PENGARUH KUALITAS PRODUK, TESTIMONI DAN HARGA TERHADAP KEPUTUSAN PEMBELIAN PRODUK MA-SUM

Ma-sum merupakan bisnis yang bergerak pada industri madu, dan madu yang di pasarkan merupakan madu asli sumbawa. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh kualitas produk, testimoni dan harga terhadap keputusan pembelian produk Ma-sum  Merupakan penelitian kausal kuantitatif dan populasi dan sampel dari penelitian ini adalah masyarakat yang pernah membeli madu Ma-sum di surabaya. Karena populasinya tidak diketahui dengan margin of error 10%, Berdasarkan hasil perhitungan maka jumlah sampel yang akan digunakan sebanyak 96.04 responden dan akan dibulatkan menjadi 97 responden. Penelitian ini menggunakan pendekatan kuantitatif yang di bantu dengan program SPSS 25. Dalam penelitian ini terdapat tiga indikator yaitu kualitas produk, testimoni dan harga. Penelitian ini menggunakan metode deskriptif dengan pendekatan kuantitatif. Alat analisis menggunakan analisis regresi linear berganda, uji hipotesis dan uji asumsi klasik. Teknik pengumpulan data dilakukan dengan menyebar kuesioner. Teknik pengambilan sampel menggunakan purposive sampling. Jumlah sampel yang diteliti 47 responden. Hasil penelitian menunjukkan bahwa hanya testimoni (X2) yang berpengaruh secara signifikan terhadap keputusan pembelian (Y) sedangkan kualitas produk (X1) dan harga (X3) tidak berpengaruh secara signifikan terhadap keputusan pembelian (Y) Kata kunci: Kualitas Produk, Testimoni, Harga dan Keputusan Pembelia

Revealing the excitation energy transfer network of Light-Harvesting Complex II by a phenomenological analysis of two-dimensional electronic spectra at 77 K

Energy equilibration in light-harvesting antenna systems normally occurs before energy is transferred to a reaction center. The equilibration mechanism is a characteristic of the excitation energy transfer (EET) network of the antenna. Characterizing this network is crucial in understanding the first step of photosynthesis. We present our phenomenology-based analysis procedure and results in obtaining the excitonic energy levels, spectral linewidths, and transfer-rate matrix of Light-Harvesting Complex II directly from its 2D electronic spectra recorded at 77 K with waiting times between 100 fs to 100 ps. Due to the restriction of the models and complexity of the system, a unique EET network cannot be constructed. Nevertheless, a recurring pattern of energy transfer with very similar overall time scales between spectral components (excitons) is consistently obtained. The models identify a "bottleneck" state in the 664-668 nm region although with a relatively shorter lifetime (similar to 4-6 ps) of this state compared to previous studies. The model also determines three terminal exciton states at 675, 677-678, and 680-681 nm that are weakly coupled to each other. The excitation energy equilibration between the three termini is found to be independent of the initial excitation conditions, which is a crucial design for the light-harvesting complexes to ensure the energy flow under different light conditions and avoid excitation trapping. We proposed two EET schemes with tentative pigment assignments based on the interpretation of the modeling results together with previous structure-based calculations and spectroscopic observables. Published under license by AIP Publishing

Solvent-Exposed Salt Bridges Influence the Kinetics of α-Helix Folding and Unfolding

Salt bridges are known to play an essential role in the thermodynamic stability of the folded conformation of many proteins, but their influence on the kinetics of folding remains largely unknown. Here, we investigate the effect of Glu-Arg salt bridges on the kinetics of α-helix folding using temperature-jump transient-infrared spectroscopy and steady-state UV circular dichroism. We find that geometrically optimized salt bridges (Glu- and Arg+ are spaced four peptide units apart, and the Glu/Arg order is such that the side-chain rotameric preferences favor salt-bridge formation) significantly speed up folding and slow down unfolding, whereas salt bridges with unfavorable geometry slow down folding and slightly speed up unfolding. Our observations suggest a possible explanation for the surprising fact that many biologically active proteins contain salt bridges that do not stabilize the native conformation: these salt bridges might have a kinetic rather than a thermodynamic function

Temperature Dependence of the Energy Transfer in LHCII Studied by Two-Dimensional Electronic Spectroscopy

We measured two-dimensional electronic spectra of light-harvesting complex II (LHCII) at various temperatures (77, 110, 150, 230, and 295 K) under conditions free from singlet-singlet annihilation. We elucidated the temperature-dependent excitation energy transfer dynamics in the Chl a manifold of LHCII. Global analysis revealed that the dynamics can be summarized in distinct time scales from 200 fs up to 15 ps. While the fastest dynamics with a decay time of similar to 0.2-0.3 ps are relatively temperature-independent, the lifetimes and relative contributions of slower components showed considerable temperature dependence. The slowest time scale of equilibration with the lowest-energy Chl a increased from similar to 5 ps at 295 K to similar to 15 ps at 77 K. The final excited state is independent of initial excitation at 230 K and above, whereas static energy disorder is apparent at lower temperatures. A clear temperature dependence of uphill energy transfer processes was also discerned, which is consistent with the detailed-balance condition

Temperature Dependence of the Energy Transfer in LHCII Studied by Two-Dimensional Electronic Spectroscopy

We measured two-dimensional electronic spectra of light-harvesting complex II (LHCII) at various temperatures (77, 110, 150, 230, and 295 K) under conditions free from singlet-singlet annihilation. We elucidated the temperature-dependent excitation energy transfer dynamics in the Chl a manifold of LHCII. Global analysis revealed that the dynamics can be summarized in distinct time scales from 200 fs up to 15 ps. While the fastest dynamics with a decay time of similar to 0.2-0.3 ps are relatively temperature-independent, the lifetimes and relative contributions of slower components showed considerable temperature dependence. The slowest time scale of equilibration with the lowest-energy Chl a increased from similar to 5 ps at 295 K to similar to 15 ps at 77 K. The final excited state is independent of initial excitation at 230 K and above, whereas static energy disorder is apparent at lower temperatures. A clear temperature dependence of uphill energy transfer processes was also discerned, which is consistent with the detailed-balance condition

Amplified Vibrational Circular Dichroism as a Probe of Local Biomolecular Structure

We show that the VCD signal intensities of amino acids and oligopeptides can be enhanced by up to 2 orders of magnitude by coupling them to a paramagnetic metal ion. If the redox state of the metal ion is changed from paramagnetic to diamagnetic the VCD amplification vanishes completely. From this observation and from complementary quantum-chemical calculations we conclude that the observed VCD amplification finds its origin in vibronic coupling with low-lying electronic states. We find that the enhancement factor is strongly mode dependent and that it is determined by the distance between the oscillator and the paramagnetic metal ion. This localized character of the VCD amplification provides a unique tool to specifically probe the local structure surrounding a paramagnetic ion and to zoom in on such local structure within larger biomolecular systems

Transient two-dimensional vibrational spectroscopy of an operating molecular machine

Synthetic molecular machines are promising building blocks for future nanoscopic devices. However, the details of their mechanical behaviour are in many cases still largely unknown. A deeper understanding of mechanics at the molecular level is essential for the design and construction of complex nanodevices. Here, we show that transient two-dimensional infrared (T2DIR) spectroscopy makes it possible to monitor the conformational changes of a translational molecular machine during its operation. Translation of a macrocyclic ring from one station to another on a molecular thread is initiated by a UV pulse. The arrival of the shuttling macrocycle at the final station is visible from a newly appearing cross peak between these two moieties. To eliminate spectral congestion in the T2DIR spectra, we use a subtraction method applicable to many other complex molecular systems. The T2DIR spectra indicate that the macrocycle adopts a boat-like conformation at the final station, which contrasts with the chair-like conformation at the initial station