280 research outputs found
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Only the best? Exploring cross-border investor preferences in US gateway cities
Despite heady growth in cross-border investment into commercial real estate over recent decades, there are few studies that examine differences in investment preferences between domestic and cross-border investors at a micro level. We address the gap by examining the characteristics of assets acquired by cross border investors in six major US metro areas, comparing them with the purchases made by US investors in those same areas. Our study uses data on more than 67 500 transactions recorded by Real Capital Analytics (RCA) over the period from Q1 2003 to Q3 2016. As well as examining cross-border investors in aggregate, we isolate and examine purchases by investors from each of the four principal source nations for cross-border real estate investment in these cities. This is important since treating cross-border investors as a single group may obscure important differences between them. We employ multilevel logit techniques and we find across a number of specifications that cross-border investors prefer larger assets, newer assets and CBD locations regardless of nationality. However, temporal and sectoral patterns of investment, as well as evidence for return chasing behavior, vary with the nationality of investor being studied
Improving In Vitro Generated Cartilage-Carrier-Constructs by Optimizing Growth Factor Combination
The presented study is focused on the generation of osteochondral implants for cartilage repair, which consist of bone substitutes covered with in vitro engineered cartilage. Re-differentiation of expanded porcine cells was performed in alginate gel followed by cartilage formation in high-density cell cultures. In this work, different combinations of growth factors for the stimulation of re-differentiation and cartilage formation have been tested to improve the quality of osteochondral implants. It has been demonstrated that supplementation of the medium with growth factors has significant effects on the properties of the matrix. The addition of the growth factors IGF-I (100 ng/mL) and TGF-β1 (10 ng/mL) during the alginate culture and the absence of any growth factors during the high-density cell culture led to significantly higher GAG to DNA ratios and Young’s Moduli of the constructs compared to other combinations. The histological sections showed homogenous tissue and intensive staining for collagen type II
Exposure to bisphosphonates and risk of common non-gastrointestinal cancers: series of nested case–control studies using two primary-care databases
Background: Bisphosphonates are the most commonly prescribed osteoporosis drugs but long-term effects are unclear, although antitumour properties are known from preclinical studies.
Methods: Nested case–control studies were conducted to investigate bisphosphonate use and risks of common nongastrointestinal cancers (breast, prostate, lung, bladder, melanoma, ovarian, pancreas, uterus and cervical). Patients 50 years and older, diagnosed with primary cancers between 1997 and 2011, were matched to five controls using the UK practice-based QResearch and Clinical Practice Research Datalink (CPRD) databases. The databases were analysed separately and the results combined.
Results: A total of 91 556 and 88 845 cases were identified from QResearch and CPRD, respectively. Bisphosphonate use was associated with reduced risks of breast (odds ratio (OR): 0.92, 95% confidence interval (CI): 0.87–0.97), prostate (OR: 0.87, 95% CI: 0.79–0.96) and pancreatic (OR: 0.79, 95% CI: 0.68–0.93) cancers in the combined analyses, but no significant trends with duration. For alendronate, reduced risk associations were found for prostate cancer in the QResearch (OR: 0.81, 95% CI: 0.70–0.93) and combined (OR: 0.84, 95% CI: 0.75–0.93) analyses (trend with duration P-values 0.009 and 0.001). There were no significant associations from any of the other analyses.
Conclusion: In this series of large population-based case–control studies, bisphosphonate use was not associated with increased risks for any common non-gastrointestinal cancers
A new technique for seeding chondrocytes onto solvent-preserved human meniscus using the chemokinetic effect of recombinant human bone morphogenetic protein-2
Many investigators are currently studying the use of decellularized tissue allografts from human cadavers as scaffolds onto which patients’ cells could be seeded, or as carriers for genetically engineered cells to aid cell transplantation. However, it is difficult to seed cells onto very dense regular connective tissue which has few interstitial spaces. Here, we discuss the development of a chemotactic cell seeding technique using solvent-preserved human meniscus. A chemokinetic response to recombinant human bone morphogenetic protein-2 (rhBMP-2) was observed in a monolayer culture of primary chondrocytes derived from femoral epiphyseal cartilage of 2-day-old rats. The rhBMP-2 significantly increased their migration upto 10 ng/ml in a dose-dependent manner. When tested with solvent-preserved human meniscus as a scaffold, which has few interstitial spaces, rhBMP-2 was able to induce chondrocytes to migrate into the meniscus. After a 3-week incubation, newly-formed cartilaginous extracellular matrix was synthesized by migrated chondrocytes throughout the meniscus, down to a depth of 3 mm. These findings demonstrate that rhBMP-2 may be a natural chemokinetic factor in vivo, which induces migration of proliferative chondrocytes into the narrow interfibrous spaces. Our results suggest a potential application of rhBMP-2 for the designed distribution of chondrocytes into a scaffold to be used for tissue engineering
Anti-HIV-1 activity of anionic polymers: a comparative study of candidate microbicides
BACKGROUND: Cellulose acetate phthalate (CAP) in soluble form blocks coreceptor binding sites on the virus envelope glycoprotein gp120 and elicits gp41 six-helix bundle formation, processes involved in virus inactivation. CAP is not soluble at pH < 5.5, normal for microbicide target sites. Therefore, the interaction between insoluble micronized CAP and HIV-1 was studied. Carbomer 974P/BufferGel; carrageenan; cellulose sulfate; dextran/dextrin sulfate, poly(napthalene sulfonate) and poly(styrene-4-sulfonate) are also being considered as anti-HIV-1 microbicides, and their antiviral properties were compared with those of CAP. METHODS: Enzyme linked immunosorbent assays (ELISA) were used to (1) study HIV-1 IIIB and BaL binding to micronized CAP; (2) detect virus disintegration; and (3) measure gp41 six-helix bundle formation. Cells containing integrated HIV-1 LTR linked to the β-gal gene and expressing CD4 and coreceptors CXCR4 or CCR5 were used to measure virus infectivity. RESULTS: 1) HIV-1 IIIB and BaL, respectively, effectively bound to micronized CAP. 2) The interaction between HIV-1 and micronized CAP led to: (a) gp41 six-helix bundle formation; (b) virus disintegration and shedding of envelope glycoproteins; and (c) rapid loss of infectivity. Polymers other than CAP, except Carbomer 974P, elicited gp41 six-helix bundle formation in HIV-1 IIIB but only poly(napthalene sulfonate), in addition to CAP, had this effect on HIV-1 BaL. These polymers differed with respect to their virucidal activities, the differences being more pronounced for HIV-1 BaL. CONCLUSIONS: Micronized CAP is the only candidate topical microbicide with the capacity to remove rapidly by adsorption from physiological fluids HIV-1 of both the X4 and R5 biotypes and is likely to prevent virus contact with target cells. The interaction between micronized CAP and HIV-1 leads to rapid virus inactivation. Among other anionic polymers, cellulose sulfate, BufferGel and aryl sulfonates appear most effective in this respect
Acceptability of Carraguard Vaginal Microbicide Gel among HIV-Infected Women in Chiang Rai, Thailand
Background: Few studies of microbicide acceptability among HIV-infected women have been done. We assessed CarraguardH vaginal gel acceptability among participants in a randomized, controlled, crossover safety trial in HIV-infected women in Thailand. Methodology/Principal Findings: Participants used each of 3 treatments (Carraguard gel, methylcellulose placebo gel, and no product) for 7 days, were randomized to one of six treatment sequences, and were blinded to the type of gel they received in the two gel-use periods. After both gel-use periods, acceptability was assessed by face-to-face interview. Responses were compared to those of women participating in two previous Carraguard safety studies at the same study site. Sixty women enrolled with a median age of 34 years; 25 % were sexually active. Self-reported adherence (98%) and overall satisfaction rating of the gels (87% liked ‘‘somewhat’ ’ or ‘‘very much’’) were high, and most (77%) considered the volume of gel ‘‘just right.’ ’ For most characteristics, crossover trial participants evaluated the gels more favorably than women in the other two trials, but there were few differences in the desired characteristics of a hypothetical microbicide. Almost half (48%) of crossover trial participants noticed a difference between Carraguard and placebo gels; 33 % preferred Carraguard while 12 % preferred placebo (p=0.01). Conclusions/Significance: Daily Carraguard vaginal gel use was highly acceptable in this population of HIV-infecte
Too close for comfort: spatial patterns in acorn barnacle populations
Spatial patterns in aggregations form as a result of the interplay between costs and benefits experienced by individuals. Such self-organisation of aggregations can be explained using a zonal model in which a short-range zone of repulsion and longer-range zone of attraction surrounding individuals leads to emergent pattern properties. The signal of these processes can be detected using spatial pattern analyses. Furthermore, in sessile organisms, post-settlement mortality reveals the relative costs and benefits of positions within the aggregation. Acorn barnacles are known to require contact with conspecifics for reproduction and are therefore believed to aggregate for this purpose; isolated individuals may also be more susceptible to abiotic stress and predation. At short distances, however, competition for space and resources is likely to occur. In this study spatial patterns of barnacles (Semibalanus balanoides L.) were analysed using pair-correlation functions. Individuals were dispersed at distances below 0.30 cm, but peak relative density occurred at a distance of 0.36 cm from conspecifics. This is much closer than required for reproductive access, implying a strong aggregative drive, up to the point of physical contact with neighbours. Nevertheless, analysis of dead barnacles illustrated that such proximity carries a cost as barnacles with many neighbours were more likely to have died. The inferences obtained from these patterns are that barnacles aggregate as closely as they can, and that local neighbourhood competition is a powerful determinant of mortality. These processes give rise to the observed pattern properties
Tissue engineering of functional articular cartilage: the current status
Osteoarthritis is a degenerative joint disease characterized by pain and disability. It involves all ages and 70% of people aged >65 have some degree of osteoarthritis. Natural cartilage repair is limited because chondrocyte density and metabolism are low and cartilage has no blood supply. The results of joint-preserving treatment protocols such as debridement, mosaicplasty, perichondrium transplantation and autologous chondrocyte implantation vary largely and the average long-term result is unsatisfactory. One reason for limited clinical success is that most treatments require new cartilage to be formed at the site of a defect. However, the mechanical conditions at such sites are unfavorable for repair of the original damaged cartilage. Therefore, it is unlikely that healthy cartilage would form at these locations. The most promising method to circumvent this problem is to engineer mechanically stable cartilage ex vivo and to implant that into the damaged tissue area. This review outlines the issues related to the composition and functionality of tissue-engineered cartilage. In particular, the focus will be on the parameters cell source, signaling molecules, scaffolds and mechanical stimulation. In addition, the current status of tissue engineering of cartilage will be discussed, with the focus on extracellular matrix content, structure and its functionality
The utility of clinical decision tools for diagnosing osteoporosis in postmenopausal women with rheumatoid arthritis
BACKGROUND: Patients with rheumatoid arthritis have a higher risk of low bone mineral density than normal age matched populations. There is limited evidence to support cost effectiveness of population screening in rheumatoid arthritis and case finding strategies have been proposed as a means to increase cost effectiveness of diagnostic screening for osteoporosis. This study aimed to assess the performance attributes of generic and rheumatoid arthritis specific clinical decision tools for diagnosing osteoporosis in a postmenopausal population with rheumatoid arthritis who attend ambulatory specialist rheumatology clinics. METHODS: A cross-sectional study of 127 ambulatory post-menopausal women with rheumatoid arthritis was performed. Patients currently receiving or who had previously received bone active therapy were excluded. Eligible women underwent clinical assessment and dual-energy-xray absorptiometry (DXA) bone mineral density assessment. Clinical decision tools, including those specific for rheumatoid arthritis, were compared to seven generic post-menopausal tools to predict osteoporosis (defined as T score < -2.5). Sensitivity, specificity, positive predictive and negative predictive values and area under the curve were assessed. The diagnostic attributes of the clinical decision tools were compared by examination of the area under the receiver-operator-curve. RESULTS: One hundred and twenty seven women participated. The median age was 62 (IQR 56-71) years. Median disease duration was 108 (60-168) months. Seventy two (57%) women had no record of a previous DXA examination. Eighty (63%) women had T scores at femoral neck or lumbar spine less than -1. The area under the ROC curve for clinical decision tool prediction of T score <-2.5 varied between 0.63 and 0.76. The rheumatoid arthritis specific decision tools did not perform better than generic tools, however, the National Osteoporosis Foundation score could potentially reduce the number of unnecessary DXA tests by approximately 45% in this population. CONCLUSION: There was limited utility of clinical decision tools for predicting osteoporosis in this patient population. Fracture prediction tools that include risk factors independent of BMD are needed
Age Affects the Expression of Maternal Care and Subsequent Behavioural Development of Offspring in a Precocial Bird
Variations of breeding success with age have been studied largely in iteroparous species and particularly in birds: survival of offspring increases with parental age until senescence. Nevertheless, these results are from observations of free-living individuals and therefore, it remains impossible to determine whether these variations result from parental investment or efficiency or both, and whether these variations occur during the prenatal or the postnatal stage or during both. Our study aimed first, to determine whether age had an impact on the expression of maternal breeding care by comparing inexperienced female birds of two different ages, and second, to define how these potential differences impact chicks’ growth and behavioural development. We made 22 2-month-old and 22 8-month-old female Japanese quail foster 1-day-old chicks. We observed their maternal behaviour until the chicks were 11 days old and then tested these chicks after separation from their mothers. Several behavioural tests estimated their fearfulness and their sociality. We observed first that a longer induction was required for young females to express maternal behaviour. Subsequently as many young females as elder females expressed maternal behaviour, but young females warmed chicks less, expressed less covering postures and rejected their chicks more. Chicks brooded by elder females presented higher growth rates and more fearfulness and sociality. Our results reveal that maternal investment increased with age independently of maternal experience, suggesting modification of hormone levels implied in maternal behaviour. Isolated effects of maternal experience should now be assessed in females of the same age. In addition, our results show, for first time in birds, that variations in maternal care directly induce important differences in the behavioural development of chicks. Finally, our results confirm that Japanese quail remains a great laboratory model of avian maternal behaviour and that the way we sample maternal behaviour is highly productive
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