Polycaprolactone (PCL) was synthesized by ring-opening polymerization of ε-caprolactone through two different enzymatic processes. The lipase from Candida antarctica B, immobilized on macroporous ...acrylic acid beads, was employed either untreated or coated with small amounts of ionic liquids (ILs). Monocationic ionic liquids, C ₙ MImNTf₂ (n = 2, 6, 12), as well as a dicationic ionic liquid, (C₄(C₆Im)₂NTf₂₂), were used to coat the immobilized lipase and also as the reaction medium. In both methods, the polarity, anion of the ILs concentration and viscosity strongly influenced the reaction. Coating the immobilized enzyme with ILs improved catalytic activity and less ILs was required to produce PCL with a higher molecular weight and reaction yield. At 60 °C and ILs/Novozyme-435 coating ratio of 3:1 (w/w) for 48 h, the highest M w and reaction yield of PCL were 35,600 g/mol and 62 % in the case of C₁₂MImNTf₂, while the M w and reaction yield of PCL was 20,300 g/mol and 54 % with C₁₂MImNTf₂ and catalyzed by untreated lipase.
Deep learning for unsupervised image segmentation remains challenging due to the absence of human labels. The common idea is to train a segmentation head, with the supervision of pixel-wise ...pseudo-labels generated based on the representation of self-supervised backbones. By doing so, the model performance depends much on the distance between the distribution of target datasets, and the one of backbones' pre-training dataset (e.g., ImageNet). In this work, we investigate a new task, namely unsupervised camouflaged object segmentation (UCOS), where the target objects own a common rarely-seen attribute, i.e., camouflage. Unsurprisingly, we find that the state-of-the-art unsupervised models struggle in adapting UCOS, due to the domain gap between the properties of generic and camouflaged objects. To this end, we formulate the UCOS as a source-free unsupervised domain adaptation task (UCOS-DA), where both source labels and target labels are absent during the whole model training process. Specifically, we define a source model consisting of self-supervised vision transformers pre-trained on ImageNet. On the other hand, the target domain includes a simple linear layer (i.e., our target model) and unlabeled camouflaged objects. We then design a pipeline for foreground-background-contrastive self-adversarial domain adaptation, to achieve robust UCOS. As a result, our baseline model achieves superior segmentation performance when compared with competing unsupervised models on the UCOS benchmark, with the training set which's scale is only one tenth of the supervised COS counterpart. The UCOS benchmark and our baseline model are now publicly available 1 .
ATP-binding cassette super family G2 (ABCG2) is recognized as the key point of the cancer cells' resistance to chemotherapy drugs. But there have been rare reports about the relationship between ...ABCG2 and the invasion, migration and animal tumor formation abilities of cancer cells. We want to establish a recombinant lentiviral vector with ABCG2 overexpression, and study the vector's effect on human breast cancer MCF-7 cells' biological abilities above to improve our understanding about ABCG2.
The recombinant lentiviral vector with ABCG2 overexpression was transfected into human breast cancer MCF-7 cells. The cells' abilities of migration and invasion were tested by wound healing assay, and transwell invasive assay. The MCF-7 cells infected were injected in the left back of the nude mice. In the meantime the MCF-7 cells without anything were injected in the right back of same nude mice as the control group. Western blotting was used to detect the expression of ABCG2 in MCF-7 cells infected, the transplantation tumor tissue and the control group MCF-7 cells.
The recombinant lentiviral vector with ABCG2 overexpression infected human breast cancer MCF-7 cells successfully, and the transfection efficiency was 95.4 ±2.8%. The wound line of MCF-7 cells infected healed after 48 hours, but the line of control group MCF-7 cells still existed. The number of the cells going through the membrane in infected MCF-7 cells was 78.34 ±0.25, and the number in control group MCF-7 cells was 15.28 ±0.12, p < 0.05. A much bigger transplantation tumor appeared in the MCF-7 cell infected nude mice. The expression of ABCG2 in infected MCF-7 cells and the transplantation tumor tissue was significantly higher than that in control group MCF-7 cells, p < 0.05.
We obtained ABCG2 overexpression in human breast cancer MCF-7 cells which showed the increasing migration, invasion and animal tumor formation abilities. Therefore, the results revealed that there might be a relationship between overexpression of ABCG2 and MCF-7 cells with increasing invasion, migration and animal tumor abilities.
Deep learning for unsupervised image segmentation remains challenging due to the absence of human labels. The common idea is to train a segmentation head, with the supervision of pixel-wise ...pseudo-labels generated based on the representation of self-supervised backbones. By doing so, the model performance depends much on the distance between the distributions of target datasets and the pre-training dataset (e.g., ImageNet). In this work, we investigate a new task, namely unsupervised camouflaged object segmentation (UCOS), where the target objects own a common rarely-seen attribute, i.e., camouflage. Unsurprisingly, we find that the state-of-the-art unsupervised models struggle in adapting UCOS, due to the domain gap between the properties of generic and camouflaged objects. To this end, we formulate the UCOS as a source-free unsupervised domain adaptation task (UCOS-DA), where both source labels and target labels are absent during the whole model training process. Specifically, we define a source model consisting of self-supervised vision transformers pre-trained on ImageNet. On the other hand, the target domain includes a simple linear layer (i.e., our target model) and unlabeled camouflaged objects. We then design a pipeline for foreground-background-contrastive self-adversarial domain adaptation, to achieve robust UCOS. As a result, our baseline model achieves superior segmentation performance when compared with competing unsupervised models on the UCOS benchmark, with the training set which's scale is only one tenth of the supervised COS counterpart.
To evaluate the correlations between p73 G4C14-A4T14 polymorphisms and clinicopathologic characteristics of patients with breast cancer.
A total of 170 patients with breast cancer were genotyped for ...p73 G4C14-A4T14 polymorphisms by Sequenom MassArray® iPLEX GOLD System. The correlations between polymorphisms and the age of patients with breast cancer, or tumor size were analyzed by t-test;the correlations between polymorphisms and clinicopathologic characteristics in patients with breast cancer were analyzed by Χ(2) test; and the relation between polymorphisms and the efficacy of chemotherapy for breast cancer was assessed by logistic regression.
There was negative correlation between p73 polymorphisms and ser veral clinicopathological characteristics, including age, tumor size, menopausal status, TNM classification, pathological type, axillary lymph node metastasis, estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, and p53(P>0.05). The frequency of GC/GC genotype in patients with "triple negative" breast cancer (estrogen receptor -negative, progesterone receptornegative, and human epidermal growth factor receptor 2-negative) was higher than that of patients with non-triple negative breast cancer (78.9% vs 57.6%, Χ(2)=5.741, P=0.017). P73 polymorphism was negatively correlated with chemosensitivity for anthracycline-based chemotherapy (P>0.05).
P73 G4C14-A4T14 polymorphisms are positively correlated with triple negative breast cancer, and the patients with breast cancer who carry GC/GC genotype may have bad prognosis.
ObjectivesWhile awareness of cigarette smoking’s harmful effects has increased, determinants associated with smoking status remain understudied, including potential racial differences. We aim to ...examine factors associated with former versus current smoking status and assess whether these associations differed by race.SettingWe performed a cross-sectional analysis using the population-based Reasons for Geographic and Racial Differences in Stroke(REGARDS)study.Outcome measuresLogistic regression was used to calculate the OR of former smoking status compared with current smoking status with risk factors of interest. Race interactions were tested using multiplicative interaction terms.Results16 463 participants reported smoking at least 100 cigarettes in their lifetime. Seventy-three per cent (n=12 067) self-reported former-smoker status. Physical activity (reference (REF) <3×/week; >3×/week: OR=1.26, 95% CI 1.11 to 1.43), adherence to Mediterranean diet (REF: low; medium: OR=1.46, 95% CI 1.27 to 1.67; high: OR=2.20, 95% CI 1.84 to 2.64), daily television viewing time (REF: >4 hours; <1 hour: OR=1.32, 95% CI 1.10 to 1.60) and abstinence from alcohol use (REF: heavy; none: OR=1.50, 95% CI 1.18 to 1.91) were associated with former-smoker status. Male sex, higher education and income $35 000–$74 000 (REF: <$20 000) were also associated with former-smoker status. Factors associated with lower odds of reporting former-smoker status were younger age (REF: ≥65 years; 45–64 years: OR=0.34, 95% CI 0.29 to 0.39), black race (OR=0.62, 95% CI 0.53 to 0.72) and single marital status (REF: married status; OR=0.66, 95% CI 0.51 to 0.87), being divorced (OR=0.60, 95% CI 0.50 to 0.72) or widowed (OR=0.70, 95% CI 0.57 to 0.85). Significant interactions were observed between race and alcohol use and dyslipidaemia, such that black participants had higher odds of reporting former-smoker status if they were abstinent from alcohol (OR=2.32, 95% CI 1.47 to 3.68) or had a history of dyslipidaemia (OR=1.31, 95% CI 1.06 to 1.62), whereas these relationships were not statistically significant in white participants.ConclusionEfforts to promote tobacco cessation should consist of targeted behavioural interventions that incorporate racial differences.
...I'd like to argue that the cultural crisis revealed in Achebe's novel in fact could predict the ecological/ environmental crisis that Okri's novel attempts to show. ...I aim to demonstrate that ...the forest is an important element in both novels that can connect the crisis of cultural hybridization to that of ecological degradation in the Nigerian history. According to Areola's survey of "Lumbering" in Ecology of Natural Resources in Nigeria (1991), deforestation in Nigeria is caused by the following reasons: 1) "food crop cultivation," especially the establishment of the four crop plantations-cocoa, citrus, rubber, and oil palm-by both individuals and government agencies; 2) "the establishment of commercial tree plantations; 3) "road construction" sponsored by oil companies; and 4) "lumbering" (25). ...the motif of the forest in both Achebe's Things Fall Apart and Okri's The Famished Road suggests that the crisis that post/colonial Nigeria was/is facing is not only the crisis of cultural hybridization, but also that of ecological degradation. According to Okehie-Offoha, Ibo people are known for their religious tolerance. 7 See William Bascom's discussion of urbanism in Yorubaland in The Yoruba of Southern Nigeria (1969); Eva Krapf-Askari's Yoruba Towns and Cities (1969); and Matthew N. O. Sadiku's "The Yoruba" in Ethnic &Cultural Diversity in Nigeria (1996).
My dissertation explores early African environmental literary criticism, which I argue, can be traced back to the 1960s. Looking closely at early African environmental literary criticism enables us ...to recognize the genesis of an Africa-focused ecocriticism, a perspective that emerged in order to critique the impact of colonialism, neocolonialism, and more recent globalization on various African environments. My dissertation also compares the genesis of an Africa-focused ecocriticism to that of early Anglo-American ecocriticism, an environment-oriented approach developed originally from Anglo-American literary criticism in the 1990s in response to "the global Environmental Crisis." Comparing the genesis of these ecocriticisms enables us to recognize a "rhizomatic," rather than "derivative," development of ecocriticism that occurred and prospered in different regions of the world. To understand and approach environmental issues in African literatures, I suggest that we should not explore the extent to which African literatures might respond to global environmental issues using an international ecocriticism defined and practiced in Anglo-American literary studies, but rather, following Ngũgĩ wa Thiong'o's concept of "poor theory," to look to African literary texts themselves. My dissertation demonstrates how African environmental literature can provide a "theory" for an Africa-focused ecocriticism. How do African authors represent African environments and address African environmental issues through literature? Focusing on the "literary aesthetics" of African environmental literature enables us to see culturally, historically, and geographically particular representations of African environments. In turn, we might question how standard histories of and approaches to environmental writing in Anglo-American literature rely on a definition of nature as pristine and untouched, while in the African context we encounter an idea of nature as interdependent with human culture. My dissertation thus explores how alternative methodologies may be applied to African literature with the larger project of imagining a global ecocriticism that does not universalize but finds its local echoes in a series of complex, lateral relations across the world. In the same vein, I locate environmental tropes and concepts that are unique to the African context. My dissertation focuses on Nigerian novels specifically in an effort to demonstrate how that problematized nation-state might both require very local, historicized approaches while enabling us to come up with new methods for reading more broadly in African literature. These novels include Chinua Achebe's Things Fall Apart (1958), Ben Okri's The Famished Road (1991), Cyprian Ekwensi's Burning Grass (1962), Gabriel Okara's The Voice (1964), Ken Saro-Wiwa's Sozaboy (1985), and Helon Habila's Oil on Water (2010). I pair these novels with a specific environmental trope in each of my body chapters—tropes including the forest, the country and the city, and oil. My dissertation carefully examines these environmental tropes recurrent in these Nigerian novels in order to show the promise, uniqueness, and complexity of an African-focused ecocriticism. While early Anglo-American ecocriticism tends to treat the first two tropes as reflections of universal human conditions, I aim to show how ecocriticism in an African context would question such universalism. As for the third trope, I argue that African writers' portrayals of the resource wars in the Niger Delta critique Western forms of state-run environmentalism—a colonial legacy in the postcolonial world that includes much of Africa. The conclusion of my dissertation indicates potential challenges an Africa-focused ecocriticism may encounter in contemporary crises related to "Chinese"-driven resource exploitation of the continent perpetrated in the name of global, neoliberal capitalism. Introducing Chinese presence in Africa and its attendant impact on African environments to an Africa-focused ecocriticism reminds us of the limit of postcolonial ecocriticism in approaching environmental crises caused by non-Western sources.
Microstructures of tungsten carbide (WC) particle reinforced high-speed steel composites fabricated by spray forming were observed by scanning electron microscope and transmission electron ...microscope. Experimental results show that the primary carbides of high-speed steel composites are MC and M
6C. The high-speed steel composites reinforced by WC particles were investigated before and after heat treatment. It is shown that heat treatment may improve the bending strength and hardness of the composites in both as-sprayed state and as-treated state.
Nowadays, e-books gradually replace the traditional paper books. People become accustomed to read e-books, increasingly. Via digital technology and Internet, authors can distribute knowledge and ...information to readers through e-books more efficient and convenient than paper books. One of the e-books' features is the contents of them being easy to copy illegally. Till to now, there is no effective technology to prevent such an illegal action. Thus, illegally copying is a real problem of e-book technology. However, one can prove that she/he has ownership to the copy of an e-book. Such an e-book copy is a legal one. Owner needs to prove the ownerships of her/his e-book copy to others. Therefore, the presented paper proposes an ID-PKC-based scheme to prove the digital ownership to a legitimate copy of e-book. The proposed scheme supports the ownership transfer of an e-book copy. Based on the properties of chameleon-hash, we can prove the proposed scheme is secure and efficient.
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