The Mulher Study: cervical cancer screening with primary HPV testing in Mozambique.

OBJECTIVE: To evaluate cervical cancer screening with primary human papillomavirus (HPV) testing in Mozambique, a country with one of the highest burdens of cervical cancer globally. METHODS: Women aged 30-49 years were prospectively enrolled and offered primary HPV testing using either self-collected or provider-collected specimens. Patients who tested positive for HPV underwent visual assessment for treatment using visual inspection with acetic acid to determine eligibility for thermal ablation. If ineligible, they were referred for excision with a loop electrosurgical excision procedure, for cold knife conization, or for cervical biopsy if malignancy was suspected. RESULTS: Between January 2020 and January 2023, 9014 patients underwent cervical cancer screening. Median age was 37 years (range 30-49) and 4122 women (45.7%) were patients living with HIV. Most (n=8792, 97.5%) chose self-collection. The HPV positivity rate was 31.1% overall and 39.5% among patients living with HIV. Of the 2805 HPV-positive patients, 2588 (92.3%) returned for all steps of their diagnostic work-up and treatment, including ablation (n=2383, 92.1%), loop electrosurgical excision procedure (n=169, 6.5%), and cold knife conization (n=5, 0.2%). Thirty-one patients (1.2%) were diagnosed with cancer and referred to gynecologic oncology. CONCLUSION: It is feasible to perform cervical cancer screening with primary HPV testing and follow-up in low-resource settings. Participants preferred self-collection, and the majority of screen-positive patients completed all steps of their diagnostic work-up and treatment. Our findings provide important information for further implementation and scale-up of cervical cancer screening and treatment services as part of the WHO global strategy for the elimination of cervical cancer.

The Capulana study: a prospective evaluation of cervical cancer screening using human papillomavirus testing in Mozambique.

BACKGROUND: Cervical cancer is the leading cause of cancer and related deaths among women in Mozambique. There is limited access to screening and few trained personnel to manage women with abnormal results. Our objective was to implement cervical cancer screening with human papillomavirus (HPV) testing, with navigation of women with abnormal results to appropriate diagnostic and treatment services. METHODS: We prospectively enrolled women aged 30-49 years living in Maputo, Mozambique, from April 2018 to September 2019. All participants underwent a pelvic examination by a nurse, and a cervical sample was collected and tested for HPV using the careHPV test (Qiagen, Gaithersburg, Maryland, USA). HPV positive women were referred for cryotherapy or, if ineligible for cryotherapy, a loop electrosurgical excision procedure. Women with findings concerning for cancer were referred to the gynecologic oncology service. RESULTS: Participants (n=898) had a median age of 38 years and 20.3% were women living with the human immunodeficiency virus. HPV positivity was 23.7% (95% confidence interval 21.0% to 26.6%); women living with human immunodeficiency virus were twice as likely to test positive for HPV as human immunodeficiency virus negative women (39.2% vs 19.9%, p<0.001). Most HPV positive women (194 of 213, 91.1%) completed all steps of their diagnostic work-up and treatment. Treatment included cryotherapy (n=158, 77.5%), loop electrosurgical excision procedure (n=30, 14.7%), or referral to a gynecologist or gynecologic oncologist (n=5, 2.5%). Of eight invasive cervical cancers, 5 (2.8%) were diagnosed in women living with human immunodeficiency virus and 3 (0.4%) in human immunodeficiency virus negative women (p=0.01). CONCLUSION: Cervical cancer screening with HPV testing, including appropriate follow-up and treatment, was feasible in our study cohort in Mozambique. Women living with human immunodeficiency virus appear to be at a significantly higher risk for HPV infection and the development of invasive cervical cancer than human immunodeficiency virus negative women.

High-energy ion (He+, Si++, Ga+, Au++) interactions with PMMA in ion beam lithography.

Resist-based ion beam lithography has been studied by exposing different species of ions (He+, Si++, Ga+ and Au++) on 700 and 2000 Å thick poly(methyl methacrylate) (or PMMA) films supported on Si substrates. By comparing the resist sensitivities to different ions and the cross-sectional shapes of the developed features with the simulation outputs from the TRIM (TRansport of Ions in Matter) software, long-chain scissoring in PMMA can be largely attributed to ion-initiated electron cascades (as evaluated by ion energy loss to the electrons) and recoil atom cascades (as evaluated by vacancy distribution in TRIM). The ion-initiated electron cascades contribute more to the resist sensitivity for the lighter ions, while the recoil atom cascades are more important for the heavier ions. A proportional relation between the resist sensitivity and the product of the ion energy loss to electrons and vacancy number is obtained semi-empirically for heavy ions. The He+ ion is the only ion species that can travel through and therefore expose the entire 2000-Å thick PMMA resist film, while the heaviest ion, Au++, provides the highest resist sensitivity. The effective energy and momentum impartment to the resist by the ion, as revealed by recoil atom cascades and vacancy formation, is important to significantly expanding the material types suitable for ion beam lithography.

Charge Transfer in Nanowire-Embedded PEDOT:PSS and Planar Heterojunction Solar Cells.

Hybrid metallic nanowire-embedded, highly conductive poly(3,4-ethylenedioxy thiophene):polystyrenesulfonate (PEDOT:PSS) with synergetic properties is indispensable for enhancing the performances of conductive polymer-based electronic devices. Here, we report embedment of silver nanowires (AgNWs), with diameter ∼100 nm and a high concentration (500 mg/mL) of nanowires dispersed in either ethanol or isopropanol, in PEDOT:PSS and compare the effects of the nanowire-dispersing solvents as well as its thicker diameter and high concentration on the overall properties and particularly its charge transfer characteristics and planar heterojunction solar cell (HSC) properties. Furthermore, electrostatic force microscopy is applied to elucidate the direct charge transfer from AgNWs to the PEDOT:PSS matrix. The AgNW-embedded PEDOT:PSS-based planar HSCs show a very high open-circuit voltage of over 638 mV and a high power conversion efficiency greater than 15.3% and without any significant influence from the AgNW dispersing solvents. While charge transfer in PEDOT:PSS without AgNWs occurs through the conducting PEDOT grains, enhanced charge transfer is realized in AgNW-embedded PEDOT:PSS with charge transport from PEDOT grains to AgNWs and then to PEDOT grains before reaching the top electrode in the HSC. The AgNW-embedded PEDOT:PSS hybrid materials pave a simple way to enhance the charge transfer performance in not only HSCs but also other hybrid or heterojunction electronics.

Highly Conducting Hybrid Silver-Nanowire-Embedded Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) for High-Efficiency Planar Silicon/Organic Heterojunction Solar Cells.

Embedding nanowires, such as silver nanowires (AgNWs), in a transparent conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) to enhance its conductivity is technologically important for improving the performances of devices comprising transparent conductive layers. Addition of nanowires in the highly conducting form of cosolvent (ethylene glycol) or mixed-cosolvent (ethylene glycol and methanol) modified PEDOT:PSS could change the nanowire structure and significantly alter the conductivity. Here, we report a simple method to embed AgNWs in PEDOT:PSS efficiently to improve its conductivity. By incorporating nanowires in the mixed cosolvent matrix prior to addition into PEDOT:PSS, this method preserves the structure of the nanowires while enabling conductivity enhancement. In contrast, the addition of AgNWs into cosolvent-premodified PEDOT:PSS leads to breaking of nanowires and conductivity impediment. The hybrid films with efficiently embedded AgNWs and mixed-cosolvent-modified PEDOT:PSS show a sheet resistance of 104 Ω/□, which is among the lowest ever reported for the as-deposited films, with conductivity enhancement of 33% relative to that of mixed-cosolvent-modified PEDOT:PSS. The resulting planar heterojunction solar cell (HSC) based on AgNW-embedded PEDOT:PSS exhibits a power conversion efficiency of greater than 15%. This demonstrates the importance of reducing sheet resistance by integrating nanowires into the PEDOT:PSS matrix as effective charge-transfer conduits interconnecting the highly conducting quinoid chains. The present approach to efficiently embed AgNWs in PEDOT:PSS could be readily extended to other nanowires or nanoparticles for improving the performance of PEDOT:PSS for applications in not just HSCs but indeed other electronic devices that require both transparent and highly conductive layers.

High-Performance Single-Active-Layer Memristor Based on an Ultrananocrystalline Oxygen-Deficient TiOx Film.

The theoretical and practical realization of memristive devices has been hailed as the next step for nonvolatile memories, low-power remote sensing, and adaptive intelligent prototypes for neuromorphic and biological systems. However, the active materials of currently available memristors need to undergo an often destructive high-bias electroforming process in order to activate resistive switching. This limits their device performance in switching speed, endurance/retention, and power consumption upon high-density integration, due to excessive Joule heating. By employing a nanocrystalline oxygen-deficient TiOx switching matrix to localize the electric field at discrete locations, it is possible to resolve the Joule heating problem by reducing the need for electroforming at high bias. With a Pt/TiOx/Pt stacking architecture, our device follows an electric field driven, vacancy-modulated interface-type switching that is sensitive to the junction size. By scaling down the junction size, the SET voltage and output current can be reduced, and a SET voltage as low as +0.59 V can be obtained for a 5 × 5 µm2 junction size. Along with its potentially fast switching (over 105 cycles with a 100 µs voltage pulse) and high retention (over 105 s) performance, memristors based on these disordered oxygen-deficient TiOx films promise viable building blocks for next-generation nonvolatile memories and other logic circuit systems.

Performance Enhancement by Secondary Doping in PEDOT:PSS/Planar-Si Hybrid Solar Cells.

Solar cells depend on effectively absorbing light and converting it into electrical current. It is therefore essential to increase conductivity and to limit both reflection and parasitic absorbance to achieve higher photoconversion efficiency. Here, we examine the effect of post-treatment on the absorbance and conductivity of hybrid solar cells comprised of p-type poly(3,4-ethylene-dioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) on an n-type silicon substrate. Three sets of cells based on pristine PEDOT:PSS film, cosolvent enhanced PEDOT:PSS film using ethylene glycol as a cosolvent, and post-treated PEDOT:PSS film using a novel 1:1 binary mixture of ethylene glycol and methanol have been studied. Markedly different film conductivities have been found for the pristine (∼0.8 S/cm), cosolvent added (637 S/cm), and post-treated films (1334 S/cm). The photoconversion efficiency obtained over a large set of samples (72 cells) was used to evaluate the cosolvent addition and post-treatment. Post-treatment is found to reproducibly provide films with not only the highest conductivities but also the highest efficiencies along with higher open-circuit voltage and fill factor but lower short-circuit current density when compared to those of the cosolvent added films. The decrease in the latter is attributed to the increase in absorbance in the PEDOT:PSS film. The present work illustrates the delicate challenge in improving the conductivity and carrier collection efficiency of the cells not at the expense of other properties such as absorption.

Defect-Rich Dopant-Free ZrO2 Nanostructures with Superior Dilute Ferromagnetic Semiconductor Properties.

Control of the spin degree of freedom of an electron has brought about a new era in spin-based applications, particularly spin-based electronics, with the potential to outperform the traditional charge-based semiconductor technology for data storage and information processing. However, the realization of functional spin-based devices for information processing remains elusive due to several fundamental challenges such as the low Curie temperature of group III-V and II-VI semiconductors (<200 K), and the low spin-injection efficiencies of existing III-V, II-VI, and transparent conductive oxide semiconductors in a multilayer device structure, which are caused by precipitation and migration of dopants from the host layer to the adjacent layers. Here, we use catalyst-assisted pulsed laser deposition to grow, for the first time, oxygen vacancy defect-rich, dopant-free ZrO2 nanostructures with high TC (700 K) and high magnetization (5.9 emu/g). The observed magnetization is significantly greater than both doped and defect-rich transparent conductive oxide nanomaterials reported to date. We also provide the first experimental evidence that it is the amounts and types of oxygen vacancy defects in, and not the phase of ZrO2 that control the ferromagnetic order in undoped ZrO2 nanostructures. To explain the origin of ferromagnetism in these ZrO2 nanostructures, we hypothesize a new defect-induced bound polaron model, which is generally applicable to other defect-rich, dopant-free transparent conductive oxide nanostructures. These results provide new insights into magnetic ordering in undoped dilute ferromagnetic semiconductor oxides and contribute to the design of exotic magnetic and novel multifunctional materials.

Plasmonic gold nanoparticles for ZnO-nanotube photoanodes in dye-sensitized solar cell application.

Surface modification of nanostructured metal oxides with metal nanoparticles has been extensively used to enhance their nanoscale properties. The unique properties of metal nanoparticles associated with their controllable dimensions allow these metal nanoparticles to be precisely engineered for many applications, particularly for renewable energy. Here, a simple electrodeposition method to synthesize gold nanoparticles (GNPs) on electrochemically grown ZnO nanotubes (NTs) is reported. The size distribution and areal density of the GNPs can be easily controlled by manipulating the concentration of AuCl3 electrolyte solution, and the deposition time, respectively. An excellent enhancement in the optical properties of ZnO NTs surface-decorated with GNPs (GNP/ZnO-NT), especially in the visible region, is attributed to their surface plasmon resonance. The plasmonic effects of GNPs, together with the large specific surface area of ZnO NTs, can be used to significantly enhance the dye-sensitized solar cell (DSSC) properties. Furthermore, the Schottky barrier at the Au/ZnO interface could prevent electron back transfer from the conduction band of ZnO to the redox electrolyte and thus could substantially increase electron injection in the ZnO conduction band, which would further improve the overall performance of the constructed DSSCs. The GNP/ZnO-NT photoanode has been found to increase the efficiency of the DSSC significantly to 6.0% from 4.7% of the pristine ZnO-NT photoanode, together with corresponding enhancements in short-circuit current density from 10.4 to 13.1 mA cm(-2) and in fill factor from 0.60 to 0.75, while the open-circuit voltage remain effectively unchanged (from 0.60 to 0.61 V). Surface decoration with GNPs therefore provides an effective approach to creating not only a high specific surface area for superior loading of dye molecules, but also higher absorbance capability due to their plasmonic effect, all of which lead to excellent performance enhancement for DSSC application.

Von recklinghausens disease: a series of four cases with variable expression.

Though neurofibromatosis type I (NFI) is a fairly common condition, it has a variable expressivity and penetrance. Here we present a series of cases with striking differences in the presentation especially in the oral cavity. NFI, also known as von Recklinghausen's neurofibromatosis, is an autosomal dominantly inherited neurogenetic disorder affecting 1:3000 newborn (Bongiorno et al., Oral Dis 12:125-129, 2006). About 50 % of NFI patients have no family history of the disease. There is no prevalence for gender or race in NFI. Expressivity in NFI is tremendously variable, but subtle phenotypic patterns may exist within subgroups of affected patients. Furthermore, 50 % of cases are sporadic and arise from germ cell mutation (Bongiorno et al., Oral Dis 12:125-129, 2006). The precise constellation of findings in any one individual is extremely variable, both within a family and between different families (Batsakis, Tumors of the head and neck: clinical and pathological considerations, 2nd edn. Williams and Wilkins, Baltimore, pp 313-333, 1979). Only 4-7 % of patients affected by neurofibromatosis exhibit oral manifestations (Güneri et al., Turk J Pediatr 48(2):155-158, 2006).

Interfacial micropore defect formation in PEDOT:PSS-Si hybrid solar cells probed by TOF-SIMS 3D chemical imaging.

Conducting p-type polymer layers on n-type Si have been widely studied for the fabrication of cost-effective hybrid solar cells. In this work, time-of-flight secondary ion mass spectrometry (TOF-SIMS) is used to provide three-dimensional chemical imaging of the interface between poly(3,4-ethylene-dioxythiophene):polystyrenesulfonate (PEDOT:PSS) and SiOx/Si in a hybrid solar cell. To minimize structural damage to the polymer layer, an Ar cluster sputtering source is used for depth profiling. The present result shows the formation of micropore defects in the interface region of the PEDOT:PSS layer on the SiOx/Si substrate. This interfacial micropore defect formation becomes more prominent with increasing thickness of the native oxide layer, which is a key device parameter that greatly affects the hybrid solar cell performance. Three-dimensional chemical imaging coupled with Ar cluster ion sputtering has therefore been demonstrated as an emerging technique for probing the interface of this and other polymer-inorganic systems.

Electro-oxidation of ascorbic acid by cobalt core-shell nanoparticles on a H-terminated Si(100) and by nanostructured cobalt-coated Si nanowire electrodes.

Determination of the concentration of ascorbic acid in a solution has attracted intense recent interest. Here we demonstrate the feasibility of electro-oxidation of ascorbic acid on spherical cobalt core-shell nanoparticles (10-50 nm dia.) prepared by electrochemical deposition on a H-terminated Si(100) substrate. Depth-profiling X-ray photoelectron spectroscopy reveals that these nanoparticles consist of a metallic cobalt core covered by a Co(OH)2 shell without any evidence of CoOx. Glancing-incidence X-ray diffraction studies further show that the metallic Co core consists of a mixture of hexagonal close packed and face centered cubic structures, the relative composition of which can be easily controlled by the deposition potential. We further demonstrate that when these Co nanoparticles are deposited on a high-surface-area electrode as provided by a Si nanowire template, the resulting nanostructured Co-coated Si nanowire electrode offers a promising high-performance sensor platform for ascorbic acid detection.

Near-surface oxidized sulfur modifications and self-assembly of thiol-modified aptamer on Au thin film substrates influenced by piranha treatment.

Self-assembly of thiol-modified oligonucleotides on Au films has great importance for biosensor applications. Prior to the self-assembly, a piranha treatment (PT) is commonly used to clean the Au surface. Here we report that near-surface oxidized sulfur modifications on Au thin films by PT for longer than 60 s have serious effects on the self-assembled monolayer (SAM) formation of thiol-modified single-stranded thrombin binding aptamer (s-TBA), and a PT time of 10-30 s is optimal for s-TBA SAM formation. These results have important implication to SAM formation of biomolecules, especially for the thiol-modified ones where a careful consideration of this key step could significantly enhance the SAM formation and biosensor performance.

Preferentially grown ultranano c-diamond and n-diamond grains on silicon nanoneedles from energetic species with enhanced field-emission properties.

The design and fabrication of well-defined nanostructures have great importance in nanoelectronics. Here we report the precise growth of sub-2 nm (c-diamond) and above 5 nm (n-diamond) size diamond grains from energetic species (chemical vapor deposition process) at low growth temperature of about 460 °C. We demonstrate that a pre-nucleation induced interface can be accounted for the growth of c-diamond or n-diamond grains on Si-nanoneedles (Si-NN). These preferentially grown allotropic forms of diamond on Si-NN have shown high electron field-emission properties and signify their high potential towards diamond-based electronic applications.

Freestanding ultrananocrystalline diamond films with homojunction insulating layer on conducting layer and their high electron field emission properties.

Freestanding ultrananocrystalline diamond (UNCD) films with homojunction insulating layer in situ grown on a conducting layer showed superior electron field emission (EFE) properties. The insulating layer of the films contains large dendrite type grains (400-600 nm in size), whereas the conducting layer contains nanosize equi-axed grains (5-20 nm in size) separated by grain boundaries of about 0.5-1 nm in width. The conducting layer possesses n-type (or semimetallic) conductivity of about 5.6 × 10(-3) (Ω cm)(-1), with sheet carrier concentration of about 1.4 × 10(12) cm(-2), which is ascribed to in situ doping of Li-species from LiNbO(3) substrates during growth of the films. The conducting layer intimately contacts the bottom electrodes (Cu-foil) by without forming the Schottky barrier, form homojunction with the insulating layer that facilitates injection of electrons into conduction band of diamond, and readily field emitted at low applied field. The EFE of freestanding UNCD films could be turned on at a low field of E(0) = 10.0 V/µm, attaining EFE current density of 0.2 mA/cm(2) at an applied field of 18.0 V/µm, which is superior to the EFE properties of UNCD films grown on Si substrates with the same chemical vapor deposition (CVD) process. Such an observation reveals the importance in the formation of homojunction on enhancing the EFE properties of materials. The large grain granular structure of the freestanding UNCD films is more robust against harsh environment and shows high potential toward diamond based electronic applications.

The effect of ultra-nanocrystalline diamond films on the proliferation and differentiation of neural stem cells.

The interaction of ultra-nanocrystalline diamond (UNCD) with neural stem cells (NSCs) has been studied along with its surface modification in order to improve its function as a biomaterial. Hydrogen- and oxygen-terminated UNCD films were compared with standard grade polystyrene in terms of their impact on the growth, expansion and differentiation of NSCs. When NSCs were cultured on these substrates in low serum and without any differentiating factors, hydrogen-terminated UNCD films spontaneously induced cell proliferation and neuronal differentiation. Oxygen-terminated UNCD films were also shown to further improve neural differentiation, with a preference to differentiate into oligodendrocytes. Hence, controlling the surface properties of UNCD could manipulate the differentiation of NSCs for different biomedical applications. These observations raise the potential for the use of UNCD as a biomaterial for central nervous system transplantation and tissue engineering.

Pedicled BFP for closure of oro-antral fistula revisited.

The Buccal Fat Pad (BFP) has been increasingly employed in the reconstruction of intra-oral defects since the procedure was first described by Egyedi. Although the use of BFP for closure of oro-antral communications has been reported in literature, it is either not a common practice or is under reported in India. This article describes predictive results with 2 cases of chronic oro-antral fistula using pedicled BFP.