Search Results (11)

Ungernia victoris and U. sewerzowii (Amaryllidaceae J.St.-Hil.) are rare medicinal species of Central Asia known as sources of biologically active alkaloids, including galantamine. In this study, antioxidant activity was comparatively evaluated across different types of plant material, including natural populations, botanical garden specimens, in vitro regenerants, callus cultures, in vitro obtained bulbs, and seeds. Micropropagation systems based on direct and indirect organogenesis were developed using Murasige and Skoog and Vollosovich et al. media with various plant growth regulator combinations. Antioxidant activity was determined with the use of DPPH and ABTS assays and expressed as IC₅₀ values. Significant variability was observed depending on population origin, type of biological material, and in vitro cultivation conditions. U. sewerzowii demonstrated higher antioxidant activity than U. victoris in natural populations. The highest activity was recorded in callus cultures, whereas in vitro-derived bulbs showed relatively low activity. A strong positive correlation between DPPH and ABTS assays confirmed the reliability of the results and indicated the contribution of multiple types of secondary metabolites. These findings highlight the potential of Ungernia callus cultures as a promising biotechnological platform for the production of antioxidant-active compounds and support sustainable utilization strategies. Full article

A reading of the American Revolution and the post-Civil War Reconstruction period through the lens of W.E.B. Du Bois’s early writings provides new insights into his theory of racial monopoly capitalism. Many Americans saw the 1776 revolution as an idealistic fight for liberty, for the slaveholding elite who held disproportionate power within the revolutionary coalition; however, consolidating power and defending their property and expansionist ambitions were primary objectives. For them, the Revolution was a strategic move to establish racial nationalism and preserve slaveholder control over economic growth and national power. A century later, Du Bois’s analysis of the “bargain of 1876” revealed a similar consolidation of power, influencing both his research on the revolutionary period and his writings on Reconstruction. The political deal in 1876 abandoned the promise of Reconstruction’s “abolition democracy,” restoring white supremacist rule. Du Bois saw this as the victory of monopoly capital, which used racism to weaken interracial labor solidarity and enforce a system of super-exploitation. By linking 1776 to 1876, Du Bois demonstrated that U.S. capitalist development had been shaped by racial oppression from its settler-colonial roots through the rise of monopoly capitalism, consistently blocking the achievement of a true, non-racial democracy. Full article

Ungernia sewertzowii (US) and U. victoris (UV) are medicinal plants and sources of biologically active compounds for pharmaceutical needs. The leaves of US contain 0.29–0.81% sum of alkaloids with a predominance of lycorine, which is 0.04–0.46% in leaves and 0.15–0.38% in bulbs. Lycorine is used to treat acute and chronic bronchitis. The leaves of UV contain 0.27–0.71% sum of alkaloids with a predominance of galanthamine—0.13–1.15%. Galanthamine is used to treat mild-to-moderate dementia (Alzheimer’s disease). The natural populations of US and UV are in danger as sources of income for local people. To resolve this problem, two protocols for microclonal propagation were developed to replace natural raw materials with in vitro regenerated plants. Callusogenesis of US and UV was induced on Murashige and Skoog (MS) nutrient media with 2.4D (0.5 mg/L) in combination with BAP (0.5 mg/L), Kin (0.5 mg/L), or Zea (0.5 mg/L). Direct (for US) and indirect (for US and UN) organogenesis were observed on MS with BAP (0.5 mg/L) or Kin (0.5 mg/L) in combination with IAA (0.5 mg/L) or NAA (0.5 mg/L). Direct organogenesis resulted in 3–5 bulbs of US on one explant; indirect organogenesis resulted in up to 100–150 bulbs of US and UV on one explant within 6 months, or five to six subcultures after transferring the callus to the nutrient medium. The tissue cultures of US and UV were characterized by very low data on antioxidant activity based on IC50 values for DPPH and ABTS radical scavenging activities, whereas in vitro regenerated plants (leaves and bulbs) had higher data. We concluded that in vitro regenerated plants are valuable sources of lycorine and galanthamine, which allow the protection of the natural populations of these two species from extinction. Full article

Automated brain tumor segmentation has significant importance, especially for disease diagnosis and treatment planning. The study utilizes a range of MRI modalities, namely T1-weighted (T1), T1-contrast-enhanced (T1ce), T2-weighted (T2), and fluid-attenuated inversion recovery (FLAIR), with each providing unique and vital information for accurate tumor localization. While state-of-the-art models perform well on standardized datasets like the BraTS dataset, their suitability in diverse clinical settings (matrix size, slice thickness, manufacturer-related differences such as repetition time, and echo time) remains a subject of debate. This research aims to address this gap by introducing a novel ‘Region-Focused Selection Plus (RFS+)’ strategy designed to efficiently improve the generalization and quantification capabilities of deep learning (DL) models for automatic brain tumor segmentation. RFS+ advocates a targeted approach, focusing on one region at a time. It presents a holistic strategy that maximizes the benefits of various segmentation methods by customizing input masks, activation functions, loss functions, and normalization techniques. Upon identifying the top three models for each specific region in the training dataset, RFS+ employs a weighted ensemble learning technique to mitigate the limitations inherent in each segmentation approach. In this study, we explore three distinct approaches, namely, multi-class, multi-label, and binary class for brain tumor segmentation, coupled with various normalization techniques applied to individual sub-regions. The combination of different approaches with diverse normalization techniques is also investigated. A comparative analysis is conducted among three U-net model variants, including the state-of-the-art models that emerged victorious in the BraTS 2020 and 2021 challenges. These models are evaluated using the dice similarity coefficient (DSC) score on the 2021 BraTS validation dataset. The 2D U-net model yielded DSC scores of 77.45%, 82.14%, and 90.82% for enhancing tumor (ET), tumor core (TC), and the whole tumor (WT), respectively. Furthermore, on our local dataset, the 2D U-net model augmented with the RFS+ strategy demonstrates superior performance compared to the state-of-the-art model, achieving the highest DSC score of 79.22% for gross tumor volume (GTV). The model utilizing RFS+ requires 10% less training dataset, 67% less memory and completes training in 92% less time compared to the state-of-the-art model. These results confirm the effectiveness of the RFS+ strategy for enhancing the generalizability of DL models in brain tumor segmentation. Full article

The aim of this study was to compare the demineralizations of the enamel surfaces around different types of orthodontic brackets in an artificial cariogenic environment. A total of 90 extracted human maxillary first premolar teeth were used in this in vitro study. The teeth were divided into 6 groups, 5 study and 1 control, each consisting of 15 samples. Victory metal, Gemini metal, Clarity self-ligating ceramic, APC Clarity Advanced ceramic and Clarity Advanced ceramic brackets (3M Unitek, Monrovia, Calif) used in the study groups were bonded to the teeth with the direct technique. The gingival, occlusal and proximal enamel surfaces adjacent to the brackets were measured with a DIAGNOdent pen (KaVo, Biberach, Germany) (T0). Then, the teeth were placed in a cariogenic suspension environment containing Streptococcus mutans, sucrose and artificial saliva. The teeth were removed from the cariogenic suspension at the end of 28 days. Enamel surfaces were remeasured with DIAGNOdent and the values were recorded (T1). Whether the obtained data were homogeneously distributed or not was determined by the Kolmogorov–Smirnov test, within-group comparisons were performed with the Wilcoxon test, and between-group comparisons were performed with Mann–Whitney U and Kruskal–Wallis tests. Significance level was accepted as p < 0.05. In all groups, the demineralization values of the enamel surfaces in the gingival, proximal and occlusal surfaces adjacent to the brackets were significantly higher in the T1 period than in the T0 period (p < 0.05). In the T1 period of Gemini metal, Clarity self-ligating ceramic and Clarity advanced ceramic bracket groups, the demineralization values of the proximal enamel surfaces were found to be significantly higher than the Victory metal and APC Clarity Advanced ceramic bracket groups (p < 0.05). In the T1 period, the demineralization values of the occlusal enamel surfaces of the Victory metal, APC Clarity Advanced ceramic bracket groups and control group were significantly lower than the Gemini metal, Clarity self-ligating ceramic and Clarity Advanced ceramic bracket groups (p < 0.05). Significant increases in enamel demineralization values were observed as a consequence of increased retention areas for microbial dental plaque on enamel surfaces adjacent to the bracket. Considering the importance of minimizing enamel demineralization in fixed orthodontic treatments, less enamel demineralization in Victory metal and APC Clarity Advanced ceramic bracket groups showed that these brackets can be preferred in patients with poor oral hygiene. Full article

U.S. President Joe Biden took his oath after being victorious in the controversial U.S. elections of 2020. The polls were conducted over postal ballot due to the coronavirus pandemic following delays of the announcement of the election’s results. Donald J. Trump claimed that there was potential rigging against him and refused to accept the results of the polls. The sentiment analysis captures the opinions of the masses over social media for global events. In this work, we analyzed Twitter sentiment to determine public views before, during, and after elections and compared them with actual election results. We also compared opinions from the 2016 election in which Donald J. Trump was victorious with the 2020 election. We created a dataset using tweets’ API, pre-processed the data, extracted the right features using TF-IDF, and applied the Naive Bayes Classifier to obtain public opinions. As a result, we identified outliers, analyzed controversial and swing states, and cross-validated election results against sentiments expressed over social media. The results reveal that the election outcomes coincide with the sentiment expressed on social media in most cases. The pre and post-election sentiment analysis results demonstrate the sentimental drift in outliers. Our sentiment classifier shows an accuracy of 94.58% and a precision of 93.19%. Full article

In 1500 m freestyle swimming races, pacing is generally represented by a parabolic or U-shaped curve indicating that swimming velocity is greatest at the start and the last laps of the race while swimmers maintain an even pace through the middle section of the race. However, there is no information to determine if 1500 m race winners select pacing different to other, less successful swimmers within the same competition. Therefore, this investigation aimed to describe the pacing strategies adopted by 1500 m freestyle competitive swimmers in World Championships (long course), from 2003 to 2019 to determine the most effective pacing to obtain victory or a medal. The official overall and split times for 1500 m freestyle races of the Fédération Internationale de Natation (FINA) were obtained from the website of this organization. In total, data of 143 swimming performances (71 male and 72 female) were extracted. With the split times, lap times, and position were calculated across the race. To determine differences in the pacing between best- and worst-ranked finalist, swimmers in each race were divided into four groups based on the final position (1st vs. 2nd vs. 3rd vs. 4–8th). All the lap times of the winners of the race were faster than those of participants classified as 4–8th position for men and women races (p < 0.05). However, there were no differences in lap velocity among the different positions achieved at the end of the race when it was normalized by average race velocity. Additionally, there were no differences in the lap-to-lap variability among swimmers with different positions at the end of the race. In summary, both men and women elite swimmers selected parabolic pacing consisting of a fast start in the first lap, an even pace close to their average race velocity in the mid-section of the race (from 50 to 1400 m), followed by an end spurt in the final lap(s). This pattern was very similar in all finalists irrespective of the final position in the race. Hence, the obtaining of a medal in the World Championships was associated to possessing a faster average race velocity rather than a specific pacing profile through the race. Full article

The 1968, 2000, and (future) 2024 U.S. presidential elections provide settings for deliberately provocative, offbeat scenarios that might have happened or could happen. Throughout, the Electoral College and plurality voting both receive blame. Scenario 1 exposes a quirk previously unnoticed: Under (albeit special) conditions, certain 1968 Humphrey voters could have made Humphrey rather than Nixon the election victor had they voted strategically for Wallace instead of Humphrey. In Scenario 2, overlooked nonidentifiability of undervotes would have plagued the 2000 Florida recount had the U.S. Supreme Court not halted it, thus raising questions about the foresightfulness of almost everyone involved; but, in addition, Gore missed an opportunity that, through use of proper statistical sampling, could have propelled him to victory. In Scenario 3, National Popular Vote Interstate Compact supporters fail to foresee that even one state, by changing its method for presidential voting, can wreck this innovative and widely promoted compact. Full article

During the Cold War, two basic schools of thought emerged among U.S. Christian leaders and ethicists concerning the implications of the nuclear revolution for the use of force by the United States. The just war thinkers held that nuclear war could in fact be conducted within the bounds of traditional just war principles, particularly those of discrimination and proportionality. Since nuclear weapons could be used in war, it followed that they could and should be developed and produced for that purpose and for the purpose of deterrence. The nuclear pacifists held that nuclear war could not be conducted within the confines of traditional just war principles. Since by its nature nuclear war could not be moral, there was no reason for the development and production of nuclear weapons, except for the purpose of deterrence. And since nuclear deterrence required one to make threats of nuclear destruction that it would not be moral to carry out, and, moreover, carried unacceptable risks of miscalculation and inadvertent or accidental use of nuclear weapons, deterrence itself could not be justified, except perhaps as a temporary way station on the path to nuclear disarmament. Although the just war thinkers initially held sway, over time they became less dominant. By the middle of the 1980s, the U.S. Catholic Church and most of the largest Mainline Protestant denominations had formally adopted a nuclear pacifist position. This essay chronicles the victory of nuclear pacifism in these churches, explains it as a reaction to the nuclear weapons and doctrine advocated by the just war thinkers, and implemented by the U.S. government and military, as well as other events and trends in American society, and inquires as to whether or not the just war thinkers and nuclear pacifists influenced the course of U.S. policy. Full article

This essay uses the concept of Christian nationalism to explore the religious dynamics of the Contra war and U.S.–Nicaraguan relations during Ronald Reagan’s presidency. Religious organizations and individuals played crucial roles on both sides in the war in Nicaragua and in the debates in the United States over support for the Contras. Evangelistic work strengthened transnational ties between Christians, but also raised the stakes of the war; supporters of the Sandinistas and Contras alike alleged a victory by their adversary imperiled the future of Christianity in Nicaragua. Christian nationalism thus manifested itself and intertwined in both the United States and Nicaragua. Examining how evangelicals and Catholics in the United States and Nicaragua, as well as the Reagan administration, the Contras, and the Sandinistas, used Christian nationalism to build support for their policy objectives sheds light on both the malleability and the power of identifying faith with the state. Having assessed Christian nationalism as a tool and a locus of conflict in the Contra war, the essay then steps back and considers the larger methodological implications of using Christian nationalism as a category of analysis in U.S. foreign relations history. Full article

This article explores the forgotten manifesto The City of Man: A Declaration on World Democracy, which was composed in 1940 by a group of prominent American and European anti-isolationist intellectuals, including Thomas Mann, Reinhold Niebuhr, and Hermann Broch. Written in response to the victories of Nazi Germany, the manifesto declared that the United States had a new global responsibility not only to lead the war against fascism and Marxism, but also to establish a global order of peace and democracy under U.S. hegemony. Moreover, the authors of the manifesto claimed that such an order would have to be based on the rejuvenation of conservative values; in their view, the collapse of Western democracies under the weight of totalitarian aggression was the consequence of inner moral and intellectual degeneration. The City of Man therefore called on the United States to lead the spiritual transformation of democracy into a modern political religion, which would bring about the intellectual and political unity of humanity under one state and one creed. This article analyzes the manifesto as a rare window into the difficulty intellectuals faced as they tried to conceptualize the totalitarian challenge prior to the United States’ entry into the war. Moreover, it claims that The City of Man expressed the emergence of postwar conservatism and Cold War ideology, as well as the unique role played by European émigrés in this process. Full article