Achieving Low-Dose Rate X-Ray Imaging Based on 2D/3D-Mixed Perovskite Films.

X-ray detection and imaging are widely used in medical diagnosis, product inspection, security monitoring, etc. Large-scale polycrystalline perovskite thick films possess high potential for direct X-ray imaging. However, the notorious problems of baseline drift and high detection limit caused by ions migration are still remained. Here, ion migration is reduced by incorporating 2D perovskite into 3D perovskite, thereby increasing the ion activation energy. This approach hinders ion migration within the perovskite film, consequently suppressing baseline drift and reducing the lowest detection limit(LOD) of the device. As a result, the baseline drifting declines by 20 times and the LOD reduces to 21.1 nGy s-1, while the device maintains a satisfactory sensitivity of 5.6 × 103 µC Gy-1 cm-2. This work provides a new strategy to achieve low ion migration in large-scale X-ray detectors and may provide new thoughts for the application of mixed-dimension perovskite.

Using N-I-N Photodiodes Made of Perovskite Single Crystals for Low Noise Gamma-Ray Spectroscopy.

Solution-processed lead halide perovskite single crystals (LHPSCs) are believed to have great potential in gamma-ray spectroscopy. However, obtaining low-defect LHPSCs from a solution at low temperatures is difficult compared to obtaining Bridgman single crystals such as CdTe and Si. Herein, noise from the intrinsic defects of LHPSCs is considered as the main problem hindering their gamma-ray detection performance. By isolating the defect-induced holes in LHPSCs via energy barriers, we show that NIN photodiodes based on three types of LHPSCs, i.e., MAPbBr3 (MA = CH3NH3), MAPbBr2.5Cl0.5, and cascade LHPSCs, have demonstrated good energy resolution in the range of 6.7-10.3% for 662 keV 137Cs gamma-ray photons. The noise for >10 mm3 devices is low, in the order of 340-860 electrons, and the electron collection efficiency reaches 23-43%. These results pave the way for obtaining low-cost, large, high energy-resolution gamma-ray detectors at room temperature (300 K).

Fast Response, High Spectral Rejection Ratio, Self-Filtered Ultranarrowband Photodetectors Based on Perovskite Single-Crystal Heterojunctions.

Narrowband photodetectors have wide application potential in high-resolution imaging and encrypted communication, due to their high-precision spectral resolution capability. In this work, we report a fast response, high spectral rejection ratio, and self-filtered ultranarrowband photodetector with a new mechanism, which introduces bulk recombination by doping Bi3+ and cooperates with surface recombination for further quenching photogenerated charges generated by short-wavelength-light excitation in perovskite single-crystal. A perovskite film focused on collecting charges is fabricated on the single crystal by a lattice-matched solution-processed epitaxial growth method. Due to the formation of PN heterojunctions, a narrowband photodetector in this mechanism has remarkable spectral selectivity and detection performance with an ultranarrow full width at half-maximum (FWHM) of 7.7 nm and a high spectral rejection ratio of 790, as well as a high specific detectivity up to 1.5 × 1010 Jones, a fast response speed with a rise time and fall time of ∼8 and 137 µs. The ultrafast and ultranarrow spectra response of self-filtered narrowband photodetector provides a new strategy in high-precision and high-resolution photoelectric detection.

Sensitive Thermography via Sensing Visible Photons Detected from the Manipulation of the Trap State in MAPbX3.

Sensitive thermometry or thermography by responding to blackbody radiation is urgently desired in the intelligent information life, including scientific research, medical diagnosis, remote sensing, defense, etc. Even though thermography techniques based on infrared sensing have undergone unprecedented development, the poor compatibility with common optical components and the high diffraction limit impose an impediment to their integration into the established photonic integrated circuit or the realization of high-spatial-resolution and high-thermal-resolution imaging. In this work, we present a sensitive temperature-dependent visible photon detection in Bi-doped MAPbX3 (X = Cl, Br, and I) and employ it for uncooled thermography. Systematic measurements reveal that the Bi dopant introduces trap states in MAPbX3, thermal energy facilitates the carriers jumping from trap states to the conduction band, while the vacancies of trap states ensure the sequential absorption of visible photons with energy less than the band gap. Subsequently, the change of response toward the visible photon is applied to construct the thermograph, and it possesses a specific sensitivity of 2.11% K-1 along temperature variation. As a result, our thermograph presents a temperature resolution of 0.21 nA K-1, a high responsivity of 2.06 mA W-1, and a high detectivity of 2.08 × 109 Jones at room temperature. Furthermore, remote thermal imaging is successfully achieved with our thermograph.

[Platelet-rich Plasma Induces M2 Macrophage Polarization via Regulating AMPK Singling Pathway].

OBJECTIVE: To investigate the role of platelet-rich plasma (PRP) in inducing the M2 macrophage polarization via regulating AMPK singling pathway. METHODS: The expressions of M1 marker CD11c and M2 marker CD206 in macrophages of blank control group, LPS group, LPS+PRP group, and LPS+PRP+Compound C group were detected by flow cytometry. Western blot was used to observe the effects of PRP on the expression of AMPK-mTOR signaling pathway-related proteins at different times (12 h, 18 h and 24 h) after LPS treatment. RNA interference technology was used to silence the expression of AMPK in macrophages, and the expression of TGF-ß protein was subsequently examined by Western blot. RESULTS: LPS significantly reduced the expression of CD206 and increased the expression of CD11c (P <0.05). After the addition of PRP, the expression of CD206 was significantly increased (P <0.05), while the expression of CD11c was significantly decreased (P <0.05). Compared with LPS group, PRP treatment significantly increased the expressions of p-AMPK and p-ULK1 proteins at 12 h, 18 h and 24 h, while significantly decreased the expression of p-mTOR protein (P <0.05). After the addition of AMPK inhibitor Compound C, the expression of CD206 was significantly reduced (P <0.05) and the expression of CD11c was significantly increased compared with LPS+PRP group (P <0.05). After silencing the expression of AMPK in macrophages, the promotion effect of PRP on TGF-ß was significantly reduced (P <0.05). CONCLUSION: PRP can stimulate the transformation of macrophages to M2 type via AMPK signalling pathway.

Cascade perovskite single crystal for gamma-ray spectroscopy.

The halide lead perovskite single crystals (HLPSCs) have great potential in gamma-ray detection with high attenuation coefficient, strong defects tolerance, and large mobility-lifetime product. However, mobile halide ions would migrate under high external bias, which would both weaken the gamma-ray response and cause additional noise. Here, we report the gamma-ray PIN photodiodes made of cascade HLPSCs including both ion-formed and electron-hole-formed electrical junctions that could suppress the ions migration and improve the charges collection. Our photodiodes based on cascade HLPSCs (MAPbBr3/MAPbBr2.5Cl0.5/MAPbCl3) show a wide halide-ion-formed depletion layer of ∼52 µm. The built-in potential along the wide ionic-formed junction ensures a high mobility-lifetime product of 1.1 × 10-2 cm2V-1. As a result, our gamma-ray PIN photodiodes exhibit compelling response to 241Am, 137Cs, and 60Co; the energy resolution can reach 9.4%@59.5keV and 5.9%@662keV, respectively. This work provides a new path toward constructing high-performance gamma-ray detectors based on HLPSCs.

Growth dynamics and sustainable development of aquatic products export trade of China and Vietnam.

The establishment of the China-ASEAN Free Trade Area has prompted closer cooperation in aquatic products trade between China and Vietnam. Studying the aquatic trade situation and export trade growth dynamics of China and Vietnam can help clarify the aquatic trade relationship between China and Vietnam and promote the sustainable development of bilateral aquatic trade cooperation. This paper analyzes the trade growth dynamics of aquatic products exported from China and Vietnam from 2002 to 2020 using the ternary marginal method. The trade growth pattern of aquatic products exported from China to Vietnam is "both quantity and price growth," and the trade growth pattern of aquatic products exported from Vietnam to China is "quantity growth mainly, extensive growth supplemented." The two countries have apparent differences in the growth dynamics of aquatic products export trade. Moreover, there is a higher complementarity when exporting Vietnam's aquatic products to China than China's aquatic products to Vietnam. Based on these, analyze the factors affecting the growth dynamics of Vietnam's aquatic products export to China: Vietnam's economic development level negatively affects the price index and quantity index of Vietnam's aquatic products exported to China, and Vietnam's aquatic product output affects the price index. China's trade freedom positively affects the price index and negatively affects the quantity index. Finally, this paper put forward suggestions to promote the sustainable development of bilateral aquatic products trade between China and Vietnam to facilitate the formulation of relevant policies between the two countries.

Digitalization, income inequality, and public health: Evidence from developing countries.

The COVID-19 pandemic has amplified the awareness and demand of public health worldwide. Based on the panel data of 81 developing countries from 2002 to 2019, this study probes into the effect of digitalization on public health and explores the mechanism through which digitalization affects public health from the perspective of income inequality. The results show that digitalization significantly enhances public health in developing countries, and this conclusion still holds after the robustness test. The heterogeneity analysis based on geographic location and income level indicates that the enhancing effect of digitalization on public health is most evident in Africa and middle-income countries. A further mechanism analysis suggests that digitalization can positively impact public health through the intermediary channel of suppressing income inequality. This study enriches the research on digitalization and public health and provides insights for comprehending public health needs and the powerful empowering effects of digitalization.

Epitaxial Perovskite Single-Crystalline Heterojunctions for Filter-Free Ultra-Narrowband Detection with Tunable Spectral Responses.

Narrowband photodetectors (NPDs) with the capability of detecting light within a selective wavelength range are in high demand for numerous emerging applications such as imaging systems, machine vision, and optical communication. Halide perovskite materials have been developed for eliminating the current complex filtering systems in NPDs due to their beneficial properties, while currently NPDs using perovskite materials are limited by hardly fully eliminated short wavelength response, low charge collection efficiency (CCE), complex fabrication process, and so forth. Herein, a series of perovskite single-crystalline heterojunctions (PSCHs) with a structure of Bi-MAPbX3/MAPbY3 are fabricated by liquid phase epitaxy for filter-free narrowband detection. By varying the halide component in the PSCH, the PSCH-based NPDs can realize continuously tunable spectral response range from blue to NIR regions and ultra-narrow full width at half-maximum (FWHM) of <20 nm. Specifically, the PSCH-based NPD with a high CCE under a large electric filed shows a high spectra rejection ratio of >1000, a fast response speed with rise/fall time of ∼160/∼225 µs, and long-term stability more than 3 months in ambient air. This work provides a simple strategy for designing low-cost and high-performance filter-free NPDs with a tunable spectral response.

A composite hydrogel containing resveratrol-laden nanoparticles and platelet-derived extracellular vesicles promotes wound healing in diabetic mice.

Diabetic wounds are difficult to heal because of persistent inflammation and limited angiogenesis. Resveratrol (RES) is an anti-inflammatory and antioxidant agent. Platelet-derived extracellular vesicles (PDEVs) are rich in growth factors and cytokines, which promote proliferation and angiogenesis. However, single drug treatment has limited efficacy and delivery efficiency. Bioengineering can improve the limited effect of single drugs by combining drugs and materials to obtain complementary or cooperative bioengineered drugs. In this study, gelatin methacrylate (GelMA) and silk fibroin glycidyl methacrylate (SFMA) were used to synthesize GelMA/SFMA composite hydrogels with suitable mechanical properties, swelling ratio and biodegradability. The composite hydrogel was used as a wound dressing for sustained drug release. RES was loaded into mesoporous silica nanoparticles (MSNs) to synthesize MSN-RES to enhance the release dynamic, and MSN-RES and PDEVs were combined with the composite hydrogels to form GelMA/SFMA/MSN-RES/PDEVs hydrogels. The GelMA/SFMA/MSN-RES/PDEVs had low cytotoxicity and good biocompatibility, inhibited macrophage iNOS expression, and promoted the tube formation by human umbilical vein endothelial cells (HUVECs) in vitro. In a diabetic mouse wound model, the GelMA/SFMA/MSN-RES/PDEVs hydrogels decreased the expression of pro-inflammatory factors TNF-α and iNOS, increased the expression of anti-inflammatory factors TGF-ß1 and Arg-1, promoted angiogenesis, and accelerated wound healing. Interestingly, the GelMA/SFMA/MSN-RES/PDEVs hydrogels promoted the expression of extracellular purinergic signaling pathway-related CD73 and adenosine 2A receptor (A2A-R). Therefore, the GelMA/SFMA/MSN-RES/PDEVs hydrogels could be used as wound dressings to regulate the inflammation and angiogenesis of diabetic wounds and accelerate wound healing. STATEMENT OF SIGNIFICANCE: Drugs often fail to function because of a continuous oxidative stress microenvironment and inflammation. Here, a GelMA/SFMA hydrogel, with enhanced mechanical properties and liquid absorption ability, is proposed for sustained release of drugs. In addition to carrying platelet-derived extracellular vesicles (PDEVs) with pro-angiogenic effects, the hydrogels were also loaded with nanoparticle-encapsulated resveratrol with anti-inflammatory activities, aiming to reduce inflammation and oxidative stress in the wound microenvironment, such that the wound could receive proliferative repair signals to achieve sequential treatment and heal quickly. We also experimentally predicted that the regulatory mechanism of the GelMA/SFMA/MSN-RES/PDEVs in wound healing might be related to the extracellular purinergic signaling pathway.

How Does Digitalization Affect Haze Pollution? The Mediating Role of Energy Consumption.

In the context of digital technology innovation, an in-depth investigation into the impact of digitalization on haze pollution is of great significance for scientifically understanding environmental effects of digitalization and building a livable civic environment. From the perspective of energy consumption intensity and structure, this paper theoretically analyzes the direct and indirect effects of digitalization on haze pollution. On this basis, the impact of digitalization on haze pollution for 81 countries over the period 2010-2019 is empirically investigated by using the system GMM and mediating effects model. Empirical results show that digitalization can effectively suppress haze pollution, and there is significant heterogeneity in this inhibiting effect. In addition, digitalization can indirectly restrain haze pollution by reducing energy consumption intensity and optimizing energy consumption structure. The findings of this paper can provide enlightenment for countries to promote digitalization, combat haze pollution, and thus enhance the health of community residents.

A Randomized Controlled Trial Evaluating the Effect of Tai Chi on the Drug Craving in Women.

This study was conducted in the purpose of investigating the effect of Tai Chi on drug craving for women with drug disorders. One hundred and twelve women were recruited from a drug rehabilitation center in China, and 47 and 48 were finally analyzed in the control group and exercise group, respectively. The exercise group underwent a 3-month Tai Chi training, whereas the control group experienced no exercise intervention during the same time period. The drug craving was measured by the visual analog scale. In data analysis, repeated-measures were utilized to test the differences between the control and exercise group over the course of the experiment time. The mean of the craving score significantly dropped from pre-test (control: mean = 5.38, SD = 3.04; exercise: mean = 4.68, SD = 2.93) to post-test (control: mean = 4.03, SD = 2.73; exercise: mean = 1.91, SD = 1.90) in both groups (control group: t = 3.84, df = 46, p < 0.001; exercise group: t = 5.941, df = 47, p < 0.001), with more decrease witnessed in the exercise group. Repeated-measures analysis with a Huynh-Feldt correction showed the significant effect of time (F = 27.383, p < 0.001) as well as the study group by time interaction (F = 3.52, p = 0.024). Tai Chi can ameliorate the drug craving in women and it could be a supportive treatment for drug addiction.

[Design and Verification of Lung Diffusion Function Detection System].

A lung diffusion function detection system is designed. Firstly, the controllable collection of air, test gas source and calibration gas source was based on single-breath method measurement principle. Secondly, pulmonary diffusing capacity for carbon monoxide (DlCO) was calculated by gas concentration measured by the non-dispersive infrared sensor to measure, the gas flow measured by the differential pressure sensor, and the temperature, humidity and atmospheric pressure sensors to test and evaluate the quantitative detection and evaluation of lung diffusion function. Moreover, a preliminary verification of the lung diffusion function detection system was implemented, and the results showed that the error of the lung carbon monoxide diffusion and the alveolar volume did not exceed 5%. Therefore, the system has high accuracy and is of great value for early screening and accurate assessment of COPD.

Electrically Modulated Near-Infrared/Visible Light Dual-Mode Perovskite Photodetectors.

Dual-mode photodetectors (PDs) have attracted increasing interest owing to their potential optoelectrical applications. However, the widespread use of PDs is still limited by the high cost of epitaxial semiconductors. In contrast, the solution processability and wide spectral tunability of perovskites have led to the development of various inexpensive and high-performance optoelectronic devices. In this study, we develop a high-performance electronically modulated dual-mode PD with near-infrared (NIR) narrowband and visible light broadband detection based on organic-inorganic hybrid methylammonium lead halide perovskite (MAPbX3; MA = CH3NH3 and X = Cl, Br, and I) single crystals with a pnp configuration. The operating mode of the dual-mode PD can be switched according to voltage bias polarity because the photon absorption region and carrier transport performance are tuned at different bias voltages. The dual-mode PD exhibits a NIR light responsivity of 0.244 A/W and a narrow full width at half-maximum of ∼12 nm at 820 nm at positive voltages and an average visible light responsivity of ∼0.13 A/W at negative voltages. The detectivities of both modes are high (∼1012 Jones), and the linear dynamic range is wide (>100 dB). Our study provides a new method for fabricating multifunctional PDs and can expand their application in integrated imaging systems.

Preparation of biocompatible wound dressings with dual release of antibiotic and platelet-rich plasma for enhancing infected wound healing.

The ever-growing threats of bacterial infection and chronic wound healing have provoked an urgent need for novel antibacterial wound dressings. In this study, we developed a wound dressing for the treatment of infected wounds, which can reduce the inflammatory period (through the use of gentamycin sulfate (GS)) and enhance the granulation stage (through the addition of platelet-rich plasma (PRP)). Herein, the sustained antimicrobial CMC/GMs@GS/PRP wound dressings were developed by using gelatin microspheres (GMs) loading GS and PRP, covalent bonding to carboxymethyl chitosan (CMC). The prepared dressings exhibited high water uptake capability, appropriate porosity, excellent mechanical properties, sustain release of PRP and GS. Meanwhile, the wound dressing showed good biocompatibility and excellent antibacterial ability against Gram-negative and Gram-positive bacteria. Moreover, in vivo experiments further demonstrated that the prepared dressings could accelerate the healing process of E. coli and S. aureus-infected full-thickness wounds in vivo, reepithelialization, collagen deposition and angiogenesis. In addition, the treatment of CMC/GMs@GS/PRP wound dressing could reduce bacterial count, inhibit pro-inflammatory factors (TNF-α, IL-1ß and IL-6), and enhance anti-inflammatory factors (TGF-ß1). The findings of this study suggested that biocompatible wound dressings with dual release of GS and PRP have great potential in the treatment of chronic and infected wounds.

Enhanced Performance of Perovskite Single-Crystal Photodiodes by Epitaxial Hole Blocking Layer.

Introducing hole/electron transporting and blocking layers is considered to enhance the performance of electronic devices based on organic-inorganic hybrid halide perovskite single crystals (PSCs). In many photodiodes, the hole/electron transporting or blocking materials are spin-coated or thermal-evaporated on PSC to fabricate heterojunctions. However, the heterojunction interfaces due to lattice mismatch between hole/electron, transporting or blocking materials and perovskites easily form traps and cracks, which cause noise and leakage current. Besides, these low-mobility transporting layers increase the difficulty of transporting carriers generated by photons to the electrode; hence, they also increase the response time for photo detection. In the present study, MAPbCl3-MAPbBr2.5Cl0.5 heterojunction interfaces were realized by liquid-phase epitaxy, in which MAPbBr2.5Cl0.5 PSC acts as an active layer and MAPbCl3 PSC acts as a hole blocking layer (HBL). Our PIN photodiodes with epitaxial MAPbCl3 PSC as HBL show better performance in dark current, light responsivity, stability, and response time than the photodiodes with spin-coated organic PCBM as HBL. These results suggest that the heterojunction interface formed between two bulk PSCs with different halide compositions by epitaxy growth is very useful for effectively blocking the injected charges under high external electric field, which could improve the collection of photo-generated carriers and hereby enhance the detection performance of the photodiode. Furthermore, the PIN photodiodes made of PSC with epitaxial HBL show the sensitivities of 7.08 mC Gyair -1 cm-2, 4.04 mC Gyair -1 cm-2, and 2.38 mC Gyair -1 cm-2 for 40-keV, 60-keV, and 80-keV X-ray, respectively.

Perovskite Photodetectors Based on p-i-n Junction With Epitaxial Electron-Blocking Layers.

Organic-inorganic hybrid perovskite single crystals (PSCs) have been emerged as remarkable materials for some optoelectronic applications such as solid-state photodetectors, solar cells and light emitting diodes due to their excellent optoelectronic properties. To decrease the dark current, function layers based on spin-coating method are frequently requested for intrinsic PSCs to block the injected current by forming energy barrier. However, the amorphous function layers suffer from small carrier mobility and high traps density, which limit the speed of the photoelectric response of perovskite devices. This work supposes to grow thick MAPbBr3 and MAPbI3 mono-crystalline thin films on the surface of intrinsic MAPbBr2.5Cl0.5 PSCs substrate by a heteroepitaxial growth technique to act as electron-blocking layers. Meanwhile, C60 and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) layers are deposited on the opposite surface of substrate PSCs by spin-coating method to block injected holes. This Au-MAPbI3-MAPbBr3-MAPbBr2.5Cl0.5PSCs-C60-PCBM-Ag heterostructure can be used as excellent X-ray photodetector (XPD) due to its low dark current density of 6.97 × 10-11 A cm-2 at -0.5 V bias, high responsivity of 870 mA/W at -100 V bias and X-ray sensitivity as high as 59.7 µC mGy-1 cm-2 at -50 V bias.

[Single Center Analysis of Pathogenic Characteristics of Lung Candida Infection and Other Pathogenic Bacteria Infection in the Patients with Hemotological Maliglancies in the Tropical Region of Hainan].

OBJECTIVE: To analyze the infection characteristics of sputum and venous blood pathogen in the patients with hematological malignancies and respiratory symptom in the Hematology Department in tropical region and to investigate its drug-resistance so as to provide etiological evidence for clinical treatment. METHODS: The pathogens and their drug-resistance of 2466 samples in the patients with hematological malignancies and respiratory symptom in the Department were analyzed retrospectively from January 2013 to November 2017. The samples were collected from sputum and venous blood. RESULTS: The sputum sample culture in patients with hematologic diseases showed that 224 strains were isolated, out of them 98 strains (43.75%) were fungi mainly candida albicans (41 strains); and then 88 Gram-negative strains (39.28%), among them the main pathogenic bacteria were Escherichia coli(22 strains) and klebsiella Klebsiella pneumoniae(12 strains); and then 38 Gram-positive strains (16.96%), among them the main pathogeni-bacteria were Enteroccocus (14 strains) and Gram-positive bacilli (14 strains). The blood samples culture of patients with hematologic diseases showed that 61 strains were isolated, out of them the isolated rate of Gram-positive bactetia was higherst, which accounted for 55.74%(34/61), mainly including staphylococcus lominis (19 strains); and the isolated rate of Gram-negative bacteria was 44.26% (27/61), among them main pathogenic bacteria was Klebsiella pneumoniae (12 strains). The resistance test of pathogenic bacteria to drugs showed that the resistant rate of Gram-negative bacteria to tigecycline, imipenem and atl-962 duenner was lowest, while the Gram-positive pathogenic bacteria such as Enterococcus, Gram-positive bacilli and Staphylococcus aureus were sensitive to vancomycin, tigecycline and linezolid was high. CONCLUSION: the patients in hematology department are infected easily in the hospital in tropical region. The main pathogens are fungal strains in the respiratory tract of patients with hematological malignancy according to the sputum culture results. The clinician in tropical regions should choose suitable antibiotics for anti-infective therapy, which is different from the situation in North China or other northern areas.

Impact of Age, Gender, and Body Composition on Bone Quality in an Adult Population From the Middle Areas of China.

Identifying modifiable factors that influence bone status during adulthood to maximize bone quality is a potential primary strategy in the prevention of osteoporosis in later life. We investigated the impact of body height, body weight, body mass index, and body composition on calcaneal bone characteristics as measured with quantitative ultrasound in 441 Chinese adults (238 women) aged 20-55 yr from the middle areas of China. Body composition, including fat-free mass (FFM), muscle mass, and fat mass were obtained by bioelectrical impedance analysis. Bivariate correlation analysis demonstrated a significant negative correlation between age and broadband ultrasound attenuation (BUA), speed of sound (SOS), and stiffness index (SI) both in men (r = -0.177, p < 0.05; r = -0.499, p < 0.001; r = -0.530, p < 0.001, respectively) and women (r = -0.344, p < 0.001; r = -0.336, p < 0.001; r = -0.369, p < 0.001, respectively). Body height, body weight, FFM, and muscle mass had positive correlations with BUA, SOS, and SI in both genders, with FFM having the strongest correlation with BUA, SOS, and SI in men (r = 0.351, p < 0.001; r = 0.391, p < 0.001; r = 0.406, p < 0.001, respectively) and women (r = 0.331, p < 0.001; r = 0.288, p < 0.001; r = 0.324, p < 0.001, respectively). Fat mass had a positive correlation with BUA (r = 0.331, p < 0.001), SOS (r = 0.288, p < 0.001), and SI (r = 0.324, p < 0.001) in women, which was not found in men. Multivariate regression analysis revealed that, in both genders, FFM was a positive predictor for all 3 quantitative ultrasound variables.

Correlation between ultrasonic power spectrum and bone density on the heel.

The purposes of this paper were to evaluate the correlation between ultrasonic power spectrum and bone density and to extract the effectiveness of parameters from power spectrum for evaluating bone density. A total of 50 persons 24-72years of age were recruited. All study participants underwent bone mineral density (BMD) measurements of the lumbar spine (vertebral levels L1-L4). The participants also underwent calcaneal measurements to determine ultrasonic power spectrum with central frequencies of 0.5MHz. Three parameters from normalized power spectrum, called principle frequency (PF), frequency band (FB), and amplitude for principle frequency (APF), were chosen and be evaluated the correlation with the lumbar spine BMD. The correlation coefficient of PF, FB and APF with BMD was r=-0.48 (p<0.001), r=0.48 (p<0.001), and r=-0.71 (p<0.001), respectively. The results showed that the correlation between APF and BMD was better than the correlation among PF, FB and BMD, and APF have a significant correlation with BMD. In conclusion, the correlations among the parameters of ultrasonic power spectrum and BMD are significant, and especially APF performs better than PF and FB in evaluating bone density of participants. These results suggest that ultrasonic power spectrum may contain substantial information not already contained in BUA and SOS. A multiple regression model including all three QUS variables was somewhat more predictive of BMD than a model including only BUA and SOS.