Undulation Instability of Epithelial Tissues

Treating the epithelium as an incompressible fluid adjacent to a viscoelastic stroma, we find a novel hydrodynamic instability that leads to the formation of protrusions of the epithelium into the stroma. This instability is a candidate for epithelial fingering observed in vivo. It occurs for sufficiently large viscosity, cell-division rate and thickness of the dividing region in the epithelium. Our work provides physical insight into a potential mechanism by which interfaces between epithelia and stromas undulate, and potentially by which tissue dysplasia leads to cancerous invasion.Comment: 4 pages, 3 figure

PENERAPAN PENDEKATAN PEMBELAJARAN KONTEKSTUAL (CONTEXTUAL TEACHING AND LEARNING) UNTUK MENINGKATKAN AKTIVITAS SISWA PADA MATA PELAJARAN MATEMATIKA

Penelitian ini dilatarbelakangi oleh rendahnya aktivitas siswa dan guru yang masih menggunakan metode ceramah pada saat pembelajaran matematika. Secara umum, penelitian ini ditujukan untuk meningkatkan aktivitas dengan menerapkan pendekatan CTL dalam mata pelajaran matematika di kelas 2C SDN Sukarasa 4 untuk, sedangkan tujuan khususnya adalah untuk mengetahui bagaimana perencanaan, pelaksanaan, dan hasil peningkatan aktivitas siswa menggunakan pendekatan CTL . Metode yang digunakan dalam penelitian ini adalah Penelitian Tindakan Kelas (PTK) yang mengadaptasi model Kemmis dan Mc. Taggart yang dilaksanakan dalam dua siklus pembelajaran . Hasil enelitian dengan menerapkan pendekatan CTL pada mata pelajaran matematika menunjukkan adanya peningkatan aktivitas belajar siswa pada setiap siklusnya. Pada siklus 1, persentase aktivitas siswa mencapai 83,81% sedangkan pada pelaksanaan pembelajaran siklus kedua mengalami peningkatan menjadi 92,96%. Berdasarkan hasil penelitian di atas, maka dapat disimpulkan bahwa penerapan pendekatan CTL dapat meningkatkan aktivitas belajar siswa pada mata pelajaran matematika. Berdasarkan hasil penelitian tersebut maka ada beberapa saran yang perlu disampaikan antara lain: (1)guru sebaiknya menerapkan pendekatan pembelajaran kontekstual karena karena bisa memberikan pembelajaran yang lebih bermakna dan menyenangkan, (2) bagi siswa, pendekatan kontekstual bisa membuat siswa lebih aktif dalam pembelajaran dan siswa lebih menemukan makna karena pembelajaran kontekstual adalah pembelajaran yang berhubungan dengan kehidupan sehari-hari siswa, (3) Peneliti selanjutnya yang akan melakukan penelitian dengan menerapkan pembelajaran kontekstual, bisa menerapkannya pada mata pelajaran lain selain matematika. Selain untuk meningkatkan aktivitas, peneliti selanjutnya juga bisa menggunakan pendekatan kontekstual sesuai dengan keperluannya.;--- This research is motivated by the low activity of the students and teachers who still use the lecture method of teaching mathematics. In general, this study aimed to enhance the activity by applying CTL approach in mathematics in grade 2C SDN Sukarasa 4's, while the specific goal is to find out how the planning, execution, and the resulting increase in student activity using CTL approach. The method used in this research is the Classroom Action Research (PTK) which adapts the model Kemmis and Mc. Taggart is conducted in two cycles of learning. Results enelitian by applying CTL approach in mathematics indicate an increase in activity of students in each cycle. In cycle 1, the percentage of student activity reached 83.81% while the implementation of learning a second cycle increased to 92.96%. Based on the above results, it can be concluded that the application of CTL approach can improve students' learning activities in mathematics. Based on these results then there are some suggestions that need to be addressed include: (1) the teacher should approach contextual learning because because it can provide learning more meaningful and enjoyable, (2) for students, a contextual approach to make students more active in learning and more students find meaning for contextual learning is the learning associated with the daily life of students, (3) The next researchers will conduct research to apply contextual learning, can apply it to other subjects besides math. In addition to increasing the activity, further research could also use a contextual approach in accordance with its requirements

Inflating bacterial cells by increased protein synthesis.

Understanding how the homeostasis of cellular size and composition is accomplished by different organisms is an outstanding challenge in biology. For exponentially growing Escherichia coli cells, it is long known that the size of cells exhibits a strong positive relation with their growth rates in different nutrient conditions. Here, we characterized cell sizes in a set of orthogonal growth limitations. We report that cell size and mass exhibit positive or negative dependences with growth rate depending on the growth limitation applied. In particular, synthesizing large amounts of "useless" proteins led to an inversion of the canonical, positive relation, with slow growing cells enlarged 7- to 8-fold compared to cells growing at similar rates under nutrient limitation. Strikingly, this increase in cell size was accompanied by a 3- to 4-fold increase in cellular DNA content at slow growth, reaching up to an amount equivalent to ~8 chromosomes per cell. Despite drastic changes in cell mass and macromolecular composition, cellular dry mass density remained constant. Our findings reveal an important role of protein synthesis in cell division control

Periodontal regeneration using collagen materials, dental stem cells and growth factors: a comparative study in minipigs

The aim of this study was to examine the regenerative potential of different collagen materials +/- a growth factor cocktail or +/- periodontal ligament stem cells comparatively in 60 class II furcation defects in swine. A significant increase in regeneration was observed in all groups. The new attachment formation reached a maximum of 77 %. The study shows that all implanted materials improved periodontal regeneration. However, neither the additional application of growth factors nor the stem cells lead to a further statistically significant increase in new attachment

Consumer Traits’ Effect on Table Banana Quality Choice in the Philippines: A Multinomial Logistic Analysis

Banana (Musa spp.) is one of the fruits that most consumers buy in the Philippines as part of daily diets. Its high demand is owed to the fruit’s nutritive value and affordable price. The Philippines has been growing 80 cultivars for domestic and international markets. Among these are ‘Lakatan’ and ‘Latundan.’ Production-related researches on banana have been well established, but little is known about the banana’s marketability and consumer preferences in the local market. The aim of this paper is to examine the effect of consumer traits on the choice of table banana quality in the Philippines. A survey was conducted with 400 consumer-respondents: 146 came from a producing area (Davao City) and 254 were from consuming markets (Manila and Cebu City). Multinomial logistic regression was applied in carrying out the objective of the study. Results reveal that the consumer’s traits—i.e., age, marital status, education, occupation, and gender—significantly affect the likelihood of choosing banana based on particular qualities (i.e., skin color, fruit size, cluster size, fruit length, degree of ripeness, softness and surface blemish) in a producing market. The result is similar in consuming markets. However, none among the consumer traits significantly affected the likelihood of choosing banana in consideration of its fruit length. In addition, price consumer index in consuming markets affect the likelihood of choosing banana quality. Therefore, consumer traits are important consideration in consumers’ buying decision vis-à-vis fruit quality. This suggests that proper market segmentation should be studied to develop sound marketing strategies and profit opportunities

Alignment of cellular motility forces with tissue flow as a mechanism for efficient wound healing

Recent experiments have shown that spreading epithelial sheets exhibit a long-range coordination of motility forces that leads to a buildup of tension in the tissue, which may enhance cell division and the speed of wound healing. Furthermore, the edges of these epithelial sheets commonly show finger-like protrusions whereas the bulk often displays spontaneous swirls of motile cells. To explain these experimental observations, we propose a simple flocking-type mechanism, in which cells tend to align their motility forceswith their velocity. Implementing this idea in amechanical tissue simulation, the proposed model gives rise to efficient spreading and can explain the experimentally observed long-range alignment of motility forces in highly disordered patterns, as well as the buildup of tensile stress throughout the tissue. Our model also qualitatively reproduces the dependence of swirl size and swirl velocity on cell density reported in experiments and exhibits an undulation instability at the edge of the spreading tissue commonly observed in vivo. Finally, we study the dependence of colony spreading speed on important physical and biological parameters and derive simple scaling relations that show that coordination of motility forces leads to an improvement of the wound healing process for realistic tissue parameters

The logistics of selling a destination\u27s tourism product

Tourism demand is becoming increasingly more discerning. It expects a well-designed and diverse product. This can be achieved with properly organised receiving-tourism facilities and services, and an array of attractions and entertainment events. Parallel to enhancing attractiveness, it is also necessary to strengthen and intensify internal and external marketing to ensure that a destination product and, in particular, its segments will find customers on the market

The Problem of Assessing Information Security Risks for Robotic Systems

Today, robotic systems are becoming very popular. They are typically used to monitor critical objects. Human lives often depend on the correct operation of a robotic system. Therefore, risk analysis of a robotic information system is an important task. However, to date there is no standard that describes this process. We conducted a study of existing standards for industrial control system and typical information systems. We have identified one common problem. If the risk assessment process is still described in these documents, then the analysis of initial security is not considered at all. This assessment of the initial level of security, the analysis of structural and functional characteristics is a very important task. If we are not completely knowledgeable about our system, then we may not fully assess the risks. Therefore, an attacker can take advantage of this. This article also discusses security incidents related to robotic systems. We concluded that an attacker may not have special means to attack, and at the same time causes substantial damage to the robotic system. Indeed, the main problem in the analysis of robotic systems is the difference of this type of network from the typical computer networks, which in turn requires the creation of new methods and approaches to the analysis of the security of a network of mobile robots