Development of a Novel Sequential Injection-Proton NMR Method for Determining Cathinones in Forensic Samples

A novel method was developed for the determination of low levels of Cathinones in authentic samples by interfacing Sequential Injection Analysis (SIA) to Proton Nuclear Magnetic Resonance Spectroscopy (NMR). In the first part of this study, solid phase extraction (SPE) was studied by SIA to preconcentrate the sample and remove matrix interferences. Phenylpropanolamine (PPA), Phenylephrine (PEP), and Methylephedrine (MEP) were studied as simulants for the Cathinones, representing primary, secondary, and tertiary amines, respectively. A variety of stationary, mobile, and eluent phases for several column geometries were examined, and a wide cylindrical column (20 mm6.6 mm) with a bed volume of 2.7 mL with a strong cation exchange (SCX) resin was selected for further study. The method was applied to authentic samples at the Wisconsin State Crime Lab (WSCL) in Milwaukee. A range of samples were analyzed that differed in the Cathinones (Methcathinone, Methylone, and N-Ethylpentylone) and interferences (Mannitol and Caffeine) that were present. Measurements were done by SIA-NMR as well as directly by NMR. When SIA-NMR was performed, the interferences were efficiently removed. However, tertiary amines were found to be more difficult to quantitatively elute than primary and secondary amines. For the second part of the study, the SPE-SIA method was optimized by application of Plackett-Burman (P-B) screening (11 factor design) and Simplex optimization (7 factor design) methods. The optimized SPE-SIA method had the following conditions: 800 mL sample volume, 21 mL/s sample aspiration flowrate, 18 mL/s carrier load flowrate, 25 mL/s elution flowrate, 100 mM phosphate buffer (pH 6.00) mobile phase, 215 mM NaCl / 60 mM HCl eluent, and 1565 mL eluent volume. For the optimized method, the Limit of Detection was 0.023 mM (70% improvement) and the precision, measured for 0.25 mM PPA (n=3), was 0.10% (93% improvement). In the final part of the study, the optimized SIA-NMR method was applied to a new set of confiscated samples provided by the WSCL in which ( N-Ethylpentylone and N-Ethylhexedrone) were present. The optimized method was effective in the determination of low levels of Cathinones in the confiscated samples for all three types of amines. Predicted proton spectra of the Cathinones were then created using the MNova software program and compared to the observed spectra. The number of peaks in the observed and predicted spectra generally agreed, but differences in the chemical shifts and multiplicities of the protons were observed

Enhancing Usability of the Multi-channel Analysis of Surface Wave (MASW) Technique for Subsurface Physical Property Mapping by Incorporating Random-Array Seismic Acquisition

Subsurface imaging is very critical to exploit subsurface resources, monitor the fluid movement in the reservoir, mapping tunnels etc. As science advances scientists and other researchers are constantly trying to develop new techniques and methods for subsurface imaging that are more effective, efficient, and are more robust under varying field conditions. The main focus of this research is one such effort to improve and increase the usability of the Multi-channel Analysis of Surface Wave method (MASW) method in determining regolith and rock properties by introducing a new type of receiver arrangement to extend its usage in places that are inaccessible for example, near embankments, military places, clandestine burials, etc. Advances in near-surface geophysical techniques, such as multi-channel analysis of surface waves (MASW), have greatly increased our ability to map subsurface variations in physical properties here on Earth. The MASW method involves deployment of multiple seismometers to acquire 1-D or 2-D shear wave velocity profiles that can be directly related to various engineering properties. The purpose of the research presented here is to demonstrate the usefulness and capabilities of MASW technique using a random receiver array 1) through controlled site experiments, 2) through Modeling experiments, and 3) And finally apply the technique at terrestrial site (the Black Point Lava Flow) with a different geologic setting. The results focus on near-surface MASW studies and interpretation of the subsurface geology using a random geophone array. The field techniques and methodologies discussed in this dissertation, although applicable on Earth, are also intended for surfaces and regolith in the future exploration of planetary bodies for possible human habitation. This would include Mars, its Moon-Phobus/Deimos, Near-Earth Asteroids (NEA’s), even Earth’s Moon. With each situation, the nature of the regolith and its formational processes will place certain restrictions and limitations upon the applications. This is expected with any change of terrains even on the Earth, let alone between planetary bodies

Employability Skill Evaluation Among Vocational Education Students in India

The changing nature of work and employment is providing individuals for more flexible multi-skilling and learning opportunities. Imparting skill-based industry-oriented teaching can bridge the skill gaps and enhance employment opportunities for students. In this context, Government of India has introduced numerous programs to provide a fillip to technical vocational education and training.  The current paper is aimed at understanding the role of vocational education and the change it brings to skill development and employability of the students.  A combination of both qualitative and quantitative research methods was deployed for the study.  In the quantitative design a multi-stage sampling process comprising of both probabilistic and non-probabilistic methods was employed.  A sample of 586 students pursuing retail vocational education was identified and administered with the questionnaire.  The statistical analysis presented the socio-economic profiles.  Further, five factors for skill development and one factor for employability skill were identified through exploratory factor analysis.  The factors identified for skill development include Initiative and Enterprise Skills (IES), Workplace Skills (WS), Professional Practice and Standards (PPS), Inter Personal Skills (IPS) and Integration Theory and Practice (ITP).  Confirmatory and regression models involving all the factors were tested and their significance was analyzed.  The study revealed that there is a positive impact of skill development on employability.  It is suggested that focus on imparting vocational education for skill development can be a panacea for increased employability. &nbsp

Calculation of tunneling current across Trapezoidal potential barrier in a Scanning Tunneling Microscope

The Planar Model of the Electrode-Vacuum-Electrode configuration for STM in which electrode surfaces are assumed to be infinite parallel planes, with atomic size separation and vacuum between them, is used to calculate tunneling current densities for both low and high bias voltages. Non WKB, Airy function solutions for the Schr\"odinger Equation for the trapezoidal barrier in the tunneling region are used to calculate the tunneling probability. Pauli blocking effects are found to cancel in the calculation of the net (Forward-Reverse) current density. Temperature dependent Fermi Factors for each electrode are introduced and the calculation involves integration over the electron energies. Thus the energy of the tunneling electrons is not limited to the Fermi energy in this calculation. In order to convert the current densities obtained in the planar model to tunneling currents the tip and sample surfaces cannot be treated as infinite plane surfaces. Instead the tip and the sample surfaces are modelled as confocal hyperboloids, and the tip sample distance is replaced by the length of the line of force (field line). The current is found by integrating the current density over a finite area of the tip. The calculated tunnel currents for a few electrode pairs at room temperature are plotted for several values of bias voltage and tip sample distances. The effect of the curvature of the tip is also studied by repeating the calculations for various tip radii. The dependence of tunneling current on electrode temperatures is also studied. Some estimate of lateral resolution and its dependence on bias voltage and tip radius is also presented.Comment: 14 pages,19 figure

IMPLEMENTING PRACTICAL SKILLS IN A DISTANCE LEARNING OF AGRIBUSINESS STUDY PROGRAM AT UNIVERSITAS TERBUKA

Program Studi Agribisnis di Universitas Terbuka, dibentuk dengan tujuan untuk menghasilkan lulusan yang kompeten di bidang penyuluhan dan komunikasi agribisnis. Salah satu cara untuk mencapai tujuan ini adalah menyusun sebuah kurikulum yang mendorong terbentuknya hard skill dan soft skill lulusan yang relevan dengan tuntutan kompetensi program studi. Hard skill yang akan dimiliki lulusan merupakan aplikasi materi, metode serta evaluasi penyuluhan berbasis agribisnis yang nantinya akan diterapkan di lapangan, yang ditujukan untuk meningkatkan keterampilan sasarannya. Sementara softskill yang perlu dikuasai lulusan meliputi kemampuan-kamampuan berkomunikasi, bekerjasama dalam tim, kepemimpinan, dan kemampuan pemecahan masalah. Program Studi Agribisnis mengakomodasi pencapaian kompetensi tersebut dengan memasukkan beberapa mata kuliah berpraktikum di dalam kurikulumnya. Hal-hal yang dikaji dalam tulisan ini meliputi perbandingan pengelolaan penyelenggaraan praktikum antara program Penyuluhan Pertanian dan Agribisnis, termasuk kekuatan dan kelemahan masing-masing, berbagai kendala yang terjadi, serta peluang-peluang yang dapat diambil untuk memperbaiki penyelenggaraan praktikum. Hasil kajian menunjukkan bahwa pengelolaan penyelenggaraan praktikum PS Agribisnis pada prinsipnya masih mengadopsi dari pengelolaan penyelenggaraan praktikum yang digunakan Program Studi D3 Penyuluhan Pertanian, dengan keterbatasan-keterbatasan yang ada. Satu hal yang perlu diupayakan ke depannya adalah terbentuknya panduan praktikum yang jelas, serta pembinaan kerja sama dengan instansi lain guna meningkatkan kualitas penyelenggaraan praktikum.   The Agribusiness Study Program at Universitas Terbuka, the Indonesian Open University, was created with the goal of producing graduates who are competent in the field of extension and communication of agribusiness. One way to achieve this goal is to create a curriculum that develops competencies in both hard and soft skills that are relevant to the professional demands of graduates. Hard skills to be acquired include the application of methods and skills of agricultural extension that will be applied in the field. Soft skills include competencies such as the ability to communicate, work in teams, leadership, and problem-solving. The Agribusiness Study program allows graduates to acquire key competencies by incorporating some practical courses in its curriculum. This presentation will describe the comparison of practical implementation of the Management between an Agricultural Extension Study Program and the Agribusiness Study Program. The topics discussed in this presentation will address the implementation of practical management skills in the Agricultural Extension and Agribusiness Study Programs, including strengths and weaknesses, various obstacles, and how the obstacles were overcome. The result of study shows that the managing of the practical implementation of PS Agribusiness basicly can be done independently as long as the equipments can be provided as the need in field

PERSEPSI MAHASISWA TENTANG PENYELENGGARAAN PRAKTIKUM PADA PENDIDIKAN TINGGI TERBUKA JARAK JAUH (KASUS: PROGRAM STUDI AGRIBISNIS FMIPA UNIVERSITAS TERBUKA)

Agribusiness Study Program at Faculty of Mathematic and Natural Sciences, Univeritas Terbuka, has several practical courses. Practical work is mandatory and must be followed by every student. Formative evaluation of the implementation of practical work conducted in order to identify the characteristics of students participated in the practical work and to obtain some input and feedback from students about the quality of the implemetation of practical work that has ever done. This article describes the results of such of formative evaluation, especially in term of the students' perceptions of the quality of practical manual, the quality of the practical work implementation in the field, as well as the obstacles faced. Eighty students from the entire 402 Agribusiness Study Program students who took the practical course at semester 2011.2 or 2012.1, from UPBJJ-UT Serang (Java) and UPBJJ-UT Pontianak (outside Java) were selected purposively. Only 53 out of 80 students who are willing to become informants of this evaluation .Evaluation results show that the characteristics of the students participating in practical work generally younger age, more women, residing far from UPBJJ-UT, has been working and educated at the high school. Most of students (over 80%) perceived the quality of practical guide as complete and clear in accordance with course competencies. This high quality of practical guide demonstrated by compliance of practical substances with the substance of learning materials (86.79%); completeness of practical guide component (84.90%), clarity of information in the practical guide (75.85%), and compliance of the substance of the practical guide with course substance, objectives and practical procedures (71.70%). Most of students too (81.76% ) perceived the implementation of practical work as very good and unhindered . The students felt that the implementation of practical work run well because it is supported by the meaningfulness of practical guide (86.79%), adequacy and affordability of practical work location (91.15%), ease of practical work procedures (92.45%), availability of equipment and practical materials ( 92.45%), ease of documentation of practical activities (94.34%), the availability and suitability of the educational background of the practical work instructors (94.34%), as well as good skills of the instructors in managing practical work (90.10%). While the lack of good quality of practical observation instruments and non standardized practical work financing is considered by students as factors that hinder the practical feasibility.   Program Studi Agribisnis FMIPA-Universitas Terbuka memiliki beberapa mata kuliah berpraktikum. Praktikum bersifat wajib dan harus diikuti oleh setiap mahasiswa. Evaluasi formatif terhadap penyelenggaraan praktikum dilaksanakan dengan maksud mengidentifikasi karakteristik mahasiwa peserta praktikum dan mendapatkan masukan serta umpan balik dari mahasiswa tentang praktikum yang pernah dilakukannya. Artikel ini menjelaskan hasil evaluasi formatif terhadap penyelengaraan praktikum tersebut, terutama persepsi mahasiswa terhadap kualitas panduan praktikum, kualitas keterlaksanan praktikum di lapangan, serta hambatan yang dihadapi. Delapan puluh orang mahasiswa dari keseluruhan 402 orang mahasiswa PS Agribisnis yang menempuh praktikum pada semester 2011.2 atau 2012.1 di UPBJJ-UT Serang (Jawa) dan UPBJJ-UT Pontianak (Luar Jawa) dipilih secara purposive dan hanya 53 orang mahasiswa yang bersedia menjadi informan evaluasi ini. Hasil evaluasi menunjukkan bahwa karakteristik mahasiswa peserta praktikum umumnya berumur muda, lebih banyak perempuan, bertempat tinggal jauh dari UPBJJ-UT, sudah bekerja dan berpendidikan setingkat SMA. Kualitas panduan praktikum dipersepsikan lengkap, jelas, dan sesuai dengan kompetensi mata kuliah oleh sebagian besar mahasiswa (lebih dari 80%). Baiknya kualitas panduan praktikum tersebut ditunjukkan oleh keseuaian substansi materi praktikum dengan materi BMP (86,79%); kelengkapan komponen panduan praktikum (84,90%), kejelasan informasi dalam panduan praktikum (75,85%); dan kesesuaian substansi panduan praktikum dengan substansi MK, tujuan dan langkah-langkah praktikum (71,70%). Kualitas pelaksanaan praktikum dipersepsikan sangat baik dan tanpa hambatan oleh 81,76% mahasiswa. Keterlaksanaan praktikum berjalan dengan sangat baik karena ditunjang oleh kebermaknaan panduan praktikum (86,79%), kememadaian dan keterjangkauan tempat praktikum (91,15%), kemudahan langkah-langkah pelaksanaan praktikum (92,45%), ketersediaan alat dan bahan praktikum (92,45%), kemudahan pendokumentasian kegiatan praktikum (94,34%), ketersediaan dan kesesuaian latar belakang pendidikan instruktur (94,34%), serta baiknya keterampilan instruktur dalam mengelola praktikum (90,10%). Sementara kurang baiknya kualitas instrumen pengamatan praktikum dan tidak bakunya pembiayaan praktikum dianggap oleh mahasiswa sebagai faktor yang menghambat keterlaksanaan praktikum