Design and construction of a refrigerator-cooled adiabatic calorimeter for heat capacity measurement in liquid helium temperature region.

Heat capacity is a fundamental thermodynamic property of a substance. Although heat capacity values and related thermodynamic functions are available for many materials, low-temperature heat capacity measurements, especially for novel materials, can still provide valuable insights for research in physics, chemistry, thermodynamics, and other fields. Reliable low-temperature heat capacity data are typically measured using classical adiabatic calorimeters, which use liquid helium as the refrigerant to provide a cryogenic environment for heat capacity measurements.

[Analyze on HPLC fingerprint of four main metropolis of herba pogostemonis].

Objective: To establish a method for analyzing HPLC fingerprint of Herba pogostemonis and compare the variability of four main producing areas.

Methods: Diamonsil (R) C18 column was used, the Methanol-0.1% phosphoric acid (gradient elution) as a mobile phase and detection wavelength was set at 254nm, column temperature was 25 degrees C and flow rate was 1.

[Seperation and structure elucidation of alkaloids from Chinese drug buzhaye, Folium Microcos].

From the chloroform extracts of the dried Folium Microcos, four compounds were isolated by using repeated column chromatography on silica gel and recrystallization and their structures were elucidated by physicochemical properties and UV, MS and NMR, separately. They are N-methyl-6alpha-(deca-1', 3', 5'-trienyl)-3beta-methoxy-2beta-methylpiperidine, 6-(deca-1', 3', 5'-trienyl)-3-methoxy-2-methylpiperidine, N-methyl-6-(deca-1', 3', 5'-trienyl)-2, 3-dimethylpiperidine and N-methyl-6-(deca-1', 3', 5'-trienyl)-2-methylpiperidine, named as micropiperidine A, micropiperidine B, micropiperidine C and micropiperidine D, respectively. The latter three are new compounds.

[Two chemotypes of Pogostemon cablin and influence of region of cultivation and harvesting time on volatile oil composition].

Aim: To analyze and compare the constituents of the volatile oil of Pogostemon cablin collected from different regions of cultivation and harvesting times in order to evaluate the quality of Shipai Huoxiang and to expound the chemical intension of Pogostemon cablin.

Methods: The combination of GC and MS.

Results: The volatile oil compositions of Herba Pogostemonis collected from various of cultivation regions and harvesting times are obviously different.

[DNA profiling of Pogostemon cablin chemotypes differing in essential oil composition].

Aim: To provide molecular evidence for quality evaluation and GAP production of Pogostemon cablin (Blanco) Benth. cultivated in different regions in Guangdong and Hainan provinces, China, by comparing two sequences (1.2 kb of plastid matK gene and 1.

[DNA sequencing and molecular identification of Patchouli and its substitute wrinkled gianthyssop].

Aim: To analyze sequences of the nuclear ribosomal RNA small subunit (18S rRNA) gene and the chloroplast matK gene of crude drug Patchouli (Pogostemon cablin) in order to provide molecular evidence for identification of Patchouli drug.

Methods: To sequence the entire 18S rRNA gene and partial matK gene of Patchouli from Guangzhou and its substitute Wrinkled Gianthyssop (Agastache rugosa) from Sichuan using PCR direct sequencing and to detect the homology of two gene sequences between these two crude drugs.

Results: The complete 18S rRNA gene sequence is 1,805 bp in length for Patchouli from Guangzhou whereas 1,794 bp for Wrinkled Gianthyssop from Sichuan.