.

Electrospun Iridium-Based Nanofiber Catalysts for Oxygen Evolution Reaction: Influence of Calcination on Activity-Stability Relation.

The enhanced utilization of noble metal catalysts through highly porous nanostructures is crucial to advancing the commercialization prospects of proton exchange membrane water electrolysis (PEMWE). In this study, hierarchically structured IrOx-based nanofiber catalyst materials for acidic water electrolysis are synthesized by electrospinning, a process known for its scalability and ease of operation. A calcination study at various temperatures from 400 to 800 °C is employed to find the best candidates for both electrocatalytic activity and stability. Morphology, structure, phase, and chemical composition are investigated using a scale-bridging approach by SEM, TEM, XRD, and XPS to shed light on the structure-function relationship of the thermally prepared nanofibers. Activity and stability are monitored by a scanning flow cell (SFC) coupled with an inductively coupled plasma mass spectrometer (ICP-MS). We evaluate the dissolution of all metals potentially incorporated into the final catalyst material throughout the synthesis pathway. Despite the opposite trend of performance and stability, the present study demonstrates that an optimum between these two aspects can be achieved at 600 °C, exhibiting values that are 1.4 and 2.4 times higher than those of the commercial reference material, respectively. The dissolution of metal contaminations such as Ni, Fe, and Cr remains minimal, exhibiting no correlation with the steps of the electrochemical protocol applied, thus exerting a negligible influence on the stability of the nanofibrous catalyst materials. This work demonstrates the scalability of electrospinning to produce nanofibers with enhanced catalyst utilization and their testing by SFC-ICP-MS. Moreover, it illustrates the influence of calcination temperature on the structure and chemical composition of the nanofibers, resulting in outstanding electrocatalytic performance and stability compared to commercial catalyst materials for PEMWE.

Perioperative Outcomes and Reimbursement Patterns Associated with the Anterior Versus Posterior Approach for Treatment of Type 2 Odontoid Fractures, a NSQIP Analysis.

OBJECTIVE: To evaluate the short-term surgical outcomes and the reimbursement patterns, after treatment of Type 2 odontoid fractures using the anterior or posterior approach. METHODS: The NSQIP database was queried for surgically treated patients with Type 2 odontoid fractures by the anterior or posterior approach between 2016 and 2020. Propensity score matching with the optimal approach was used to balance the cohorts. RESULTS: A total of 96 patients in the anterior and 352 patients in the posterior surgery group were included in the unmatched analysis. After propensity score matching 1:1, 96 anterior and 96 posterior cases were included in the matched analysis. Operative times were shorter in the anterior group (92.0 vs. 145.0 minutes, p<0.001). The need for intra- or postoperative transfusions was higher in the posterior group (15% vs. 2.1% ; p=0.002). However, there were no significant differences in complications between groups (p>0.05). Hospital stay was significantly longer in the posterior group (4.5 days vs. 3.0; p=0.049). Non-routine discharge was more frequent in the posterior group (55% vs. 40%, p=0.030). However, the rate of 30-day readmission, reoperation, and mortality did not differ between groups (p>0.05). Also, the work relative value units (WRVUs) were significantly higher in the anterior group (22.7 vs. 20.6, p<0.001), indicating higher reimbursement trends for this approach. CONCLUSION: In this matched analysis, the anterior approach for type 2 odontoid fractures was superior to the posterior approach. The anterior approach was associated with significantly shorter operation times, hospital stays, fewer transfusions, non-routine discharges, and higher reimbursements.

Allocation of nitrogen and phosphorus in the leaves, stems, and roots of Artemisia: a case study in phylogenetic control.

Introduction: The allocation of nitrogen (N) and phosphorus (P) among plant organs is an important strategy affecting growth and development as well as ecological processes in terrestrial ecosystems. However, due to lack of systematic investigation data, the allocation strategies of N and P in the three primary plant organs (e.g., leaves, stems and roots) are still unclear. Methods: A total of 912 individuals of 62 Artemisia species were examined across a broad environmental expanse in China, and the N and P concentrations of leaves, stems and roots were measured to explore the allocation strategies in different subgenera, ecosystem types, and local sites. Results and discussion: Across all 62 species, the N vs. P scaling exponents for leaves, stems and roots were 0.67, 0.59 and 0.67, respectively. However, these numerical values differed among subgenera, ecosystem types, and local sites. Overall, the numerical values of N vs. P scaling exponents comply with a 2/3-power function for each Artemisia organ-type reflecting a phylogenetically conserved allocation strategy that has nevertheless diversified with respect to local environmental conditions. These results inform our understanding of N and P stoichiometric patterns and responses to abiotic factors in an ecologically broadly distributed angiosperm genus.

Change of self-rated physical health predicts mortality in aging individuals: results of a population-based cohort study.

BACKGROUND: Self-rated physical health (SRPH) is known as an important predictor of mortality. Previous studies mostly used baseline values of self-rated health to predict long-term mortality. The effect of change in self-rated physical health on mortality during the course of aging has rarely been researched. The present study aimed to determine SRPH over time in women and men of an aging population, assess whether and how change in SRPH affects mortality while adjusting for known determinants of mortality, and test effect modification by sex on the relation between course of SRPH and mortality. METHODS: Data of N = 12,423 respondents of the 5-year follow-up of the Gutenberg Health Study (GHS) with participation at the baseline assessment were analysed. All-cause mortality from 5-year follow-up onwards was defined as the primary outcome. SRPH was assessed by a single item. Cox proportional hazards models with adjustment for age, sex, socio-economic status and physical diseases were fitted to assess the predictive power of baseline score and course of SRPH. Additionally, effect modification by sex was assessed. RESULTS: During a median follow-up period of 7.3 years (quartiles 6.0-8.5 years), 618 (5%) participants died. Overall, 70.9% of the participants indicated good or very good SRPH at baseline (T1) and follow-up (T2), 6.9% rated their SRPH as not so good at T1 and T2, and 0.6% reported bad SRPH at T1 and T2. An improvement of SRPH was indicated by 9.6% and 12.0% indicated deterioration of their SRPH. Change in SRPH added substantial predictive information to the Cox proportional hazards models, when adjusting for relevant covariates. In men, deterioration and constantly bad SRPH were associated with the strongest increase in risk of mortality by 87%, resp. 228%. While improvements increased mortality risk in men (67%), women with an improved SRPH had a lower risk (57%). CONCLUSION: A sizeable subgroup of aging participants reported deterioration of SRPH over five years. The association between change of SRPH and mortality is modified by sex. Deterioration of SRPH predicts mortality over baseline-assessment even when adjusted for relevant covariates. SRPH should be assessed regularly as part of an older individual's health evaluation. Deterioration, constantly bad and improved SRPH should be taken seriously as unfavorable prognostic indicators, the latter only in men.

In-Situ Electrolyte for Electrosynthesis: Scalable Anodically-Enabled One-Pot Sequence from Aldehyde to Isoxazol(in)es.

Electrochemical transformations are considered a green alternative to classical redox chemistry as it eliminates the necessity for toxic and waste producing redox reagents. Typical electrochemical reactions require the addition of a so-called supporting electrolyte - a salt bridge - and other additives, such as hexafluorisopropanol, to enhance conductivity and reaction outcomes, respectively. However, this is often accompanied by an increase in the amount of produced waste. Here, we report an "in-situ electrolyte" concept for facile, transition-metal-free, additive-free one-pot electrochemical preparation of isoxazol(in)es, important scaffolds for biologically active natural and synthetic molecules, from the respective aldehydes. The protocol utilizes no halogenated solvents and no external oxidants, while salt side-products provide the ionic conductivity necessary for the electrosynthesis. The electrolysis is performed in an undivided cell, using the state-of-the-art electrodes for the chlor-alkali industry dimensionally stable and scalable mixed metal oxide anode and platinized titanium anode of high durability. The cascade transformation comprises the condensation of aldehyde to oxime followed by its anodic oxidation and subsequent intra- and/or intermolecular [3+2] cycloadditions with an appropriate dipolarophile. Chemical yields up to 97%, and good Faradaic efficiency, scalability, and stability are observed for most substrates in a broad scope.

Surface Loading Dictates Triplet Production via Singlet Fission in Anthradithiophene Sensitized TiO2 Films.

Singlet fission, the process of transforming a singlet excited state into two lower energy triplet excited states, is a promising strategy for improving the efficiency of dye-sensitized solar cells. The difficulty in utilizing singlet fission molecules in this architecture is understanding and controlling the orientation of dyes on mesoporous metal oxide surfaces to maximize triplet production and minimize detrimental deactivation pathways, such as electron injection from the singlet or excimer formation. Here, we varied the concentration of loading solutions of two anthradithiophene dyes derivatized with either one or two carboxylic acid groups for binding to a metal oxide surface and studied their photophysics using ultrafast transient absorption spectroscopy. For the single carboxylic acid case, an increase in dye surface coverage led to an increase in apparent triplet excited-state growth via singlet fission, while the same increase in coverage with two carboxylic acids did not. This study represents a step toward controlling the interactions between molecules at mesoporous interfaces.

Long-Term Functional Outcomes Following Enzymatic Debridement of Deep Hand Burns Using Nexobrid®: A Retrospective Analysis.

Background: For years, surgical debridement with autografting has been considered the standard of care in the treatment of severe burns of the hand. However, in recent years, enzymatic debridement has increasingly been reported as a good alternative, especially for burns of the hand, as it selectively preserves viable tissue. In this study, we aim to evaluate the long-term function of the hand after enzymatic debridement in deep dermal burns. Methods: A retrospective chart review was conducted as well as measurements of subjective and objective outcome measures through physical examination and Disabilities of the Arm, Shoulder, and Hand (DASH), Patient and Observer Scar Assessment Scale (POSAS), and Vancouver Scar Scale (VSS) scores. Results: A total of 32 enzymatically debrided hands of 24 patients were included with a mean age of 42.4 ± 16.8 years and a mean follow-up of 31 months. Postoperatively, 19 of these could be managed conservatively using skin substitutes such as "Suprathel", 13 had to undergo subsequent autografting. The mean DASH score for the entire study population was eight with a mean value of four in the conservatively managed group and fourteen in the autografted group. The mean Patient, Observer POSAS, and VSS values were nineteen, thirteen, and two. A total of 30 cases showed an effortless complete fist closure, and, also in 30 cases, patients attested to be satisfied with the esthetic appearance of the hand on being asked. Conclusions: The descriptive analysis of these results in our study population suggests that the enzymatic debridement of deep burns of the hand, especially combined with subsequent conservative management with skin substitutes, was associated with low long-term hand disability scores at a follow-up of two years.

Evaluating Surgical Outcomes Between Estrogen Receptor Positive Invasive Lobular and Invasive Ductal Carcinoma of the Breast-A Propensity Matched Analysis.

INTRODUCTION: Invasive lobular carcinoma (ILC) contributes significantly to the global cancer burden and is the most common of the histological "special types" of breast cancer. ILC has unique features setting it apart from the more common invasive ductal carcinoma (IDC). Despite differences, treatment algorithms do not consider histological differences. AIM: To determine the differences in treatment and outcomes of ILC relative to IDC in a strict case-matched cohort study at a tertiary referral, specialist, breast cancer center. METHODS: All Estrogen receptor positive (ER+) ILCs from 1999 to 2015 were matched for; age, tumor size, grade, PR/HER2 status, nodal stage and metastases with ER+ IDCs from the same period. Surgical and systemic treatments were assessed along with overall (OS) and disease-free survival (DFS). RESULTS: 762 cases in total were analyzed (1:1 matching; ILC:IDC). ILC cases were more often treated with mastectomy (37.5% vs. 28.6%, P .009) and those who received breast conserving surgery (BCS) more often had an incomplete resection (30.2% vs. 19.6%, P .01). IDC were more often treated with NACT (5.5% vs. 14.4%, P < .001). Mean DFS were similar between ILC and IDC; 148.3 vs. 141.4 months (P .112) but OS was significantly longer in the ILC group; 165.7 vs. 134 months (P .002). This trend was consistent among the subset of patients undergoing BCS. For ILC undergoing BCS, mean DFS was 129.8 vs. 128.3 months for IDC (P .418) and OS was 155.4 and 110.7 months respectively (P < .001). Incomplete resection at the time of index surgery did not alter the disease free or overall survival in either the ILC or IDC patients to a level that reached statistical significance. CONCLUSION: In this cohort study, the strict matching of ILC and IDCs for a number of prognostic indicators, demonstrates the impact of lobular histology with a clarity not previously observed. ILCs have comparable survival outcomes to patients with IDC but at the expense of more extensive index and revisional surgery. There is a need for awareness of these facts among surgeons and patients for optimal treatment prioritization and provision.

Prevalence of current suicidal thoughts and lifetime suicide attempts in individuals with cancer and other chronic diseases in Germany: Evidence for differential associations from a representative community cohort.

BACKGROUND: Research indicates an elevated risk for suicidal thoughts and behaviors (STBs) among individuals with cancer, but community-based studies on the prevalence of STBs in comparison to the general population and other chronic diseases are lacking. METHODS: Data was drawn from the representative population-based, prospective Gutenberg Health Study (GHS). Participants (N = 12,382; age: M = 59.5, SD = 10.8; 48.9 % women) completed highly standardized medical assessments and validated questionnaires such as the PHQ-9. In addition to prevalence estimates (stratified by STBs and gender), logistic regression models were calculated (controlling for confounders). RESULTS: The sample included 1910 individuals with cancer, 8.2 % of whom reported current suicidal thoughts and 2.0 % reported lifetime suicide attempts. There was neither a significant association between a cancer diagnosis and suicidal thoughts (p = .077) nor suicide attempts (p = .17) in models adjusting for age, gender, and income. Other chronic diseases were linked to suicidal thoughts and attempts only in men. LIMITATIONS: Although the investigation of the two kinds of STB are a strength of the study, the items' different time frames complicate comparisons. In addition, the cross-sectional design limits the ability to understand observed relationships and to identify periods of risk. CONCLUSION: This study expands the evidence base regarding the vulnerability to STBs in individuals with cancer, including long-term survivors. It highlights their heterogeneity, differential risk factors underlying suicidal thoughts and attempts, and the relevance of other (contextual) factors shaping an individual's susceptibility to suicidal crises.

Unconstrained precision mitochondrial genome editing with αDdCBEs.

DddA-derived cytosine base editors (DdCBEs) enable the targeted introduction of C•G-to-T•A conversions in mitochondrial DNA (mtDNA). DdCBEs work in pairs, with each arm composed of a transcription activator-like effector (TALE), a split double-stranded DNA deaminase half, and a uracil glycosylase inhibitor. This pioneering technology has helped improve our understanding of cellular processes involving mtDNA and has paved the way for the development of models and therapies for genetic disorders caused by pathogenic mtDNA variants. Nonetheless, given the intrinsic properties of TALE proteins, several target sites in human mtDNA are predicted to remain out of reach to DdCBEs and other TALE-based technologies. Specifically, due to the conventional requirement for a thymine immediately upstream of the TALE target sequences (i.e., the 5'-T constraint), over 150 loci in the human mitochondrial genome are presumed to be inaccessible to DdCBEs. Previous attempts at circumventing this requirement, either by developing monomeric DdCBEs or utilizing DNA-binding domains alternative to TALEs, have resulted in suboptimal specificity profiles with reduced therapeutic potential. Here, aiming to challenge and elucidate the relevance of the 5'-T constraint in the context of DdCBE-mediated mtDNA editing, and to expand the range of motifs that are editable by this technology, we generated DdCBEs containing TALE proteins engineered to recognize all 5' bases. These modified DdCBEs are herein referred to as αDdCBEs. Notably, 5'-T-noncompliant canonical DdCBEs efficiently edited mtDNA at diverse loci. However, they were frequently outperformed by αDdCBEs, which exhibited significant improvements in activity and specificity, regardless of the most 5' bases of their TALE binding sites. Furthermore, we showed that αDdCBEs are compatible with the enhanced DddAtox variants DddA6 and DddA11, and we validated TALE shifting with αDdCBEs as an effective approach to optimize base editing outcomes. Overall, αDdCBEs enable efficient, specific, and unconstrained mitochondrial base editing.

Temporal dynamics of white and gray matter plasticity during motor skill acquisition: a comparative diffusion tensor imaging and multiparametric mapping analysis.

Learning new motor skills relies on neural plasticity within motor and limbic systems. This study uniquely combined diffusion tensor imaging and multiparametric mapping MRI to detail these neuroplasticity processes. We recruited 18 healthy male participants who underwent 960 min of training on a computer-based motion game, while 14 were scanned without training. Diffusion tensor imaging, which quantifies tissue microstructure by measuring the capacity for, and directionality of, water diffusion, revealed mostly linear changes in white matter across the corticospinal-cerebellar-thalamo-hippocampal circuit. These changes related to performance and reflected different responses to upper- and lower-limb training in brain areas with known somatotopic representations. Conversely, quantitative MRI metrics, sensitive to myelination and iron content, demonstrated mostly quadratic changes in gray matter related to performance and reflecting somatotopic representations within the same brain areas. Furthermore, while myelin and iron-sensitive multiparametric mapping MRI was able to describe time lags between different cortical brain systems, diffusion tensor imaging detected time lags within the white matter of the motor systems. These findings suggest that motor skill learning involves distinct phases of white and gray matter plasticity across the sensorimotor network, with the unique combination of diffusion tensor imaging and multiparametric mapping MRI providing complementary insights into the underlying neuroplastic responses.

The "Leafing Intensity Premium" Hypothesis and the Scaling Relationships of the Functional Traits of Bamboo Species.

The "leafing intensity premium" hypothesis proposes that leaf size results from natural selection acting on different leafing intensities, i.e., the number of leaves per unit shoot volume or mass. The scaling relationships among various above-ground functional traits in the context of this hypothesis are important for understanding plant growth and ecology. Yet, they have not been sufficiently studied. In this study, we selected four bamboo species of the genus Indocalamus Nakai and measured the total leaf fresh mass per culm, total non-leaf above-ground fresh mass, total number of leaves per culm, and above-ground culm height of 90 culms from each species. These data were used to calculate leafing intensity (i.e., the total number of leaves per culm divided by the total non-leaf above-ground fresh mass) and mean leaf fresh mass per culm (i.e., the total leaf fresh mass per culm divided by the total number of leaves per culm). Reduced major axis regression protocols were then used to determine the scaling relationships among the various above-ground functional traits and leafing intensity. Among the four species, three exhibited an isometric (one-to-one) relationship between the total leaf fresh mass per culm and the total non-leaf above-ground fresh mass, whereas one species (Indocalamus pumilus) exhibited an allometric (not one-to-one) relationship. A negative isometric relationship was found between the mean leaf fresh mass per culm and the leafing intensity for one species (Indocalamus pedalis), whereas three negative allometric relationships between mean leaf fresh mass per culm and leafing intensity were observed for the other three species and the pooled data. An exploration of the alternative definitions of "leafing intensity" showed that the total number of leaves per culm divided by the above-ground culm height is superior because it facilitates the non-destructive calculation of leafing intensity for Indocalamus species. These results not only confirm the leafing intensity premium hypothesis for bamboo species but also highlight the interconnected scaling relationships among different functional traits, thereby contributing to our understanding of the ecological and evolutionary significance of leaf size variation and biomass investment strategies.

Is There Evidence to Support Probiotic Use for Healthy People?

Probiotics are typically marketed as foods and dietary supplements, categories for products intended to maintain health in generally healthy populations and which, unlike drugs, cannot claim to treat or cure disease. This review addresses the existing evidence that probiotics are beneficial to healthy people. Our approach was to perform a descriptive review of efficacy evidence that probiotics can prevent urinary, vaginal, gastrointestinal, and respiratory infections, and improve risk factors associated with cardiovascular health or reduce antibiotic use. Other endpoints such as mental, dental, or immune health were not specifically addressed. We concluded that there is sufficient evidence of efficacy and safety for clinicians and consumers to consider using specific probiotics for some indications - such as the use of probiotics to support gut function during antibiotic use or to reduce the risk of respiratory tract infections - for certain people. However, we did not find a sufficiently high level of evidence to support unconditional, population-wide recommendations for other preventive endpoints we reviewed for healthy people. Although evidence for some indications is suggestive of the preventive benefits of probiotics, additional research is needed.

Scaling relationships between the total number of leaves and the total leaf area per culm of two dwarf bamboo species.

Total leaf area per plant is an important measure of the photosynthetic capacity of an individual plant that together with plant density drives the canopy leaf area index, that is, the total leaf area per unit ground area. Because the total number of leaves per plant (or per shoot) varies among conspecifics and among mixed species communities, this variation can affect the total leaf area per plant and per canopy but has been little studied. Previous studies have shown a strong linear relationship between the total leaf area per plant (or per shoot) (A T) and the total number of leaves per plant (or per shoot) (N T) on a log-log scale for several growth forms. However, little is known whether such a scaling relationship also holds true for bamboos, which are a group of Poaceae plants with great ecological and economic importance in tropical, subtropical, and warm temperate regions. To test whether the scaling relationship holds true in bamboos, two dwarf bamboo species (Shibataea chinensis Nakai and Sasaella kongosanensis 'Aureostriatus') with a limited but large number of leaves per culm were examined. For the two species, the leaves from 480 and 500 culms, respectively, were sampled and A T was calculated by summing the areas of individual leaves per culm. Linear regression and correlation analyses reconfirmed that there was a significant log-log linear relationship between A T and N T for each species. For S. chinensis, the exponent of the A T versus N T scaling relationship was greater than unity, whereas that of S. kongosanensis 'Aureostriatus' was smaller than unity. The coefficient of variation in individual leaf area increased with increasing N T for each species. The data reconfirm that there is a strong positive power-law relationship between A T and N T for each of the two species, which may reflect adaptations of plants in response to intra- and inter-specific competition for light.