Effects of manipulations of oblique pulling on the biomechanics of the sacroiliac joint: a cadaveric study.

BACKGROUND: There are many reports on the treatment of sacroiliac joint dysfunction by manipulation of oblique pulling (MOP). However, the specific mechanism of MOP on the sacroiliac joint remains unclear. This study aimed to investigate the effect of MOP on the biomechanics of the sacroiliac joint and the effect of the anterior sacroiliac ligament on the stability of the sacroiliac joint. METHODS: First, MOP-F1 (F: force) and MOP-F2 were applied to nine cadaveric pelvises. Then, segmental resection of the anterior sacroiliac ligament was performed. The range of motion of the sacroiliac joint was observed in all procedures. RESULTS: Under MOP-F1 and F2, the average total angles were 0.84° ± 0.59° and 1.52° ± 0.83°, and the displacements were 0.61 ± 0.21 mm and 0.98 ± 0.39 mm, respectively. Compared with MOP-F1, MOP-F2 caused greater rotation angles and displacements of the sacroiliac joint (p = 0.00 and p = 0.01, respectively). In addition, the rotation angles and displacements of the sacroiliac joint significantly increased after complete resection of the anterior sacroiliac ligament (p = 0.01 and p = 0.02, respectively). The increase was mainly due to the transection of the upper part of the anterior sacroiliac ligament. CONCLUSIONS: MOP-F2 caused greater rotation angles and displacements of the sacroiliac joint and was a more effective manipulation. The anterior sacroiliac ligament played an important role in maintaining the stability of the sacroiliac joint; the upper part of the anterior sacroiliac ligament contributed more to the stability of the joint than the lower part.

Manipulations of Oblique Pulling Affect Sacroiliac Joint Displacements and Ligament Strains: A Finite Element Analysis.

Objective: Clinical studies have found that manipulation of oblique pulling has a good clinical effect on sacroiliac joint pain. However, there is no uniform standard for manipulation of oblique pulling at present. The purpose of this study was to investigate the effects of four manipulations of oblique pulling on sacroiliac joint and surrounding ligaments. Methods: A three-dimensional finite element model of the pelvis was established. Four manipulations of oblique pulling were simulated. The stresses and displacements of sacroiliac joint and the strains of surrounding ligaments were analyzed under four manipulations of oblique pulling. Results: Manipulation of oblique pulling F2 and F3 caused the highest and lowest stress on the pelvis, at 85.0 and 52.6 MPa, respectively. Manipulation of oblique pulling F3 and F1 produced the highest and lowest stress on the left sacroiliac joint, at 6.6 and 5.6 MPa, respectively. The four manipulations of oblique pulling mainly produced anterior-posterior displacement. The maximum value was 1.21 mm, produced by manipulation of oblique pulling F2, while the minimal value was 0.96 mm, produced by manipulation of oblique pulling F3. The four manipulations of oblique pulling could all cause different degrees of ligament strain, and manipulation of oblique pulling F2 produced the greatest ligament strain. Conclusions: The four manipulations of oblique pulling all produced small displacements of sacroiliac joint. However, they produced different degrees of ligament strain. Manipulation of oblique pulling F2 produced the largest displacement of sacroiliac joint and the greatest ligament strain, which could provide a certain reference for physiotherapists.

Experimental Guidelines to Image Transient Single-Molecule Events Using Graphene Liquid Cell Electron Microscopy.

In quest of the holy grail to "see" how individual molecules interact in liquid environments, single-molecule imaging methods now include liquid-phase electron microscopy, whose resolution can be nanometers in space and several frames per second in time using an ordinary electron microscope that is routinely available to many researchers. However, with the current state of the art, protocols that sound similar to those described in the literature lead to outcomes that can differ. The key challenge is to achieve sample contrast under a safe electron dose within a frame rate adequate to capture the molecular process. Here, we present such examples from different systems─synthetic polymer, lipid assembly, DNA-enzyme─in which we have done this using graphene liquid cells. We describe detailed experimental procedures and share empirical experience for conducting successful experiments, starting from fabrication of a graphene liquid cell, to identification of high-quality liquid pockets from desirable shapes and sizes, to effective searching for target sample pockets under electron microscopy, and to discrimination of sample molecules and molecular processes of interest. These experimental tips can assist others who wish to make use of this method.

Corrigendum: Risk factors for tuberculous or nontuberculous spondylitis after percutaneous vertebroplasty or kyphoplasty in patients with osteoporotic vertebral compression fracture: A case-control study.

[This corrects the article DOI: 10.3389/fsurg.2022.962425.].

Risk factors for tuberculous or nontuberculous spondylitis after percutaneous vertebroplasty or kyphoplasty in patients with osteoporotic vertebral compression fracture: A case-control study.

Objectives: The contributing factors for spondylitis after percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) remain unclear. Here, we sought to investigate the factors affecting spondylitis occurrence after PVP/PKP. We also compared the clinical characteristics between patients with tuberculous spondylitis (TS) and nontuberculous spondylitis (NTS) following vertebral augmentation. Methods: Literature searches (from January 1, 1982 to October 16, 2020) using MEDLINE, EMBASE, Google Scholar and Web of science databases were conducted to identify eligible studies according to predefined criteria. The local database was also retrospectively reviewed to include additional TS and NTS patients at our center. Results: Thirty studies from the literature and 11 patients from our local institute were identified, yielding a total of 23 TS patients and 50 NTS patients for analysis. Compared with NTS group, patients in the TS group were more likely to have a history of trauma before PVP/PKP treatment. Univariate analyses of risk factors revealed pulmonary tuberculosis and diabetes were significant factors for TS after PVP/PKP. Analyzing NTS, we found obesity, a history of preoperative trauma, urinary tract infection, diabetes and multiple surgical segments (≥2) were significantly associated with its occurrence following PVP/PKP treatment. Multivariate logistic analyses showed a history of pulmonary tuberculosis and diabetes were independent risk factors for TS after PVP/PKP, while diabetes and the number of surgically treated segments independently influenced NTS development. Conclusions: A history of pulmonary tuberculosis and diabetes were independent risk factors for TS. For NTS, diabetes and the number of surgically treated segments significantly influenced the occurrence of postoperative spinal infection. These data may be helpful for guiding risk stratification and preoperative prevention for patients, thereby reducing the incidence of vertebral osteomyelitis after PVP/PKP.

Room-Temperature Grafting from Synthesis of Protein-Polydisulfide Conjugates via Aggregation-Induced Polymerization.

The reversible modification of proteins with lipoic acid (LPA)-derived polydisulfides (PDS) is an important approach toward the transient regulation and on-demand recovery of protein functions. The in situ growth of PDS from the cysteine (Cys) residue of a protein, however, has been challenging due to the near-equilibrium thermodynamics of the ring-opening polymerization of LPA. Here, we report the protein-mediated, aggregation-induced polymerization (AIP) of amphiphilic LPA-derived monomers at room temperature, which can be performed at a concentration as low as ∼2% of the equilibrium monomer concentration normally needed. The aggregation of monomers increases the effective monomer concentration in aqueous solutions to the degree that the polymerizations behave similarly to those in bulk. The PDS conjugation enhances the thermostability, protease resistance, and tolerance to freeze-thaw treatments of the target proteins. Moreover, the PDS conjugation allows rapid and convenient purification of Cys-bearing proteins by taking advantage of the liquid-liquid phase separation of the protein-PDS conjugates and the full recovery of native proteins under mild reducing conditions. This AIP effect may shed light on facilitating other polymerizations with a similar near-equilibrium character. The PDS conjugation can open up new avenues to protein delivery, dynamic and reversible protein engineering, enzyme preservation, and recycling.

Clinical effect of different maintenance doses of caffeine citrate in the treatment of preterm infants requiring assisted ventilation: a pilot multicenter study. / ä¸åŒç»´æŒå‰‚é‡æž¸æ©¼é ¸å’–å•¡å› å¯¹è¾ åŠ©é€šæ°”æ—©äº§å„¿çš„ç–—æ•ˆè¯„ä¼°ï¼šä¸€é¡¹åˆæ­¥å¤šä¸­å¿ƒç ”ç©¶.

OBJECTIVES: To explore the optimal maintenance dose of caffeine citrate for preterm infants requiring assisted ventilation and caffeine citrate treatment. METHODS: A retrospective analysis was performed on the medical data of 566 preterm infants (gestational age ≤34 weeks) who were treated and required assisted ventilation and caffeine citrate treatment in the neonatal intensive care unit of 30 tertiary hospitals in Jiangsu Province of China between January 1 and December 31, 2019. The 405 preterm infants receiving high-dose (10 mg/kg per day) caffeine citrate after a loading dose of 20 mg/kg within 24 hours after birth were enrolled as the high-dose group. The 161 preterm infants receiving low-dose (5 mg/kg per day) caffeine citrate were enrolled as the low-dose group. RESULTS: Compared with the low-dose group, the high-dose group had significant reductions in the need for high-concentration oxygen during assisted ventilation (P=0.044), the duration of oxygen inhalation after weaning from noninvasive ventilation (P<0.01), total oxygen inhalation time during hospitalization (P<0.01), the proportion of preterm infants requiring noninvasive ventilation again (P<0.01), the rate of use of pulmonary surfactant and budesonide (P<0.05), and the incidence rates of apnea and bronchopulmonary dysplasia (P<0.01), but the high-dose group had a significantly increased incidence rate of feeding intolerance (P=0.032). There were no significant differences between the two groups in the body weight change, the incidence rates of retinopathy of prematurity, intraventricular hemorrhage or necrotizing enterocolitis, the mortality rate, and the duration of caffeine use (P>0.05). CONCLUSIONS: This pilot multicenter study shows that the high maintenance dose (10 mg/kg per day) is generally beneficial to preterm infants in China and does not increase the incidence rate of common adverse reactions. For the risk of feeding intolerance, further research is needed to eliminate the interference of confounding factors as far as possible.

Percutaneous spinal endoscopy with unilateral interlaminar approach to perform bilateral decompression for central lumbar spinal stenosis: radiographic and clinical assessment.

BACKGROUND: Recently, a percutaneous spinal endoscopy unilateral posterior interlaminar approach to perform bilateral decompression has been proposed for use in treatment of lumbar spinal stenosis, As a development and supplement to traditional surgery, its advantages regarding therapeutic effects and prognosis, such as minor soft tissue damage, little intraoperative blood loss, and a quick return to daily life. However, there are few analyses of this surgery with a follow-up of more than 1 year,we conducted this study in order to quantitatively investigate radiographic and clinical efficacies of this surgery for central lumbar spinal stenosis. MATERIALS AND METHODS: Forty-six patients with central lumbar spinal stenosis were enrolled from January 2017 to July 2018. The visual analog scale (VAS) for back pain and leg pain, Oswestry disability index (ODI), modified MacNab criteria were used to evaluate clinical efficiency at preoperative and postoperative time points. The intervertebral height index (IHI), cross-sectional area of the spinal canal (CSAC), calibrated disc signal (CDS) and spinal stability were examined to assess radiographic decompression efficiency via magnetic resonance imaging and X-ray at preoperative and postoperative time points. RESULTS: The VAS score for lower back pain and leg pain improved from 7.50 ± 0.78 to 1.70 ± 0.66 and from 7.30 ± 0.79 to 1.74 ± 0.68, respectively, and the ODI improved from 72.35 ± 8.15 to 16.15 ± 4.51. In terms of modified MacNab criteria, 91.3% of the patients achieved good or excellent outcomes. Furthermore, significant changes after surgery were observed for the percentage of CSAC, increasing from 125.3 ± 53.9 to 201.4 ± 78 mm2; however, no significant differences were observed for the remaining measurement indicators. CONCLUSIONS: The clinical and radiographic efficacies of this surgery for central lumbar spinal stenosis were good in short-term follow-up, and this surgery did not cause meaningful changes in IHI, CDS, and spine stability in short-term follow-up. The effect of long-term follow-up needs further investigation.

Hydrostachys flabellifera (Hydrostachyaceae), a new species from Madagascar.

Hydrostachys flabellifera, a new species of Hydrostachyaceae found in a stream in Manandriana, Madagascar, is described and illustrated herein. It is similar to H. verruculosa and H. laciniata in morphology, but can be distinguished from them by its leaves with sparsely arranged, flabelliform and palmately parted emergences, obvious rachis and the pattern of segments arranged on the male bracts. Molecular phylogenetic analysis of the nuclear ribosomal internal transcribed spacer (ITS) dataset provides a robust support for it as a new species as well.

A finite element analysis of sacroiliac joint displacements and ligament strains in response to three manipulations.

BACKGROUND: Clinical studies have found that manipulations have a good clinical effect on sacroiliac joint (SIJ) pain without specific causes. However, the specific mechanisms underlying the effect of manipulations are still unclear. The purpose of this study was to investigate the effects of three common manipulations on the stresses and displacements of the normal SIJ and the strains of the surrounding ligaments. METHODS: A three-dimensional finite element model of the pelvis-femur was developed. The manipulations of hip and knee flexion (MHKF), oblique pulling (MOP), and lower limb hyperextension (MLLH) were simulated. The stresses and displacements of the SIJ and the strains of the surrounding ligaments were analyzed during the three manipulations. RESULTS: MOP produced the highest stress on the left SIJ, at 6.6 MPa, while MHKF produced the lowest stress on the right SIJ, at 1.5 MPa. The displacements of the SIJ were all less than 1 mm during the three manipulations. The three manipulations caused different degrees of ligament strain around the SIJ, and MOP produced the greatest straining of the ligaments. CONCLUSION: The three manipulations all produced small displacements of the SIJ and different degrees of ligament strains, which might be the mechanism through which they relieve SIJ pain. MOP produced the largest displacement and the greatest ligament strains.

lncRNA SNHG1 attenuates osteogenic differentiation via the miR­101/DKK1 axis in bone marrow mesenchymal stem cells.

The imbalance induced by inhibition of bone mesenchymal stem cell (BMSC) osteogenic differentiation results in osteoporosis (OP); however, the underlying regulatory mechanism is not completely understood. Long non­coding RNAs (lncRNAs) serve crucial roles in osteogenic differentiation; therefore, investigating their regulatory role in the process of osteogenic differentiation may identify a promising therapeutic target for OP. The expression of small nucleolar RNA host gene 1 (SNHG1), Dickkopf 1 (DKK1), microRNA (miR)­101, RUNX family transcription factor 2 (RUNX2), osteopontin (OPN) and osteocalin (OCN) were detected via reverse transcription­quantitative PCR. The protein expression levels of DKK1, ß­catenin, RUNX2, OPN, OCN, osterix and collagen type I α1 chain were analyzed by performing western blotting. The osteoblastic phenotype was assessed by conducting alkaline phosphatase activity detection and Alizarin Red staining. The interaction between SNHG1 and miR­101 was validated by bioinformatics and luciferase assays. The regulatory role of SNHG1 in BMSC osteogenic differentiation was assessed. SNHG1 expression was downregulated in a time­dependent manner during the process of osteogenic differentiation. SNHG1 overexpression inhibited osteogenic differentiation compared with the pcDNA group. The results indicated that SNHG1 and DKK1 directly interacted with miR­101. Moreover, SNHG1 regulated the Wnt/ß­catenin signaling pathway to inhibit osteogenic differentiation via the miR­101/DKK1 axis. The present study indicated that lncRNA SNHG1 could attenuate BMSC osteogenic differentiation via the miR­101/DKK1 axis as a competitive endogenous RNA. Therefore, the present study furthered the current understanding of the potential mechanism underlying lncRNAs in in osteogenic differentiation.

Exacerbations, Health Resource Utilization, and Costs Among Medicare Beneficiaries with Chronic Obstructive Pulmonary Disease Treated with Nebulized Arformoterol Following a Respiratory Event.

BACKGROUND: Long-acting beta2-agonists (LABAs), with or without inhaled corticosteroids (ICSs), delivered by handheld inhalers or nebulizers are recommended as maintenance therapy in chronic obstructive pulmonary disease (COPD). This study evaluated exacerbations, health resource utilization (HRU), and costs among Medicare beneficiaries with COPD on handheld ICS+LABA who switched to nebulized arformoterol (ARF) or continued ICS+LABA following a respiratory event. METHODS: Using Medicare claims, we identified beneficiaries with COPD (international classification of disease, 9th revision, clinical modification [ICD-9-CM] 490-492.xx, 494.xx, 496.xx) between 2010-2014 who had ≥ 1 year of continuous enrollment in Parts A, B, and D; ≥ 2 COPD-related outpatient visits ≥ 30 days apart or ≥ 1 hospitalization(s); ICS+LABA use 90-days before ARF initiation; and a respiratory event (COPD-related hospitalization or emergency department [ED] visit < 30 days before ARF initiation). Using propensity scores, 423 beneficiaries who switched to ARF were matched to 423 beneficiaries who continued on handheld ICS+LABA (controls). Difference-in-difference regression models examined outcomes at 180-days follow-up. RESULTS: Beneficiaries who switched to ARF had 1.5 fewer exacerbations (p=0.015) but no difference in hospitalizations and ED visits compared to controls. Durable medical equipment (DME) costs were higher among ARF users than controls ($1590), yet total health care costs were similar due to cost offsets by ARF in pharmacy (-$794), inpatient (-$524), and outpatient care (-$65). ARF accounted for 55% ($886.63) of DME costs, with the remaining costs attributed to oxygen therapy ($428.10) and nebulized corticosteroids ($590.85). CONCLUSIONS: Switching from handheld ICS+LABA to nebulized ARF resulted in fewer COPD exacerbations among Medicare beneficiaries. Nebulized LABAs may improve outcomes in selected patients with COPD.

Medication management patterns among Medicare beneficiaries with chronic obstructive pulmonary disease who initiate nebulized arformoterol treatment.

Purpose: Global evidence-based treatment strategies for chronic obstructive pulmonary disease (COPD) recommend using long-acting bronchodilators (LABDs) as maintenance therapy. However, COPD patients are often undertreated. We examined COPD treatment patterns among Medicare beneficiaries who initiated arformoterol tartrate, a nebulized long-acting beta2 agonist (LABA), and identified the predictors of initiation. Methods: Using a 100% sample of Medicare administrative data, we identified beneficiaries with a COPD diagnosis (ICD-9 490-492.xx, 494.xx, 496.xx) between 2010 and 2014 who had ≥1 year of continuous enrollment in Parts A, B, and D, and ≥2 COPD-related outpatient visits within 30 days or ≥1 hospitalization(s). After applying inclusion/exclusion criteria, three cohorts were identified: (1) study group beneficiaries who received nebulized arformoterol (n=11,886), (2) a subset of the study group with no LABD use 90 days prior to initiating arformoterol (n=5,542), and (3) control group beneficiaries with no nebulized LABA use (n=220,429). Logistic regression was used to evaluate predictors of arformoterol initiation. Odds ratios (ORs), 95% confidence intervals (CIs), and p values were computed. Results: Among arformoterol users, 47% (n=5,542) had received no LABDs 90 days prior to initiating arformoterol. These beneficiaries were being treated with a nebulized (50%) or inhaled (37%) short-acting bronchodilator or a systemic corticosteroid (46%), and many received antibiotics (37%). Compared to controls, beneficiaries who initiated arformoterol were significantly more likely to have had an exacerbation, a COPD-related hospitalization, and a pulmonologist or respiratory therapist visit prior to initiation (all p<0.05). Beneficiaries with moderate/severe psychiatric comorbidity or dual-eligible status were significantly less likely to initiate arformoterol, as compared to controls (all p<0.05). Conclusion: Medicare beneficiaries who initiated nebulized arformoterol therapy had more exacerbations and hospitalizations than controls 90 days prior to initiation. Findings revealed inadequate use of maintenance medications, suggesting a lack of compliance with evidence-based treatment guidelines.

Predictors of Nebulized Arformoterol Treatment: A Retrospective Analysis of Medicare Beneficiaries with Chronic Obstructive Pulmonary Disease.

This study examined sociodemographic and clinical characteristics, treatment patterns, and health resource utilization among Medicare beneficiaries with chronic obstructive pulmonary disease (COPD) to identify predictors of nebulized arformoterol treatment. Using Medicare administrative data from 2010 to 2014, beneficiaries with ≥2 COPD outpatient visits ≥30 d apart or ≥1 COPD-related hospitalization(s) (ICD-9-CM 491.xx, 492.xx, and 496) were identified. Inclusion criteria required ≥1 COPD medication claim(s) and continuous enrollment in Parts A, B, and D. Four cohorts were identified: (a) 11,887 arformoterol users, (b) a subsample of arformoterol users (n = 1,778) who were hospitalized and discharged 30 d before initiating arformoterol, (c) 450,178 controls who had not received arformoterol, and (d) a subsample of controls (n = 21,910) who had hospitalizations. Logistic regression analysis was used to evaluate predictors of arformoterol treatment. The majority of beneficiaries were older than 70 years of age, female, Caucasian, and 47% were dual-eligible. The strongest predictors of arformoterol treatment were oxygen therapy, systemic corticosteroid or methylxanthine use, an exacerbation, a COPD-related hospitalization, and receiving care from a pulmonologist (all p < .001). Dual-eligibility, being a racial/ethnic minority, and having severe psychiatric comorbidity or immunodeficiency lowered the odds of receiving nebulized arformoterol (all p < .001). Among beneficiaries with recent hospitalizations, exacerbations and COPD-related admissions increased the odds of receiving arformoterol (p < .001). Nebulized arformoterol treatment was more likely to be initiated in sicker patients with COPD. Ensuring access to nebulized maintenance therapy is important and particularly warranted for COPD populations with greater medical needs.

The Changing Pattern of Nutrition Intake by Social Class in Contemporary China, 1991-2011.

OBJECTIVES: To explore the changing pattern of nutrition intake by social class in contemporary China. METHODS: We defined social class in 2 ways. The first definition was based on employment, and the second definition was based on per capita household income levels. We used China Health and Nutrition Survey data from 1991 to 2011 to show the changes in the relation between social class and nutrition intake. RESULTS: The relation between social class and nutrition intake in China changed significantly within the 2 decades. For example, in the early 1990s, the lowest social class (defined by employment or income) had more caloric intake than did the highest social class; 20 years later, however, the relation reversed, and the lowest social class consumed significantly fewer calories. CONCLUSIONS: China has seen a great reversal in its social class-nutrition relationship since the early 1990s. Our study calls for wider recognition that insufficient consumption of food and nutrition is increasingly an issue for people in the lower social classes in China.

Health Care Decisions among Mental Health Services Consumers in San Diego County: Implications for Integrated Care.

People living with serious mental illness are at elevated risk for chronic diseases compared with those in the general population. Whether integrated care for this population would be most accessible in primary care or mental health settings is unclear. The cross-sectional study described in this article used descriptive analyses and multinomial logistic regression to assess factors associated with using physical health services from primary or mental health providers. Data were drawn from a large-scale assessment of client-reported use of primary care services in a large and ethnically diverse public mental health system. Most people (80.4 percent) reported accessing primary care services from one or more service settings. Having chronic conditions was associated with accessing physical health care from multiple service settings, whereas having poor self-rated emotional health decreased health services use from any setting. It was concluded that mental health services consumers access health care from various service settings. Social workers can play a critical role in enhancing care coordination across the mental health and primary care systems.

Psychiatric readmissions in a community-based sample of patients with mental disorders.

OBJECTIVE: This study examined whether receipt of outpatient psychiatric services after hospital discharge was associated with reduced risk of readmission. METHODS: Treatment records from patients admitted to San Diego County psychiatric hospitals over a one-year period were obtained from the San Diego County Behavioral Health Services electronic health record system. A discrete-time proportional hazards model was used to examine the association of receipt of outpatient psychiatric services with readmission within 30 days of discharge from the index hospitalization. RESULTS: Of the 4,663 patients, 16% were readmitted within 30 days. In an adjusted model, receipt of outpatient therapy after discharge was associated with a greater likelihood of being readmitted (hazard ratio=1.36, 95% confidence interval=1.14-1.67), whereas receipt of case management or medication management was not associated with readmission. CONCLUSIONS: The differential risk of readmission by service type suggests a need for studies that explore reasons for an increased risk of readmission with certain types of services.

Do black-white racial disparities in breastfeeding persist in the military community?

We conduct a comparative analysis of breastfeeding behavior between military and civilian-affiliated mothers. Our focus is on African American mothers among whom breastfeeding rates are lowest. The military context may mitigate conditions associated with low breastfeeding prevalence by (a) providing stable employment and educational opportunities to populations who face an otherwise poor labor market and (b) providing universal healthcare that includes breastfeeding consultation. Using pregnancy risk assessment monitoring system (PRAMS) data for which we received special permission from each state to flag military affiliation, we analyze civilians and military affiliate in breastfeeding initiation using logistic regression and breastfeeding duration using Cox proportional hazard analysis. We find that breastfeeding is more prevalent among all women in the military setting and that the black-white gap in breastfeeding duration common among civilians is significantly reduced among military affiliates. Breastfeeding is a crucial component of maternal and child health and eliminating racial disparities in its prevalence is a public health priority. This study is the first to identify the military as an important institutional context that deserves closer examination to glean potential policy implications for civilian society.

Repair of critical size bone defects with porous poly(D,L-lactide)/nacre nanocomposite hollow scaffold.

OBJECTIVE: To generate a novel porous poly(D,L-lactide)/nacre nanocomposite hollow scaffold. METHODS: This study was performed in the Department of Spine Surgery, Southern Medical University, Guangzhou, China from September 2010 to September 2011. Nacre nanoparticles were prepared using a physical process and identified by x-ray diffraction and transmission electron microscopy, to generate a novel scaffold though the salt leaching processing technique. The morphology and structure properties of this scaffold were further investigated under scanning electron microscope and mechanical property testing. Additionally, the biological characteristics were evaluated by cell culture experiments in vitro. Thirty-six rabbits were randomly divided into 3 groups. The defects were implanted with/without poly(D,L-lactide)/nacre scaffold or poly(D,L-lactide) scaffold. The results were assessed by radiographs and bone mineral density to monitor bone repairing. RESULTS: The nacre nanoparticles were spherical in shape, with a diameter range from 45-95 nm. The scaffolds possessed an interconnected porous structure with an average pore size of 322.5+/-50.8 µm, and exhibited a high porosity (82.5 +/-0.8%), as well as good compressive strength of 4.5+/-0.25 Mpa. Primary biocompatibility experiments in vitro showed that cells adhered and proliferated well on the scaffolds. The animal study further demonstrated that the scaffolds could repair the critical size segmental bone defects in 12 weeks. CONCLUSION: Newly established scaffolds may serve as a promising biomaterial for bone tissue engineering.

Dependence of photoacoustic speckles on boundary roughness.

Speckles have been considered ubiquitous in all scattering-based coherent imaging technologies. However, as an optical-absorption-based coherent imaging technology, photoacoustic (PA) tomography (PAT) suppresses speckles by building up prominent boundary signals. We theoretically study the dependence of PAT speckles on the boundary roughness, which is quantified by the root-mean-squared value and the correlation length of the boundary height. Both the speckle visibility and the correlation coefficient between the reconstructed and actual boundaries are quantified. If the root-mean-squared height fluctuation is much greater than, and the height correlation length is much smaller than the imaging resolution, the reconstructed boundaries become fully developed speckles. In other words, speckle formation requires large uncorrelated height fluctuations within the resolution cell. The first- and second-order statistics of PAT speckles are also studied experimentally. While the amplitude of the speckles follows a Gaussian distribution, the autocorrelation of the speckle patterns tracks that of the system point spread function.