Selective sorting of hexane isomers by anion-functionalized metal-organic frameworks with optimal energy regulation.

Extensive efforts have been made to improve the separation selectivity of hydrocarbon isomers with nearly distinguishable boiling points; however, how to balance the high regeneration energy consumption remains a daunting challenge. Here we describe the efficient separation of hexane isomers by constructing and exploiting the rotational freedom of organic linkers and inorganic SnF62- anions within adaptive frameworks, and reveal the nature of flexible host-guest interactions to maximize the gas-framework interactions while achieving potential energy storage. This approach enables the discrimination of hexane isomers according to the degree of branching along with high capacity and record mono-/di-branched selectivity (6.97), di-branched isomers selectivity (22.16), and upgrades the gasoline to a maximum RON (Research Octane Number) of 105. Benefitting from the energy regulation of the flexible pore space, the material can be easily regenerated only through a simple vacuum treatment for 15 minutes at 25 °C with no temperature fluctuation, saving almost 45% energy compared to the commercialized zeolite 5 A. This approach could potentially revolutionize the whole scenario of alkane isomer separation processes.

Effects of evidence-based nursing on surgical site wound infections in patients undergoing surgery for liver cancer: A meta-analysis.

This study aimed to systematically evaluate the impact of evidence-based nursing (EBN) on perioperative wound infections and postoperative complications in patients undergoing surgery for liver hepatocellular carcinoma (LIHC). Randomised controlled trials (RCTs) on the application of EBN on patients receiving LIHC surgery were searched in PubMed, Web of Science, Cochrane Library, Embase, Wanfang, China Biomedical Literature Database and China National Knowledge Infrastructure from the inception of each database to September 2023. Studies were screened and evaluated by two investigators based on inclusion and exclusion criteria, and data were extracted from the final included literature. RevMan 4.0 was used for data analysis. Overall, 15 RCTs involving 1374 patients with LIHC were included, with 687 in the EBN group and 687 in the conventional care group. The analysis revealed that the incidence of wound infections (odds ratio [OR] = 0.32, 95% confidence interval [CI]: 0.18-0.56, p < 0.001) and postoperative complications (OR = 0.22, 95% CI: 0.15-0.31, p < 0.001) was significantly lower in the EBN group than in the conventional care group. The available evidence suggests that nursing strategies for EBN applied in the perioperative period in patients with LIHC receiving surgery can effectively reduce the incidence of wound infections and postoperative complications and promote postoperative recovery.

One-step removal of alkynes and propadiene from cracking gases using a multi-functional molecular separator.

Refineries generally employ multiple energy-intensive distillation/adsorption columns to separate and purify complicated chemical mixtures. Materials such as multi-functional molecular separators integrating various modules capable of separating molecules according to their shape and chemical properties simultaneously may represent an alternative. Herein, we address this challenge in the context of one-step removal of alkynes and propadiene from cracking gases (up to 10 components) using a multi-functional and responsive material ZU-33 through a guest/temperature dual-response regulation strategy. The responsive and guest-adaptive properties of ZU-33 provide the optimized binding energy for alkynes and propadiene, and avoid the competitive adsorption of olefins and paraffins, which is verified by breakthrough tests, single-crystal X-ray diffraction experiments, and simulation studies. The responsive properties to different stimuli endow materials with multiple regulation methods and broaden the boundaries of the applicability of porous materials to challenging separations.

Efficient separation of xylene isomers by a guest-responsive metal-organic framework with rotational anionic sites.

The separation of xylene isomers (para-, meta-, orth-) remains a great challenge in the petrochemical industry due to their similar molecular structure and physical properties. Porous materials with sensitive nanospace and selective binding sites for discriminating the subtle structural difference of isomers are urgently needed. Here, we demonstrate the adaptively molecular discrimination of xylene isomers by employing a NbOF52--pillared metal-organic framework (NbOFFIVE-bpy-Ni, also referred to as ZU-61) with rotational anionic sites. Single crystal X-ray diffraction studies indicate that ZU-61 with guest-responsive nanospace/sites can adapt the shape of specific isomers through geometric deformation and/or the rotation of fluorine atoms in anionic sites, thereby enabling ZU-61 to effectively differentiate xylene isomers through multiple C-H···F interactions. ZU-61 exhibited both high meta-xylene uptake capacity (3.4 mmol g-1) and meta-xylene/para-xylene separation selectivity (2.9, obtained from breakthrough curves), as well as a favorable separation sequence as confirmed by breakthrough experiments: para-xylene elute first with high-purity (≥99.9%), then meta-xylene, and orth-xylene. Such a remarkable performance of ZU-61 can be attributed to the type anionic binding sites together with its guest-response properties.

Changes of Serum Adiponectin and Glycated Albumin Levels in Gestational Diabetes Mellitus Patients and Their Relationship with Insulin Resistance.

BACKGROUND: We aimed to investigate the changes of serum adiponectin and glycated albumin (GA) levels in gestational diabetes mellitus patients and their relationship with insulin resistance. METHODS: Overall, 137 pregnant women were enrolled from Jinan City People's Hospital, Laiwu District, China from Jan 2015 to Jun 2018. Among them, 71 pregnant women with gestational diabetes mellitus were examined as diabetes group, and 66 normal pregnant women as normal pregnant women group. In addition, 58 normal non-pregnant women of childbearing age who were examined in our hospital during the same period were selected as a control group. The serum adiponectin and GA levels of the three groups were compared, and the relationship between serum adiponectin, GA levels and insulin resistance was analyzed. RESULTS: The serum adiponectin level of pregnant women in gestational diabetes mellitus (GDM) group was significantly lower than that of normal pregnant women and control group (P=0.031, P=0.027). The serum GA level of pregnant women in GDM group was significantly higher than that of normal pregnant women and control group (P<0.001). Pearson correlation analysis showed that GA was positively correlated with Fasting plasma glucose (FPG), Fasting insulin (FINS) and Insulin resistance index(HOMA-IR) levels (P<0.001), while adiponectin was negatively correlated with FPG FINS and HOMA-IR levels (P<0.001). CONCLUSION: Abnormal levels of serum GA and adiponectin are closely related to insulin resistance in patients with gestational diabetes mellitus. Detection of serum GA and adiponectin levels can diagnose gestational diabetes mellitus quickly and effectively.

Molecular Sieving of C2 -C3 Alkene from Alkyne with Tuned Threshold Pressure in Robust Layered Metal-Organic Frameworks.

C2 -C3 alkyne/alkene separation is of great importance; however, designing materials for an efficient molecular sieving of alkenes from alkynes remains challenging. Now, two hydrolytically stable layered MOFs, [Cu(dps)2 (GeF6 )] (GeFSIX-dps-Cu, dps=4,4'-dipyridylsulfide) and [Zn(dps)2 (GeF6 )] (GeFSIX-dps-Zn), can achieve almost complete exclusion of both C3 H6 and C2 H4 from their alkyne analogues. GeFSIX-dps-Cu displays a notable advanced threshold pressure for alkynes adsorption and thus substantial uptakes at lower pressures, providing record C3 H4 /C3 H6 uptake ratios and capacity-enhanced C2 H2 /C2 H4 sieving for a wide composition range. Metal substitution (Zn to Cu) affords fine tuning of linker rotation and layer stacking, creating slightly expanded pore aperture and interlayer space coupled with multiple hydrogen-bonding sites, allowing easier entrance of alkyne while excluding alkene. Breakthrough experiments confirmed tunable sieving by these MOFs for C3 H4 /C3 H6 and C2 H2 /C2 H4 mixtures.

Separation of Xe from Kr with Record Selectivity and Productivity in Anion-Pillared Ultramicroporous Materials by Inverse Size-Sieving.

The separation of xenon/krypton (Xe/Kr) mixture is of great importance to industry, but the available porous materials allow the adsorption of both, Xe and Kr only with limited selectivity. Herein we report an anion-pillared ultramicroporous material NbOFFIVE-2-Cu-i (ZU-62) with finely tuned pore aperture size and structure flexibility, which for the first time enables an inverse size-sieving effect in separation along with record Xe/Kr selectivity and ultrahigh Xe capacity. Evidenced by single-crystal X-ray diffraction, the rotation of anions and pyridine rings upon contact of larger-size Xe atoms adapts cavities to the shape/size of Xe and allows strong host-Xe interaction, while the smaller-size Kr is excluded. Breakthrough experiments confirmed that ZU-62 has a real practical potential for producing high-purity Kr and Xe from air-separation byproducts, showing record Kr productivity (206 mL g-1 ) and Xe productivity (42 mL g-1 , in desorption) as well as good recyclability.

Polycatenated Molecular Cage-Based Propane Trap for Propylene Purification with Recorded Selectivity.

The propane (C3H8)-selective adsorption technology is recognized as a promising energy-efficient way to directly afford high-purity propylene (C3H6). Here, a novel strategy via cage construction, combining with multiple interaction and shape selectivity, was raised to achieve preferential C3H8 adsorption. We revealed that the polycatenated molecular cage within a microporous framework of [Ni(bpe)2(WO4)] (bpe = 1,2-bis(4-pyridyl)ethylene) showed preferential C3H8 adsorption behavior with recorded C3H8/C3H6 selectivity (1.62-2.75), as well as the high adsorption enthalpy around 42 kJ mol-1. The cage afforded dense electronegative binding sites, enabling the multiple Cδ--Hδ+. . .Cδ- interaction with C3H8 molecule and thus the higher affinity for C3H8 than C3H6. Additionally, the cage exhibited shape selectivity to oblate C3H8, and was unfavorable to C3H6 with relatively planar configuration as indicated by modeling studies. The high purity propylene (99.6%) was directly obtained without the extra adsorption-desorption cycles through the column breakthrough experiment.

Trabecular and cortical microstructure and fragility of the distal radius in women.

Fragility fractures commonly involve metaphyses. The distal radius is assembled with a thin cortex formed by fusion (corticalization) of trabeculae arising from the periphery of the growth plate. Centrally positioned trabeculae reinforce the thin cortex and transfer loads from the joint to the proximal thicker cortical bone. We hypothesized that growth- and age-related deficits in trabecular bone disrupt this frugally assembled microarchitecture, producing bone fragility. The microarchitecture of the distal radius was measured using high-resolution peripheral quantitative computed tomography in 135 females with distal radial fractures, including 32 girls (aged 7 to 18 years), 35 premenopausal women (aged 18 to 44 years), and 68 postmenopausal women (aged 50 to 76 years). We also studied 240 fracture-free controls of comparable age and 47 healthy fracture-free premenopausal mother-daughter pairs (aged 30 to 55 and 7 to 20 years, respectively). In fracture-free girls and pre- and postmenopausal women, fewer or thinner trabeculae were associated with a smaller and more porous cortical area (r = 0.25 to 0.71 after age, height, and weight adjustment, all p < 0.05). Fewer and thinner trabeculae in daughters were associated with higher cortical porosity in their mothers (r = 0.30 to 0.47, all p < 0.05). Girls and premenopausal and postmenopausal women with forearm fractures had 0.3 to 0.7 standard deviations (SD) fewer or thinner trabeculae and higher cortical porosity than controls in one or more compartment; one SD trait difference conferred odds ratio (95% confidence interval) for fracture ranging from 1.56 (1.01-2.44) to 4.76 (2.86-7.69). Impaired trabecular corticalization during growth, and cortical and trabecular fragmentation during aging, may contribute to the fragility of the distal radius.

New insights into the effects of primary hyperparathyroidism on the cortical and trabecular compartments of bone.

In primary hyperparathyroidism (PHPT), protracted elevation of serum parathyroid hormone (PTH) is held to be associated with cortical, but not trabecular, bone loss. However, an alternative explanation for the apparent preservation of trabecular bone is fragmentation of the cortex by intracortical remodeling. The cortical fragments resemble trabeculae and so may be erroneously included in the quantification of 'trabecular' bone density. To test this hypothesis, we compared bone microarchitecture in 43 patients with untreated PHPT (mean 62.9 years, range 31-84) with 47 healthy age-matched controls and 25 patients with surgically treated PHPT (63.6 years, 30-82). Images of the distal radius and tibia were acquired using high-resolution peripheral quantitative CT and analysed using StrAx1.0, a new software program that quantifies bone morphology in-vivo. Results were expressed as the mean number of standardized deviations (SD) from the age-specific mean (Z scores, mean±SEM). In subjects with PHPT, total tibial cortical area was reduced -0.26±0.08 SD; p=0.002). Cortical volumetric bone mineral density (vBMD) was reduced (-0.29±0.06 SD; p<0.001) due to higher cortical porosity (0.32±0.06 SD; p<0.001) and lower tissue mineralization density (-0.21±0.06 SD; p=0.002). Medullary area was increased (0.26±0.08 SD; p=0.002) and trabecular vBMD was reduced (-0.14±0.04 SD; p<0.001). In subjects who underwent successful parathyroidectomy, cortical area (-0.18±0.10 SD; NS) and medullary area (0.18±0.10 SD; NS) did not differ from controls. Cortical vBMD was reduced (-0.15±0.05 SD; p=0.003) due to high porosity (0.15±0.05 SD; p=0.006), values numerically lower than in untreated PHPT. Tissue mineralization density (-0.26±0.04 SD; p<0.001) and trabecular vBMD were reduced (-0.16±0.04 SD, p<0.001). The results were similar in the distal radius. In PHPT, chronically elevated endogenous PTH does not spare trabecular bone; it causes bone loss and microarchitectural deterioration in both cortical and trabecular compartments of bone.

Serum osteocalcin is not associated with glucose but is inversely associated with leptin across generations of nondiabetic women.

CONTEXT: The skeleton is recognized as an important player in energy metabolism through its interactions with other tissues. Whether the association of osteocalcin with glucose metabolism is age dependent has not been fully addressed. OBJECTIVE: The objective of the study was to examine the age-specific association between different forms of osteocalcin and glucose and adipokines. DESIGN: This was a family-based study across three generations. SETTING: The study was conducted at a university laboratory. PARTICIPANTS: Sixty-four daughter-premenopausal mother-maternal grandmother trios participated in the study. METHODS: Fasting plasma glucose and insulin concentrations, serum total (tOC), carboxylated (cOC), and uncarboxylated (ucOC = tOC - cOC) osteocalcin, leptin, and adiponectin levels, and fat masses were assessed. Generalized estimating equations (GEE) model was used to assess the associations of bone biomarkers with glucose metabolism variables and adipokines. RESULTS: No significant difference in insulin was found between generations, whereas glucose and leptin increased with age. Levels of tOC, cOC, and ucOC were highest in girls and lowest in mothers (P < 0.01). Grandmothers had higher leptin and adiponectin than mothers and girls. Despite the differences in insulin and glucose between the low and high homeostasis model assessment insulin resistance index (HOMA-IR) groups within generations, no significant differences in tOC, cOC, and ucOC were found. Compared with their low HOMA-IR counterparts, the high HOMA-IR group had significantly higher leptin and lower adiponectin in mothers and grandmothers. The tOC, cOC, and ucOC levels did not correlate with HOMA-IR, leptin, or adiponectin when the three generations were evaluated together, but when separated by generation, leptin was inversely correlated with tOC (P = 0.003) and cOC (P = 0.047) in mothers and with ucOC in grandmothers (P = 0.042). CONCLUSIONS: Osteocalcin, glucose, and adipokines change with age but in a noncommensurate manner. We infer that the association between osteocalcin and glucose metabolism is minor and age specific in nondiabetic women. Leptin, however, strongly correlated with insulin resistance independently of fat masses, suggesting that obesity, as a metabolic disorder risk factor, affects glucose metabolism, partly through the role of leptin.

[Progresses on plant AP2/ERF transcription factors].

Plant AP2/ERF transcription factor with AP2/ERF domain containing 60-70 amino acids is a huge gene family present in all plant. AP2/ERF transcriptional factors are involved in various biological functions such as plant development, flower development, fruit and seed maturation, wounding, pathogen defense, high salty, drought, and so on. AP2/ERF transcription factor are involved in salicylic acid, jasmonic acid, ethylene, abscisic acid signal transduction pathways and among them. The transcription factors are cross-talk factor in stress signal pathway. This paper summarizes the most advanced researches on types, biological functions, and gene regulations of plant AP2/ERF transcription factors.

Is bone loss the reversal of bone accrual? Evidence from a cross-sectional study in daughter-mother-grandmother trios.

Bone adapts to mechanical loads applied on it. During aging, loads decrease to a greater extent at those skeletal sites where loads increase most in earlier life. Thus, the loss of bone may occur preferentially at sites where most bone has been deposited previously; ie, bone loss could be the directional reversal of accrual. To test this hypothesis, we compared the bone mass distribution at weight-bearing (tibia) and non-weight-bearing (radius) bones among 18-year-old girls, their premenopausal mothers, and their postmenopausal maternal grandmothers. Bone and muscle properties were measured by pQCT, and polar distribution of bone mass was obtained in 55 girl-mother-maternal grandmother trios. Site-matched differences in bone mass were compared among three generations. The differences between girls and mothers and between mothers and grandmothers were used to represent the patterns of bone mass accrual from early adulthood to middle age and bone loss from middle to old age, respectively. Compared to the mothers, 18-year old girls had less bone mass in the anterior and medial-posterior regions of the tibial shaft, while the grandmothers had less bone in the anterior and posterior regions. In contrast, the bone mass differences in the radial shaft between girls and mothers and mothers and grandmothers were relatively uniform. We conclude that both bone accrual and loss are direction-specific in weight-bearing bones but relatively uniform in non-weight-bearing bones. Bone loss in old age is largely, but not completely, a reversal of the preferential deposition of bone in the most highly loaded regions during early life.

Concerted actions of insulin-like growth factor 1, testosterone, and estradiol on peripubertal bone growth: a 7-year longitudinal study.

A better understanding of how bone growth is regulated during peripuberty is important for optimizing the attainment of peak bone mass and for the prevention of osteoporosis in later life. In this report we used hierarchical models to evaluate the associations of insulin-like growth factor 1 (IGF-1), estradiol (E(2) ), and testosterone (T) with peripubertal bone growth in a 7-year longitudinal study. Two-hundred and fifty-eight healthy girls were assessed at baseline (mean age 11.2 years) and at 1, 2, 3.5, and 7 years. Serum concentrations of IGF-1, E(2) , and T were determined. Musculoskeletal properties in the left lower leg were measured using peripheral quantitative computed tomography (pQCT). Serum levels of IGF-1, E(2) , and T increased dramatically before menarche, whereas they decreased, plateaued, or increased at a lower rate, respectively, after menarche. IGF-1 level was positively associated with periosteal circumference (PC) and total bone mineral content (tBMC) throughout peripuberty but not after adjustment for muscle cross-sectional area (mCSA). On the other hand, IGF-1 was associated with tibial length (TL) independently of mCSA before menarche. T was positively associated with TL, PC, tBMC, and cortical volumetric bone mineral density, independent of mCSA, before menarche but not after. E(2) was associated with TL positively before menarche but negatively after menarche. These findings suggest that during puberty, circulating IGF-1 promotes bone periosteal apposition and mass accrual indirectly, probably through stimulating muscle growth, whereas the effects of sex steroids on bone growth differ before and after menarche, presenting a biphasic pattern. Hence the concerted actions of these hormones are essential for optimal bone development in peripuberty.

Trabecular bone of growth plate origin influences both trabecular and cortical morphology in adulthood.

Skeletal fragility is common at metaphyseal regions of long bones. The cortices of this region are derived by coalescence of trabeculae around the periphery of the growth plate, not by periosteal apposition, as occurs in the diaphyses. We therefore hypothesized that trabecular bone in childhood predicted both cortical and trabecular morphology in adulthood. To test this hypothesis, we measured distal radial and tibial structure using high-resolution peripheral quantitative computed tomography in 61 daughter-mother pairs, mean age 12.5 years (range 7 to 19 years) and 44.1 years (range 32 to 50 years), respectively. The daughters' trabecular bone volume (BV/TV), thickness, number, and separation predicted the corresponding traits in their mothers. Their trabecular BV/TV also predicted their mothers' cortical thickness (r = 0.32, p = .02). By contrast, the daughters' cortical thickness did not predict their mothers' cortical thickness. The daughters had higher trabecular BV/TV than their mothers (mean ± SD, radius 0.134 ± 0.024 versus 0.124 ± 0.033, p = .03; tibia 0.145 ± 0.021 versus 0.135 ± 0.032, p < .01) owing to greater trabecular number, not thickness, and less trabecular separation. Abnormalities in the development of metaphyseal trabecular bone are likely to influence fragility in both trabecular and cortical bone of this region in adulthood.

Expression of pathogenesis related genes in response to salicylic acid, methyl jasmonate and 1-aminocyclopropane-1-carboxylic acid in Malus hupehensis (Pamp.) Rehd.

BACKGROUND: Many studies have been done to find out the molecular mechanism of systemic acquired resistance (SAR) in plants in the past several decades. Numbers of researches have been carried out in the model plants such as arabidopsis, tobacco, rice and so on, however, with little work done in woody plants especially in fruit trees such as apple. Components of the pathway of SAR seem to be extremely conserved in the variety of species. Malus hupehensis, which is origin in China, is strong resistance with rootstock. In the study, we attempted to make the expression pattern of pathogenesis related (PR) genes which were downstream components of the SAR pathway in response to salicylic acid(SA), methyl jasmonate(MeJA) and 1-aminocyclopropane-1-carboxylic acid(ACC) in Malus hupehensis. FINDINGS: In order to analyze the expression pattern, the partial sequence of three PR genes from Malus hupehensis, MhPR1, MhPR5 and MhPR8 was isolated. These three PR genes were induced by SA, MeJA and ACC. However, MhPR1, MhPR5 and MhPR8 performed a distinct pattern of expression in different plant organs. MhPR5 and MhPR8 were basal expression in leaves, stems and roots, and MhPR1 was basal expression only in stems. The expression of MhPR1, MhPR5 and MhPR8 was enhanced during the first 48 h post-induced with SA, MeJA and ACC. CONCLUSIONS: The results showed that a distinct pattern of expression of PR genes in Malus hupehensis which differed from the previous reports on model plants arabidopsis, tobacco and rice. MhPR1, MhPR5 and MhPR8 were induced by SA, MeJA and ACC, which were regarded as the marker genes in the SAR response in Malus hupehensis. In contrast with herbal plants, there could be specific signal pathway in response to SA, JA and ET for woody plants.

Fat mass accumulation compromises bone adaptation to load in Finnish women: a cross-sectional study spanning three generations.

Body weight and lean mass correlate with bone mass, but the relationship between fat mass and bone remains elusive. The study population consisted of 396 girls and 138 premenopausal mothers and 114 postmenopausal grandmothers of these girls. Body composition and tibial length were assessed using dual-energy X-ray absorptiometry (DXA), and bone traits were determined at the tibia using peripheral quantitative computed tomography (pQCT) in the girls at the ages of 11.2 ± 0.8, 13.2 ± 0.9, and 18.3 ± 1.0 years and in the mothers (44.7 ± 4.1 years) and grandmothers (70.7 ± 6.3 years). The values of relative bone strength index (RBSI), an index reflecting the ratio of bone strength to the load applied on the tibia, were correlated among family members (all p < .05). The mean values of RBSI were similar among 11- and 18-year-old girls and premenopausal women but significantly lower in 13-year-old girls and postmenopausal women. However, in each age group, subjects in the highest BMI tertiles had the lowest RBSI values (all p < .01). RBSI was inversely associated with body weight (all p < .01), indicating a deficit in bone strength relative to the applied load from greater body weight. RBSI was inversely associated with fat mass (all p < .001) across age groups and generations but remained relatively constant with increasing lean mass in girls and premenopausal women (all p > .05), indicating that the bone-strength deficit was attributable to increased fat mass, not lean mass. Moreover, the adverse effect of fat mass was age-dependent, with every unit increase in fat mass associated with a greater decrease in RBSI in pre- and postmenopausal women than in girls (all p < .001). This is largely due to the different capacity of young and adult bones to increase diaphyseal width by periosteal apposition in response to increased load. In summary, increasing body weight with fat accumulation is accompanied by an age-dependent relative bone-strength deficit in women because the beneficial effects of increased fat mass on bone, if any, do not compensate for the mechanical burden that it imposes.

Familial resemblance and diversity in bone mass and strength in the population are established during the first year of postnatal life.

Familial resemblance and diversity in bone structure and strength in adulthood are determined in part during growth. Whether these characteristics are established during gestation or shortly after birth is not known. Total-body, lumbar spine, and femoral neck size and mass and indices of tibial bending strength and distal radial compressive strength were measured using bone densitometry and quantitative computed tomography in 236 girls at 18.5 years of age. Among them, 219, 141, and 105 girls had crown-heel length (CHL) and weight recorded at birth and at 6 and 12 months of age, and then height and weight were recorded at 3, 5, 10, 13, and 15 years of age in 181, 176, 127, 111, and 228 girls, respectively. Of these girls, 101 and 93 girls also had bone structure assessed at 11 and 13 years of age, respectively. Similar bone measurements were made once in 78 mother-father pairs. CHL and weight at birth did not correlate or did so weakly with bone traits in girls at 18 years of age. By contrast, CHL at 6 months correlated with the height, bone traits, and strength at puberty and at 18 years of age (r = 0.24-0.56, p < .001) in girls and with their parents' height and bone traits (r = 0.15-0.37, p < .05). When the girls' CHL at 6 months was stratified into quartiles, the absolute and relative differences in bone traits observed at puberty (approximately 11.5 years) were maintained as these traits tracked during the ensuing 7 years. Similarly, weight at 6 months correlated with the girls' bone traits at puberty and 18 years of age (r = 0.22-0.55, p < .05). During puberty and at 18 years of age, the girls' bone traits correlated with the corresponding traits in their parents (r = 0.32-0.43, p < .01). It is concluded that familial resemblance in bone structural strength and the position of an individual's bone traits relative to others in adulthood are likely to be established during the first year of life. Thus susceptibility to bone fragility late in life has its antecedents established early in life.

Rapid growth produces transient cortical weakness: a risk factor for metaphyseal fractures during puberty.

Fractures of the distal radius in children have a similar incidence to that found in postmenopausal women but occur more commonly in boys than in girls. Fractures of the distal tibia are uncommon in children and show no sex specificity. About 90% of lengthening of the radius but only 30% of lengthening of the tibia during puberty occur at the distal growth plate. We speculated that more rapid modeling at the distal radial metaphysis results in a greater dissociation between growth and mineral accrual than observed at the distal tibia. We measured the macro- and microarchitecture of the distal radial and tibial metaphysis using high-resolution peripheral quantitative computed tomography in a cross-sectional study of 69 healthy boys and 60 healthy girls aged from 5 to 18 years. Bone diameters were larger but total volumetric bone mineral density (vBMD) was lower at the distal radius (not at the distal tibia) by 20% in boys and by 15% in girls at Tanner stage III than in children of the same sex at Tanner stage I (both p < .05). In boys at Tanner stage III, total vBMD was lower because the larger radial total cross-sectional area (CSA) had a thinner cortex with lower vBMD than in boys at Tanner stage I. In girls at Tanner stage III, the larger total radial CSA was not associated with a difference in cortical thickness or cortical vBMD relative to girls in Tanner stage I. Cortical thickness and density at both sites in both sexes after Tanner stage III were greater than in younger children. Trabecular bone volume fraction (BV/TV) was higher in boys than in girls at both sites and more so after puberty because trabeculae were thicker in more mature boys but not in girls. There was no sex- or age-related differences in trabecular number at either site. We infer that longitudinal growth outpaces mineral accrual in both sexes at the distal radius, where bone grows rapidly. The dissociation produces transitory low cortical thickness and vBMD in boys but not in girls. These structural features in part may account for the site and sex specificity of metaphyseal fractures during growth.

Low volumetric BMD is linked to upper-limb fracture in pubertal girls and persists into adulthood: a seven-year cohort study.

The aetiology of increased incidence of fracture during puberty is unclear. This study aimed to determine whether low volumetric bone mineral density (vBMD) in the distal radius is associated with upper-limb fractures in growing girls, and whether any such vBMD deficit persists into adulthood. Fracture history from birth to 20 years was obtained and verified by medical records in 1034 Finnish girls aged 10-13 years. Bone density and geometry at distal radius, biomarkers and lifestyle/behavioural factors were assessed in a subset of 396 girls with a 7.5-year follow-up. We found that fracture incidence peaked during puberty (relative risk 3.1 at age of 8-14 years compared to outside this age window), and 38% of fractures were in the upper-limb. Compared to the non-fracture cohort, girls who sustained upper-limb fracture at ages 8-14 years had lower distal radial vBMD at baseline (258.9+/-37.5 vs. 287.5+/-34.1 mg/cm(3), p=0.001), 1-year (252.0+/-29.3 vs. 282.6+/-33.5 mg/cm(3), p=0.001), 2-year (258.9+/-32.2 vs. 289.9+/-40.1 mg/cm(3), p=0.003), and 7-year follow-ups (early adulthood, 307.6+/-35.9 vs. 343.6+/-40.9 mg/cm(3), p=0.002). There was a consistent trend towards larger bone cross-sectional area in the fracture cohort compared to non-fracture. In a logistic regression model, lower vBMD (p=0.001) was the only significant predictor of upper-limb fracture during the period of 8-14 years. Our results indicate that low BMD is an important factor underlying elevated upper-limb fracture risk during puberty, and that low BMD in pubertal girls with fracture persists into adulthood. Hence low vBMD during childhood is not a transient deficit. Methods to monitor vBMD and to maximise bone mineral accrual and reduce risks of falling in childhood should be developed.