background: thalassemia/haemoglobinopathy is a hereditary disease with increased erythropoiesis and expansion of the bone marrow cavity. consequently, there is a reduction in trabecular bone tissue resulting in osteopenia/osteoporosis. the present study was performed to determine bone mineral density (bmd) in children and adolescents with major thalassemia and its correlation with serum ferriti...

Noncontact thermometry with micron-scale lateral spatial resolution and fast time resolution is shown to be enabled by measuring the temperature dependence of two-photon absorption TPA on crystalline semiconductors. In the proof-of-concept experiments reported here, for studies of Si, an Er:fiber laser at =1.56 m is split into pump and probe beams; where they overlap, the large TPA signal chang...

T w o decades ago researchers at the University of Wisconsin showed that 125I photon absorptiometry could be used to measure bone mineral in the forearm easily and accurately with little radiation exposure (1). Surrounding the arm with water or other soft tissue-equivalent material of constant thickness provided uniform extra-skeletal attenuation; the incremental attenuation by bones was linear...

This study presents a detailed investigation of near-infrared one- and two-photon absorption (TPA) in a series of highly conjugated (porphinato)zinc(II) compounds. The chromophores interrogated include meso-to-meso ethyne-bridged (porphinato)zinc(II) oligomers (PZn(n) species), (porphinato)zinc(II)-spacer-(porphinato)zinc(II) (PZn-Sp-PZn) complexes, PZn(n) structures featuring terminal electron...

Two-photon absorption (TPA) cross sections of four representative series of octupolar molecules are theoretically investigated. The general structure--TPA-property relationship is described by using the effective four-state valence-bond three-charge-transfer model. As the charge-transfer character of the ground electronic state increases due to the strong donors or acceptors, (i) the transition...

Peripheral assessment of bone density using photon absorptiometry techniques has been available for over 40 yr. The initial use of radio-isotopes as the photon source has been replaced by the use of X-ray technology. A wide variety of models of single- or dual-energy X-ray measurement tools have been made available for purchase, although not all are still commercially available. The Official Po...

When two-photon interactions are induced by down-converted light with a bandwidth that exceeds the pump bandwidth, they can obtain a behavior that is pulselike temporally, yet spectrally narrow. At low photon fluxes this behavior reflects the time and energy entanglement between the down-converted photons. However, two-photon interactions such as two-photon absorption TPA and sum-frequency gene...

Although single-photon absorptiometry (SPA) has been the predominant tool used to assess bone mineral density (BMD) in the forearm, the development of dual-energy x-ray absorptiometry (DEXA) provides the benefits of greater source stability, reduced scanning time, and improved image resolution compared to SPA. In the present study we used the DEXA bone densitometer (Hologic, Inc., Waltham, MA) ...