Ashfaq Khan | University College London (original) (raw)

Papers by Ashfaq Khan

International Journal of Gynecology & Obstetrics, 2009

Aim: This study is conducted to assess the effects of mothers' education through volunteer women ... more Aim: This study is conducted to assess the effects of mothers' education through volunteer women (Rabbet) on their adolescent girls'knowledge and attitude about adolescence health in Mashad, Iran, in 2005-6. Methods: In this study 100 Rabets randomly assigned to the intervention and control groups. Intervention group participated in a workshop on adolescents' physical and mental health. The content of program include anatomy and physiology of reproductive tract, physiology of puberty, nutrition, physical exercises, menstruation, adolescents' mental health, communicating with adolescent girls and educating them and religious rules about the puberty. Rabets transform the educations to the mothers and wanted them to learn them to their adolescent daughters. Knowledge and attitude of rabbets, mothers and girls were evaluated before and 4 weeks after the education and compared to the control group. Results: After conducting the program of education, the knowledge and attitude of the rabbets significantly increased compared to the control group (p = 0.01, p = 0.01). Before the study the knowledge of mothers and girls was low and after the educational program the knowledge and attitude of the mothers (p = 0.001, p = 0.03) and the adolescent girls (p = 0.002, p = 0.03) were significantly improved. Conclusion: Performing perfect communication and necessary knowledge transformation, the mothers can play an effective role in their adolescent daughters' health. Training volunteer women is an effective way of educating the mothers who have adolescent girls.

Oncogene, 2010

The cellular transcription factor Brn-3a differentially regulates different human papilloma virus... more The cellular transcription factor Brn-3a differentially regulates different human papilloma virus (HPV)-16 variants that are associated with different risks of progression to cervical carcinoma in infected humans. The upstream regulatory regions (URRs) of high-and intermediate-risk HPV-16 variants are activated by the cellular transcription factor Brn-3a, whereas the URR of a low-risk HPV-16 variant is not. In this study, we show in transfection assays that Brn-3a and the smoking-related substance nicotine produce stronger responsiveness of the URR of the low-and high-risk variants than with either factor alone, but not the intermediate-risk variant. We determined that this synergistic activity of Brn-3a/ nicotine is due to two nucleotide differences in the URR, crucial for oncogenic E6/E7 transactivation. Mutant constructs in which the nucleotide residues were substituted alter Brn-3a/nicotine responsiveness. Importantly, women smokers with high levels of Brn-3a infected with low-or high-risk HPV-16 variants have augmented E6 levels, and were more frequently diagnosed with higher grades of cervical intraepithelial neoplasia (CIN) and cancer, as compared with non-smokers who were infected with similar variants and expressed similar levels of Brn-3a. Therefore, this study defines the specific interplay between the cellular transactivator Brn-3a, the environmental smoking-related substance nicotine and specific HPV variants in cervical carcinogenesis, and thus helps to explain why some women are susceptible to rapid CIN progression and cancer and others are not.

Obstetrics and Gynecology International, 2009

The cellular transactivator Brn-3a has previously been shown to be expressed at elevated levels i... more The cellular transactivator Brn-3a has previously been shown to be expressed at elevated levels in the cervix of women with squamous cell carcinoma of the cervix (SCC) and to activate the expression of HPV E6 mRNA. In this study, we show that common and rare cervical precancer lesions, including those of adenocarcinoma (AC), which are usually difficult to diagnose using classical procedures, also expressed high levels of Brn-3a and can be diagnosed by measuring the levels of Brn-3a and E6 mRNAs.

Nature Communications, 2011

The imaging resolution of a conventional optical microscope is limited by diffraction to ~ 200 nm... more The imaging resolution of a conventional optical microscope is limited by diffraction to ~ 200 nm in the visible spectrum. Efforts to overcome such limits have stimulated the development of optical nanoscopes using metamaterial superlenses, nanoscale solid immersion lenses and molecular fl uorescence microscopy. These techniques either require an illuminating laser beam to resolve to 70 nm in the visible spectrum or have limited imaging resolution above 100 nm for a white-light source. Here we report a new 50-nm-resolution nanoscope that uses optically transparent microspheres (for example, SiO 2 , with 2 μ m < diameter < 9 μ m) as far-fi eld superlenses (FSL) to overcome the white-light diffraction limit. The microsphere nanoscope operates in both transmission and refl ection modes, and generates magnifi ed virtual images with a magnifi cation up to × 8. It may provide new opportunities to image viruses and biomolecules in real time.

Journal of Physics D-applied Physics, 2010

Although laser surface nanopatterning by particle-lens arrays, utilizing near field enhancement, ... more Although laser surface nanopatterning by particle-lens arrays, utilizing near field enhancement, has been extensively utilized previously, a suitable technique for the deposition of Particle Lens Arrays (PLA) on curved surface of cylinder was not available. In this paper, a novel technique for nano-patterning on curved surfaces using particle-lens arrays is demonstrated. In the proposed technique, a hexagonal closed pack monolayer of SiO 2 spheres is first formed by self assembly on a flat glass surface. The formed monolayer of particles is then picked up by a flexible optically transparent sticky surface and placed on the substrate to be patterned. A 532 nm wavelength Nd:YVO 4 laser was used to irradiate the substrate with the laser passing through the flexible, transparent surface and the particles. Experimental investigations are made to ascertain the properties of the patterns. In addition, the optical near-field distribution around the particles is numerically simulated. The proposed technique is validated for nanopatterning of curved surface of a cylinder.

Applied Surface Science, 2011

Direct laser surface micro/nanopatterning by using Contact Particle Lens Array (CPLA) has been wi... more Direct laser surface micro/nanopatterning by using Contact Particle Lens Array (CPLA) has been widely utilized. The method involves laser scanning of a monolayer of transparent particles arranged on the substrate to be patterned. Despite the different techniques available for CPLA deposition; the particles monolayer can only be formed on hydrophilic surfaces, which restrict the range of substrates that could be patterned by this method. In this study, a technique for patterning of hydrophobic surfaces by using CPLA has been proposed. In the proposed technique, monolayer of CPLA is formed on a hydrophilic substrate and then transported to a hydrophobic substrate by using a flexible sticky plastic. The transported CPLA is then scanned by a laser for patterning the hydrophobic substrate. The plastic pre-selected for this work was transparent to the laser. Experimental investigations were carried out to generate bumps and bowl shaped patterns using transported particles. Features smaller than the diffraction limit have been generated. The optical near field and associated temperatures around the particles were numerically simulated with a coupled electromagnetic and thermal modelling technique.

International Journal of Gynecology & Obstetrics, 2009

Aim: This study is conducted to assess the effects of mothers' education through volunteer women ... more Aim: This study is conducted to assess the effects of mothers' education through volunteer women (Rabbet) on their adolescent girls'knowledge and attitude about adolescence health in Mashad, Iran, in 2005-6. Methods: In this study 100 Rabets randomly assigned to the intervention and control groups. Intervention group participated in a workshop on adolescents' physical and mental health. The content of program include anatomy and physiology of reproductive tract, physiology of puberty, nutrition, physical exercises, menstruation, adolescents' mental health, communicating with adolescent girls and educating them and religious rules about the puberty. Rabets transform the educations to the mothers and wanted them to learn them to their adolescent daughters. Knowledge and attitude of rabbets, mothers and girls were evaluated before and 4 weeks after the education and compared to the control group. Results: After conducting the program of education, the knowledge and attitude of the rabbets significantly increased compared to the control group (p = 0.01, p = 0.01). Before the study the knowledge of mothers and girls was low and after the educational program the knowledge and attitude of the mothers (p = 0.001, p = 0.03) and the adolescent girls (p = 0.002, p = 0.03) were significantly improved. Conclusion: Performing perfect communication and necessary knowledge transformation, the mothers can play an effective role in their adolescent daughters' health. Training volunteer women is an effective way of educating the mothers who have adolescent girls.

Oncogene, 2010

The cellular transcription factor Brn-3a differentially regulates different human papilloma virus... more The cellular transcription factor Brn-3a differentially regulates different human papilloma virus (HPV)-16 variants that are associated with different risks of progression to cervical carcinoma in infected humans. The upstream regulatory regions (URRs) of high-and intermediate-risk HPV-16 variants are activated by the cellular transcription factor Brn-3a, whereas the URR of a low-risk HPV-16 variant is not. In this study, we show in transfection assays that Brn-3a and the smoking-related substance nicotine produce stronger responsiveness of the URR of the low-and high-risk variants than with either factor alone, but not the intermediate-risk variant. We determined that this synergistic activity of Brn-3a/ nicotine is due to two nucleotide differences in the URR, crucial for oncogenic E6/E7 transactivation. Mutant constructs in which the nucleotide residues were substituted alter Brn-3a/nicotine responsiveness. Importantly, women smokers with high levels of Brn-3a infected with low-or high-risk HPV-16 variants have augmented E6 levels, and were more frequently diagnosed with higher grades of cervical intraepithelial neoplasia (CIN) and cancer, as compared with non-smokers who were infected with similar variants and expressed similar levels of Brn-3a. Therefore, this study defines the specific interplay between the cellular transactivator Brn-3a, the environmental smoking-related substance nicotine and specific HPV variants in cervical carcinogenesis, and thus helps to explain why some women are susceptible to rapid CIN progression and cancer and others are not.

Obstetrics and Gynecology International, 2009

The cellular transactivator Brn-3a has previously been shown to be expressed at elevated levels i... more The cellular transactivator Brn-3a has previously been shown to be expressed at elevated levels in the cervix of women with squamous cell carcinoma of the cervix (SCC) and to activate the expression of HPV E6 mRNA. In this study, we show that common and rare cervical precancer lesions, including those of adenocarcinoma (AC), which are usually difficult to diagnose using classical procedures, also expressed high levels of Brn-3a and can be diagnosed by measuring the levels of Brn-3a and E6 mRNAs.

Nature Communications, 2011

The imaging resolution of a conventional optical microscope is limited by diffraction to ~ 200 nm... more The imaging resolution of a conventional optical microscope is limited by diffraction to ~ 200 nm in the visible spectrum. Efforts to overcome such limits have stimulated the development of optical nanoscopes using metamaterial superlenses, nanoscale solid immersion lenses and molecular fl uorescence microscopy. These techniques either require an illuminating laser beam to resolve to 70 nm in the visible spectrum or have limited imaging resolution above 100 nm for a white-light source. Here we report a new 50-nm-resolution nanoscope that uses optically transparent microspheres (for example, SiO 2 , with 2 μ m < diameter < 9 μ m) as far-fi eld superlenses (FSL) to overcome the white-light diffraction limit. The microsphere nanoscope operates in both transmission and refl ection modes, and generates magnifi ed virtual images with a magnifi cation up to × 8. It may provide new opportunities to image viruses and biomolecules in real time.

Journal of Physics D-applied Physics, 2010

Although laser surface nanopatterning by particle-lens arrays, utilizing near field enhancement, ... more Although laser surface nanopatterning by particle-lens arrays, utilizing near field enhancement, has been extensively utilized previously, a suitable technique for the deposition of Particle Lens Arrays (PLA) on curved surface of cylinder was not available. In this paper, a novel technique for nano-patterning on curved surfaces using particle-lens arrays is demonstrated. In the proposed technique, a hexagonal closed pack monolayer of SiO 2 spheres is first formed by self assembly on a flat glass surface. The formed monolayer of particles is then picked up by a flexible optically transparent sticky surface and placed on the substrate to be patterned. A 532 nm wavelength Nd:YVO 4 laser was used to irradiate the substrate with the laser passing through the flexible, transparent surface and the particles. Experimental investigations are made to ascertain the properties of the patterns. In addition, the optical near-field distribution around the particles is numerically simulated. The proposed technique is validated for nanopatterning of curved surface of a cylinder.

Applied Surface Science, 2011

Direct laser surface micro/nanopatterning by using Contact Particle Lens Array (CPLA) has been wi... more Direct laser surface micro/nanopatterning by using Contact Particle Lens Array (CPLA) has been widely utilized. The method involves laser scanning of a monolayer of transparent particles arranged on the substrate to be patterned. Despite the different techniques available for CPLA deposition; the particles monolayer can only be formed on hydrophilic surfaces, which restrict the range of substrates that could be patterned by this method. In this study, a technique for patterning of hydrophobic surfaces by using CPLA has been proposed. In the proposed technique, monolayer of CPLA is formed on a hydrophilic substrate and then transported to a hydrophobic substrate by using a flexible sticky plastic. The transported CPLA is then scanned by a laser for patterning the hydrophobic substrate. The plastic pre-selected for this work was transparent to the laser. Experimental investigations were carried out to generate bumps and bowl shaped patterns using transported particles. Features smaller than the diffraction limit have been generated. The optical near field and associated temperatures around the particles were numerically simulated with a coupled electromagnetic and thermal modelling technique.