CMOS X-ray imager for dental radiography

This paper describes a 64 pixels X-ray imager architecture and fabrication process. The imager is composed by a 8×8 photodiodes array, fabricated in CMOS process, and an array of wells £lled with scintillating crystals. A thick-£lm of aluminum is etched in order to achieve square wells with 500 um depth. The wells are filled with CsI:Tl scintillating crystals and placed above the photodiodes. The scintillating crystals convert the X-ray energy into visible light, which is guided into the photodiodes by the re¤ective aluminum walls, avoiding crosstalk between adjacent detectors. Usually, the spatial resolution of the scintillating x-rays detectors is identical to the scintillators thickness. By using the light guides, the scintillator thickness can be adjusted in order to achieve optimal absorption ef£ciency, since the spatial resolution is established by the pixel size (200 um side)

CMOS X-rays microdetector based on scintillating light guides

This paper describes a pixel imaging array consisting in 400 um x 400 um photodiodes fabricated in CMOS technology. Above the photodiodes, an array of scintillating CsI:Tl crystals are placed. The scintillating crystals are encapsulated in aluminum walls forming a light path to guide the produced visible light into the photodiodes. So, the x-ray energy is first converted into visible light which is then detected by the photodiode at the end of each light guide. The scintillator is 800 um thick, absorbing almost all of 20 keV x-ray photons. Usually, the spatial resolution of the scintillating x-rays detectors is identical to the scintillator thickness. By using the light guides, the scintillator thickness can be increased, without decreasing the spatial resolution. The increase of the scintillator thickness is desirable in order to increase the x-rays absorption efficiency. Tests carried out on the system show very promising results near 20 keV.This work was supported by The Foundation of Science and Technology, Portugal, FCT-CTM/POCTI/33751/1999; Grant-BD SFRH/BD/1296/2000

Xray detector based on bulk micromachined photodiode

This paper reports the design, fabrication, assembly and testing of a xray detector based on a bulk micromachined photodiode (BMMPD) with a cavity filled with a scintillating crystal. The xray photons that reach the detector are first converted to visible light by the scintillating crystal. The visible light is then detected by the BMMPD, producing an electric current whose value is proportional to the incident xray intensity. The tests are done using a xray tube powered with a voltage of 35 kV, and a current ranging from 0 mA to 1 mA. With this setup, very promising results were obtained. may be divided into three classes: Dose reduction, image processing and display in real time, and flexibility in image storage and retrieval. The first advantage of digital radiography is the possibility of dose reduction. In conventional radiology, the dose is determined by the sensitivity ofThis work was supported by the Foundation Science and Technology, Portugal: FCT-CTM/POCTI/33751/1999; Grant-BD SFRH/BD/1296/2000

Muscle damage, physiological changes and energy balance in ultra-endurance mountain event athletes

The biological response to ultra-endurance mountain race events is not yet well understood. The aim of this study was to determine the biochemical and physiological changes after performing an ultra-endurance mountain race in runners. We recruited 11 amateur runners (age: 29.7 ± 10.2 years; height: 179.7 ± 5.4 cm; body mass: 76.7 ± 10.3 kg). Muscle damage, lactate concentration, energy balance, rating of perceived exertion (RPE), heart rate (HR), heart rate variability (HRV), body composition changes, and jump performance were analyzed before, during (only lactate, HR, and HRV), and after the race. Athletes completed 54 km in 6 h, 44 min (±28 min). After the race, myoglobin and creatine kinase concentration increased from 14.9 ± 5.2 to 1419.9 ± 1292.1 μg/L and from 820.0 ± 2087.3 to 2421.1 ± 2336.2 UI/L, respectively (p < 0.01). In addition, lactate dehydrogenase and troponin I significantly increased after the race (p < 0.01). Leukocyte and platelet count increased by 180.6% ± 68.9% and 23.7% ± 11.2%, respectively (p < 0.001). Moreover, after the competition, athletes presented a 3704 kcal negative energy balance; a significant increase in RPE values; a decrease in countermovement and squat jump height; and a decrease in body mass and lower limb girths. During the event, lactate concentration did not change and subjects presented a mean HR of 158.8 ± 17.7 beats/min, a significant decrement in vagal modulation, and a significant increase in sympathetic modulation. Despite the relative “low” intensity achieved, ultra-endurance mountain race is a stressful stimulus that produces a high level of muscle damage in the athletes. These findings may help coaches to design specific training programs that may improve nutritional intake strategies and prevent muscle damage.Actividad Física y Deport

Comparison between bulk micromachined and CMOS detectors for X-ray measurements

This paper compares two x-ray detectors fabricated using two different technologies: one is based on a bulk micromachined silicon photodetector and the other is based on a standard CMOS photodetector. The working principle of the two detectors is similar: a scintillating layer of CsI:Tl is placed above the photodetector, so the x-rays are first converted into visible light (560 nm) which is then converted into an electrical signal by the photodetector. The different aspects of the fabrication and the experimental results of both x-ray detectors are presented and discussed.This work was supported by The Foundation of Science and Technology, Portugal, FCT-CTM/POCTI/33751/1999; Grant-BD SFRH/BD/1296/2000

Nucleating Effect of Carbon Nanoparticles and Their Influence on the Thermal and Chemical Stability of Polypropylene

The effect of carbon nanofibers (CNFs) and carbon nanotubes (CNTs) on the thermal and chemical stability of polypropylene (PP) when subjected to oxidation in a strong acid medium was studied. The effect of CNFs and CNTs on the crystalline morphology and the melting and crystallization temperatures was also studied. The thermal stability increased markedly; the decomposition temperature, for example, increased from 293∘C for pure PP to 312 and 320∘C for PP with CNFs and CNTs, respectively. The crystallization temperature increased perceptibly with the addition of CNTs or CNFs, from 107∘C for pure PP to 112 and 114∘C for PP with CNFs and CNTs, respectively. The oxidative degradation with nitric acid produced a reduction in molecular weight; however, this negative effect was less pronounced in the PP compositions with carbon nanoparticles. After 8 hours in nitric acid, this reduction was from 141,000 to 68,000 (for pure PP), to 75,000 (for PP-CNFs), and 79,500 (for PP-CNTs). X-ray diffraction showed that the alpha type crystallinity remains, irrespective of the nucleating agent. Finally, the intensity ratio between the (040) (at 16.7∘) and the (110) (at 13.9∘) reflections increased, which was taken as an indication of an increasing nucleating efficiency

Nucleating Effect of Carbon Nanoparticles and Their Influence on the Thermal and Chemical Stability of Polypropylene

The effect of carbon nanofibers (CNFs) and carbon nanotubes (CNTs) on the thermal and chemical stability of polypropylene (PP) when subjected to oxidation in a strong acid medium was studied. The effect of CNFs and CNTs on the crystalline morphology and the melting and crystallization temperatures was also studied. The thermal stability increased markedly; the decomposition temperature, for example, increased from 293 • C for pure PP to 312 and 320 • C for PP with CNFs and CNTs, respectively. The crystallization temperature increased perceptibly with the addition of CNTs or CNFs, from 107 • C for pure PP to 112 and 114 • C for PP with CNFs and CNTs, respectively. The oxidative degradation with nitric acid produced a reduction in molecular weight; however, this negative effect was less pronounced in the PP compositions with carbon nanoparticles. After 8 hours in nitric acid, this reduction was from 141,000 to 68,000 (for pure PP), to 75,000 (for PP-CNFs), and 79,500 (for PP-CNTs). X-ray diffraction showed that the alpha type crystallinity remains, irrespective of the nucleating agent. Finally, the intensity ratio between the (040) (at 16.7 • ) and the (110) (at 13.9 • ) reflections increased, which was taken as an indication of an increasing nucleating efficiency

Antebrachial microvascular flap for reconstruction of the pelvic limb: case report

Complex defects in the soft tissues of the foot and ankle caused by high-energy trauma, infection, cancer or diabetes require rapid and effective treatment which decreases the risk of infection, bone healing time, hospital stay and number total of surgical approaches. Authors report a clinical case of a 23-year-old female patient who suffers high-energy trauma due to a motorcycle accident which causes exposure of the distal third of the tibia, loss of the tibial joint face, and loss of tissue throughout the region of the malleolus medial of the right pelvic extremity. Tissue transfer to the pelvic limb is performed using left contralateral radial antebrachial free flap as donor area. This case report aims to emphasize the key aspects of the high energy trauma approach by using microvascular flaps, as well as the satisfactory evolution of the patient that directly affects the prognosis for life and function

The Fabrication of Nano-Particles in Aqueous Solution From Oxyfluoride Glass Ceramics by Thermal Induction and Corrosion Treatment

An innovative route is reported to fabricate nano-particles in aqueous solution from oxyfluoride glass by the thermal induction and corrosion treatment in this letter. The investigations of X-ray diffraction and transmission electron microscope based on nano-particles in glass ceramics (GCs) and aqueous solution indicate that the nano-particles formed in glass matrix during the thermal induction process are released to aqueous solution and their structure, shape and luminescent properties in glass host can be kept. Owing to the designable composition of the nano-particles during glass preparation process, the method is a novel way to obtain nano-particles in aqueous solution from GCs