Light-driven Transport of Plasmonic Nanoparticles on Demand

Light-driven Transport of Plasmonic Nanoparticles on Demand Abstract With the advance of science and technology, the control and movement of plasmonic nanoparticles can be achieved via laser traps. The effect of the optical manipulation tool has been tested before on the multiple particles [1]. Here, this is proved that manipulation and transport of large plasmonic nanoparticles can be applied on the sample which previously prepared. These verities include developments related to many technological applications. Introduction Metal plasmonic nanoparticles are highly preferred because they have specific properties. These are gold and silver nanoparticles. As we know when the light hits the surface of the metal, a part of the light is reflected. Some of it is absorbed. Metal atoms have electron clouds that are constantly moving around them. The light which is absorbed by metal has energy. That energy causes the vibration of the electron clouds. The vibrations of the electron clouds are called plasmon [2]. If we look at the reflected light while we change an angle of incidence we see that reflected light intensity reduces. Resonance angle or SPR angle is the angle at which the maximum loss occurs on the intensity of the reflected light. Localized surface plasmon resonance (LSPR) is the total excitation at the closed surface of a small particle (see Figure 1). These datas are about plasmonics. Plasmonics is an area that consists use of data transmission via plasmons and applications of its various fields. Figure 1: Localized Surface Plasmon Resonance (LSPR) Laser trap is a method which uses configurable lasers to hold atoms or particles and trap them in a restricted area. There are several different species of laser traps that can be used to trap a different kind of particles. One of the most common types of laser trap is the single-beam gradient force trap also known as optical tweezers or laser tweezers [3]. Dielectric objects are interested in the center of the beam, relatively above the beam waist, shown in the figure (see Figure 2). The force applied on the object depends linearly on its change of location from the trap center just as with a simple arc system [4]. In contrast to other laser traps, the proposed confinement mechanism exploits transverse phase gradient forces that allows working with resonant and off-resonant wavelengths on both red/blue-detuned sides of the LSPR. Figure 2: Optical trap principle The figure below (see Figure 3) shows us spectral absorption on gold and silver nanoparticles. The trapped laser is focused on the sample. Specifically, it is considered colloidal silver NPs of 150 nm (10 nm thick triangular plate, LSPR at 950 nm) and gold NPs of 100 nm (sphere, LSPR at 570 nm). The laser wavelength is arranged 532 nm, which is on the blue-detuned side near the LSPR of gold NPs. In contrast, this wavelength being far from the LSPR of the silver NPs allows avoiding significant optical heating, Figure 3: Spectral absorbance of silver and gold nanoparticles Dark field illumination was applied to create an image of the nanoparticles. With the same microscope objective, focuses on the capture beam on the top glass slides, allowing NPs to be displayed depending on the scattered light (see Figure 4). Figure 4: Spectral absorbance Dark field illumination (or Dark field microscopy) is a method which creates the contrast between the object and the field around the specimen. In this method, the samples and the other materials shine on the dark background (see Figure 5). Figure 5: Principle of dark field microscopy Optical microscopes use dark field illumination technique for enhancing the contrast in unstained samples. The light penetrates the microscopes for illumination of the specimen. The condenser lens and objective lens focuses the light against the specimen. The center is blocked out. The specimen appears bright on a dark background. The nanoparticles are bounded by the upper glass lamella surrounding the sample (by transverse phase gradient forces, white arrows, and see Figure 6). Figure 6: The NPs are confined near the top glass coverslip Methods A dipolar NP with size a below the laser wavelength (a < ÃŽ ») experiences time averaged radiation-induced forces: Where, q = x, y, z is a placeholder for the coordinates, ÃŽ ±(ÃŽ ») = ÃŽ ±Ã¢â‚¬ ² (ÃŽ ») + iÃŽ ±Ã¢â‚¬ ² †² (ÃŽ ») is the particle polarizability while ÃŽ µ is the permittivity of the surrounding medium, and E is the electric field of the focused laser beam. The particle experiences traverse scattering forces: Where, I = |E(x, y)|2 and à Ã¢â‚¬ ¢ are the intensity and phase distributions of the field with u⊠¥, being normal and tangent vectors to the curve. Therefore, the transverse scattering forces in the normal and tangential directions naturally arise from the phase gradients along such directions. The laser traps have been created by focusing the following beam over the sample. This is the formula of beam shaping technique: The sample was formed as like this: the specimen was enclosed into a chamber made by attaching two glass coverslip (thickness 0.17 mm). A Scotch tape (thickness ~50 ÃŽ ¼m) was used as spacer between the coverslips. The nanoparticles were filled into the sample cell directly from the aqueous solution provided by the manufacturer: 150 nm silver NPs (NanoComposix Inc., 10 nm thick triangular plates, PVP coated, Lott. JMW1340) and 100 nm gold NPs (Sigma-Aldrich, citrate stabilized Au spheres, 742031, Lott. MKBS6913V). Results Bottom panel shows the intensity and phase of the laser trap focused according to their shapes (see Figure 7): Figure 7: It shows us the density and the phase of the laser trap (plane z1) focused into a circle. It shows us the density and the phase of the laser trap focused into a square. It shows us the density and the phase of the laser trap focused into a triangle. For each case, the XZ plane profile is shown in a1, b1 and c1 accordingly. In order to display the shape of the toroidal channel displayed in each case of a zoom item (inset) a1, b1 and c1 of the density distribution in plane z2. In the lower panel (a-c) a rotating flow of bound NPs is shown in the toroidal channel for each trap shape. Time skipped images of the stream were also shown[5]. Six small clusters of nanoparticles attached to the coverslip have been used to mimic targets or obstacles as displayed in Figure 8: Figure 8 (a) Small clusters of gold nanoparticles which anchored glass microscope slide are carried along a curved Bà ©zier path through six target objects. The intensity and phase of the trapped light (charge l = -30) is configured to avoid these objects as shown in the bottom panel of (b, c). In part (d), proposed approach to automated route finding based on several Bà ©zier curves displayed with different colors. (e,f) distributions of reciprocal and propulsive forces acting on particles[6-9]. Discussion In this article, gold and silver nanoparticles were controlled and transferred in a prepared sample before thanks to optical manipulation technique. This allows for guiding metal nanoparticles along tailored trajectories for interaction with objects, exploiting off-resonant but also resonant laser wavelengths for simultaneous nanoparticle heating. Their optical response can be tuned in the visible and infrared spectral range as a function of the nanoparticle shape and size. These nanoparticles strongly absorb and scatter light in the spectral region near to their localized surface plasmon resonance (LSPR), and therefore, can be applied as heat nanosources for lithography, photoacustic imaging, photothermal therapy, etc. In this experiment the laser wavelength was 532 nm[5]. References 1.Rodrigo, J.A. and T. Alieva, Freestyle 3D laser traps: tools for studying light-driven particle dynamics and beyond. Optica, 2015. 2(9): p. 812-815. 2.Esentà ¼rk, E.N. and A.H. Walker, Anisotropik Ã…Å ¾ekilli AltÄ ±n Nanoparà §acÄ ±klarÄ ±nÄ ±n Sentezi, Karakterizasyonu ve FonksiyonlandÄ ±rÄ ±lmasÄ ±. 3.https://people.smp.uq.edu.au/TimoNieminen/trapping.html 4.https://en.wikipedia.org/wiki/Optical_tweezers 5.Alieva, j.A.R.a.T., Light-driven transport of plasmonic nanoparticles on demand. scientific reports, 2016. 6.Carey, K.B., et al., Enhancing Readiness-to-Change Substance Abuse in Persons with Schizophrenia A Four-Session Motivation-Based Intervention. Behavior Modification, 2001. 25(3): p. 331-384. 7.Sanchot, A., et al., Plasmonic nanoparticle networks for light and heat concentration. ACS nano, 2012. 6(4): p. 3434-3440. 8.Lal, S., S. Link, and N.J. Halas, Nano-optics from sensing to waveguiding. Nature photonics, 2007. 1(11): p. 641-648. 9.Svoboda, K. and S.M. Block, Optical trapping of metallic Rayleigh particles. Optics letters, 1994. 19(13): p. 930-932.

The Mentally Ill in Jail Essay -- essays research papers

The Mentally Ill in Jail The articles inform that more mentally ill people are in jail than in hospitals. According to statistics 159,000 of mentally ill are presently incarcerated in jails and prisons, mostly of crimes committed because they were not being treated. Some of them become violent and may terrorize their families and neighborhoods. Tragically, most of those instances of incarceration are unnecessary. We know what to do, but for economic, legal and ideological reasons, we fail to do it. The deinstitutionalisation of the severely mentally ill in the 60ties qualifies a as one of the largest social experiments in American history. In 1995, there were 558,239 severely mentally ill patients in the nations public psychiatric hospitals. In 1995, the number has been reduced to...

Integrity, Confidentiality and Professional Behavior of Internal Auditors

Integrity According to The Institute of Internal Auditors (IIA), â€Å"The integrity of internal auditors established trust and thus provides the basis for reliance on their judgement†. IIA further added that to be integrity, internal auditors: * Shall perform their work with honestly, diligence, and responsibility. * Shall observe the law and make disclosures expected by the law and the profession. * Shall not knowingly be a party to any illegal activity, or engage in acts that are discreditable to the profession * Shall respect and contribute to the legitimate and ethical objectives of the organization.According to the 2009 Global Integrity Survey conducted by Compliance Week and Integrity Interactive, polled more than 150 ethics and compliance executives at global companies worldwide. The survey shown that nearly two-third (64 percent) of respondents use risk assessment specifically to review their integrity risks and to modify their programs as necessary. It also shown tha t 57 percent said their internal auditors have periodically audit their integrity programs and functions.Besides that, the survey shown that nearly 80 percent of respondents commented they use the internal audit function to some extent. Melissa Klein Aguilar (2009) further added that internal audit departments play an important role in ensuring the effectiveness of the company's integrity function. IIA do also issue a guidance says that internal auditors should â€Å"evaluate the design, implementation, and effectiveness of the organization's ethics-related objectives, programs, and activities. Confidentiality According to Institute of Internal Auditors (IIA), confidentiality is one of the four principles that internal auditors are expected to apply and uphold. IIA further explain that under confidentiality's principle, internal auditors respect the value and ownership of information they receive and do not disclose information without appropriate authority unless there is a legal or professional obligation to do so.IIA had also outlined the rules of conduct for confidentiality, in which internal auditors: * Shall be prudent in the use and protection of information acquired in the course of their duties. * Shall not use information for any personal gain or in any manner that would be contrary to the law or detrimental to the legitimate and ethical objectives of the organization. Office of Internal Audit of Wayne State University further elaborates the rules of conduct that internal auditors are expected to follow in compliance with confidentiality's principle.It stated that internal auditors shall: * Not participate in any activity or relationship that may impair or be presumed to impair their unbiased assessment. This participation includes those activities or relationships that may be in conflict with the interest of the organization. * Not accept anything that may impair or be presumed to impair their professional judgment. * Disclose all material facts kn own to them that, if not disclosed, may distort the reporting of activities under review. Be prudent in the use and protection of information acquired in the course of their duties. * Not use information for any personal gain or in any manner that would be contrary to the law or detrimental to the legitimate and ethical objectives of the organization. According to Chartered Institute of Internal Auditors, this principle is pertinent to internal auditors as they have access to a wide range of information and the employing organization needs to be assured that accessed information will be treated confidentially.Internal auditors also gather information through interviews, and interviewees need to feel assured that the information provided will be treated appropriately. Numerous corporate fraud cases happen in recent century such as Enron and WorldCom have triggered not only extensive academic whistleblowing studies, but also have caused legal ramifications that have led to the passage of Sarbanes-Oxley Act in 2002 (Eaton & Akers, 2007; Lacavo & Ripley, 2003). Before this, there are limited studies that have used internal auditors as subjects.This could be because to the argument that the reporting make by internal auditors on corporate wrongdoings is not an act of whistleblowing, but is the role on internal auditor within the ambit of their profession (Jubb, 2000). Xu and Ziegenfuss counter-argue that what Cynthia Cooper (an internal auditor) did in the WorldCom was considered as whistleblowing, this shown that public may perceive that the internal auditor as a whistleblower. Another possibility is because of misperception that whistleblowing only relates to reporting parties outside of the organization (Keenan & Krueger, 1992).According to Eaton & Akers, 2007; Figg, 2000; Keenan & Krueger, 1992; Near & Miceli, 2008, whistleblowing can in fact occur internally or externally. Near and Miceli (1995) argue that internal auditors have higher credibility and power as whistleblower than other organizational members as they are more likely to influence management to terminate wrongdoing. According to The Global Economic Crime Survey conducted by PricewaterhouseCooper (PricewaterhouseCoopers, 2009), internal auditing profession is indeed an important role in organizations as most frauds were detected by internal audit.It was supported by Miceli et al. (2008) states compared to other professions, the highest reported observation of wrongdoing was reported by internal auditors. Because of the nature of their works, internal auditors have directly or indirectly seen or confronted many opportunities for corporate wrongdoing and unethical acts to occurs, and the responsibility of disclosure of any wrongdoing is embedded in their job description (Near & Miceli, 1985). Another issue is on whether or not internal auditors should whistleblow when they discover organizational wrongdoings.Internal auditors always face situations that involve conflict of inte rest while executing their dual-role duties (Armold & Ponemon, 1991; E. Z. Taylor & Curtis, 2010). The dual-role duties mentioned here are the role of internal auditors as employed by the organization, which subject to the needs and requirements of their employment, and the role as members of a professional body, they are required to adhere to the profession's ethical requirements.Ahmad and Taylor support the view and assert that the role of internal auditors in providing auditing tasks for their organizational may cause ongoing conflicts. Zhang, Chiu and Wei (2009) argue that the â€Å"disclosing insider information to outsider's breaches obligation to the organization, violates the written or unspoken contract, and elicits damaging publicity†. However, ethically, internal whistleblowing, as opposed to external whistleblowing, is preferred.This is due to severe damage caused by external whistleblowing as compared to internal whistleblowing (Park & Blenkinsopp, 2009). In orde r to avoid the severe damages caused by whistleblowing, Vinten (1996) has suggested that an organization may minimize the risk by internalizing the whistleblowing procedure as part of the corporate communications. By having a proper whistleblowing procedure, organizations stand to benefit from actions of whistleblowers that may cause further substantial adverse consequences such as loss of sales, costly lawsuits and negative publicity.Professional Behaviour The general public demand professional accountants maintain a high ethical standard in order to maintain public confidence in the accountancy profession (Gordon Kiernander, 2009). The ethical principles that guide the work of auditors are listed as follows: * Integrity * Objectivity * Professional Competence and Due Care * Confidentiality * Professional Behavior (Farid Kerimov, 2011)Then, the professional behavior has been defined as high expectations for the auditing profession include compliance with laws and regulations and av oidance of any conduct that might bring discredit to auditors' work, including actions that would cause an objective third party with knowledge of the relevant information to conclude that the auditors' work was professionally deficient. Professional behavior includes auditors' putting forth an honest effort in performance of their duties and professional services in accordance with the relevant technical and professional standards (Government Auditing Standards, 2010).The main objective of an auditor is to purvey services at the highest standards of performance to satisfy public interest (Michael C. Knapp, 2009). However, frequently, users don’t have the needful ability to appreciate if the services offered by the auditor are or are not in accordance qualitatively with their requests, reason of which they are forced to accept till the contrary test that the auditors act in a competent and professional way.The guarantee of integrity and professional competency of an auditor c an be assured by the adhesion of them at an ethical code of the profession to which they belong (R. A. Kishore Nadkarni, 2000). If internal auditors or the internal audit activity is prohibited by law or regulation from conformance with certain parts of the Standards, conformance with all other parts of the Standards and appropriate disclosures are needed.Then, IIA’s International Standards for the Professional Practice of Internal Auditing (Standards) is essential in meeting the responsibilities of internal auditors and the internal audit activity (The Institute of Internal Auditors, 2010). According to IIA’s International Standards for the Professional Practice of Internal Auditing (Standards) Internal auditing is conducted in diverse legal and cultural environments; within organizations that vary in purpose, size, complexity, and structure; and by persons within or outside the organization.While differences may affect the practice of internal auditing in each enviro nment, conformance with The IIA’s International Standards for the Professional Practice of Internal Auditing (Standards) is essential in meeting the responsibilities of internal auditors and the internal audit activity (The Institute of Internal Auditors, 2010). Standards for the Professional Practice of Internal Auditing differentiate among the varied responsibilities of the entity, the internal audit department, the director of internal auditing, and internal auditors.The responsibilities as a consultant or internal auditor are listed as follows: I. Internal auditors should be independent of the activities they audit. II. Internal audits should be performed with proficiency and due professional care. III. The scope of internal auditing should encompass the examination and evaluation of the adequacy and effectiveness of the organization’s system of internal control and the quality of performance in carrying out assigned responsibilities. IV.Audit work should include p lanning the audit, examining and evaluating information, communication results, and follow up. V. The Director of Internal Auditing Should Properly Manage the Internal Audit Department. (IIA Standards, 2010) The Public Interest Disclosure Act 1998 (the Act) amended the Employment Rights Act 1996 and created a right to redress, enforceable by tribunal, in the event of unfair discrimination or dismissal by one’s employer as a result of â€Å"whistleblowing† – making a disclosure in the public interest.The Act sets conditions as to the subject matter of the disclosure, the motivation and beliefs of the worker, and the person(s) to whom the disclosure is made (Public Interest Disclosure Act 1998). According to Public Interest Disclosure Act 1998, the purposes of the act are: I. It aims to help prevent such disasters and corporate malpractice in general by encouraging workers with relevant information to come forward responsibly. II.The Act seeks to achieve this by o ffering a right to redress in the event of victimization if workers raise their concerns in the ways specified in the legislation. III. It is also hoped that the Act will promote a change in culture amongst employers, and encourage them to establish procedures to receive disclosures in good faith and act on them appropriately. The scope of the Act includes disclosures which, in the reasonable belief of the worker, show one or more of the following, taking place either in the past, the present, or likely to take place in the future: * A crime; Breach of a legal obligation (regulatory, administrative, contract law or common law); * Miscarriage of justice; (for which the appropriate prescribed person in England and Wales is the Chief Executive of the Criminal Cases Review Commission); * Danger to health and safety; (for which the appropriate prescribed person is the Health and Safety Executive, or the relevant local authority); * Damage to the environment; (for which the appropriate pr escribed person in England and Wales is the Environment Agency); or * Attempts to cover up such malpractice.Apart from that, whistleblowers making an external disclosure to a prescribed person, instead of to their employer or via internal procedures, will be entitled to redress under the Act in the event that they suffer unfair discrimination or dismissal provided they: * make the disclosure in good faith; * reasonably believe that the information, and any allegation it contains, are substantially true; and * reasonably believe that the matter falls within the description of matters for which the person is prescribed.

Mandinka Empire - 21578 Words

Bound to Africa: the Mandinka Legacy in the New World Schaffer, Matt. History in Africa, Volume 32, 2005, pp. 321-369 (Article) Published by African Studies Association DOI: 10.1353/hia.2005.0021 For additional information about this article http://muse.jhu.edu/journals/hia/summary/v032/32.1schaffer.html Access Provided by your local institution at 03/10/13 1:43PM GMT BOUND TO AFRICA: THE MANDINKA LEGACY IN THE NEW WORLD MATT SCHAFFER I I offer here a theory of â€Å"cultural convergence,† as a corollary to Darwin’s natural selection, regarding how slave Creoles and culture were formed among the Gullah and, by extension, supported by other examples, in the Americas. When numerous speakers from different, and sometimes†¦show more content†¦Curtin notes that slave-buying proclivities in the Charleston slave market, emphasizing Mande and including the Mandinka of Senegal and Gambia, might have caused other states such as Virginia to have a slight preference for Senegambian slaves as well. When Curtin’s Table 45 speculates that 13.3% of all slaves imported to North America were from Senegambia, 5.5% from Sierra Leone, and 11.4% were from the Windward Coast or Liberia, he emphasizes the regions of west Africa where large numbers of Mande still live today, including Mandingo, Mende, Malinke, Maninke, Mandinka, Susu, Bambara, Vai, and Dyula among others, distributed among non-M ande groups.3 How many Mande or Mandinka were really in these percentages? The linguistic map showing which ethnic groups in west Africa speak Mande-related languages is immense, with many groups on the coasts or relatively near slave ports.4 Of course the vast area of eastern Mali—the heartland—contains Mande-speakers. But from here the influence spread out all along the 2 3 4 Curtin, 1969:156-57. His numerous sources include the work of Elizabeth Donnan. Ibid. Vydrine/Bergman 2001. The Mandinka Legacy in The New World 323 Gambia River, the Pakao region of southern Senegal, northern Guinea-Bissau, major regions of Guinea and Sierra Leone, significant territory in Liberia, Ivory Coast, Burkina Faso, and even a border area of northwestern Nigeria. The seeming fragmentation of the Mande among so manyShow MoreRelatedSamore Toure Mandinka Empire3953 Words   |  16 Pagesbegan to amass a personal following in the mid-1850s, establishing a military base on the Upper Niger. By 1870 his authority was acknowledged throughout the Kanaka region of the River Milo, in what is now eastern Guinea. By 1880 he ruled a vast Dyula empire, from the Upper Volta in the east to the Fouta Djallon in the west, over which he attempted to create a single Islamic administrative system. 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