| 1. |
- Chen, Delong, et al.
(author)
-
Laser-based gas absorption spectroscopy in decaying hip bone : water vapor as a predictor of osteonecrosis
- 2019
-
In: Journal of Biomedical Optics. - 1083-3668. ; 24:6, s. 1-6
-
Journal article (peer-reviewed)abstract
- Affluent blood flow through a complicated net of vessels supplies skeletal bone tissue with oxygen and nutrients. Due to accidental events or physiological processes, the blood supply might be deficient or even disrupted, and the healthy bone decays in a process that, for the hip location, is denoted as osteonecrosis of the femoral head (ONFH) or avascular femoral head necrosis. Early diagnosis is important for the prognosis. X-ray-based imaging, such as CT or MRI, is not of much value for the early detection. As the decay theoretically is associated with the development of gas-filled pores, gas analysis should have diagnostic value. We have introduced gas in scattering media absorption spectroscopy, as a complementary modality. Eighteen extracted femoral joint heads, diseased as well as normal, were investigated. Diseased samples are associated with clear signals due to water vapor, whereas the normal ones largely lack such features. The results suggest that free water vapor could serve as an early indicator of pore development and thus as a promising predictor of ONFH pathological changes, once the technique has been fully refined.
|
|
| 2. |
- Chen, Peng, et al.
(author)
-
Assessment of Free Gas in the Tibial Condyle Bone of the Human Knee by Diode Laser Spectroscopy with Possible Application to Arthrosis Diagnostics
- 2019
-
In: IEEE Journal of Selected Topics in Quantum Electronics. - 0792-1233. ; 25:1
-
Journal article (peer-reviewed)abstract
- The gas in scattering media absorption spectroscopy (GASMAS) technique was used to investigate the possible presence of free gas pores in human condyle bones, extracted from the tibia in knee revision surgical procedures in response to arthrosis development. Following earlier studies showing free gas presence in femoral head bones, decaying because of inadequate blood flow, we investigated condyle bone, where the arthrosis degeneration process, affecting the cartilage cup, is of different origin. Only a minor gas presence was observed in affected condyle samples, in accordance with our finding for non-arthrosis samples. Further, studies of fresh or initially frozen samples showed very similar signals, suggesting that the handling procedure has only a minor importance in these studies. In contrast to the situation for femoral heads, the monitoring of a gas presence would add only little in assessing the arthrosis status in the view of elective surgical procedures.
|
|
| 3. |
- Hu, Lingna, et al.
(author)
-
Optical detection of otitis media using modified spectroscopic otoscope
- 2018
-
In: 2018 Asia Communications and Photonics Conference, ACP 2018. - 9781538661581 ; 2018-October
-
Conference paper (peer-reviewed)abstract
- Otitis media is a common infectious disease in early childhood. We use an optical diagnostic system combining otoscopy and spectroscopy to improve the accuracy of diagnosis of otitis media.
|
|
| 4. |
- Hu, Lingna, et al.
(author)
-
Towards an optical diagnostic system for otitis media using a combination of otoscopy and spectroscopy
- 2019
-
In: Journal of Biophotonics. - : Wiley. - 1864-063X .- 1864-0648. ; 12:6
-
Journal article (peer-reviewed)abstract
- An improved method, where conventional otoscope investigation of human suspicious otitis media is combined with diffuse reflectance spectroscopy and gas in scattering media absorption spectroscopy (GASMAS) is being developed. Otitis media is one of the most common infectious diseases in children, whose Eustachian tube connecting the middle ear with the nasal cavity is more horizontal than for adults, which leads to impaired fluid drainage. At present, the use of an otoscope to visually observe possible changes in the tympanic membrane appearance is the main diagnostics method for otitis media. Inaccurate diagnosis related to similar symptoms, and the difficulty for small children to describe the condition experienced, frequently leads to over-prescription of antibiotics and alarming increase in bacterial resistance development. More accurate diagnostic methods are highly desirable. Diffuse reflectance spectroscopy is a non-invasive quantitative spectroscopic technique that enables to objectively quantify changes in the hemoglobin content of the tympanic membrane related to inflammation. If an infection is present, the ventilatory function of the Eustachian tube is frequently impaired and the middle-ear cavity will be filled with fluid. GASMAS, a non-invasive detection method, can non-invasively determine if gas is replaced by fluid in the middle-ear cavity.
|
|
| 5. |
- Li, Wansha, et al.
(author)
-
Detection of free oxygen and water vapor in fertilized and unfertilized eggs by diode laser spectroscopy-Exploration of diagnostics possibilities
- 2018
-
In: Journal of Biophotonics. - : Wiley. - 1864-063X. ; 11:3
-
Journal article (peer-reviewed)abstract
- Nonintrusive methods for characterizing food products are of increasing interest related to the greater awareness of food safety issues. Hen eggs are an important part in food consumption in most parts of the world. We have investigated an optical method utilizing tunable diode lasers for monitoring free gas in eggs. We show that oxygen signals, recorded around 760nm, increase steadily as eggs become older. Further, we investigated fertilized eggs, which show a quite different temporal behavior during the hatching time. The oxygen signal decreases here with time, while water vapor, recorded around 937nm, shows a steady increase. Conclusions regarding the size of the air cell and the oxygen availability in fertilized eggs are drawn. The technique might be developed for automatic control of egg freshness, as well as for assessing if eggs are fertilized or not.
|
|
| 6. |
- Li, Ying, et al.
(author)
-
Non-intrusive studies of gas contents and gas diffusion in hen eggs
- 2019
-
In: Biomedical Optics Express. - 2156-7085. ; 10:1, s. 83-91
-
Journal article (peer-reviewed)abstract
- A detailed study of the condition of eggs was performed using tunable diode lasers to monitor free gas in hen eggs. We detected oxygen and water vapor signals from 13 unfertilized eggs and studied the growth of the egg air cell over a time period of 3 weeks. We also studied the gas exchange through the egg shell, which is of particular interest for fertilized eggs. Four fertilized and five unfertilized eggs were followed over 3 weeks, the hatching period for hen eggs, and significant variations were found both in time and for the two types of eggs. Our results indicate that the techniques could be developed for automatic control of egg freshness, as well as for monitoring the hatching progress of fertilized eggs.
|
|
| 7. |
- Lin, Huiying, et al.
(author)
-
Diagnostics of femoral head status in humans using high-resolution laser spectroscopy : In vitro studies
- 2017
-
In: CLEO: Applications and Technology, CLEO_AT 2017. - 9781943580279 ; Part F43-CLEO_AT 2017
-
Conference paper (peer-reviewed)abstract
- Osteonecrosis of the femoral head is caused by inadequate blood supply to the affected bone. The bone decay process due to lacking blood supply would be likely to be accompanied by the formation of gas-filled pores. We have introduced diode laser absorption spectroscopy to successfully detect water vapor signals from pores in the femoral heads retrieved from hip replacement operations in 19 patients. The Gas in Scattering Media Absorption Spectroscopy (GASMAS) variety of tunable laser spectroscopy was employed. The results open up for the possibility of improved diagnostics for a very common disease.
|
|
| 8. |
|
|
| 9. |
- Malmqvist, Elin, et al.
(author)
-
The bat–bird–bug battle : Daily flight activity of insects and their predators over a rice field revealed by high-resolution scheimpflug lidar
- 2018
-
In: Royal Society Open Science. - : The Royal Society. - 2054-5703. ; 5:4
-
Journal article (peer-reviewed)abstract
- We present the results of, to our knowledge, the first Lidar study applied to continuous and simultaneous monitoring of aerial insects, bats and birds. It illustrates how common patterns of flight activity, e.g. insect swarming around twilight, depend on predation risk and other constraints acting on the faunal components. Flight activity was monitored over a rice field in China during one week in July 2016, using a high-resolution Scheimpflug Lidar system. The monitored Lidar transect was about 520 m long and covered approximately 2.5 m3. The observed biomass spectrum was bimodal, and targets were separated into insects and vertebrates in a categorization supported by visual observations. Peak flight activity occurred at dusk and dawn, with a 37 min time difference between the bat and insect peaks. Hence, bats started to feed in declining insect activity after dusk and stopped before the rise in activity before dawn. A similar time difference between insects and birds may have occurred, but it was not obvious, perhaps because birds were relatively scarce. Our observations are consistent with the hypothesis that flight activity of bats is constrained by predation in bright light, and that crepuscular insects exploit this constraint by swarming near to sunset/sunrise to minimize predation from bats.
|
|
| 10. |
- Svanberg, Katarina, et al.
(author)
-
Laser spectroscopy to meet some challenges in medicine
- 2017
-
In: International Conference on Photonics and Imaging in Biology and Medicine, PIBM 2017. - 9781557528209 ; Part F70-PIBM 2017
-
Conference paper (peer-reviewed)abstract
- Laser based spectroscopic techniques can be used in the detection and therapy of many human diseases. Examples will be given from a variety of clinical areas, such as oncology, orthopedics and pediatrics, and also from the field of food safety and antibiotic control.
|
|
