Transition Metal Doped Phosphorene: First-Principles Study

Hashmi, Arqum,Hong, Jisang American Chemical Society 2015 The Journal of Physical Chemistry Part C Vol.119 No.17

<P>Recently, a newly fabricated two-dimensional layer structured material so-called phosphorene is receiving great research interests due to its peculiar physical properties. So far, mostly electrical properties are explored because it has a direct band gap and its nonmagnetic behavior in pristine layer. In this report, we propose that the transition metal doped phosphorene layer can have dilute magnetic semiconductor properties. Here, we investigated the structural property, binding energy, and magnetic property by changing the TM impurity dopants in the substitutional site. Our results demonstrate that spin polarized semiconducting state is realized in phosphorene by substitutional doping of Ti, Cr, and Mn, while a half-metallic state is obtained by V and Fe doping. In particular, we suggest that the most promising dopants are Cr and Mn because the spin polarized state is achieved with a band gap larger than 0.5 eV. The magnetic interaction between two same types of TM atoms is also checked. Magnetic ground state was obtained with GGA and GGA+U approaches are quite consistent, except for Mn- and Fe-doped systems. These findings indicate that the TM-doped phosphorene can be used as a potential next-generation spintronics material.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2015/jpccck.2015.119.issue-17/jp511574n/production/images/medium/jp-2014-11574n_0007.gif'></P>

Ideal structure for tunneling magnetoresistance and spin injection into semiconductros: Ni(111)/BN/Co(111)

Hashmi Arqum,Jicheol Son,Jisang Hong 한국자기학회 2013 한국자기학회 학술연구발표회 논문개요집 Vol.2013 No.12

Half metallic g-C₄N₃ on BN layer

Hashmi Arqum,Jicheol Son,Jisang Hong 한국자기학회 2014 한국자기학회 학술연구발표회 논문개요집 Vol.2014 No.5

Distribution of Ki67 Proliferative Indices among WHO Subtypes of Non-Hodgkin's Lymphoma: Association with other Clinical Parameters

Hashmi, Atif Ali,Hussain, Zubaida Fida,Faridi, Naveen,Khurshid, Amna Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.20

Background: Non-hodgkin lymphoma (NHL) is a diverse group of disease encompassing divergent tumor types with contrasting clinical behaviors. We aimed to evaluate the usefulness of Ki67 index in segregating indolent from aggressive NHL and its association with clinical parameters. Materials and Methods: During a study period of 4.5 years, a total of 215 cases of lymphomas were diagnosed among of which 172 cases were NHL. Ki67 immunohistochemical staining was performed by the DAKO envision method. Average proportion of tumor cells stained was calculated to determine the proliferative index. Results: The mean age at diagnosis was 46.2 years +19.8 (3-81) with a male to female ratio of 1.5:1. Mean Ki67 index for indolent NHL included 23% for small cell, 25% for mantle cell, 28.5% for marginal zone and 34.6% for follicular lymphoma. On the other hand, mean Ki67 index for aggressive lymphomas were 66.4%, 66.9%, 80.3%, 83.3% and 94.4% for diffuse large B cell, T cell (NOS), anaplastic large cell, lymphoblastic and burkitts lymphoma respectively. No significant correlation was found between Ki67 index and other clinical parameters like age and extra nodal involvement. Conclusions: Ki67 index is a valuable IHC marker to distinguish indolent from aggressive lymphomas especially in small needle biopsies where exact typing may not be possible.

Accuracy of Frozen Section Analysis of Sentinel Lymph Nodes for the Detection of Asian Breast Cancer Micrometastasis - Experience from Pakistan

Hashmi, Atif Ali,Faridi, Naveen,Khurshid, Amna,Naqvi, Hanna,Malik, Babar,Malik, Faisal Riaz,Fida, Zubaida,Mujtuba, Shafaq Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.4

Background: Intraoperative sentinel lymph node biopsy has now become the standard of care for patients with clinically node negative breast cancer for diagnosis and also in order to determine the need for immediate axillary clearance. Several large scale studies confirmed the diagnostic reliability of this method. However, micrometastases are frequently missed on frozen sections. Recent studies showed that both disease free interval and overall survival are significantly affected by the presence of micrometastatic disease. The aim of this study was to determine the sensitivity and specificity of intraoperative frozen section analysis of sentinel lymph nodes (SLNs) for the detection of breast cancer micrometastasis and to evaluate the status of non-sentinel lymph nodes (non-SLNs) in those patients subjected to further axillary sampling. Materials and Methods: We performed a retrospective study on 154 patients who underwent SLN biopsy from January 2008 till October 2011. The SLNs were sectioned at 2 mm intervals and submitted entirely for frozen sections. Three levels of each section submitted are examined and the results were compared with further levels on paraffin sections. Results: Overall 40% of patients (62/154) were found to be SLN positive on final (paraffin section) histology, out of which 44 demonstrated macrometastases (>2mm) and 18 micrometastases (<2mm). The overall sensitivity and specificity of frozen section analysis of SLN for the detection of macrometastasis was found to be 100% while those for micrometastasis were 33.3% and 100%, respectively. Moreover 20% of patients who had micrometastases in SLN had positive non-SLNs on final histology. Conclusions: Frozen section analysis of SLNs lacks sufficient accuracy to rule out micrometastasis by current protocols. Therefore these need to be revised in order to pick up micrometastasis which appears to have clinical significance. We suggest that this can be achieved by examining more step sections of blocks.

Clinicopathologic Patterns of Adult Renal Tumors in Pakistan

Hashmi, Atif Ali,Ali, Rabia,Hussain, Zubaida Fida,Faridi, Naveen Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.5

Background: Renal cancer is a serious public health problem which may be under reported and registered in our setup, since the Karachi cancer registry documented only 43 cases out of 4,268 incident cancer cases over 3 year duration. Therefore we aimed to determine the clinicopathologic characteristics of adult renal tumors in our setup. Materials and Methods: The study was conducted in histopathology department, Liaquat National Hospital and included total of 68 cases of adult renal tumors over 4 years. Detailed histopathologic characteristics of tumors were analyzed. Results: Mean age of patients was 56.4 (18-84) years. Renal cell carcinoma (RCC) was the most common cell type (78%) cases; followed by transitional/urothelial carcinoma (12.5%), leiomyosarcoma (4.7%), oncocytoma (1.6%), squamous cell carcinoma (1.6%) and high grade pleomorphic undifferentiated sarcoma (1.6%). Among 50 RCC cases; 62% were conventional/clear cell RCC (CCRCC) type followed by papillary RCC(PRCC), 24%; chromophobe RCC(CRCC), 6% and sarcomatoid RCC(SRCC), 8%. Mean tumor size for RCC was 7.2 cm. Most RCCs were intermediate to high grade (60% and 40% respectively). Capsular invasion, renal sinus invasion, adrenal gland involvement and renal vein invasion was seen in 40%, 18%, 2% and 10% of cases respectively. Conclusions: We found that RCC presents at an earlier age in our setup compared to Western populations. Tumor size was significantly larger and most of the tumors were of intermediate to high grade. This reflects late presentation of patients after disease progression which necessitates effective measures to be taken in primary care setup to diagnose this disease at an early stage.

Spin-Dependent Transport and Optical Properties of Transparent Half-Metallic g-C₄N₃ Films

Hashmi, Arqum,Farooq, M. Umar,Hu, Tao,Hong, Jisang American Chemical Society 2015 The Journal of Physical Chemistry Part C Vol.119 No.4

<P>Half-metallic materials play an essential role in the spin-dependent transport study, and so far it is believed that the 3d transitional metal elements are necessary to obtain a ferromagnetic state. Herein, we demonstrate that the metal free two-dimensional graphitic carbon nitride (g-C<SUB>4</SUB>N<SUB>3</SUB>) film show half metallic state and this is independent of the film thickness and stacking order. We find that the half-metallicity results in a very large magnetoresistance even at finite bias. Moreover, we have also investigated various optical properties. The g-C<SUB>4</SUB>N<SUB>3</SUB> thin films have a very high refractive index for parallel polarization and extremely weak reflectivity for perpendicular polarization. Additionally, the g-C<SUB>4</SUB>N<SUB>3</SUB> thin films are optically transparent because of very weak absorption coefficients. Overall, our findings suggest that the transparent half-metallic g-C<SUB>4</SUB>N<SUB>3</SUB> thin films can be used for both spintronics and optical applications because of potential multifunctionality.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2015/jpccck.2015.119.issue-4/jp510179p/production/images/medium/jp-2014-10179p_0007.gif'></P>

Band gap and effective mass of multilayer BN/graphene/BN: van der Waals density functional approach

Hashmi, Arqum,Hong, Jisang American Institute of Physics 2014 Journal of Applied Physics Vol.115 No.19

Using the van der Waals density functional theory method (DFT-D2), we have investigated thickness dependent energy band gaps and effective masses of multilayer BN/graphene/BN structures by changing the stacking order. The band gap is substantially dependent on the stacking order. For instance, the calculated band gap in ABA stacking is about 150 meV, whereas it becomes 31 meV in ABC stacking. No significant thickness dependent band gap is observed in both ABA and ABC stackings although the band gap is gradually increasing with the BN thickness in ABA stacking. In addition, the effective mass is found to be strongly dependent on the stacking order. The effective mass in ABA stacking is much larger than that found in ABC stacking. On the other hand, the effective mass along K-M direction is smaller than that along K-Gamma direction in ABA stacking. However, it is independent on the band direction in ABC stacking. We have found that the inclusion of van der Waals interaction alters thickness dependent band gap and effective mass of BN/graphene/BN multilayer systems compared with those found with standard density functional theory. (C) 2014 AIP Publishing LLC.

Supramolecular Interaction Controlled Diffusion Mechanism and Improved Mechanical Behavior of Hybrid Hydrogel Systems of Zwitterions and CNT

Hashmi, Saud,GhavamiNejad, Amin,Obiweluozor, Francis O.,Vatankhah-Varnoosfaderani, Mohammad,Stadler, Florian J. American Chemical Society 2012 Macromolecules Vol.45 No.24

<P>Hybrid hydrogels of poly(<I>N</I>-isopropylacrylamide) (pNIPAM) containing carboxylate carbon nanotubes (CNTs) and/or zwitterions are synthesized by free radical polymerization. The supramolecular interactions among zwitterionic monomers and CNTs influence the mechanical properties and diffusion mechanism in hybrid hydrogel systems. These supramolecular interactions and response behavior of hybrid hydrogels were tested mechanically and with respect to their swelling characteristics. Hybrid hydrogels of pNIPAM and CNT or pNIPAM, zwitterions, and CNT follow a Fickian diffusion behavior, while adding zwitterions leads to an anomalous triple-stage swelling behavior and stiffening of the gel due to the interactions of the zwitterions with each other, which significantly increase the viscous dissipation and change the microscopic structure. While CNT itself stiffens the gel and slightly increases the diffusion speed, it complexes zwitterions, which leads to a novel property profile that is both potentially antibiotic and electrically conductive. CNT affords a relaxation process at long relaxation times, while zwitterion attachment and detachment lead to dissipation predominantly at high frequencies. Dynamic rheological measurements were performed during swelling of these complex materials.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2012/mamobx.2012.45.issue-24/ma301366h/production/images/medium/ma-2012-01366h_0014.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ma301366h'>ACS Electronic Supporting Info</A></P>

Establishing National Science and Technology Park in Pakistan

Hashmi, Amer,Shah, Ali World Technopolis Association 2013 World Technopolis Review Vol.1 No.4

This paper presents the concept of the National Science and Technology Park (NSTP) in Islamabad, Pakistan. Keeping in line with Karl Popper's Piecemeal Social Engineering theory, a critical-pragmatic approach is adopted in shedding light on the strategic thrusts and expected outcomes of this knowledge-driven, entrepreneurially-spirited, multi-industry project. Based on Triple-Helix perspectives, we investigate the role of the National University of Sciences and Technology, Islamabad in efforts aimed at developing NSTP as an intermediary hybrid organization that enhances industry-academia-government linkages, with the potential to serve as an engine for regional and national economic growth and competitiveness.