ISOLATION AND CHARACTERISATION OF RAPAMYCIN, TEMSIROLIMUS REGIO ISOMER (MONOESTER) AND TEMSIROLIMUS DIESTER IN TEMSIROLIMUS DRUG

Objective: Separation and identification of the process impurities in the manufacture of temsirolimus drug viz., rapamycin, temsirolimus regioisomer (monoester) (TS monoester), and temsirolimus diester (TS diester). Methods: During the process development of temsirolimus (TS), three process impurities-rapamycin, temsirolimus regioisomer (monoester) and temsirolimus diester-were detected by high-performance liquid chromatography (HPLC). Impurities were isolated by medium pressure liquid Chromatography (MPLC) and characterized by ESI-MS/MS, 1H NMR, FT-IR spectral data. Results: These impurities are characterised with the help of ESI MS/MS, 1H NMR, and FT-IR data. The impurities are identified and characterised as the process impurities. One of them is the starting material i.e. rapamycin and the other two are formed during the manufacture of the drug. This method offers advantages over using photodiode-array UV detection (LC-PDA) for the determination of peak purity, viz. components with similar UV spectra can be distinguished. Conclusion: The structures of these impurities were characterized as rapamycin, TS Monoester, and TS Diester. Out of these process impurities, rapamycin has been previously identified while the other two are previously unreported

The determinants of Western Australia’s foreign investment in China

The growing economic importance of China with its major economic power in the East Asia region has become a popular host destination for receiving foreign investment from Hong Kong, Korea, and Taiwan. With China’s growth and development, this nation has over time become one of Australia’s main trading partners. As new investment opportunities have emerged, Australian companies, especially from Western Australia have shown interest in the Chinese marketplace. Despite the popular consensus that Australian companies are increasingly investing in China, to date relevant literature examining this notion is limited. Specifically, studies of elements that motivate or deter owners / managers of Australian companies, especially from Western Australia to invest in China are restricted. Consequently, the purpose of this study was to investigate the likely relationships between four independent constructs (1. market size, 2. labour cost, 3. infrastructure, and 4. business ethics) in China and the intensity of foreign investment from Western Australia, and to evaluate if and how these relationships are mediated by personality attributes (i.e., gender), organisational properties (i.e., size), and networking.To empirically investigate the determining factor for undertaking investment in China, this study employed both quantitative and qualitative approaches. The use of the quantitative method positivist approach is deemed as a suitable, partial approach, which assists in determining the statistical relationships between the investigated variables. Moreover, a qualitative approach was used in a complementing context to understand the quantitative results. Given the dynamic business environment in China, the use of a qualitative approach has potential for gaining a more comprehensive understanding of quantitative findings as well as providing rich information for further interpretations.This study was conducted with 43 respondents of Western Australian companies. A salient feature of the study companies is that they either have capabilities to invest or are already investing in mainland China (People’s Republic of China, in this study identified as China). The targeted companies are involved in manufacturing and services industries, such as mining, education, banking, and telecommunication. Although collecting primary data appeared to be a challenge, the data were robust for statistical analysis. In addition, the data were from decision makers of the study companies, which further indicate the richness of the sample.The findings of this study revealed that China’s large market size plays a positive role in attracting investments from WA to China. Similarly, the adequate level of infrastructure and the level of familiarity of business ethics in China tend to somewhat encourage WA investors to conduct business in China. In contrast, China’s cheap labour cost was not the primary driver that motivates WA companies to invest in China. In relation to the mediating effects of personality attributes (e.g., gender), organisational properties (i.e., size), and networking the study findings revealed that networking plays a significant mediating role in the investment decision. However, due to the relatively small sample size, personality attributes and organisational properties were established to provide insufficient analytical rigor in the decision to invest in China by WA companies.The implications for this study may offer insightful information to enrich the understanding of the determinants of Australian foreign investment in general, and in the Chinese marketplace in particular. In addition, by empirically investigating the perceptions of the decision makers of WA companies in relation to their investment decisions in China, the findings of this research may assist foreign companies to undertake better planning of their investment decisions. More specifically, this study may offer additional insight to those companies that are operating or planning to invest in the Chinese marketplace. For example, this study may be particularly useful for international managers or owners, as it may provide some fruitful information to assist a better understanding of the issues that relate to business ethics with Chinese operations. In addition, the phenomenon of guanxi in China has been considered as a major determinant for facilitating business engagement in the Chinese marketplace. It may, therefore, be argued that the phenomenon of guanxi in assisting business operations in China has become increasingly important, and international managers or owners may need to gain a deeper understanding of this phenomenon

Glycosylation of Erythrocyte Spectrin and Its Modification in Visceral Leishmaniasis

Using a lectin, Achatinin-H, having preferential specificity for glycoproteins with terminal 9-O-acetyl sialic acid derivatives linked in α2-6 linkages to subterminal N-acetylgalactosamine, eight distinct disease-associated 9-O-acetylated sialoglycoproteins was purified from erythrocytes of visceral leishmaniaisis (VL) patients (RBCVL). Analyses of tryptic fragments by mass spectrometry led to the identification of two high-molecular weight 9-O-acetylated sialoglycoproteins as human erythrocytic α- and β-spectrin. Total spectrin purified from erythrocytes of VL patients (spectrinVL) was reactive with Achatinin-H. Interestingly, along with two high molecular weight bands corresponding to α- and β-spectrin another low molecular weight 60 kDa band was observed. Total spectrin was also purified from normal human erythrocytes (spectrinN) and insignificant binding with Achatinin-H was demonstrated. Additionally, this 60 kDa fragment was totally absent in spectrinN. Although the presence of both N- and O-glycosylations was found both in spectrinN and spectrinVL, enhanced sialylation was predominantly induced in spectrinVL. Sialic acids accounted for approximately 1.25 kDa mass of the 60 kDa polypeptide. The demonstration of a few identified sialylated tryptic fragments of α- and β-spectrinVL confirmed the presence of terminal sialic acids. Molecular modelling studies of spectrin suggest that a sugar moiety can fit into the potential glycosylation sites. Interestingly, highly sialylated spectrinVL showed decreased binding with spectrin-depleted inside-out membrane vesicles of normal erythrocytes compared to spectrinN suggesting functional abnormality. Taken together this is the first report of glycosylated eythrocytic spectrin in normal erythrocytes and its enhanced sialylation in RBCVL. The enhanced sialylation of this cytoskeleton protein is possibly related to the fragmentation of spectrinVL as evidenced by the presence of an additional 60 kDa fragment, absent in spectrinN which possibly affects the biology of RBCVL linked to both severe distortion of erythrocyte development and impairment of erythrocyte membrane integrity and may provide an explanation for their sensitivity to hemolysis and anemia in VL patients

Modulation of Sn concentration in ZnO nanorod array: intensification on the conductivity and humidity sensing properties

Tin (Sn)-doped zinc oxide (ZnO) nanorod arrays (TZO) were synthesized onto aluminum-doped ZnO-coated glass substrate via a facile sonicated sol–gel immersion method for humidity sensor applications. These nanorod arrays were grown at different Sn concentrations ranging from 0.6 to 3 at.%. X-ray diffraction patterns showed that the deposited TZO arrays exhibited a wurtzite structure. The stress/strain condition of the ZnO film metamorphosed from tensile strain/compressive stress to compressive strain/tensile stress when the Sn concentrations increased. Results indicated that 1 at.% Sn doping of TZO, which has the lowest tensile stress of 0.14 GPa, generated the highest conductivity of 1.31 S cm− 1. In addition, 1 at.% Sn doping of TZO possessed superior sensitivity to a humidity of 3.36. These results revealed that the optimum performance of a humidity-sensing device can be obtained mainly by controlling the amount of extrinsic element in a ZnO film

Default risk, state ownership and the cross-section of stock returns: evidence from China

We apply a structural model to estimate firm-level default risk in China and investigate the stock return predictability of default risk and the moderating effects of state ownership for the sample period from 2003 to 2015. We show unique evidence that in China, default risk is positively associated with expected stock returns and state ownership matters considerably to the return predictability of default risk. We find investors of state-owned enterprises (SOEs) are not compensated appropriately in China despite of their higher default risk exposure. Our empirical evidence supports the conjecture on shareholder advantages and suggests that a strong bargaining power of equity holders would have a negative impact on stock returns

A Search for Technosignatures Around 11,680 Stars with the Green Bank Telescope at 1.15-1.73 GHz

We conducted a search for narrowband radio signals over four observing sessions in 2020-2023 with the L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank Telescope. We pointed the telescope in the directions of 62 TESS Objects of Interest, capturing radio emissions from a total of ~11,680 stars and planetary systems in the ~9 arcminute beam of the telescope. All detections were either automatically rejected or visually inspected and confirmed to be of anthropogenic nature. In this work, we also quantified the end-to-end efficiency of radio SETI pipelines with a signal injection and recovery analysis. The UCLA SETI pipeline recovers 94.0% of the injected signals over the usable frequency range of the receiver and 98.7% of the injections when regions of dense RFI are excluded. In another pipeline that uses incoherent sums of 51 consecutive spectra, the recovery rate is ~15 times smaller at ~6%. The pipeline efficiency affects calculations of transmitter prevalence and SETI search volume. Accordingly, we developed an improved Drake Figure of Merit and a formalism to place upper limits on transmitter prevalence that take the pipeline efficiency and transmitter duty cycle into account. Based on our observations, we can state at the 95% confidence level that fewer than 6.6% of stars within 100 pc host a transmitter that is detectable in our search (EIRP > 1e13 W). For stars within 20,000 ly, the fraction of stars with detectable transmitters (EIRP > 5e16 W) is at most 3e-4. Finally, we showed that the UCLA SETI pipeline natively detects the signals detected with AI techniques by Ma et al. (2023).Comment: 22 pages, 9 figures, submitted to AJ, revise