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Objective: To evaluate the result of gamma knife radiosurgery (GKRS) for drug-resistant primary trigeminal neuralgia (TN). Methods: Patients who were diagnosed with drug-resistant primary TN were treated with GKRS at the Nuclear Medicine and Oncology Center, Bach Mai Hospital from January 2015 to June 2020. Using the pain rating scale of the Barrow Neurological Institute (BNI), follow-ups and evaluations were conducted at 1 month, 3 months, 6 months, and 9 month, and 1, 2 years, 3 years, and 5 years after radiosurgery. Comparisons of pain levels was performed before and after radiosurgery according to the BNI scale. Results: From January 2015 to June 2020, 33 patients were treated with GKS. There were 23 female patients and 10 male patients; the average age was 61.9. The average onset time of disease was 4.42 years. Among all patients, 84.8% of patients were relieved from pain and 78.8% were pain-free without medication. The mean time for pain relief was 3 months and was not related to the dose of GKS (

The present paper reported on the analysis of structural defects and their influence on the red‐emitting γ‐Al2O3:Mn4+,Mg2+ nanowires using positron annihilation spectroscopy (PAS). The nanowires were synthesized by hydrothermal method and low‐temperature post‐treatment using glucose as a reducing agent. X‐ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and photoluminescence excitation (PLE) were utilized, respectively, for determining the structural phase, morphology and red‐emitting intensity in studied samples. Three PAS experiments, namely, positron annihilation lifetime (PAL), Doppler broadening (DB), and electron momentum distribution (EMD), were simultaneously performed to investigate the formations of structural defects in synthesized materials. Obtained results indicated that the doping concentration of 0.06% was optimal for the substitution of Mn4+ and Mg2+ to two Al3+ sites and the formation of oxygen vacancy (VO)‐rich vacancy clusters (2VAl + 3VO) and large voids (~0.7 nm) with less Al atoms. Those characteristics reduced the energy transfer between Mn4+ ions, thus consequently enhanced the PL and PLE intensities. Moreover, this optimal doping concentration also effectively controlled the size of nanopores (~2.18 nm); hence, it is expected to maintain the high thermal conductivity of γ‐Al2O3 nanowire‐phosphor. The present study, therefore, demonstrated a potential application of γ‐Al2O3 nanowire‐phosphor in fabricating the high‐performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

To assess the effectiveness of radiosurgery with a rotating gamma system (RGS) for paediatric brain tumours and arteriovenous malformation (AVM), this work was carried out on 123 patients with brain tumours or AVM received radiosurgery at Bach Mai hospital. The median dose was 13 Gy from a range of 8 to 20 Gy. Endpoints include the effects of increased intracranial pressure, seizures, hemiplegia, and tumour size on the syndrome. Results exhibited that the percentages of patients with complete response, partial response, and disease progression out of 59 patients with headache accounted for 11.9, 69.5, and 18.6%, respectively. Of the 20 patients with seizures, 30% had complete response, 65% partial response, and 5% stable disease. Regarding brain tumour size, 9 months after treatment, those with complete response, partial response, stable disease, and disease progression made up 18.7, 50.4, 14.6, and 16.3% of the total patients, respectively. There was no statistically significant effect of radiation dose on the results. This study showed a high percentage of children with brain tumours and AVM undergoing radiosurgery with a RGS had symptomatic responses after treatment.

Our study aimed to compare the essential oil (EO) concentration and composition of several Apiaceae species growing in the Northern region of Vietnam. The yields of EOs from materials ranged from 0.03% (root EO of Angelica acutiloba and aerial parts EO of Heracleum bivittatum)−0.27% (leaf EO of Xyloselinum vietnamense). Gas chromatography-mass spectrometry (GC-MS) allowed the identification of 74 components in the EOs of six Apiaceae species, making up 94.4%–100.0% of the oils. In EO from Angelica acutiloba , (Z)-ligustilide accounted for an extremely large proportion (94.9%). EO of Angelica pubescens was dominated by six characteristic components including α-pinene (21.5%), β-phellandrene (18.1%), p -cymene (12.2%), 3-methylnonane (8.7%), o -cymene (8.1%), and D-sylvestrene (6.2%). The EO from Cryptotaenia japonica was characterized by high amounts of α-selinene (48.7%), β-selinene (23.7%), and trans -β-farnesene (5.4%). The EOs from leaves and stems of Xyloselinum vietnamense were characterized by high concentrations of sabinene (69.8% and 33.8%), 4-terpineol (8.7% and 7.4%) and β-pinene (4.0% and 6.5%) while EOs from aerial parts and root of Xyloselinum leonidii comprise four characteristic monoterpenes including α-pinene (28.2% and 52.8%), β-pinene (7.9% and 10.3%), β-phellandrene (7.6% and 15.3%), and sabinene (3.0% and 4.1%). Additionally, cryptone is also one of the major components in the EO of Xyloselinum leonidii (13.2% in the aerial parts oil and 2. 8% in the root oil). In the EOs isolated from the aerial parts and root of Heracleum bivittatum , α-pinene (22.5% and 70.2%) and β-pinene (43.2% and 20.0%) were the predominant monoterpenes. Sabinene appeared in the EO from aerial parts of Heracleum bivittatum with a relatively high concentration (13.5%) while bornyl acetate (5.1%) was also one of the main components in the EO from its aerial parts but was not detected in other Apiaceae species in the present study. These databases help identify and control the quality of plant material studied from the family Apiaceae growing in Vietnam. [ABSTRACT FROM AUTHOR]

Increasing active sites in catalysts is of utmost importance for catalytic processes. In this regime, single‐atom dispersing on graphitic carbon nitrides (g‐C3N4) to produce fine chemicals, such as hydrogen peroxide (H2O2), is of current interest due to not only enhancing catalytic performance but also reducing the loading of necessary metals. Herein, g‐C3N4 is engineered by atomically dispersing aluminum (Al) or indium (In) sites to provide catalytic active centers via one‐step thermal shock polymerization. The addition of Al and In sites can accelerate the catalytic efficacy owing to the Lewis acid–base interactions between these metals and oxygen (O2). Under catalytic conditions, the formation of oxygenic radicals will strongly be associated with the enhanced formation of H2O2, confirmed by in situ electron paramagnetic resonance spectroscopy. Furthermore, the empirical analyses from positron annihilation spectroscopy show that In atoms will occupy the near positions of carbon vacancies (VC) to form NVC@InO bonds. This replacement will produce the highest formation energy based on the density functional theory calculations, improving the stability of atom‐dispersive materials. Therefore, via the combination of experimental and theoretical proofs, this study suggests the exact location of In atoms in g‐C3N4 structures, which can help boost the catalytic production of H2O2. [ABSTRACT FROM AUTHOR]

Elucidating the impact of heteroatoms in graphitic carbon nitrides (g‐C3N4) is of utmost importance to rationalize materials. Hence, in this study, oxygen‐doped g‐C3N4 containing trace amounts of halogen in the structures for piezo‐photosynthesis of hydrogen peroxides (H2O2) is fabricated. The findings reveal that oxygen atoms may be inserted into g‐C3N4 in‐plane structures, while halogen atoms tend to become intercalated between g‐C3N4 layers. Furthermore, the presence of ammonium molten salts (NH4X) during the synthesis alters the concentration of mono and cluster vacancies of carbon and nitrogen in the materials, certifying by positron annihilation spectroscopy (PAS). These defective contributions will be meaningfully accelerate catalytic performance by providing trapping states. Additionally, the decomposition of generated H2O2 can produce highly oxidative hydroxyl radicals, inducing degradations on the catalyst's structures and unexpectedly decreasing catalytic outcomes. From the mechanistic view, different reduction and oxidation channels will be play a pivotal role in generating H2O2. Moreover, the influence of ultrasound and light is also carefully investigated in the work to gain more insights into how the catalysts are triggered to improve catalytic performance. Thus, this study highlights the importance of carefully characterizing structures of g‐C3N4 to precisely understand the catalytic properties, benefiting catalytic design and development. [ABSTRACT FROM AUTHOR]

Keteleeria davidiana (C.E.Bertrand) Beissn. is a species of conifer native to southern China, Laos and Vietnam. The species has been listed as vulnerable in Vietnam. Essential oil samples have been isolated from leaves, twigs and wood, and their compositions investigated for the first time by combination of chromatographic and spectroscopic techniques [GC-FID, GC-MS and13C NMR]. The composition of leaf essential oil was dominated by α-pinene (28.1%), β-pinene (15.8%) and (E)-β-caryophyllene (13.8%). Twig essential oil contained mainly α-pinene (37.9%) and β-pinene (24.7%) accompanied by (E)-β-caryophyllene (8.3%) and β-phellandrene (7.5%). Lastly, α-pinene (27.9%), α-terpineol (20.3%) and (E)-β-caryophyllene (20.8%) were predominant in wood essential oil. [ABSTRACT FROM AUTHOR]