The Influence of Home Country Factors on Immigrant Entrepreneurship in the U.S.

This paper uses a Poisson regression model to determine the effects of entrepreneurial conditions of home countries on immigrant founded startup activity in the United States. The study determines that the most relevant factors are innovation, internal market dynamics, governmental support and policies, financing, and internal market openness. It then analyzes the change rates of these entrepreneurial conditions between 2007 and 2017 in China, India, and the United States to determine the implications of changing power dynamics in the global economy on flows of immigrant entrepreneurship and innovation in the global entrepreneurial ecosystem. The study finds that after being in the lead in 2007, the United States had fallen behind China and India in all entrepreneurial conditions, with the exception of innovation, by 2017. With the way trends are moving, this paper predicts that innovation in the U.S. will be the next metric to fall behind

Saturn illustrated chronology: Saturn's first eleven years, April 1957 - April 1968

A history of the Saturn launch vehicles is presented for the period of April 1957 to April 1958

An illustrated chronology of the NASA Marshall Center and MSFC programs 1960-1973

The role that NASA's Marshall Space Flight Center played in the space program during the past 13 years is highlighted with pictures and text, plus background information concerning events that were important in the center's formation

Phytochemicals and nutritional characteristics of ethanol extract of the leaf and bark of Njangsa (Ricinodendron Heudelotii) plant

The phytochemical, proximate and mineral content of leaf and bark of Njangsa (Ricinodendron Heudelotii) plant were analysed, using standard procedures described by Harbone, 1973, Sofowora, 1993; Trease and Evans, 1989 and Association of Official Analytical Chemist (AOAC) Official method, 1990; 1984 respectively. The preliminary phytochemical screening revealed the presence of tannins, steroids, terpernoids, alkaloids, flavonoids, cardiac glycosides, reducing sugars and saponins found only for the plant bark. The result of proximate analysis showed that the leaf and bark of the extract contain respectively: moisture content (25.80% and 10%), protein (17.47% and 3.73%), crude fat(1.80% and 2.00%) ash (11.00% and 10.95%), crude fibre (41.00% and 20.50%) carbohydrate (2.93% and 52.82%).The mineral analysis of the plant leaf and bark respectively yielded calcium – 2640.00 mg/kg and 1772 mg/kg, magnesium – 2383 mg/kg and 1605 mg/kg, iron – 25.00 mg/kg and 6.6 mg/kg, zinc – 29.30 mg/kg and 4.4 mg/kg, copper – 14.60 mg/kg and 6 mg/kg and phosphorus – 1012 mg/kg and 305 mg/kg. Manganese was absent in the bark but yielded 1.1 mg/kg in the leaf. Sodium and potassium were found to be absent in the leaf and bark. The presence of some phytochemicals (flavonoids, cardiac glycosides, reducing sugar, tannins and terpernoids) and some essential minerals suggest that it is a potential source of medicine and food.Keywords: Phytochemical, Nutritional Characteristics, Proximate, Mineral, Medicinal, Analysi

The effect of versican G3 domain on local breast cancer invasiveness and bony metastasis

Abstract Introduction Increased versican expression has been associated with local breast cancer invasiveness and a more aggressive tumor phenotype. The cellular mechanisms are not fully understood and this study evaluated versican G3 domain with its EGF-like motifs in influencing tumor invasion and metastasis. Methods One recombinant construct was synthesized (a signal peptide for product secretion and the versican G3 domain). The construct was stably transfected into human breast carcinoma MT-1 cells. Cell viability in vitro was evaluated in low serum and serum starvation conditions. In vivo study of tumor growth was evaluated in a nude mouse model. G3 effects on rodent vascular endothelial cells were evaluated in vitro on cell survival, apoptosis, migration, and vascular formation. The effects of VEGF, fibronectin, and G3 on vascular formation were examined. An intracardiac injection model of metastatic human breast carcinoma tested the effect of G3 on distant bony and soft tissue metastasis. Analysis of metastatic burden included histology, radiographs, and micro-CT quantification of osteolysis. Results A greater viability of cancer cells was observed in low serum and serum-free conditions in the presence of versican G3. Larger subcutaneous tumors were obtained in the G3 group following tumor cell injection into CD1 mice. G3 induced a greater degree of rodent vascular endothelial cell proliferation and migration in vitro. Simultaneous presence of fibronectin, VEGF, and G3 promoted endothelial cell migration in wound-healing assays as compared to the treatments containing none, one or two of these molecules. Systemic tumor burden to distant bony and soft tissue metastatic sites was greater in the G3 group using the intracardiac injection metastatic model Conclusion Versican G3 domain appears to be important in local and systemic tumor invasiveness of human breast cancer. Effects include enhancing cell viability, proliferation, migration and enhancing local tumor growth. Potential effects on angiogenesis include enhancing vascular endothelial proliferation, migration, and vessel formation. The interactions between tumor cells, surrounding stromal components and neo-vascularization in breast cancer may include interactions with VEGF and fibronectin. The propensity of versican G3 to influence tumor invasion to bone and the mechanisms of G3 mediated osteolysis warrants ongoing studies

Characterisation of Gamma Herpesviruses in the Horse by PCR

AbstractA polymerase chain reaction (PCR) based on a combination of oligonucleotide primers selected using the octamer frequency disparity method with primers specific for EHV-5 (described by other authors) recognized all of a series of gamma herpesvirus field isolates. This PCR produced only three fragments: (1) one EHV-2-specific; (2) one EHV-5-specific; and (3) a fragment that occurred alone or in combination with the other two. Cloning and sequencing of four different isolates yielding only the last PCR product showed that this corresponds to a deletion/insertion mutant of EHV-2. The fact that this mutant was also plaque-purified from a culture producing all three PCR fragments demonstrated that the virus producing this fragment was distinct from the other two and that this specific DNA fragment was not an artefact due to PCR amplification. These data show that equine gamma herpesviruses are genetically more heterogeneous than previously assumed. The PCR failed to directly detect gamma herpesviruses from the DNA extracted from the same starting material used for the isolation of gamma herpesvirus by cocultivation with indicator cells. This demonstrates that the most reliable method for detection of equine gamma herpesviruses is the cocultivation with indicator cells

Long term in-vivo studies of a photo-oxidized bovine osteochondral transplant in sheep

BACKGROUND: Articular cartilage has limited capacity to repair. Defects greater than 3 mm heal with formation of inferior fibrous cartilage. Therefore, many attempts have been made to find the ideal graft for larger cartilage lesions. Different grafts, such as untreated or cryopreserved osteochondral transplants, have been used with variable success. METHODS: Photo-oxidized osteochondral grafts were implanted in both femoral condyles of one ovine knee. Untreated xenogeneic and autogeneic grafts served as controls. Three groups of 8 sheep each were formed and they were sacrificed 6, 12 or 18 months after surgery. RESULTS: The macroscopic evaluation of the condyle and graft showed a well-maintained cartilage surface in most grafts at all time points. However, the host cartilage matrix deteriorated considerably in all xenogeneic, most autogeneic and fewer of the photo-oxidized grafts at 12 and 18 months, respectively. The blue colour of the photo-oxidized grafts resulting from the process of photo-oxidation was visible in all grafts at 6 months, had diminished at 12 months and had completely disappeared at 18 months after surgery. Histologically a loss of matrix staining was almost never noticed in untreated xenografts, transiently at 6 months in photo-oxidized grafts and increased at 12 and 18 months. Fusion between graft and host cartilage could be seen in photo-oxidized grafts at 12 and 18 months, but was never seen in autografts and xenografts. CONCLUSIONS: The photo-oxidation of osteochondral grafts and its use as transplant appears to have a beneficial effect on cartilage and bone remodelling. Osteochondral grafts pre-treated with photo-oxidation may be considered for articular cartilage replacement and therefore may delay artificial joint replacements in human patients

Targeting tissue factor on tumour cells and angiogenic vascular endothelial cells by factor VII-targeted verteporfin photodynamic therapy for breast cancer in vitro and in vivo in mice

<p>Abstract</p> <p>Background</p> <p>The objective of this study was to develop a ligand-targeted photodynamic therapy (tPDT) by conjugating factor VII (fVII) protein with photosensitiser verteporfin in order to overcome the poor selectivity and enhance the effect of non-targeted PDT (ntPDT) for cancer. fVII is a natural ligand for receptor tissue factor (TF) with high affinity and specificity. The reason for targeting receptor TF for the development of tPDT is that TF is a common but specific target on angiogenic tumour vascular endothelial cells (VEC) and many types of tumour cells, including solid tumours and leukaemia.</p> <p>Methods</p> <p>Murine factor VII protein (mfVII) containing a mutation (Lys341Ala) was covalently conjugated via a cross linker EDC with Veterporfin (VP) that was extracted from liposomal Visudyne, and then free VP was separated by Sephadex G50 spin columns. fVII-tPDT using mfVII-VP conjugate, compared to ntPDT, was tested <it>in vitro </it>for the killing of breast cancer cells and VEGF-stimulated VEC and <it>in vivo </it>for inhibiting the tumour growth of breast tumours in a mouse xenograft model.</p> <p>Results</p> <p>We showed that: (i) fVII protein could be conjugated with VP without affecting its binding activity; (ii) fVII-tPDT could selectively kill TF-expressing breast cancer cells and VEGF-stimulated angiogenic HUVECs but had no side effects on non-TF expressing unstimulated HUVEC, CHO-K1 and 293 cells; (iii) fVII targeting enhanced the effect of VP PDT by three to four fold; (iii) fVII-tPDT induced significantly stronger levels of apoptosis and necrosis than ntPDT; and (iv) fVII-tPDT had a significantly stronger effect on inhibiting breast tumour growth in mice than ntPDT.</p> <p>Conclusions</p> <p>We conclude that the fVII-targeted VP PDT that we report here is a novel and effective therapeutic with improved selectivity for the treatment of breast cancer. Since TF is expressed on many types of cancer cells including leukaemic cells and selectively on angiogenic tumour VECs, fVII-tPDT could have broad therapeutic applications for other solid cancers and leukaemia.</p

The effect of cartilage and bone density of mushroom-shaped, photooxidized, osteochondral transplants: an experimental study on graft performance in sheep using transplants originating from different species

BACKGROUND: Differences in overall performance of osteochondral photooxidized grafts were studied in accordance of their species origin and a new, more rigorous cleansing procedure using alcohol during preparation. METHODS: Photooxidized mushroom-shaped grafts of bovine, ovine, human and equine origin were implanted in the femoral condyles of 32 sheep (condyles: n = 64). No viable chondrocytes were present at the time of implantation. Grafts were evaluated at 6 months using plastic embedded sections of non-decalcified bone and cartilage specimens. Graft incorporation, the formation of cyst-like lesions at the base of the cartilage junction as well as cartilage morphology was studied qualitatively, semi-quantitatively using a score system and quantitatively by performing histomorphometrical measurements of percentage of bone and fibrous tissue of the original defects. For statistical analysis a factorial analysis of variance (ANOVA- test) was applied. RESULTS: Differences of graft performance were found according to species origin and cleansing process during graft preparation. According to the score system cartilage surface integrity was best for equine grafts, as well as dislocation or mechanical stability. The equine grafts showed the highest percentage for bone and lowest for fibrous tissue, resp. cystic lesions. The new, more rigorous cleansing process decreased cartilage persistence and overall graft performance. CONCLUSION: Performance of grafts from equine origin was better compared to bovine, ovine and human grafts. The exact reason for this difference was not proven in the current study, but could be related to differences in density of cartilage and subchondral bone between species