Direct production of polyhydroxybutyrate and alginate from crude glycerol by Azotobacter vinelandii using atmospheric nitrogen

廃棄物から生分解性プラスチック素材へ --大気窒素活用型発酵生産への展開--. 京都大学プレスリリース. 2022-06-08.While biodiesel is drawing attention as an eco-friendly fuel, the use of crude glycerol, a byproduct of the fuel production process, has increasingly become a concern to be addressed. Here we show the development of a low-cost fermentation technology using an atmospheric nitrogen-fixing bacterium to recycle crude glycerol into functional biopolymers. Azotobacter vinelandii showed substantial growth on tap water-diluted crude glycerol without any pretreatment. The number of viable A. vinelandii cells increased over 1000-fold under optimal growth conditions. Most of the glycerol content (~ 0.2%) in the crude glycerol medium was completely depleted within 48 h of culture. Useful polymers, such as polyhydroxybutyrate and alginate, were also produced. Polyhydroxybutyrate productivity was increased ten-fold by blocking the alginate synthesis pathway. Although there are few examples of using crude glycerol directly as a carbon source for microbial fermentation, there are no reports on the use of crude glycerol without the addition of a nitrogen source. This study demonstrated that it is possible to develop a technology to produce industrially useful polymers from crude glycerol through energy-saving and energy-efficient fermentation using the atmospheric nitrogen-fixing microorganism A. vinelandii

Recent results of a postal dose audit for radiotherapy machine in Japan with non-reference condition

Purpose In Japan, postal dose audits have been performed on the radiation therapy units using a radiophotoluminescent glass dosimeter (RGD) since 2007. In 2010, the audit for the non-reference condition including field size change or wedge insertion was initiated. This study summarizes the latest results of non-reference condition.Methods Through these 4 years, 458 beams have been measured for different field size from 5 x 5 cm2 to 25 x 25 cm2 and 301 beams have been measured for different wedge angle from 15 to 60 degrees.Results For the beams with the field size change, the mean differences of measured from stated dose at each field size, 5 x 5 (n = 197), 15 x 15 (n = 55), 20 x 20 (n = 173), and 25 x 25 (n =33) cm2, were -0.3%, 0.3%, 0.4%, and 0.2% respectively. The standard deviations of the distribution at each field size were 1.0%, 1.0%, 1.2%, and 1.5% respectively. For the wedged beam irradiation, the mean of the differences of measured from stated dose with each wedge angles, 15° (n = 112), 30° (n = 102), 45° (n = 45), and 60° (n = 42), were 0.1%, 0.1%, 0.1%, and 0.3% respectively. The standard deviations of the distribution at each wedged angle were 1.0%, 1.3%, 1.2%, and 1.3% respectively. Conclusion The postal dose audit using RGD to non-reference condition has been successfully performed. The mean differences of measured from stated dose were within 0.5% for every field size and wedge angle.The 7th Korea-Japan Joint Meeting on Medical Physic

Analysis of the uncertainties in the dose audit system using radiophotoluminescent glass dosimeters in Japanese radiotherapy units

A dosimetry audit of radiotherapy units in Japan was performed usingradiophotoluminescent glass dosimeters (RPLDs). This study analyses theuncertainties associated with the procedure for determining the absorbed dose by anRPLD from a high-energy photon beam in radiotherapy units. The absorbed dose isderived using six parameters: the indicated value given by the RPLD, the individualdosimeter sensitivity correction factor for each element, the calibration coefficient forthe reference radiation quality, the correction factor for the radiation quality, thecorrection factor for the phantom material, and the correction factor of nonlinearity. Theuncertainty of each parameter was estimated based on the ISO standard methodology,“Guide to the Expression of Uncertainty in Measurement.” The estimated combinedstandard uncertainty of the dose measured by RPLD was 1.4% under the referencecondition. This value was compared to the standard deviation of the differencebetween the measured and intended doses obtained from the actual audit results(4,447 beams from 577 hospitals) over 13 years. The average percentage differencebetween the measured and calculated doses under the reference condition was 0.4%,with a standard deviation (k=1) of 1.3%. The results were consistent with theuncertainty estimated by this report and demonstrate the reliability of the RPLDdosimetry method

Malignant Lymphoma in the Psoas Major Muscle

An 84-year-old Japanese man taking warfarin to prevent cerebral infarction secondary to atrial fibrillation was admitted to our hospital for evaluation of a painless right back mass. Magnetic resonance imaging (MRI) showed an oval-shaped mass in the right psoas major muscle. The mass showed high intensity on T1-, T2-, and diffusion-weighted imaging and mimicked an acute-phase hematoma. However, it showed no chronological changes typical of a hematoma, and MRI revealed enlargement of the mass 1 week after admission. Histopathological examination of a biopsy specimen revealed diffuse large B-cell lymphoma (DLBCL). Although skeletal muscle lymphoma is rare, physicians should be familiar with its MRI characteristics. In addition, determination of the lymphoma subtype has important implications for the treatment of skeletal muscle lymphoma because DLCBL may have an especially poor prognosis

Application of radiophotoluminescent glass dosimeter to radiotherapy dosimetry audit

Background and ObjectivesRadiophotoluminescent glass dosimeter (RPLD) has been used in Japan as dosimeter of postal dose audit in external radiotherapy. Due to its advantages of compactness, repeatable readout, good precision and small fading1), RPLD become a suitable dosimeter for the audit. In Japan, the permanent auditing system using RPLD for external radiotherapy was launched in 2007. Currently, in multicenter clinical studies conducted in the framework of the Forum for Nuclear Cooperation in Asia (FNCA), the RPLD is also used as a dosimeter for brachytherapy dosimetry audit.Material　The glass dosimeter (DOSE ACE, ASAHI TECHNO GLASS CORPORATION; ATG) is silver-activated phosphate glass. Its weight composition is as follows: 11.0% Na, 31.55% P, 51.16% O, 6.12% Al and 0.17% Ag [14]. Its dimensions are 1.5mm in diameter and 12mm in length. A solid-state laser (ultraviolet wavelength) is used for reading. On its reading, 10 to 20 pulses of laser are irradiated per second, and the average value is obtained. In order to suppress variations in light emission amount depending on slight position fluctuation including rotation of the element, sensitive setup of the element is necessary. In addition, the whole reading process is repeated for 5 times, to improve the statistics. Dosimetry audit for external radiotherapy　RPLD elements are embedded in a solid phantom (Tough water phantom, manufactured by Kyoto Science Co., Ltd.), and it is set to be the reference condition of linear accelerator, and the reference dose (1 Gy) is irradiated. Phantom and RPLD are sent to the radiotherapy hospital according to their request. After irradiation, those are sent back to NIRS to evaluate the dose irradiated to the RPLD.Dosimetry audit for brachytherapy　The use of RPLD as a dose auditing tool for image-guided brachytherapy performed as a multicenter clinical study of cervical cancer has been studied. We are planning an end-to-end test that enables validation including the same flow as the actual patient, such as CT acquisition and treatment plan, rather than simple source intensity measurement. Although the beam quality is close to the cobalt irradiation field that calibrates the RPLD, it is affected by the dose gradient caused by the distance from the source close, and it is necessary to consider the volume effect. The phantom photograph produced is shown in the figure below. It was manufactured so that the RPLD element can be inserted into the evaluation points which are clinical dose evaluation points, point A right and left, and representative points of risk organs, bladder and the rectum (ICRU reference point). Currently we are doing Monte Carlo simulation for basic data verification and beam quality correction. Conclusion　RPLD is a useful solid state dosimeter for the external dosimetry audit in radiation therapy.19th International Conference on Solid State Dosimetry (SSD19