Quantized Redshift and its Significance for Recent Observation

With the recent observational evidence in extragalactic astronomy,the interpretation of the nature of quasar redshift continues to be a research interest.Very high redshifts are being detected for extragalactic objects that are presumably very distant and young while also exhibiting properties that are characteristic of a more mature galaxy such as ours.According to Halton Arp and Geoffrey Burbidge,redshift disparities consist of an intrinsic component and are related to an evolutionary process.Karlsson observed redshift periodicity at integer multiples of0.089 in log scale and Burbidge observed redshift periodicity at integer multiples of 0.061 in linear scale.Since Singular Value Decomposition based periodicity estimation is known to be superior for noisy data sets,especially when the data contain multiple harmonics and overtones,mainly irregular in nature,we have chosen it to be our primary tool for analysis of the quasar-galaxy pair redshift data.We have observed a fundamental periodicity of0.051 with a confidence interval of 95%in linear scale with the site-available Sloan Digital Sky Survey Data Release 7(SDSS DR7)quasar-galaxy pair data set.We have independently generated quasar-galaxy pair data sets from both 2d F and SDSS and found fundamental periodicities of 0.077 and 0.089,respectively,in log scale with a confidence interval of 95%.

Irreversible electroporation for metastatic pancreatic carcinoma with liver metastasis:What does the evidence say

Irreversible electroporation is a promising non-thermal ablation method that has been shown to increase overall survival in locally advanced pancreatic cancer in some studies.However,higher quality studies with proper controls and randomization are required to establish its superiority when added with neoadjuvant chemotherapy over the current management of choice,which is chemotherapy alone.Further studies are required before establishment of any survival benefit in metastatic pancreatic carcinoma,and such evidence is lacking at present.

Verification and Validation of High-Resolution Inviscid and Viscous Conical Nozzle Flows

Capturing elaborated flow structures and phenomena is required for well-solved numerical flows.The finite difference methods allow simple discretization of mesh and model equations.However,they need simpler meshes,e.g.,rectangular.The inverse Lax-Wendroff(ILW)procedure can handle complex geometries for rectangular meshes.High-resolution and high-order methods can capture elaborated flow structures and phenomena.They also have strong mathematical and physical backgrounds,such as positivity-preserving,jump conditions,and wave propagation concepts.We perceive an effort toward direct numerical simulation,for instance,regarding weighted essentially non-oscillatory(WENO)schemes.Thus,we propose to solve a challenging engineering application without turbulence models.We aim to verify and validate recent high-resolution and high-order methods.To check the solver accuracy,we solved vortex and Couette flows.Then,we solved inviscid and viscous nozzle flows for a conical profile.We employed the finite difference method,positivity-preserving Lax-Friedrichs splitting,high-resolution viscous terms discretization,fifth-order multi-resolution WENO,ILW,and third-order strong stability preserving Runge-Kutta.We showed the solver is high-order and captured elaborated flow structures and phenomena.One can see oblique shocks in both nozzle flows.In the viscous flow,we also captured a free-shock separation,recirculation,entrainment region,Mach disk,and the diamond-shaped pattern of nozzle flows.

Chronic pancreatitis as a driving factor for pancreatic cancer:An epidemiological understanding

The retrospective study by Lew et al(2022)examined the rising hospitalization rates for chronic pancreatitis(CP)and its association with pancreatic ductal adenocarcinoma(PDAC),revealing significant ethno-racial disparities and risk factors.Overweight black men aged 40-59 years and white men over 40 years with higher incomes showed an elevated risk of PDAC among CP patients.The study,which included 14.2 million admissions from 2016-2017,found that 2.6%of adult patients were diagnosed with CP,with white males being the majority.Multivariate regression analysis identified men,black individuals,those aged 40-59 years,and individuals with a body mass index(BMI)between 25 and 29.9 as having an increased risk for CP.Moreover,0.78%of CP patients also had PDAC,with older age and BMI being significant risk factors for developing PDAC in CP patients.The study also highlighted disparities in healthcare access and utilization among different socioeconomic and ethno-racial groups,which may impact the risk and outcomes of CP and PDAC.

Oncometabolites in pancreatic cancer:Strategies and its implications

Pancreatic cancer(PanCa)is a catastrophic disease,being third lethal in both the genders around the globe.The possible reasons are extreme disease invasiveness,highly fibrotic and desmoplastic stroma,dearth of confirmatory diagnostic approaches and resistance to chemotherapeutics.This inimitable tumor microenvironment(TME)or desmoplasia with excessive extracellular matrix accumulation,create an extremely hypovascular,hypoxic and nutrient-deficient zone inside the tumor.To survive,grow and proliferate in such tough TME,pancreatic tumor and stromal cells transform their metabolism.Transformed glucose,glu-tamine,fat,nucleotide metabolism and inter-metabolite communication between tumor and TME in synergism,impart therapy resistance,and immunosuppression in PanCa.Thus,a finer knowledge of altered metabolism would uncover its metabolic susceptibilities.These unique metabolic targets may help to device novel diagnostic/prognostic markers and therapeutic strategies for better management of PanCa.In this review,we sum up reshaped metabolic pathways in PanCa to formulate detection and remedial strategies of this devastating disease.

Emerging role of non-invasive and liquid biopsy biomarkers in pancreatic cancer

A global increase in the incidence of pancreatic cancer(PanCa)presents a major concern and health burden.The traditional tissue-based diagnostic techniques provided a major way forward for molecular diagnostics;however,they face limitations based on diagnosis-associated difficulties and concerns surrounding tissue availability in the clinical setting.Late disease development with asymptomatic behavior is a drawback in the case of existing diagnostic procedures.The capability of cell free markers in discriminating PanCa from autoimmune pancreatitis and chronic pancreatitis along with other precancerous lesions can be a boon to clinicians.Early-stage diagnosis of PanCa can be achieved only if these biomarkers specifically discriminate the non-carcinogenic disease stage from malignancy with respect to tumor stages.In this review,we comprehensively described the non-invasive disease detection approaches and why these approaches are gaining popularity for their early-stage diagnostic capability and associated clinical feasibility.

Novel Analysis of Two Kinds Hybrid Models in Ferro Martial Inserting Variable Lorentz Force Past a Heated Disk:An Implementation of Finite Element Method

In this article,the rheology of Ferro-fluid over an axisymmetric heated disc with a variable magnetic field by considering the dispersion of hybrid nanoparticles is considered.The flow is assumed to be produced by the stretching of a rotating heated disc.The contribution of variable thermophysical properties is taken to explore themomentum,mass and thermal transportation.The concept of boundary layermechanismis engaged to reduce the complex problem into a simpler one in the form of coupled partial differential equations system.The complex coupled PDEs are converted into highly nonlinear coupled ordinary differential equations system(ODEs)and the resulting nonlinear flow problem is handled numerically.The solution is obtained via finite element procedure(FEP)and convergence is established by conducting the grid-independent survey.The solution of converted dimensionless problem containing fluid velocity,temperature and concentration field is plotted against numerous involved emerging parameters and their impact is noted.From the obtained solution,it is monitored that higher values of magnetic parameter retard the fluid flow and escalating values of Eckert number results in to enhance temperature profile.Ferro-fluid flow and heat energy for the case of the Yamada Ota hybrid model are higher than for the case of the Hamilton Crosser hybrid model.Developing a model is applicable to the printing process,electronic devices,temperature measurements,engineering process and food-making process.The amount of mass species is reduced vs.incline impacts of chemical reaction and Schmidt parameter.

Appraisal of pollution and health risks associated with coal mine contaminated soil using multimodal statistical and Fuzzy-TOPSIS approaches

The present study assesses the concentration,probabilistic risk,source classification,and dietary risk arising from heavy metal(HMs)pollution in agricultural soils affected by coal mining in eastern part of India.Analyses of soil and rice plant indicated significantly elevated levels of HMs beyond the permissible limit in the contaminated zones(zone 1:PbSoil:108.24±72.97,CuSoil:57.26±23.91,CdSoil:8.44±2.76,CrSoil:180.05±46.90,NiSoil:70.79±25.06 mg/kg;PbGrain:0.96±0.8,CuGrain:8.6±5.1,CdGrain:0.65±0.42,CrGrain:4.78±1.89,NiGrain:11.74±4.38 mg/kg.zone 2:PbSoil:139.56±69.46,CuSoil:69.89±19.86,CdSoil:8.95±2.57,CrSoil:245.46±70.66,NiSoil:95.46±22.89 mg/kg;PbGrain:1.27±0.84,CuGrain:7.9±4.57,CdGrain:0.76±0.43,CrGrain:8.6±1.58,NiGrain:11.50±2.46 mg/kg)compared to the uncontaminated zone(zone 3).Carcinogenic and non-carcinogenic health risks were computed based on the HMs concentration in the soil and rice grain,with Pb,Cr,and Ni identified as posing a high risk to human health.Monte Carlo simulation,the solubility-free ion activity model(FIAM),and severity adjusted margin of exposure(SAMOE)were employed to predict health risk.FIAM hazard quotient(HQ)values for Ni,Cr,Cd,and Pb were>1,indicating a significant non-carcinogenic risk.SAMOE(risk thermometer)results for contaminated zones ranged from low to moderate risk(CrSAMOE:0.05,and NiSAMOE:0.03).Fuzzy-TOPSIS and variable importance plots(from random forest)showed that Ni and Cr were mostly responsible for the toxicity in the rice plant,respectively.A self-organizing map for source classification revealed common origin for the studied HMs with zone 2 exhibiting the highest contamination.The positive matrix factorization model for the source apportionment identified coal mining and transportation as the predominant sources of HMs.Spatial distribution analysis indicated higher contamination near mining sites as compared to distant sampling sites.Consequently,this study will aid environmental scientists and policymakers controlling HM pollution in agricultural soils near coal mines.

Evidence of the oldest extant vascular plant(horsetails)from the Indian Cenozoic

Equisetum(Equisetaceae)has long been a focus of attention for botanists and palaeontologists because,given its extensive and well-documented fossil record,it is considered the oldest extant vascular plant and a key element in understanding vascular plant evolution.However,to date,no authentic fossil evidence of Equisetum has been found from the Indian Cenozoic.Here,we describe a new fossil species,namely,E.siwalikum sp.nov.,recovered from the middle Siwalik(Late Miocene)sediments of Himachal Pradesh,western Himalaya.We identified fossil specimens based on morphological and epidermal characters.In addition,X-Ray diffraction(XRD)analysis was used to determine the mineral composition of compressed stems of Equisetum.The close affinity of our recovered Siwalik fossils to Equisetum is supported by the presence of both macromorphological and epidermal characters.Because Equisetum generally grows in wet conditions around water reservoirs,our findings indicate that the fossil locality was humid and surrounded by swamp and lowland regions during deposition.Ample fossil evidence indicates that this sphenopsid once existed in the western Himalaya during the Siwalik period.However,at present Equisetum is confined to a particular area of our fossil locality,probably a consequence of severe environmental changes coupled with competition from opportunistic angiosperms.Our discovery of Equisetum fossils in appreciable numbers from the Siwalik sediments of the Himachal Himalayas is unique and constitutes the first reliable recognition of Equisetum from the Indian Cenozoic.

Carbon, Water, Ecological Footprints, Energy and Nutritional Densities of Omnivore and Vegan Culinary Preparations

This study aimed to evaluate energy and nutritional densities, water, carbon and ecological footprints, cost, of omnivorous and vegan main courses served in a university restaurant in the city of Rio de Janeiro. A cross-sectional, analytical study was conducted with 40 main dish-type preparations, 20 of which are omnivorous and 20 vegans, served at lunch, to assess energy and nutritional densities, carbon, water and ecological footprints and cost of preparations. We propose a healthy and sustainable preparation index (HSPI) to evaluate from the list, the best preparation options considering the nutritional quality combined with the impact that the food causes on the environment. Preparations with the highest HSPI were considered the best options because they have a good relation between the nutritional profile and the environmental impact. Results: Regarding energy (ED), nutritional (ND) densities and water, carbon and ecological footprints, omnivorous preparations presented much higher values when compared to the vegan ones. The omnivorous preparations had the highest average cost (R$ 3.44). Regarding the HSPI, vegan preparations showed better rates than omnivorous preparations. Food services should promote healthy and sustainable choices by offering menus with low energy density preparations, high nutritional density, and low environmental impact, considering local realities and customer needs. Conclusion: This study was able to evaluate the best preparation options, considering the nutritional profile and the food impact on the environment, using health and sustainable indicators. Obtaining indicators of preparations regarding healthiness and sustainability, in practice, translates environmental aspects in menu planning, which contribute to changes in food consumption patterns in food services, in addition to contributing to the reduction of the environmental impact. In this way, they can be used as tools added to the menu planning process for the analysis of the environmental impact of menus, in addition to nutritional and qualitative aspects.

Deoxyribonucleic acid methylation driven aberrations in pancreatic cancer-related pathways

Pancreatic cancer(PanCa)presents a catastrophic disease with poor overall survival at advanced stages,with immediate requirement of new and effective treatment options.Besides genetic mutations,epigenetic dysregulation of signaling pathway-associated enriched genes are considered as novel therapeutic target.Mechanisms beneath the deoxyribonucleic acid methylation and its utility in developing of epi-drugs in PanCa are under trails.Combinations of epigenetic medicines with conventional cytotoxic treatments or targeted therapy are promising options to improving the dismal response and survival rate of PanCa patients.Recent studies have identified potentially valid pathways that support the prediction that future PanCa clinical trials will include vigorous testing of epigenomic therapies.Epigenetics thus promises to generate a significant amount of new knowledge of biological and medical importance.Our review could identify various components of epigenetic mechanisms known to be involved in the initiation and development of pancreatic ductal adenocarcinoma and related precancerous lesions,and novel pharmacological strategies that target these components could potentially lead to breakthroughs.We aim to highlight the possibilities that exist and the potential therapeutic interventions.

Model-Free Feature Screening via Maximal Information Coefficient (MIC) for Ultrahigh-Dimensional Multiclass Classification

It is common for datasets to contain both categorical and continuous variables. However, many feature screening methods designed for high-dimensional classification assume that the variables are continuous. This limits the applicability of existing methods in handling this complex scenario. To address this issue, we propose a model-free feature screening approach for ultra-high-dimensional multi-classification that can handle both categorical and continuous variables. Our proposed feature screening method utilizes the Maximal Information Coefficient to assess the predictive power of the variables. By satisfying certain regularity conditions, we have proven that our screening procedure possesses the sure screening property and ranking consistency properties. To validate the effectiveness of our approach, we conduct simulation studies and provide real data analysis examples to demonstrate its performance in finite samples. In summary, our proposed method offers a solution for effectively screening features in ultra-high-dimensional datasets with a mixture of categorical and continuous covariates.

Model-Free Ultra-High-Dimensional Feature Screening for Multi-Classified Response Data Based on Weighted Jensen-Shannon Divergence

In ultra-high-dimensional data, it is common for the response variable to be multi-classified. Therefore, this paper proposes a model-free screening method for variables whose response variable is multi-classified from the point of view of introducing Jensen-Shannon divergence to measure the importance of covariates. The idea of the method is to calculate the Jensen-Shannon divergence between the conditional probability distribution of the covariates on a given response variable and the unconditional probability distribution of the covariates, and then use the probabilities of the response variables as weights to calculate the weighted Jensen-Shannon divergence, where a larger weighted Jensen-Shannon divergence means that the covariates are more important. Additionally, we also investigated an adapted version of the method, which is to measure the relationship between the covariates and the response variable using the weighted Jensen-Shannon divergence adjusted by the logarithmic factor of the number of categories when the number of categories in each covariate varies. Then, through both theoretical and simulation experiments, it was demonstrated that the proposed methods have sure screening and ranking consistency properties. Finally, the results from simulation and real-dataset experiments show that in feature screening, the proposed methods investigated are robust in performance and faster in computational speed compared with an existing method.

Products of Odd Numbers or Prime Number Can Generate the Three Members’ Families of Fermat Last Theorem and the Theorem Is Valid for Summation of Squares of More Than Two Natural Numbers

Fermat’s last theorem, had the statement that there are no natural numbers A, B, and C such that An + Bn = Cn, in which n is a natural number greater than 2. We have shown that any product of two odd numbers can generate Fermat or Pythagoras triple (A, B, C) following n = 2 and also it is applicable A2 + B2 + C2 + D2 + so on =An2 where all are natural numbers.

Functional Genes in Relation to Residual Feed Intake in Murrah Buffalo Heifers

High Feed efficiency (FE) in growing heifers has economic importance in dairy, but remains less understood in buffaloes. Feed conversion efficiency is defined as dry matter intake (DMI) per unit body weight gain and is determined as residual feed intake (RFI), i.e., the difference between actual and predicted feed intake to gain unit body weight during a feed trial run for 78 days under control feeding. A large variation was identified ranging between -0.42 to 0.35 in growing buffalo heifers (n = 40) of age between 11 to 15 months. An average daily weight gain (ADG) varied between 382.0 and 807.6 g/day when compared with the control-fed heifers at an organized buffalo farm. The whole blood transcriptome data obtained from the selected growing heifers from extremes of estimated high and low RFI efficiency were compared with the reference assembly generated from the transcriptome of multiparous buffaloes (n = 16) of diverse age of maturity, period of regaining post partum cyclicity and level of milk production. Differentially expressed genes (DEGs) were identified using the reference genome of Mediterranean water buffalo. GO: terms (Padj 0.05, FDR 0.05) enriched by annotated DEGs and biological pathways in gene network for RFI efficiency trait were identified. GO: terms specific to pre-transcriptional regulation of nucleus and Chromatin organization under Nucleoplasm, Energy balancing, Immunity, Cell signaling, ROS optimization, ATP generation through the Electron Transport chain and cell proliferation were determined. The study reveals the indicators targeting the actual metabolic changes and molecular functions underlying the feed utilization capacity of buffaloes. Estimated RFI efficiency revealed a large variation over heifers which may lower the DMI even up to 13.6% thus, enabling an increase in ADG up to 16% by involving efficient heifers in breeding plan. The study revealed a scope of high gain by selective breeding for FE in heifers. FE variants catalogued in the study are useful breed-specific RFI markers for future reference. The study contributes to the understanding of feed efficiency in buffaloes and its association with key interactive traits such as reproduction and growth. This knowledge can be utilized to develop more effective breeding programs.

Classification of Nonlinear Confusion Component Using Hybrid Multi-Criteria Decision Making

In today’s digital world,the most inevitable challenge is the protection of digital information.Due to the weak confidentiality preserving techniques,the existing world is facing several digital information breaches.To make our digital data indecipherable to the unauthorized person,a technique forfinding a crypto-graphically strong Substitution box(S-box)have presented.An S-box with sound cryptographic assets such as nonlinearity(NL),strict avalanche criterion(SAC),bit independence criteria(BIC),bit independence criteria of nonlinearity(BIC-NL),Bit independence criteria of Strict avalanche criteria(BIC-SAC),and Input/output XOR is considered as the robust S-box.The Decision-Making Trial and Evaluation Laboratory(DEMATEL)approach of multi-criteria decision making(MCDM)is proposed forfinding the interrelation among cryptographic properties.A combination of two MCDM methods namely Entropy and multi-objective optimization based on ratio analysis(MOORA)is applied for the best S-box selection.A robust substitution box is selected for secure communications in cryptography by using the combination of DEMETAL selection criteria,entro-py weight assigning,and MOORA ranking scheme.The combination of these three methods provides a fast selection procedure for the secure confusion com-ponent.The offered selection method can also be utilized for the choice of the best cryptosystem with highly secure properties and resistive against all possible linear and differential attacks in the cryptanalysis.

重组人血小板生成素治疗实体肿瘤患者化疗后血小板减少的多中心临床试验

目的 评价国产重组人血小板生成素(rhTPO)治疗实体肿瘤患者化疗后血小板减少的临床疗效和安全性。方法 采用随机交叉自身对照研究,154例实体瘤患者随机分为A、B两组,每组77例,接受方案和剂量相同的两周期化疗。A组:第1个周期(用药周期)注射rhTPO,第二个周期(对照周期)不注射rhTPO;B组:第1个周期(对照周期)不注射rhTPO,第2个周期(用药周期)注射rhTPO。两组患者均于用药周期化疗结束后6～24 h皮下注射rhTPO 1.0μg·kg-1·d-1,连续用药最长14 d。监测血尿便常规、肝肾功能、凝血功能、胸片、心电图及血清抗rhTPO抗体。结果 A、B两组用药周期与对照周期血小板减少程度和持续时间差异无显著性。154例实体瘤患者用药周期与对照周期比较:(1)化疗后血小板下降的最低值分别为(64.4±45.4)×109/L和(52.4±30.9)×109/L(P=0.000),血小板计数恢复后的最高值分别为(263.9±142.5)×109/L和(148.9±67.7)×109/L(P=0.000);(2)化疗后血小板<50×109/L的持续时间分别为(2.5±3.9)和(3.7±5.7)d(P=0.04);(3)用药周期化疗后血小板恢复至75×109/L、100×109/L以上所需天数为(10.3±8.7)和(14.0±8.9)d,而对照周期为(15.9±10.5)和(21.1±9.5)d(P=0.000);(4)血小板平均输注量两周期比较无差异;(5)化疗后血红蛋白、白细胞?

河北省正常人群肺功能检测分析

目的 探讨河北省正常人群肺功能的生理预计值及其不同生活环境、年龄、身高、体重等因素与肺功能的关系。方法 2002年8～10月对进行过基础体检并确定为正常的1 587名不同年龄段人群采用便携式肺功能仪进行肺容量及肺通气量检测,分析不同地域、年龄、性别、身高、体重等因素对肺功能的影响。结果检测的各项肺功能指标城乡之间差异无显著性(P>0.05);不同性别之间差异有显著性(P=0.000);多数肺功能指标在男12～16岁、女12～14岁为肺功能增长突增期,肺活量(VC)、用力呼气肺活量(FYC)、一秒量(FEV1)26岁达到高峰并维持到34岁左右,然后呈逐渐下降趋势;最高呼气流速(PEF)、25％用力呼气流速(FEF25％)可持续增长到34～44岁其后呈下降趋势(均P<0.01);FEF50％、FEF75％等18岁为高峰随后随年龄增长逐渐下降(P<0.01)。身高、体重与各项肺功能指标均有相关性,但身高的影响大于体重。结论年龄、身高、体重与各项肺功能均有相关性,肺功能随年龄的增长而发生变化,青少年期、成年期、中老年期应有不同的生理预计值;本研究为正常人群肺功能值提供了一个参考值。

广西壮族自治区1816名健康人群跟骨超声骨密度测量

目的 探讨广西壮族自治区健康人群跟骨超声骨密度与年龄、身高、体重等的关系，初步建立该地区健康人群跟骨超声硬度指数（SI）的正常参考值范围，为骨质疏松的诊断和预防提供科学依据。方法 采用Achilles Express跟骨超声骨密度测定仪对广西地区1816名（男性775名、女性1041名）11-90岁健康志愿者进行跟骨SI测定。按不同性别，每5岁为1个年龄组，70岁以上合并为1组，男女各分为13组，对测量数据进行统计学分析。结果 男女跟骨SI分别在21-25岁（111．45±21．19）和16—20岁（101．26±17．51）年龄组达到峰值，之后均随年龄而下降，女性呈现出典型的双峰特征；61岁以上女性的SI显著低于同年龄组男性（P〈0．05）。多元线性逐步回归分析显示男女SI与年龄呈显著负相关（P〈0．001）；与体重呈显著正相关（男性P〈0．05、女性P〈0．01）；女性SI与身高呈显著的正相关（P〈0．01），但男性SI与身高无相关性。结论 广西壮族自治区健康人群SI与年龄、身高、体重均有显著的相关性，本研究获得的SI值可为临床和流行病学研究中诊断骨质疏松症提供参考。

2342例北京地区儿童血清钙、无机磷水平检测分析

目的 研究北京地区儿童血清钙(Ca)、无机磷(P)水平及在儿童生长发育中的变化趋势和影响因素。方法 采用分层不等概率二阶整群抽样方法,于2001年9～12月对北京城区和郊区的2 342名10～18岁男女健康儿童进行血清钙(离子电极法)和无机磷 (比色法)检测以及膳食状况调查,统计分析血清钙、磷水平与性别、年龄、身高、体重及膳食的关系。结果 (1)北京地区儿童血清钙为(2.39±0.12)mmol/L,与年龄、身高和体重均呈正相关(P<0.01)。总体水平女童略高于男童[男:(2.38±0.12)mmol/L,女:(2.39±0.12)mmol/L,P<0.05];城区儿童明显高于郊区儿童[城区:(2.40±0.13)mmol/L,郊区:(2.37±0.10)mmol/L,P<0.001]。(2)北京地区儿童血清无机磷为:(1.39±0.18)mmol/L,与年龄、身高和体重均呈负相关(P<0.01),男童无机磷显著高于女童[男:(1.43±0.18)mmol/L,女:(1.36±0.17)mmol/L,P<0.001];城区儿童显著高于郊区儿童[城区:(1.41±0.19)mmol/L,郊区:(1.38±0.16)mmol/L,P<0.001]。(3)儿童血清钙与无机磷呈负相关(r=-0.141,P<0.01),[Ca]·[P]浓度(mmol/L)乘积为3.32±0.44,13～14岁达到峰值3.45±0.46后,随年龄增加而降低。结论 北京地区儿童血清钙和无机磷水平随性别、年龄、生长发育和饮食结构等因素变化,健康儿童随年龄增加。