book on the Calculus, basedon the method of limits, that should be within the 1. CHAPTER II. Limit. Increment. Derivative. Definition of Limit. 8. Derivative of the Sine and Cosine . The right way to begin a calculus book is with calculus. Differentiation goes from f to v; integration goes from v to f. Differentiation Formulas. Product and Quotient Rule – In this section we will took at differentiating products and quotients of functions. Derivatives of Trig.
|Language:||English, Spanish, Indonesian|
|Distribution:||Free* [*Register to download]|
Summary. 1. Derivative of usual functions. . Graphically, the derivative of a function corresponds to the slope of its tangent line at one specific point. ❘ CHAPTER 2 ❘ Differentiation: Basic Concepts ❘. s t. 2. Secant line of exponential notation in Appendix A1 at the back of the book.) For example. The differential calculus was introduced sometime during or , when Isaac Newton first concieved the process we now know as differentiation (a.
Classically, this transformation has been viewed as the step-wise accumulation of genetic and epigenetic aberrations which results in an increasingly more malignant phenotype Singh et al. A key feature of this progression model is the explicitly one-way nature of gene mutation. Based on this view of melanoma progression, a theory reminiscent of Darwinian natural selection has been conceived to explain the inevitable development of cellular heterogeneity and therapeutic resistance in melanoma tumors.
Specifically, it is commonly believed that melanoma cells are constantly accumulating novel, prometastatic genetic mutations, which inevitably lead to the development of dominant subpopulations of tumor cells with a distinct survival advantage.
As new dominant subpopulations are generated from ongoing genomic instability, the constantly evolving tumor is able to both maintain cellular heterogeneity, as well as develop dynamic resistance to chemotherapeutic agents. As tumor cells acquire more mutations, their properties dynamically change, as measured by changes in global gene expression or by changes in their capacity for relevant functions such as motility, proliferation, or invasion.
By convention, these changes in cellular phenotype define a new cell fate, and reflect a process of differentiation albeit dysregulated that parallels the observed maturation of non-cancerous cells during development. To appreciate concepts such as differentiation and cell fate in the dysregulated setting of melanoma, one needs to have some contextual understanding of differentiation and cell fate determination in the normal development of cells that may serve as precursors for this deadly cancer.
While the cell of origin for melanoma is almost certainly of neural crest origin, and likely in the melanocytic lineage, the recent unexpected finding that murine epidermal melanocytes can arise from a niche of Schwann cell precursors highlights the incomplete nature of our current understanding Adameyko et al. This finding suggests that an understanding of Schwann cell biology could be potentially relevant for identifying and treating melanomas that may arise from this distinct precursor population, since these melanomas could conceivably display different cellular phenotypes than melanomas derived from non-Schwann cell-derived melanocytes.
Likewise, the observation that melanocytes can de-differentiate to a precursor cell that gives rise to mature glia Dupin et al. Insight from gene expression profiling studies An emerging body of evidence is re-defining the conventional genetic model of melanoma progression. Gene expression profiling studies using multi-center cohorts of patient tumors have previously revealed the existence of two major expression signatures Hoek, ; Hoek et al.
These signatures correlate to two distinct populations of melanoma cells, one with a predominantly proliferative phenotype and the other with a predominantly invasive phenotype. Subsequent transcriptional profiling studies in melanoma cells have revealed two discrete states of differentiation Hoek, ; Tap et al.
The first state results in a phenotype closely resembling primary human melanocytes, while the second results in a phenotype resembling neuronal stem cells Hoek, ; Tap et al. Further, melanoma cells with a proliferative phenotype tend to be in a melanocytic differentiation state, while cells which acquire an invasive phenotype tend to dedifferentiate into a neuronal state.
The ability of melanoma cells to constantly switch phenotypes undoubtedly contributes to the resistance of melanoma to treatment.
Cancer stem cells and melanoma Traditional chemotherapy operates largely under the premise that all cancer cells have equal malignant potential, with drug therapy focused on decreasing the population of cells within the tumor. Recently, studies looking at melanoma and other cancers have introduced the concept that certain populations within the tumor, often referred to as cancer stem cells CSCs , have increased tumor initiating capabilities along with increased resistance to traditional chemotherapeutic approaches Dou et al.
Consequently, the ability to identify, study and manipulate cells with the highest tumor-initiating capacity will be critical for developing effective therapeutic strategies. In the case of melanoma, the exact nature of CSCs remains controversial, with several putative CSC markers having been proposed in the literature Zabierowski and Herlyn, However, additional reports have demonstrated that tumor initiating capacity may actually be quite common among melanoma cells, and does not depend on the expression of any of the published putative melanoma CSC markers Quintana et al.
In the context of cellular differentiation, studies have also found that like other cancers, melanoma exhibits similarities to embryonic stem cells Klein et al.
The ability to correlate features of melanoma cells such as gene expression profiles with functional phenotypes such as tumor-initiating capacity a hallmark of CSCs will further delineate the role of cell fate in regulating melanoma progression. Tumor heterogeneity and plasticity While the cellular heterogeneity of tumors is a long-recognized phenomenon Fidler, , these recent studies highlight the variability within populations highlight regarding both gene signature and phenotypic plasticity.
The concepts of phenotype switching and cancer stem cells in melanoma may both represent what happens within the tumor environment. This type of model could reconcile both sets of observations, and implies an inherent plasticity of melanoma cells that would undoubtedly complicate therapeutic efforts and potentially contribute to the variability seen with the use of cell surface markers to isolate CSC populations.
The proliferative phenotype of melanoma cells Since cell fate and differentiation in the setting of cancer most closely parallels phenotype, this review will focus in particular on phenotypic characteristics that have been the center of efforts to understand melanoma at the molecular level.
The first of the two major phenotypes expressed by malignant melanoma cells is the proliferative phenotype. As the name suggests, this phenotype is associated with a high rate of proliferation, as well as minimal invasive potential Hoek et al.
Two key features of this group of cells help to account for their proliferative nature, including the activity of microphthalmia-associated transcription factor MITF Levy et al.
Microphthalmia transcription factor MITF MITF is a transcription factor that plays a critical role in the differentiation of melanoblasts from other cells derived from the neural crest Levy et al. It also plays a critical role in the normal functioning of differentiated primary melanocytes, regulating genes involved in the manufacture of melanosomes and melanin Hornyak, As previously mentioned, the primary role of MITF in a normally functioning melanocyte cell, where MITF expression is highest, is the regulation of genes involved in melanosome and melanin production Lekmine et al.
Although the exact mechanism of this change is still not clear, it is primarily thought to be the result of altered post-translational modification of MITF, causing MITF to be targeted towards a different set of genes Hoek and Goding, According to the rheostat model, overall MITF activity is also thought to be lower in malignant melanoma cells as compared to melanocytes Hoek and Goding, Consequently, MITF expression in this cell population results in suppression of senescence and increased proliferation, as well as decreased invasiveness, both hallmarks of melanoma cells in the proliferative gene expression cluster.
There have been many mechanisms proposed to help explain how MITF expression leads to increased proliferation of melanoma cells. For example, suppression of p27kip1, or cyclin-dependent kinase inhibitor 1B CDKN1B , is thought to be of primary importance in this process. The main function of p27kip1 is to impede cell cycle progression at G1. In melanoma cells with a proliferative phenotype, there is decreased p27kip1 expression Carreira et al.
This is thought to be the result of increased expression of diaphanous-related formin DIA1, a protein which is upregulated by MITF and has a role in the regulation of a wide variety of cellular functions, including actin polymerization and E-cadherin organization.
While BCL2 upregulation imparts apoptotic resistance on melanoma cells, increased expression of cyclin-dependent kinase 2 results in cell cycle dysregulation and thus increased proliferation Cheli et al. Based on the results of Carreira et al. MITF also appears to be a negative regulator of the Notch signalling cascade, which is itself a driver of invasive potential Thurber et al.
Interestingly, although immortalization is often associated with proliferation, Delmas et al. First, melanomas from the mouse model appear to originate from the bulge region of the hair follicle, which is the proposed niche for melanocytic stem cells Delmas et al.
Intuitively, the activation of signaling by secreted Wnt ligand is subject to modulation by extrinsic factors including endogenous inhibitors i. The invasive phenotype of melanoma cells The second major gene expression signature of melanoma cells results in a phenotype characterized by a high degree of invasiveness and relatively lower rates of proliferation.
Normally, WNT5A signalling plays an important role in the regulation of cell fate, embryogenic patterning and cell motility Chien et al. In many forms of cancer, including colon, breast and liver cancer, WNT5A acts as a tumor suppressor Chien and Moon, In the context of melanoma cell differentiation, which is assessed largely through gene signatures, the continued appearance of WNT5A as a major determinant of melanoma clusters in transcriptional profiling studies speaks to its likely importance as a genetic marker Bittner et al.
Functionally, WNT5A is thought to contribute significantly to the invasive phenotype by regulating cellular migration, both through PKC and the re-distribution of cellular adhesion molecules Dissanayake et al. Conceivably, the role of WNT5A in neuronal cells may overlap with the phenotypic effects seen with WNT5A activation in melanoma cells, thereby contributing to whether these cells may display a phenotype that is neuronal as opposed to melanocyte-like.
Alternatively, the expression of WNT5A in melanoma may simply be a reflection of cellular differentiation state, which would be consistent with transcriptional profiling studies where WNT5A is enriched in melanoma cells with a gene signature suggestive of neuroprogenitor cells Tap et al.
Notch signaling Another pathway implicated in melanoma is the Notch signaling cascade, which is one of the prototypical regulators of cell fate determination during embryonic development Kopan and Ilagan, Like other primary transforming mutations in melanoma such as BRAF and NRAS, constitutive activation of the Notch1 receptor was in itself sufficient for the malignant transformation of human melanocytes Pinnix et al.
However, the expression of Notch is negatively regulated by MITF, and thus its contribution to cellular phenotype is most pronounced in invasive melanoma cells where MITF is down-regulated Thurber et al. You can also use them to introduce issues and invite students to respond to these issues in their journals. Making your read-aloud your teaching text will ensure that every student has access to the information and skills they need to become a better reader.
Teach with diverse materials. Avoid using one text for the entire class. Instead, use multiple texts at diverse reading levels for your units of study. This will enable every student to gather information from books and magazines they can truly read Robb, ; Worthy et al.
Organize for instruction so you meet all reading levels. Set aside 15 to 30 minutes of class time, at least three times a week, for students to read books at their comfort levels — and these levels carry from student to student.
Show students how to construct meaning while reading. Students can become better readers only if they understand how to construct meaning as they read. By modeling the ways you think about texts during your read alouds, while you work with small reading groups, and in your one-to-one instructional conferences with students, you are offering students mutliple opportunities for learning how to consruct meaning Encourage discussion.
Discussion is especially important in a differentiated reading classroom because it provides a powerful way to build on every student's understandings and knowledge of facts. It also provides them with opportunities to clarify meaning and to build comprehension. By asking students to move beyond memorizing the facts to applying those facts to issues and problems through discussion, students deepen their understanding and recall. In-depth discussions among small groups, and with the entire class, can show students how their peers think and reason, can build background knowledge, and can make the facts relevant to their own lives.
Write to explore, think, learn, and improve comprehension. These insights support planning interventions for individuals, pairs, small groups, and, at times, the entire class. Use ongoing assessments to support each student.
Study the assessments students complete for a unit to discover their successes and their areas of need. Then support each student in your class by getting to know him or her so you can provide targeted instruction. Ongoing assessments allow you to do this. Plan your units carefully. Thinking through each unit of study enables you to understand what you want students to learn about a genre, an issue, and reading strategies Tomlinson, It will also ensure that you have gathered reading materials that meet the needs of each student, as well as appropriate texts for your read alouds.
Algebraic Topology. Differential Topology. Geometric Topology. Applied Mathematics. Differential Equations. Discrete Mathematics. Graph Theory. Number Theory. Probability Theory. Set Theory. Category Theory.
Basic Mathematics. Classical Analysis. History of Mathematics.
Arithmetic Geometry. Mathematical Series. Modern Geometry. Basic Algebra.