Search Results (4)

Vietnam’s tourism sector has experienced rapid expansion, yielding significant economic gains, but also escalating environmental and socio-cultural challenges. This necessitates a shift toward sustainable tourism practices. This study develops and tests an integrative model combining the Theory of Planned Behavior (TPB) and Value–Belief–Norm (VBN) theory to investigate the Sustainable Consumption Behavior (SCB) of domestic travelers in Vietnam. Grounded in the country’s collectivist culture—characterized by a strong emphasis on communal values and social harmony—the research examines how rational decision-making and normative pressures jointly drive eco-friendly travel behaviors. Data were collected from 549 Vietnamese tourists through stratified sampling across three major regions, and were analyzed through a robust multi-step methodology, including Exploratory Factor Analysis, Confirmatory Factor Analysis, and structural equation modeling (SEM), supplemented by regression analysis. The SEM results indicate that the proposed model accounts for 60.8% of the variance in SCB, underscoring its explanatory power. Within the TPB framework, Attitude, Subjective Norms, and Perceived Behavioral Control significantly predict Behavioral Intention, which, in turn, mediates their influence on SCB. In the VBN component, Environmental Awareness shapes Altruistic and Biospheric Values, fostering the New Environmental Paradigm and activating Personal Norms, which exert a direct effect on SCB. This direct influence of Personal Norms, bypassing Behavioral Intention, highlights the role of implicit moral obligations in Vietnam’s collectivist cultural context and challenges Western-centric behavioral models. Beyond these frameworks, Destination Attributes and Consumer Innovativeness emerge as critical direct predictors of SCB, with Destination Attributes showing the strongest effect. Mediation analyses confirm Behavioral Intention’s central role, while moderation tests reveal that gender and travel experience modulate TPB-based relationships, suggesting the value of targeted interventions. Theoretically, this study advances TPB–VBN integration by applying it to a collectivist setting, revealing how cultural norms amplify normative influences on sustainable behavior. Practically, it advocates for strategies such as community-driven initiatives leveraging Personal Norms, educational campaigns to enhance Perceived Behavioral Control, and sustainable destination management initiatives in locations like Da Nang and Ha Long Bay. While the cross-sectional design limits causal claims, the findings provide a foundation for future longitudinal studies and cross-cultural comparisons, particularly in other collectivist societies, potentially incorporating digital engagement and policy incentives as novel factors. Full article

A fully integrated 24-GHz radar transceiver with one transmitter (TX) and two receivers (RXs) for compact frequency modulated continuous wave (FMCW) radar applications is here presented. The FMCW synthesizer was realized using a fractional-N phase-locked loop (PLL) and programmable chirp generator, which are completely integrated in the proposed transceiver. The measured output phase noise of the synthesizer is −80 dBc/Hz at 100 kHz offset. The TX consists of a three-bit bridged t-type attenuator for gain control, a two-stage drive amplifier (DA) and a one-stage power amplifier (PA). The TX chain provides an output power of 13 dBm while achieving <0.5 dB output power variation within the range of 24 to 24.25 GHz. The RX with a direct conversion I-Q structure is composed of a two-stage low noise amplifier (LNA), I-Q generator, mixer, transimpedance amplifier (TIA), a two-stage biquad band pass filter (BPF), and a differential-to-single (DTS) amplifier. The TIA and the BPF employ a DC offset cancellation (DCOC) circuit to suppress the strong reflection signal and TX-RX leakage. The RX chain exhibits an overall gain of 100 dB. The proposed radar transceiver is fabricated using a 65 nm CMOS technology. The transceiver consumes 220 mW from a 1 V supply voltage and has 4.84 mm² die size including all pads. The prototype FMCW radar is realized with the proposed transceiver and Yagi antenna to verify the radar functionality, such as the distance and angle of targets. Full article

This paper describes Monolithic Microwave Integrated Circuits (MMICs) for an X-band radar transceiver front-end implemented in 0.25 μm GaN High Electron Mobility Transistor (HEMT) technology. Two versions of single pole double throw (SPDT) T/R switches are introduced to realize a fully GaN-based transmit/receive module (TRM), each of which achieves an insertion loss of 1.21 dB and 0.66 dB at 9 GHz, IP_1dB higher than 46.3 dBm and 44.7 dBm, respectively. Therefore, it can substitute a lossy circulator and limiter used for a conventional GaAs receiver. A driving amplifier (DA), a high-power amplifier (HPA), and a robust low-noise amplifier (LNA) are also designed and verified for a low-cost X-band transmit-receive module (TRM). For the transmitting path, the implemented DA achieves a saturated output power (P_sat) of 38.0 dBm and output 1-dB compression (OP_1dB) of 25.84 dBm. The HPA reaches a P_sat of 43.0 dBm and power-added efficiency (PAE) of 35.6%. For the receiving path, the fabricated LNA measures a small-signal gain of 34.9 dB and a noise figure of 2.56 dB, and it can endure higher than 38 dBm input power in the measurement. The presented GaN MMICs can be useful in implementing a cost-effective TRM for Active Electronically Scanned Array (AESA) radar systems at X-band. Full article

IL-8/MCP-1 act as neutrophil/monocyte chemoattractants, respectively. Oxidative stress emerges as a key player in the pathophysiology of obesity. However, it remains unclear whether the TNF-α/oxidative stress interplay can trigger IL-8/MCP-1 expression and, if so, by which mechanism(s). IL-8/MCP-1 adipose expression was detected in lean, overweight, and obese individuals, 15 each, using immunohistochemistry. To detect the role of reactive oxygen species (ROS)/TNF-α synergy as a chemokine driver, THP-1 cells were stimulated with TNF-α, with/without H₂O₂ or hypoxia. Target gene expression was measured by qRT-PCR, proteins by flow cytometry/confocal microscopy, ROS by DCFH-DA assay, and signaling pathways by immunoblotting. IL-8/MCP-1 adipose expression was significantly higher in obese/overweight. Furthermore, IL-8/MCP-1 mRNA/protein was amplified in monocytic cells following stimulation with TNF-α in the presence of H₂O₂ or hypoxia (p ˂ 0.0001). Synergistic chemokine upregulation was related to the ROS levels, while pre-treatments with NAC suppressed this chemokine elevation (p ≤ 0.01). The ROS/TNF-α crosstalk involved upregulation of CHOP, ERN1, HIF1A, and NF-κB/ERK-1,2 mediated signaling. In conclusion, IL-8/MCP-1 adipose expression is elevated in obesity. Mechanistically, ROS/TNF-α crosstalk may drive expression of these chemokines in monocytic cells by inducing ER stress, HIF1A stabilization, and signaling via NF-κB/ERK-1,2. NAC had inhibitory effect on oxidative stress-driven IL-8/MCP-1 expression, which may have therapeutic significance regarding meta-inflammation. Full article