Unexpected early loosening was noted in some patients who had bipolar hemiarthroplasties using aspecific combination of head and stem. A review of all patients who had received this implant combination was performed to establish whether... more
Unexpected early loosening was noted in some patients who had bipolar hemiarthroplasties using aspecific combination of head and stem. A review of all patients who had received this implant combination was performed to establish whether there was a higher than expected failure rate and to identify those patients who had evidence of early loosening requiring further intervention or monitoring. Theatre records were reviewed to identify those who had undergone bipolar hemiarthroplasty using these products. All surviving patients were contacted and offered an appointment at which they underwent clinical and radiological review. Following review, revision rates were compared to published Australian joint registry data. Of 247 eligible for recall, 139 attended for clinical and radiological review. The cumulative revision rate was 6.8 % at 4 years, with a mean time to revision of 26 months; however, there was a significantly higher revision rate of 12.1 % in those aged under 75 years at the time of surgery (p = 0.01). This is significantly higher than rates quoted for bipolar hemiarthroplasties in Australian joint registry data. Overall, higher than expected revision rates due to early loosening were seen for this product combination,especially in patients aged\75 years at the time of the initial surgery.
Research Interests: Medicine, Humans, Female, Male, Aged, and 5 moreMiddle Aged, Adult, Age Factors, Reoperation, and Medical and Health Sciences
Although cadmium zinc telluride (CZT) is one of leading materials for fabricating room-temperature nuclear-radiation- detectors, different defects in the crystals can degrade the performance of CZT detectors. Post-growth thermal annealing... more
Although cadmium zinc telluride (CZT) is one of leading materials for fabricating room-temperature nuclear-radiation- detectors, different defects in the crystals can degrade the performance of CZT detectors. Post-growth thermal annealing potentially offers a satisfactory way to eliminate the deleterious influence of these defects. Here, we report that the annealing of CZT in Cd vapor effectively lowers the density of Te
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CdZnTe (CZT) and CdMnTe (CMT) materials come into the spotlight for room-temperature semiconductor detectors. Nonethelss, both materials still have limitations for the production of economical, uniform, and large-volume devices due to the... more
CdZnTe (CZT) and CdMnTe (CMT) materials come into the spotlight for room-temperature semiconductor detectors. Nonethelss, both materials still have limitations for the production of economical, uniform, and large-volume devices due to the zinc (Zn) segregation in CZT and manganese purity in CMT. The effective segregation coefficient of Zn in the CdTe host is nearly 1.3, so about 5–6% of Zn
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Cadmium manganese telluride (CMT) has high potential as a material for room-temperature nuclear-radiation detectors. We investigated indium-doped CMT crystals taken from the stable growth region of the ingot, and compared its... more
Cadmium manganese telluride (CMT) has high potential as a material for room-temperature nuclear-radiation detectors. We investigated indium-doped CMT crystals taken from the stable growth region of the ingot, and compared its characteristics with that from the last-to-freeze region. We employed different techniques, including synchrotron white-beam X-ray topography (SWBXT), current-voltage (I-V) measurements, and low-temperature photoluminescence spectra, and we also assessed their
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CdZnTe (CZT) crystals used for nuclear-radiation detectors often contain high concentrations of subgrain boundaries and networks of poligonized dislocations that can significantly degrade the performance of semiconductor devices. These... more
CdZnTe (CZT) crystals used for nuclear-radiation detectors often contain high concentrations of subgrain boundaries and networks of poligonized dislocations that can significantly degrade the performance of semiconductor devices. These defects exist in all commercial CZT materials, regardless of their growth techniques and their vendor. We describe our new results from examining such detectors using IR transmission microscopy and white X-ray
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Research Interests: X Rays and Electric Field
To evaluate the performance of mungbean genotypes, an experiment was conducted at Agricultural Research Farm of NWFP Agricultural University, Peshawar during summer 2005. The experiment was laid out in randomized complete block design... more
To evaluate the performance of mungbean genotypes, an experiment was conducted at Agricultural Research Farm of NWFP Agricultural University, Peshawar during summer 2005. The experiment was laid out in randomized complete block design with three replications. Data was collected on number of leaves plant-1, pod length, number of pods plant -1 , number of seeds pod -1 , 100-seed weight
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We evaluated a spectroscopy-grade 15×15×7mm3 CdZnTe (CZT) crystal with a high μτ-product, >10−2cm2/V, but impaired by microscopic extended defects, such as walls of dislocations, low-angle and sub-grain boundaries, and Te inclusions.... more
We evaluated a spectroscopy-grade 15×15×7mm3 CdZnTe (CZT) crystal with a high μτ-product, >10−2cm2/V, but impaired by microscopic extended defects, such as walls of dislocations, low-angle and sub-grain boundaries, and Te inclusions. First, we evaluated a planar detector fabricated from this crystal using a Micro-scale X-ray Detector Mapping (MXDM) technique. Then, we fabricated from the same crystal a pixel detector to study local non-uniformities of the electric field. The measured X-ray response maps confirmed the presence of non-uniformities in the charge transport, and they showed that the global- and local-distortions of the internal E-field correlated to the extended defects and space-charge buildup on the side surfaces.
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Passivation is an important process that reduces surface leakage current and its attendant noise. We treated detector-grade large-volume CdMnTe: In samples with an (NH 4)-based passivant, and compared the results with untreated samples by... more
Passivation is an important process that reduces surface leakage current and its attendant noise. We treated detector-grade large-volume CdMnTe: In samples with an (NH 4)-based passivant, and compared the results with untreated samples by measuring current ...
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Epoxy resin is being used as the most common structural adhesive by virtue of its high cohesive and adhesive strength, low shrinkage, and versatility in formulating and processing. Cured epoxy resin, however, has a brittle nature with... more
Epoxy resin is being used as the most common structural adhesive by virtue of its high cohesive and adhesive strength, low shrinkage, and versatility in formulating and processing. Cured epoxy resin, however, has a brittle nature with poor resistance to crack growth. As a result, it is ...
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Using photoluminescence (PL) and current deep-level transient spectroscopy (I-DLTS), we investigated the electronic defects of indium-doped detector-grade CdMnTe:In (CMT:In) crystals grown by the vertical Bridgman method. We similarly... more
Using photoluminescence (PL) and current deep-level transient spectroscopy (I-DLTS), we investigated the electronic defects of indium-doped detector-grade CdMnTe:In (CMT:In) crystals grown by the vertical Bridgman method. We similarly analyzed CdZnTe:In (CZT:In) and undoped CdMnTe (CMT) crystals grown under the amount of same level of excess Te and/or indium doping level to detail the fundamental properties of the electronic defect structure more readily. Extended defects, existing in all the samples, were revealed by synchrotron white beam x-ray diffraction topography and scanning electron microscopy. The electronic structure of CMT is very similar to that of CZT, with shallow traps, A-centers, Cd vacancies, deep levels, and Te antisites. The 1.1-eV deep level, revealed by PL in earlier studies of CZT and CdTe, were attributed to dislocation-induced defects. In our I-DLTS measurements, the 1.1-eV traps showed different activation energies with applied bias voltage and an exponential dependence on the trap-filling time, which are typical characteristics of dislocation-induced defects. We propose a new defect-trap model for indium-doped CMT crystals.
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ABSTRACT Existing tomato (Solanum lycopersicum L.) cultivars may not retain the ability to yield at desired levels. Twenty-eight tomato hybrids were studied to determine effects of heterosis on vine length, internode length, stem... more
ABSTRACT Existing tomato (Solanum lycopersicum L.) cultivars may not retain the ability to yield at desired levels. Twenty-eight tomato hybrids were studied to determine effects of heterosis on vine length, internode length, stem diameter, pH of tomato juice, total soluble solids, and reducing sugar from eight parental diallel excluding reciprocal crosses (half diallel) to quantify heterotic effects. Differences among parents indicated genetic diversity, and varying degrees of heterotic effects occurred for traits among hybrids. Maximum heterosis in the desired direction was for vine length, internode length, stem diameter, pH of tomato juice, total soluble solids, and reducing sugar over the mid-parent as well as the better parent. Hybrids P30 × P45 and P45 × P54 were best for most traits and could be potential sources for improved tomatoes for morphological traits; hybrids P30 × P45, E-02 × P28, and P54 × P59 might be used to improve tomato flavor attributes.
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ABSTRACT Although CdZnTe (CZT) and CdMnTe (CMT) materials are leading contenders for room-temperature semiconductor detectors, nonetheless, both materials have limitations hindering their full usage in producing economical, uniform,... more
ABSTRACT Although CdZnTe (CZT) and CdMnTe (CMT) materials are leading contenders for room-temperature semiconductor detectors, nonetheless, both materials have limitations hindering their full usage in producing economical, uniform, large-volume devices due to their grain/twin boundaries, material purity, secondary-phase Te defects and material segregation. We tried to prevent the generation of twin and subgrain boundaries to achieve large-volume CZT crystals by means of local temperature control between the CZT melt and quartz crucible. Also, we have expanded the understanding of the electrical and structural properties of coherent/incoherent twin boundaries. The high residual impurities in the starting source materials, especially in manganese, were identified as obstacles against obtaining high-performance CMT detectors. We found that purifying manganese telluride (MnTe) via a floating Te melt-zone very effectively removes impurities, leading to better detectors. CMT detectors fabricated with purified material give a 2.1% energy resolution for 662 keV with a $^{137}$Cs gamma source without any electron-loss corrections. Secondary-phase Te defects deteriorate detector performance due to incomplete charge collection caused by charge trapping. In situ growth interface studies reveal the thermo-migration of Te inclusions to CZT melts and the dependence of Te-inclusion size on the cooling rate. The effective segregation coefficient of Zn in the CdTe host is nearly 1.3, so about 5%–6% of Zn deviation was reported in Bridgman-grown CZT (Zn$,=$10% ingots. Such uncontrolled Zn variations cause a significant variation of the band-gap throughout the ingot and, consequently, affect the nonuniformity of the detectors' responses. Practically, this means that manufacturers cannot cut the ingot parallel to the crystal growth direction. We also de- onstrated that the segregation of Zn can be controlled by creating particular thermal environments after growth.
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ABSTRACT New results from testing an array of 6$,times,$6$,times,$15 mm$^{3}$ virtual Frisch-grid CdZnTe (CZT) detectors with common-cathode readout for charge signals correction and rejection of incomplete charge collection events (ICC)... more
ABSTRACT New results from testing an array of 6$,times,$6$,times,$15 mm$^{3}$ virtual Frisch-grid CdZnTe (CZT) detectors with common-cathode readout for charge signals correction and rejection of incomplete charge collection events (ICC) are presented. The array employs parallelepiped-shaped crystals of a large geometrical aspect ratio with two planar contacts on the top and bottom surfaces (anode and cathode) and an additional shielding electrode placed on the sides to create the virtual Frisch-grid effect. The detectors are arranged in 2$,times,$2 or 3$,times,$3 detector modules with the common cathode readout by a single electronic channel. Because of the common cathode, the length of the shielding electrode can be further reduced with no adverse effects on the device performance. By implementing a novel technique for rejecting ICC events caused by the extended defects, we can achieve good spectral responses from ordinary CZT crystals, which can be produced with higher yield and at lower cost. For such crystals, the resolution of individual detectors is expected to be in the range of 0.8–1.5% FWHM at 662 keV with an average value of 1.3%. Arrays of virtual Frisch-grid detectors offer a robust and low-cost approach for making large-area detection modules that can potentially substitute for more advanced, but also more expensive and less available, pixel detectors in applications with slightly relaxed requirements on position- and energy-resolution (e.g., for coded aperture telescopes). In addition, such virtual Frisch-grid arrays will require a comparably smaller number of readout channels, which allows for lower power consu- ption.
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Large-volume CdZnTe (CZT) single crystals with electron lifetimes exceeding 10 $\mu\hbox{s}$ recently became available commercially for making large effective area gamma-ray arrays. However, significant variations were observed in the... more
Large-volume CdZnTe (CZT) single crystals with electron lifetimes exceeding 10 $\mu\hbox{s}$ recently became available commercially for making large effective area gamma-ray arrays. However, significant variations were observed in the performance of detectors made from such arrays. We evaluated the spectroscopic performance of such a large-volume, 20$\times$ 20$\times$15 mm$^{3}$ , coplanar-grid (CPG) CdZnTe detector, intended for use in a handheld radioisotope-identifier,
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Research Interests: Orthopedic Surgery, Computed Tomography, Treatment, Computer assisted orthopaedic surgery, Humans, and 15 moreComputer Model, Female, Male, Orthopedics, Clinical Sciences, Aged, Middle Aged, Reliability Modeling, Adult, Retrospective Studies, Three Dimensional, Reproducibility of Results, Related, Navigation System, and Femoral Neck Fracture
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Crosslinking has been shown to improve the wear resistance of ultra-high molecular weight polyethylene in both in vitro and clinical in vivo studies. The molecular mechanisms and material properties that are responsible for this marked... more
Crosslinking has been shown to improve the wear resistance of ultra-high molecular weight polyethylene in both in vitro and clinical in vivo studies. The molecular mechanisms and material properties that are responsible for this marked improvement in wear resistance are still not well understood. In fact, following crosslinking a number of mechanical properties of UHMWPE are decreased including toughness, modulus, ultimate tensile strength, yield strength, and hardness. In general, these changes would be expected to constitute a precursor for lower wear resistance, presenting a paradox in that wear resistance increases with crosslinking. In order to understand better and to analyze this paradoxical behaviour of crosslinked UHMWPE, we investigated the wear behavior of (i) radiation-crosslinked GUR 1050 resin, (ii) peroxide-crosslinked GUR 1050 resin and (iii) peroxide-crosslinked Himont 1900 resin using a bi-directional pin-on-disk (POD) machine. Wear behavior was analyzed as a function of crystallinity, ultimate tensile strength (UTS), yield strength (YS), and molecular weight between crosslinks (Mc). The crosslink density increased with increasing radiation dose level and initial peroxide content. The UTS, YS, and crystallinity decreased with increasing crosslink density. While these variations followed the same trend, the absolute changes as a function of crosslink density were different for the three types of crosslinked UHMWPE studied. There was no unified correlation for the wear behavior of the three types of crosslinked UHMWPE with the crystallinity, UTS and YS. However, the POD wear rate showed the identical linear dependence on Mc with all three types of crosslinked UHMWPEs studied. Therefore, we have strong evidence to propose that Mc or crosslink density is a fundamental material property that governs the lubricated adhesive and abrasive wear mechanisms of crosslinked UHMWPEs, overriding the possible effects of other material properties such as UTS, YS and crystallinity on the wear behavior.
Research Interests: Biomaterials, Wear, Multidisciplinary, Molecular Mechanics, Humans, and 14 moreCrosslinking, Polyethylene, Abrasive wear, Radiation Dose, Molecular weight, prosthesis Design, Wear resistance, Yield Strength, Materials Testing, Polyethylenes, Tensile Strength, Material Properties, Biocompatible Materials, and Total Hip-arthroplasty
We utilized a low-temperature spatially resolved micro-photoluminescence mapping technique to investigate the spatial variation of photoluminescence- and electronic-defect states in areas of CdZnTe (CZT) single crystals containing... more
We utilized a low-temperature spatially resolved micro-photoluminescence mapping technique to investigate the spatial variation of photoluminescence- and electronic-defect states in areas of CdZnTe (CZT) single crystals containing structural-imperfections. Photoluminescence mapping of the donor-bound-exciton emission reveals an unexpected blue-shift of the CZT bandgap at Te inclusions, which indicates that for optical measurements the localized strain field needs to be considered for
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... Type, Summary. Journal Title, Sarhad Journal of Agriculture. ISSN, 1016-4383. Vol. No. v. 14(3) p. 227-233. Abstract (English), Four maize synthetics viz., Sarhad White, Ihsan, Kisan and Toxpino-C6 were crossed in all possible... more
... Type, Summary. Journal Title, Sarhad Journal of Agriculture. ISSN, 1016-4383. Vol. No. v. 14(3) p. 227-233. Abstract (English), Four maize synthetics viz., Sarhad White, Ihsan, Kisan and Toxpino-C6 were crossed in all possible combinations during spring, 1992. ...
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... MARYAM BIBI1, NAQIB ULLAH KHAN1, FIDA MOHAMMAD1, ROZINA GUL1, ABDUL AZIZ KHAKWANI2 AND OBAID ULLAH SAYAL2 1Department of Plant Breeding & Genetics, Khyber Pakhtunkhwa Agricultural... more
... MARYAM BIBI1, NAQIB ULLAH KHAN1, FIDA MOHAMMAD1, ROZINA GUL1, ABDUL AZIZ KHAKWANI2 AND OBAID ULLAH SAYAL2 1Department of Plant Breeding & Genetics, Khyber Pakhtunkhwa Agricultural University, Peshawar, Pakistan 2Faculty of Agriculture, Gomal ...