Influence of tillage methods combined with mulching on soil physical properties and potato yield in dry farming area under different precipitation years.

We conducted a field experiment in the dry farming area in south Ningxia from 2018 to 2021, to explore the influence of tillage methods combined with mulching on soil bulk density, aggregate content, soil water storage and potato yield under different precipitation years. There were four tillage methods (15 cm depth ploughing, and 30 cm, 40 cm and 50 cm depth subsoiling) and three mulching measures (mulching with oat straw, plastic film and no mulching), with the ploughing depth of 15 cm without mulching as control. The results showed the combination of tillage and mulching effectively reduced soil bulk density in 0-60 cm layer after three years of farming compared with that prior to the experiment. Under the same tillage mode, the best effect was achieved in mulching with oat straw under different precipitation years. To be specific, the best effect in 20 cm and 40 cm soil layers was achieved in mulching with oat straw for 30 cm depth subsoiling, in 60 cm soil layer for 15 cm ploughing in wet year, and for 40 cm depth subsoiling in 20 cm, 40 cm and 60 cm soil layers in normal and dry years. In 0-20 cm soil layer, the content of >0.25 mm soil aggregate was the highest for 40 cm depth subsoiling with oat straw mul-ching in all the three years. In 20-40 cm soil layer, the content was the highest for 15 cm depth ploughing with oat straw mulching in wet year, and for 40 cm depth subsoiling with oat straw mulching in normal and dry years. In 40-60 cm soil layer, content was the highest for 15 cm depth ploughing with plastic film mulching, 30 cm depth subsoiling with plastic film mulching, and 30 cm depth subsoiling with oat straw mulching in wet, normal and dry years, which was increased by 18.8%, 27.0%, and 35.8%, respectively, compared with the control. In the key growth stage (from squaring to tuber expansion) of potatoes, soil water storage in 0-100 cm layer was optimal for 30 cm depth subsoiling with oat straw mulching in wet year and for 40 cm depth subsoiling with oat straw mulching in normal and dry years, with an increase of 19.4%, 19.5%, and 23.7%, respectively. Potato yield was the highest for 30 cm depth subsoiling with oat straw mulching in wet year and for 40 cm depth subsoiling in normal and dry years, with an increase of 84.6%, 81.7%, and 106.3%, respectively. The correlation analysis showed that improved soil physical properties played a significant role in increasing potato yield, with the most significant role of soil bulk density and soil water storage at the squaring stage. Potato yield was high at a tillage depth of 34.67-36.03 cm. We concluded that the combination of tillage method and mulching could effectively improve soil physical pro-perties and increase soil water storage in the growth stage of potatoes, thereby significantly increa-sing potato yield. Potato yield in dry farming area could be enhanced through 30 cm depth subsoiling with oat straw mulching in wet years, and 40 cm depth subsoiling with oat straw mulching in normal and dry years.

Observation of plaid-like spin splitting in a noncoplanar antiferromagnet.

Spatial, momentum and energy separation of electronic spins in condensed-matter systems guides the development of new devices in which spin-polarized current is generated and manipulated1-3. Recent attention on a set of previously overlooked symmetry operations in magnetic materials4 leads to the emergence of a new type of spin splitting, enabling giant and momentum-dependent spin polarization of energy bands on selected antiferromagnets5-10. Despite the ever-growing theoretical predictions, the direct spectroscopic proof of such spin splitting is still lacking. Here we provide solid spectroscopic and computational evidence for the existence of such materials. In the noncoplanar antiferromagnet manganese ditelluride (MnTe2), the in-plane components of spin are found to be antisymmetric about the high-symmetry planes of the Brillouin zone, comprising a plaid-like spin texture in the antiferromagnetic (AFM) ground state. Such an unconventional spin pattern, further found to diminish at the high-temperature paramagnetic state, originates from the intrinsic AFM order instead of spin-orbit coupling (SOC). Our finding demonstrates a new type of quadratic spin texture induced by time-reversal breaking, placing AFM spintronics on a firm basis and paving the way for studying exotic quantum phenomena in related materials.

On the topological surface states of the intrinsic magnetic topological insulator Mn-Bi-Te family.

We review recent progress in the electronic structure study of intrinsic magnetic topological insulators (MnBi2Te4) · (Bi2Te3)n ([Formula: see text]) family. Specifically, we focus on the ubiquitously (nearly) gapless behavior of the topological Dirac surface state observed by photoemission spectroscopy, even though a large Dirac gap is expected because of surface ferromagnetic order. The dichotomy between experiment and theory concerning this gap behavior is perhaps the most critical and puzzling question in this frontier. We discuss various proposals accounting for the lack of magnetic effect on the topological Dirac surface state, which are mainly categorized into two pictures, magnetic reconfiguration and topological surface state redistribution. Band engineering towards opening a magnetic gap of topological surface states provides great opportunities to realize quantized topological transport and axion electrodynamics at higher temperatures.

Fecal microbiota as a predictor of acupuncture responses in patients with postpartum depressive disorder.

Background: There are several clinical and molecular predictors of responses to antidepressant therapy. However, these markers are either too subjective or complex for clinical use. The gut microbiota could provide an easily accessible set of biomarkers to predict therapeutic efficacy, but its value in predicting therapy responses to acupuncture in patients with depression is unknown. Here we analyzed the predictive value of the gut microbiota in patients with postpartum depressive disorder (PPD) treated with acupuncture. Methods: Seventy-nine PPD patients were enrolled: 55 were treated with acupuncture and 24 did not received any treatment. The 17-item Hamilton depression rating scale (HAMD-17) was used to assess patients at baseline and after eight weeks. Patients receiving acupuncture treatment were divided into an acupuncture-responsive group or non-responsive group according to HAMD-17 scores changes. Baseline fecal samples were obtained from the patients receiving acupuncture and were analyzed by high-throughput 16S ribosomal RNA sequencing to characterize the gut microbiome. Results: 47.27% patients responded to acupuncture treatment and 12.5% patients with no treatment recovered after 8-week follow-up. There was no significant difference in α-diversity between responders and non-responders. The ß-diversity of non-responders was significantly higher than responders. Paraprevotella and Desulfovibrio spp. were significantly enriched in acupuncture responders, and these organisms had an area under the curve of 0.76 and 0.66 for predicting responder patients, respectively. Conclusions: Paraprevotella and Desulfovibrioare may be useful predictive biomarkers to predict PPD patients likely to respond to acupuncture. Larger studies and validation in independent cohorts are now needed to validate our findings.

Peripheral Blood Inflammatory Cytokine Factors Expressions are Associated with Response to Acupuncture Therapy in Postpartum Depression Patients.

Background: Increasing evidences demonstrate that immune dysregulation can result in depression, and it is reported that persistent inflammatory response is related to the unresponsiveness of antidepressant treatment. Purpose: This study aimed to explore the reason why some responded but some not responded to acupuncture in treating postpartum depression (PPD), and whether it related to the levels of inflammatory cytokines. Patients and Methods: Women diagnosed with PPD were recruited in to accept 8-week acupuncture. All subjects were assessed the 17-item Hamilton Depression Rating Scale (HDRS17) at baseline, week 1, week 2, week 4 and week 8 during the treatment. A panel of 9 cytokines was measured at baseline and 8 weeks. Results: Of the 121 participants, 96 completed the 8-week assessment and 46 completed the blood sample collection. HDRS17 scores of 96 subjects showed significant statistical reduction since the first week (P = 0.002) and reached to 5.31 (P < 0.000) at the end of therapy. And we divided the 46 subjects into responders and non-responders according to the response rate of HDRS17 scores. Responders and non-responders did not differ significantly between-group in changes in the 9 cytokines. In responders, IL-6, IL-10 and IFN-γ levels were statistically lower (P = 0.006; P = 0.033; P = 0.024), while TGF-ß1 was statistically higher after 8 weeks treatment (P < 0.000). In non-responders, the levels of IL-5, TNF-α and TGF-ß1 were statistically higher (P = 0.018; P < 0.000; P < 0.000), while IFN-γ was statistically lower (P = 0.005). Conclusion: Acupuncture could alleviate depressive symptoms of patients with PPD and might through adjusting peripheral inflammatory response by up-regulating anti-inflammatory cytokines and down-regulating pro-inflammatory cytokines.

Development of an innovative nomogram of risk factors to predict postoperative recurrence of gastrointestinal stromal tumors.

BACKGROUND: There are many staging systems for gastrointestinal stromal tumors (GISTs), and the risk indicators selected are also different; thus, it is not possible to quantify the risk of recurrence among individual patients. AIM: To develop and internally validate a model to identify the risk factors for GIST recurrence after surgery. METHODS: The least absolute shrinkage and selection operator (LASSO) regression model was performed to identify the optimum clinical features for the GIST recurrence risk model. Multivariable logistic regression analysis was used to develop a prediction model that incorporated the possible factors selected by the LASSO regression model. The index of concordance (C-index), calibration curve, receiver operating characteristic curve (ROC), and decision curve analysis were used to assess the discrimination, calibration, and clinical usefulness of the predictive model. Internal validation of the clinical predictive capability was also evaluated by bootstrapping validation. RESULTS: The nomogram included tumor site, lesion size, mitotic rate/50 high power fields, Ki-67 index, intracranial necrosis, and age as predictors. The model presented perfect discrimination with a reliable C-index of 0.836 (95%CI: 0.712-0.960), and a high C-index value of 0.714 was also confirmed by interval validation. The area under the curve value of this prediction nomogram was 0.704, and the ROC result indicated good predictive value. Decision curve analysis showed that the predicting recurrence nomogram was clinically feasible when the recurrence rate exceeded 5% after surgery. CONCLUSION: This recurrence nomogram combines tumor site, lesion size, mitotic rate, Ki-67 index, intracranial necrosis, and age and can easily predict patient prognosis.

[Mild and moderate postpartum depression treated with acupuncture of Tiaoren Tongdu: a real world study].

OBJECTIVE: To observe the clinical therapeutic effect on mild and moderate postpartum depression treated with acupuncture of Tiaoren Tongdu (regulating the conception vessel and unblocking the governor vessel) on the base of real world. METHODS: A total of 116 patients with mild and moderate postpartum depression were divided into an acupuncture group (103 cases) and a non-acupuncture group (13 cases) according to treatment regimen provided. In the acupuncture group, acupuncture of Tiaoren Tongdu was applied to Baihui (GV 20), Yintang (GV 29), Zhongwan (CV 12), Qihai (CV 6), Guanyuan (CV 4), Neiguan (PC 6), Shenmen (HT 7), Hegu (LI 4), Zusanli (ST 36), Sanyinjiao (SP 6) and Taichong (LR 3). Needles were retained for 30 min each time, the treatment was given once every other day, 3 times a week. In the non-acupuncture group, psychotherapy was provided, once daily. The duration of treatment in the two groups was 8 weeks. According to the treatment times of acupuncture, the acupuncture group was subdivided into an acupuncture A group (60 cases with total treatments ≥ 6 times) and an acupuncture B group (43 cases with total treatments<6 times). Using propensity score matching method, the patients of the acupuncture A and B groups were matched each other. Finally, 31 pairs of cases were matched successfully. Before treatment, at 1st, 2nd, 4th and 8th weeks of treatment, as well as at 3-month follow-up, the scores of Hamilton depression scale (HAMD) were compared in patients among the three groups. Using Logistic regression, the impact of acupuncture frequencies on the therapeutic effect was analyzed and the clinical therapeutic effect was assessed. RESULTS: The total effective rate of the acupuncture A group was 100.0% (31/31), better than 76.9% (10/13) in the non-acupuncture group and 58.1% in the acupuncture B group (18/31) (P<0.05). HAMD score at each time point after treatment was lower than that before treatment in the patients of each group (P<0.05). But HAMD score at each time point after treatment in either the acupuncture A group or the acupuncture B group was lower than that in the non-acupuncture group separately (P<0.05), HAMD scores in the acupuncture A group at the 4th and 8th weeks of treatment and at follow-up were lower than those in the acupuncture B group (P<0.05). Logistic regression analysis showed that the total times of acupuncture treatment and the persistent days of treatment had a certain relation to therapeutic effect (P<0.05). CONCLUSION: Acupuncture of Tiaoren Tongdu effectively improves in mild and moderate postpartum depression and its therapeutic effect is closely related to treatment course.

Pressure-Tuned Intralayer Exchange in Superlattice-Like MnBi2Te4/(Bi2Te3)n Topological Insulators.

The magnetic structures of MnBi2Te4(Bi2Te3)n can be manipulated by tuning the interlayer coupling via the number of Bi2Te3 spacer layers n, while the intralayer ferromagnetic (FM) exchange coupling is considered too robust to control. By applying hydrostatic pressure up to 3.5 GPa, we discover opposite responses of magnetic properties for n = 1 and 2. MnBi4Te7 stays at A-type antiferromagnetic (AFM) phase with a decreasing Néel temperature and an increasing saturation field. In sharp contrast, MnBi6Te10 experiences a phase transition from A-type AFM to a quasi-two-dimensional FM state with a suppressed saturation field under pressure. First-principles calculations reveal the essential role of intralayer exchange coupling from lattice compression in determining these magnetic properties. Such magnetic phase transition is also observed in 20% Sb-doped MnBi6Te10 because of the in-plane lattice compression.

Fermi Velocity Reduction of Dirac Fermions around the Brillouin Zone Center in In2 Se3 -Bilayer Graphene Heterostructures.

Emergent phenomena such as unconventional superconductivity, Mott-like insulators, and the peculiar quantum Hall effect in graphene-based heterostructures are proposed to stem from the superlattice-induced renormalization of (moiré) Dirac fermions at the graphene Brillouin zone corners. Understanding the corresponding band structure commonly demands photoemission spectroscopy with both sub-meV resolution and large-momentum coverage, beyond the capability of the current state-of-the-art. Here the realization of moiré Dirac cones around the Brillouin zone center in monolayer In2 Se3 /bilayer graphene heterostructure is reported. The renormalization is evidenced by reduced Fermi velocity (≈23%) of the moiré Dirac cones and the reshaped Dirac point at the Γ point where they intersect. While there have been many theoretical predictions and much indirect experimental evidence, the findings here are the first direct observation of Fermi velocity reduction of the moiré Dirac cones. These features suggest strong In2 Se3 /graphene interlayer coupling, which is comparable with that in twisted bilayer graphene. The strategy expands the choice of materials in the heterostructure design and stimulates subsequent broad investigations of emergent physics at the sub-meV energy scale.

Te-Vacancy-Induced Surface Collapse and Reconstruction in Antiferromagnetic Topological Insulator MnBi2Te4.

MnBi2Te4 is an antiferromagnetic topological insulator that has stimulated intense interest due to its exotic quantum phenomena and promising device applications. The surface structure is a determinant factor to understand the magnetic and topological behavior of MnBi2Te4, yet its precise atomic structure remains elusive. Here we discovered a surface collapse and reconstruction of few-layer MnBi2Te4 exfoliated under delicate protection. Instead of the ideal septuple-layer structure in the bulk, the collapsed surface is shown to reconstruct as a Mn-doped Bi2Te3 quintuple layer and a MnxBiyTe double layer with a clear van der Waals gap in between. Combined with first-principles calculations, such surface collapse is attributed to the abundant intrinsic Mn-Bi antisite defects and the tellurium vacancy in the exfoliated surface, which is further supported by in situ annealing and electron irradiation experiments. Our results shed light on the understanding of the intricate surface-bulk correspondence of MnBi2Te4 and provide an insightful perspective on the surface-related quantum measurements in MnBi2Te4 few-layer devices.

Surgical indication and strategy for liver hemangioma in the caudate lobe: a multi-institutional retrospective analysis with 137 patients.

OBJECTIVE: To investigate the surgical indication and tactics for liver hemangioma in the caudate lobe METHODS: From January 1994 to July 2019, 137 patients, including 51 males and 86 females with the average age of 49.2 years old were diagnosed with liver hemangioma in caudate lobe and received treatment at five tertiary referral hospitals. Clinical features, correlations between tumor size and clinical manifestations, treatments, and prognosis were analyzed. RESULTS: Of the 137 patients identified, 40 (29.20%) patients were asymptomatic, whereas other 94 patients had clinical symptoms mainly presented as upper abdominal discomfort, epigastric distention, upper abdominal dull pain, nausea, and vomiting. Fifteen (93.75%), 18 (39.13%), and 7 (10.45%) patients presented no clinical symptoms among those tumor size was less than 3 cm (D ≤ 3 cm, n = 16), 3 cm < D ≤ 6 cm (n = 46), and 6 cm < D ≤ 9 cm (n = 67), respectively, while all 8 patients with tumor larger than 9 cm were symptomatic. Tumor diameter was obviously associated with the presence of clinical symptoms. In follow-up period, 7 patients in the conservative group (n = 39) received surgery because of tumor growth or symptom appearance. Totally 105 patients received operation including partial resection or isolated complete resection of caudate lobe and caudate lobe resection combined with liver segment resection, right liver resection, or left liver resection. All operations went smoothly, and no severe complications appeared. CONCLUSION: Tumor diameter was obviously associated with the presence of clinical symptoms in patients with hemangioma in caudate lobe. Surgical therapy is not recommended for asymptomatic patients and available for patient who has symptoms. Effective surgical strategies should be put into use to reduce operative bleeding.

Transcriptomic evidence that insulin signalling pathway regulates the ageing of subterranean termite castes.

Insulin is a protein hormone that controls the metabolism of sugar, fat and protein via signal transduction in cells, influencing growth and developmental processes such as reproduction and ageing. From nematodes to fruit flies, rodents and other animals, glucose signalling mechanisms are highly conserved. Reproductive termites (queens and kings) exhibit an extraordinarily long lifespan relative to non-reproductive individuals such as workers, despite being generated from the same genome, thus providing a unique model for the investigation of longevity. The key reason for this molecular mechanism, however, remains unclear. To clarify the molecular mechanism underlying this phenomenon, we sequenced the transcriptomes of the primary kings (PKs), primary queens (PQs), male (WMs) and female (WFs) workers of the lower subterranean termite Reticulitermes chinensis. We performed RNA sequencing and identified 33 insulin signalling pathway-related genes in R. chinensis. RT-qPCR analyses revealed that EIF4E and RPS6 genes were highly expressed in WMs and WFs workers, while mTOR expression was lower in PKs and PQs than in WMs and WFs. PQs and PKs exhibited lower expression of akt2-a than female workers. As the highly conserved insulin signalling pathway can significantly prolong the healthspan and lifespan, so we infer that the insulin signalling pathway regulates ageing in the subterranean termite R. chinensis. Further studies are recommended to reveal the biological function of insulin signalling pathway-related genes in the survival of termites to provide new insights into biomolecular homeostasis maintenance and its relationship to remarkable longevity.

Effects of Intensive Fattening With Total Mixed Rations on Carcass Characteristics, Meat Quality, and Meat Chemical Composition of Yak and Mechanism Based on Serum and Transcriptomic Profiles.

The objective of this study was to investigate the effects of intensive fattening with total mixed rations (TMR) on carcass characteristics, meat quality, and chemical composition of the yak meat. Theoretical data has been provided for evaluating the quality of yak meat during natural grazing and short-term fattening. Based on the analysis, we found that in fattening yak, the carcass weight (CWT) was increased by 106.43%, whereas the cooking loss, tenderness, and drop loss were significantly improved due to higher intramuscular fat content and lower moisture (P < 0.05). Protein, fat, calcium, and amino acids were also much higher (P < 0.01) in fattening yak compared with the grazing yak. The levels of albumin (ALB), lactate dehydrogenase (LDH), triglyceride (TRIG), and amylase (AMYL) in serum indicated better nutritional status for fattening yaks. The transcriptomics analysis showed that the high expression of ACSL1 and ACACB genes improved the synthesis and deposition of fat in fattening yak, whereas the regulation of SLC7A8, ATP1A4, ATP1A1, SLC3A2, and CPA3 gene expression weakened the proteolysis. These results indicated that fattening with TMR improves the yield and quality of the yak meat.

Autologous Blood Transfusion and Pringle Maneuver in Laparoscopic Segmental Hepatectomy for Benign Hepatic Neoplasms: A Retrospective Study.

Objectives: To investigate the effect of autologous blood transfusion (ABT) and Pringle maneuver (PM) on postoperative early liver function and short-term postoperative results following laparoscopic liver resection in patients with benign hepatic neoplasms. Materials and Methods: We retrospectively analyzed the clinical data for 125 consecutive patients who underwent laparoscopic segmental hepatectomy from January 2015 to May 2018 (68 in the ABT group versus 57 in the PM group). We compared patients' characteristics and intra- and postoperative short-term outcomes between the groups. Results: The 2 groups were well matched regarding patients' clinical characteristics, types of liver resection, operative time, and histopathological findings (P > .05). Median blood loss was significantly lower in the PM group versus the ABT group (200 mL versus 750 mL, respectively; P < .01), and overall complication rates were similar (n = 12 [17%] versus n = 9 [16%], respectively; P > .05). The ABT group had significantly lower mean levels of total bilirubin, indirect bilirubin, aspartate transaminase, and alanine aminotransferase on postoperative days 1 and 3 (P < .05). The ABT group had a shorter hospital stay compared with the PM group (5.8 days versus 7.7 days, respectively; P < .05) and lower hospitalization costs (55,400 ± 15,400 versus 667,000 ± 21,600 CN dollars, respectively; P < .05). Conclusions: Compared with Pringle's maneuver, laparoscopic hepatectomy with ABT promoted early recovery of liver function and reduced hospitalization costs in select patients with benign hepatic neoplasms.

DRAM1 regulates the migration and invasion of hepatoblastoma cells via autophagy-EMT pathway.

DNA-damage regulated autophagy modulator 1 (DRAM1) is known as a target of TP53-mediated autophagy, and has been reported to promote the migration and invasion abilities of glioblastoma stem cells. However, the precise contribution of DRAM1 to cancer cell invasion and migration, and the underlying mechanisms remain unclear. In the present study, small interfering (si)RNA or short hairpin RNA mediated knockdown of DRAM1 was performed in hepatoblastoma cells and the migration and invasion abilities were detected in vitro and in vivo. To investigate the underlying mechanisms, western blotting and immunofluorescence were used to detect the expression of autophagy-associated proteins and epithelial-mesenchymal-transition (EMT)-associated markers. The results showed that DRAM1 knockdown by specific siRNA abrogated cell autophagy, as well as inhibited the migration and invasion of HepG2 cells in Transwell assays, which may be reversed by rapamycin treatment. In addition, DRAM1 knockdown increased the expression of E-Cadherin while decreased the expression of vimentin in HepG2 cells, which was also be reversed by rapamycin treatment. Taken together, these results suggest that DRAM1 is involved in the regulation of the migration and invasion of HepG2 cells via autophagy-EMT pathway.

Unexpected Large Hole Effective Masses in SnSe Revealed by Angle-Resolved Photoemission Spectroscopy.

SnSe has emerged as an efficient thermoelectric material since a high value of the thermoelectric figure of merit (ZT) has been reported recently. Here we show with systematic angle resolved photoemission spectroscopy data that the low-lying electronic structures of undoped and hole-doped SnSe crystals exhibit noticeable temperature variation from 80 to 600 K. In particular, the hole effective masses for the two lowest lying valence band maxima are found to be very large and increase with decreasing temperature. Thermoelectric parameters derived from such hole-mass enhancement agree well with the transport values, indicating comprehensively a reduced impact of multivalley transport to the system's thermoelectric performance.

Totally laparoscopic gallbladder-preserving surgery: A minimally invasive and favorable approach for cholelithiasis.

The aim of the present study was to investigate the effectiveness of laparoscopic gallbladder-preserving surgery (L-GPS) for cholelithiasis and the feasibility and value of totally laparoscopic GPS (TL-GPS). A total of 517 patients underwent L-GPS, including 365 cases of laparoscopy-assisted GPS (LA-GPS), 143 cases of TL-GPS (preservation rate, 98.3%) and nine conversions to laparoscopic cholecystectomy. The surgeries were all performed by one medical team and the mean operating time was 72 min. All macroscopic calculi were removed through endoscopy. The number of calculi observed in the patients was between one and several dozen; diameters ranged between 0.1 and 2.5 cm. Only three cases of incisional infection were noted in the LA-GPS group and long-term follow-up showed a low recurrence rate of 1.2%. L-GPS is, therefore, an excellent approach to cure cholelithiasis and TL-GPS is a feasible and effective option that could avoid incisional complications.

Calcium supplementation and bone mineral accretion in Chinese adolescents aged 12-14 years: a 12-month, dose-response, randomised intervention trial.

A 12-month, dose-response, randomised, intervention trial was conducted to determine adequate Ca intake levels for Chinese adolescents by investigating the effect of Ca supplementation on bone mineral accretion. A total of 220 Han adolescents (111 girls and 109 boys) aged 12-14 years were recruited. All subjects were randomly divided into three groups. The bone mineral content (BMC) and bone mineral density (BMD) of the whole body, lumbar spine (L1-L4), left hip and femoral neck were measured by dual-energy X-ray absorptiometry. Girls in the high-Ca group (actual Ca intake: 1243 (sd 193) mg/d) exhibited greater increases in the femoral neck BMC compared with those in the low-Ca group (9·7 v. 6·4 %, P =0·04) over the 1-year intervention period. The increases in femoral neck BMC were greater in boys in the high-Ca and medium-Ca groups (actual Ca intake: 985 (sd 168) mg/d) than in those in the low-Ca group (15·7 v. 11·7 %, P =0·03; 15·8 v. 11·7 %, P =0·03). Ca supplementation had significant effects on the whole-body BMC and BMD in subjects with physical activity levels>34·86 metabolic equivalents and on the spine BMD and BMC and BMD of most sites in subjects with Tanner stage < 3. Increasing Ca intake levels with Ca supplementation enhanced femoral neck mineral acquisition in Chinese adolescents. Furthermore, high physical activity levels and low Tanner stage appeared to significantly contribute to the effect of Ca supplementation on bone mass. Whether this is a lasting beneficial effect leading to the optimisation of peak bone mass needs to be determined in other long-term prospective studies.

Effects of milk salt supplementation on bone mineral gain in pubertal Chinese adolescents: a 2-year randomized, double-blind, controlled, dose-response trial.

BACKGROUND/OBJECTIVE: Adequate calcium intakes may enhance bone mineral accumulation during childhood. Little is known about the optimal calcium intake in Chinese adolescents. We examined the effects of three levels of calcium intake on bone mineral accretion in adolescents. METHODS: This was a 2-year randomized, double-blind, controlled trial. The subjects were randomly assigned to receive 40 g of milk powder containing 300 mg of calcium and 200 IU of vitamin D (Low-Ca group), or same milk powder additionally fortified with 300 mg of calcium (Mid-Ca group) or 600 mg of calcium (High-Ca group) for 2 years. The subjects' bone mineral density (BMD) and bone mineral content (BMC) at the total body, lumbar spine and left hip were determined by dual-energy X-ray absorptiometry at baseline and after the second year of treatment. Of the 111 girls and 109 boys (aged 12-14 years) enrolled, 91 girls and 91 boys completed the trial. RESULTS: The girls in the High-Ca group (1,110 mg/d) had 2.3%, 2.7% and 2.6% greater BMD accretion at the total hip, femoral neck and shaft (P<0.05) but not at total body less head and spine than those in the Low-Ca group (655 mg/d). A significant effect of higher calcium intake was also observed for percentage change of size-adjusted BMC at femur neck (P=0.047). Bonferroni tests indicated no significant differences in the percentage changes in BMD, BMC or size-adjusted BMC between the Mid- and Low-Ca groups and between the High- and Mid-Ca groups. Extra calcium had no observable additional effect in the boys (P>0.05). CONCLUSION: An intake of 1000 mg/d or more might be helpful in maximizing bone mineral accretion in the hip for girls. But further large studies are required to identify its long-term effects and the optimal calcium intake for boys.