Typical Pulse Research Articles

Effect of discharge parameters on electric-spark deposition material transfer

In order to study the influence of discharge parameters on the electric spark deposition process, an automatic electric spark deposition device is built by a closed-loop control system of discharge parameters. An automatic electric spark deposition test is carried out at different control voltages. By analyzing the effective discharge waveform parameters, transfer efficiency, deposition efficiency, contact force in the deposition process, surface morphology, and cross-sectional morphology of the deposition layer under different control voltages, etc. Analysis of the results shows that changing the control voltage has a direct effect on the number of discharge types in the deposition process. With the appropriate control voltage, better transfer efficiency and deposition quality can be achieved. Contact discharge has a greater effect on material transfer efficiency than other types of discharge. The transfer of the electrode to the material on the workpiece is mainly achieved by contact discharge. Automatic control of discharge parameters can also be applied to automatic control of discharge pulse types.

Two types of ultrafast mode-locking operations from an Er-doped fiber laser based on germanene nanosheets

As a member of Xenes family, germanene has excellent nonlinear saturable absorption characteristics. In this work, we prepared germanene nanosheets by liquid phase exfoliation and measured their saturation intensity as 0.6 GW/cm2 with a modulation depth of 8%. Then, conventional solitons with a pulse width of 946 fs and high-energy noise-like pulses with a pulse width of 784 fs were obtained by using germanene nanosheet as a saturable absorber for a mode-locked Erbium-doped fiber laser. The characteristics of the two types of pulses were investigated experimentally. The results reveal that germanene has great potential for modulation devices in ultrafast lasers and can be used as a material for creation of excellent nonlinear optical devices to explore richer applications in ultrafast photonics.Graphical

Determining plasma boundary in Alvand-U tokamak

One of the major topic of tokamak research is the determination of the magnetic profile due to magnetic coil fields and plasma current by mean of data from magnetic probes. The most practical approach is to use the current filament method, which models the plasma column with multiple current carrying filaments and the total current of these filaments is equal to the plasma current. Determining the plasma boundary in Alvand-U tokamak is the main purpose of this paper. In order to determine the magnetic field profile and plasma boundary, information concerning the magnetic coils, their position, and current is required in the computing code. Then, the plasma shape is determined and finally the plasma boundary is extracted by the code. In the conducted research, we discuss how to determine the plasma boundary and the performance of the computing code for extraction of the plasma boundary. The developed algorithm shows to be effective by running it in the regular pc machine with characteristics of Intel (R) core (TM) i3-10100 CPU @3.60 GHz and 8.00 GB of RAM. Finally, we present results of a test run for computing code using a typical experimental pulse.

Investigation on different type of pulses due to strong third order dispersion effect in mode-locked fiber lasers

Here we have numerically investigated the pulse property in a wavelength switchable mode-locked fiber laser which is achieved with a tunable filter. Owing to the strong third-order dispersion (TOD) of dispersion-compensating fiber, the net cavity group velocity dispersion of the proposed fiber laser can be manipulated and exhibits wavelength-dependent feature. Our findings indicate that different types of pulses, including conventional solitons, dispersion-managed solitons, and dissipative solitons, can be achieved, and switched in various wavelengths. The pulse characteristics including pulse width and spectrum bandwidth have been investigated, in addition to with the intracavity dynamics. The influence of the length of dispersion-compensating fiber is also investigated. These results provide an excellent foundation for understanding the formation dynamics of various pulse waveforms in the laser cavity and help the development of a multi-wavelength fiber laser with a strong TOD cavity.

Phase I study of adoptive T cell therapy following HER2-pulsed dendritic cell vaccine and pepinemab/trastuzumab in patients with metastatic HER2-positive breast cancer (MBC).

TPS1113 Background: Despite major improvement of overall survival of HER2+ MBC with effective HER2 targeted therapies, many patients experience significant toxicities and develop progressive disease during treatment. Therefore, new and more effective therapeutic options are needed. This novel approach will evaluate whether the combination of three immunotherapies in addition to trastuzumab: dendritic cell (DC) vaccination, anti-SEMA4D blocking antibody (pepinemab) and CD4+ T cell adoptive transfer can lead to improved outcomes for patients with MBC refractory to HER2-targeted agents. BC have been considered as immunologically cold which is attributed to immune evasion and suppression of host effector immune cells homing into tumor bed. Progressive loss of Th1 immunity against HER2 oncodriver correlates with poor prognosis. HER2 peptide pulsed type I dendritic cells (HER2-DC1) restored anti-HER2 CD4+ Th1 immune response and improved pathologic complete response (pCR) in HER2+ BC. Antibodies to SEMA4D have been shown to modulate the TME by increasing effector cell infiltration and reducing immunosuppression. In preclinical studies, treatment with anti-SEMA4D and HER2-DC1 in mice bearing established HER2+ tumors improved DC homing, expansion of CD4+ T cells, and complete tumor regression, compared to treatment with anti-SEMA4D or HER2-DC1 alone. Further, subsequent expansion and adoptive transfer of CD4+ T cells induced synergistic anti-tumor activity by activating CD8+ T mediated cytotoxicity. Pepinemab was well-tolerated and showed signs of anti-tumor activity in in immunotherapy-resistant and PD-L1 negative/low non-small cell lung cancer patients when combined with checkpoint inhibitor (avelumab). Methods: This open label Phase 1 study is enrolling up to 28 patients with HER2+ MBC. Patients will be treated with 6 weekly injections of dendritic cell (DC1) vaccines in combination with trastuzumab and pepinemab. We hypothesize these therapies may elicit CD4+ HER2-specific T cell responses. HER2-specific T cells will be expanded ex vivo and subsequently infused to patients following lymphodepletion with cyclophosphamide. Trastuzumab and pepinemab will be given as maintenance in addition to booster DC1 vaccines. Patients (ECOG 0,1) must have had disease progression while on trastuzumab for the treatment of HER2+ MBC and received no more than 3 lines of chemotherapy in the setting of metastatic disease. Dose escalation will consist of 3-6 patients each with increasing amounts of transferred CD4+ T cells, followed by dose expansion of 10 patients at the MTD. The primary objective is safety and tolerability; secondary objectives will include evaluation of T cell immunity and immune subsets, efficacy, PK/PD/ADA of pepinemab, and biomarker assessments. Clinical trial information: NCT05378464 .

Immunogenic Cell Death in Electroporation-Based Therapies Depends on Pulse Waveform Characteristics.

Traditionally, electroporation-based therapies such as electrochemotherapy (ECT), gene electrotransfer (GET) and irreversible electroporation (IRE) are performed with different but typical pulse durations-100 microseconds and 1-50 milliseconds. However, recent in vitro studies have shown that ECT, GET and IRE can be achieved with virtually any pulse duration (millisecond, microsecond, nanosecond) and pulse type (monopolar, bipolar-HFIRE), although with different efficiency. In electroporation-based therapies, immune response activation can affect treatment outcome, and the possibility of controlling and predicting immune response could improve the treatment. In this study, we investigated if different pulse durations and pulse types cause different or similar activations of the immune system by assessing DAMP release (ATP, HMGB1, calreticulin). Results show that DAMP release can be different when different pulse durations and pulse types are used. Nanosecond pulses seems to be the most immunogenic, as they can induce the release of all three main DAMP molecules-ATP, HMGB1 and calreticulin. The least immunogenic seem to be millisecond pulses, as only ATP release was detected and even that assumingly occurs due to increased permeability of the cell membrane. Overall, it seems that DAMP release and immune response in electroporation-based therapies can be controlled though pulse duration.

Supercooling behaviours of thermoelectric coolers with different continuous Double-pulse current waveforms

This study innovatively identifies techniques to improve the transient supercooling performance of thermoelectric coolers (TECs) through continuous double-pulse currents with different waveforms. Some applications need to operate at a specific temperature while obtaining the requirement for long periods of refrigeration, thus the new effective cold-holding time (teff-hold) for the defined effective cooling line and the variation curve of the cold-end temperature was used as the main index to measure the transient performance of the TEC. In addition, the cold-end minimum temperature (Tc,min), overshoot temperature (Tc,max), and the time for recovery to steady-state temperature (trec) of TEC were considered comprehensively. A three-dimensional (3D) multi-physics coupling transient model was constructed using numerical simulations, and its accuracy was verified by experimental data. Five typical pulse waveforms (-t−2, -t1/2, t0, t1/2, and t2) were used as the research objects. The results demonstrated that the waveform of the continuous double-pulse current plays an important role in improving the teff-hold of TECs under transient working conditions. In this simulation, the pulse widths (τ1 and τ2) of the first and second pulse currents were both 4 s when the pulse initial current was the optimal current (0.6A). When the pulse amplitudes (P1 and P2) were equal and small, the pulse current combination of t0 + t1/2 was applied, which could achieve relatively large teff-hold values. However, -t2 + t1/2 was more appropriate. Additionally, large teff-hold values for TECs could be achieved by reasonably choosing the pulse widths (τ1 and τ2) and amplitudes (P1 and P2) of continuous double-pulse waveforms and the initial current of the second pulse current (Iini,2). It is important to ensure that P1 is not too large, or it may lead to significant increases in Tc,min and Tc,max, a growth in trec, and a reduction in teff-hold. In this study, the optimal teff-hold was achieved (8.38 s) when the pulse current combination was -t2 + t1/2, P1 = 4, P2 = 3, τ1 = τ2 = 4 s, and Iini,2 = 0.55A.

Fabrication of Screen‐Printed Single‐Electrode Triboelectric Nanogenerator‐Based Self‐Powered Sensor for Pulse Measurement and Its Characterization

The development of triboelectric nanogenerator technology has many benefits across various fields, particularly in healthcare applications; herein, a concise single‐electrode pulse sensor with a high output performance at a reasonable cost is suggested. The device is made up of a polydimethylsiloxane film with a spacer‐created trench structure stacked on top of a graphene‐coated polyethylene terephthalate film. A comprehensive examination of sensor fabrication together with material and electrical characterization is explained. The entire study is carried out using a graphene–silver composite electrode device, giving an output performance of ≈1.66 and ≈2.9 V for tapping movement in plain and microstructured triboelectric surfaces, respectively; however, for the graphene electrode device, the output obtained is ≈5.5 V. This wearable sensor can successfully extract the typical human wrist pulse, which displays the pressure wave from the radial artery in the range of ≈5 V with the help of an exemplary amplifier circuit and will be suitable to integrate with IoT.

Single and Bunch Soliton Generation in Optical Fiber Lasers Using Bismuth Selenide Topological Insulator Saturable Absorber.

In this work, we present the generation of two distinct types of soliton pulses using a Bismuth Selenide (Bi2Se3) saturable absorber (SA) synthesized in our laboratory. The soliton pulses were generated in two different laser cavity configurations, resulting in two types of solitons: a soliton pulse with Kelly sidebands and a bunched soliton pulse with peak-dip sidebands. Both solitons operated at the fundamental repetition rate-23.3 MHz (for the soliton with Kelly sidebands) and 13 MHz (for the bunched soliton with peak-dip sidebands). We observed that the accumulation of nonlinear phase shift from the added single mode fiber (SMF) split the single soliton pulse into 44 pulses in a bunched oscillation envelope. At the same time, peak-dip sidebands were imposed on the bunched soliton spectrum due to constructive and destructive interferences between soliton pulse and dispersive waves. The measured pulse width for both solitons were 0.63 ps (for the soliton with Kelly sidebands) and 1.52 ps (for the bunched soliton with peak-dip sidebands), respectively. Our results demonstrate the potential of Bi2Se3 SAs in generating different types of soliton pulses, which could have potential applications in various areas of optical communication and spectroscopy.

Controlling inversion and time-reversal symmetries by subcycle pulses in the one-dimensional extended Hubbard model

Owning to their high controllability, laser pulses have contributed greatly to our understanding of strongly correlated electron systems. However, typical multicycle pulses do not control the symmetry of systems, which plays an important role in the emergence of novel quantum phases. Here, we demonstrate that subcycle pulses whose oscillation is less than one period within a pulse envelope can control inversion and time-reversal symmetries in the electronic states of the one-dimensional extended Hubbard model. Using an ultrashort subcycle pulse, one can generate a steady electric current (SEC) in a photoexcited state due to an Aharonov-Bohm flux instantaneously introduced through the phase of an electric field. Consequently, time-reversal symmetry is broken. In contrast, a broad subcycle pulse does not induce SEC but instead generates electric polarization, thus breaking inversion symmetry. Both symmetry breakings in a photoexcited state can be monitored by second-harmonic generation. These findings provide a new methodology for designing the symmetries of electronic states and open up a new field of subcycle-pulse engineering.

Non-aqueous magnetization following adiabatic and selective pulses in brain: T1 and cross-relaxation dynamics.

Inversion pulses are commonly employed in MRI for T1 -weighted contrast and relaxation measurements. In brain, it is often assumed that adiabatic pulses saturate the non-aqueous magnetization. We investigated this assumption using solid-stateNMRto directly monitor the non-aqueous signal following adiabatic inversion and compared this to signals following hard and soft inversion pulses. The effects of the different preparations on relaxation dynamics were explored. Inversion recovery experiments were performed on ex vivo bovine and porcine brains in 360 MHz (8.4 T) and 200 MHz (4.7 T) NMR spectrometers, respectively, using broadband rectangular, adiabatic, and sinc inversion pulses as well as a long rectangular saturation pulse. Analogous human brain MRI experiments were performed at 3 T using single-slice echo-planar imaging. Relaxation data were fitted by mono- and bi-exponential decay models. Further fitting analysiswas performed using only two inversion delay times. Adiabatic and sinc inversion left much of the non-aqueous magnetization along B0 and resulted in bi-exponential relaxation. Saturation of both aqueous and non-aqueous magnetization components led to effectively mono-exponential T1 . relaxation. Typical adiabatic inversion pulses do not, as has been widely assumed, saturate the non-aqueous proton magnetization in white matter. Unequal magnetization states in aqueous and non-aqueous .H reservoirs prepared by soft and adiabatic pulses result in bi-exponential T1 . relaxation. Both pools must be prepared in the same magnetization state (e.g. saturated or inverted) in order to observe consisten mono-exponential relaxation.

Effect of infrared heating on the nutritional properties of yellow pea and green lentil flours

AbstractBackground and ObjectivesTo enhance the utilization of pulse ingredients, greater knowledge of the effect of infrared (IR) processing on protein and starch nutrition is needed. The current study investigated the use of tempering (20% vs. 30% moisture) with IR heating (120°C vs. 140°C) to improve the nutritional value of two commercially important pulses: green lentils and yellow peas.FindingsProximate composition remained mostly unchanged after IR heating for both pulse types. The protein's secondary structure transitioned to a state with a higher amount of random coils as IR processing conditions intensified (increase in moisture and temperature). In vitro protein digestibility (IVPD) increased from 73% to 78%−82% for green lentil and 78% to 81%−85% for yellow pea, depending on IR processing treatment. Tryptophan was the limiting amino acid in all samples. The IVPD corrected amino acid scores were not significantly altered by IR processing. The content of rapidly (RDS) and slowly (SDS) digestible starches increased, whereas that of resistance starch declined with IR processing.ConclusionsThe combined effect of tempering moisture and IR heat as a premilling treatment changed the protein secondary structure but did not improve the overall protein quality of the pulses. Starch digestibility was improved with IR processing.Significance and NoveltyEmploying tempering and IR heating techniques on pulses may be useful in food and feed applications where improved starch digestibility is desired.

Abstract 3197: Adoptive T cell therapy using IL-7 and IL-15 expanded HER2-specific CD4 T cells for metastatic breast cancer

Abstract BACKGROUND: Adoptive cell therapy (ACT) has had limited success due to low T cell infiltration in breast cancer (BC) patients. We have shown that administration of class II HER2 peptide pulsed type I polarized dendritic cell (DC1) vaccines leads to increase in CD4 T cells in the periphery of BC patients. In this study, we investigated the feasibility of expanding CD4 T cells from peripheral blood mononuclear cells (PBMC) of HER2-DC1 vaccinated BC patients. METHODS: PBMCs from BC patients receiving HER2-DC1 vaccines were used for CD4 T cell expansion. PBMCs were co-cultured with HER2-DC1 at 10:1 ratio for initial activation followed by expansion with cytokines- IL-2 and IL-7 or IL-15. Expanded T cells were assessed for immune marker phenotyping by flow cytometry and TCRvb analysis. For TCRvB analysis, pre, post DC1, IL-7 and IL-15 expanded CD4 T cells were pelleted for DNA isolation and sequenced using Immunoseq Analyzer platform. In addition, we investigated the in vivo efficacy of adoptively transferred mouse IL-7/IL-15 expanded Her2 specific CD4 T cells in HER2+ TUBO mouse model. RESULTS: Co-culturing of patient PBMCs with HER2-DC1 in the presence of cytokines IL-2, IL-7 and IL-15 expanded CD4 T cells ranging from 8-43 fold expansion in different samples with 92-98% CD4 phenotype. CD4 T cells expanded in IL-7 had stem like memory phenotype while IL-15 skewed to terminally differentiated CD4 T cells. IL-7 expanded T cells had significantly higher Tim3 and Ox40 expression, and effector memory proportion as compared to the IL-15 expanded T cells. Restimulation of expanded T cells with HER2 pulsed DCs showed HER2 specificity as measured by increased interferon-gamma production We identified top five clones in PBMCs from DC1-HER2 vaccinated BC patients compared to baseline. We observed differential abundance of TCR clones under IL-7 and IL-15 conditions and identified unique clones for IL-7 and IL-15. ACT using a combination of IL-7 and IL-15 expanded mouse CD4 T cells led to 50% tumor regression in HER2+ model. CONCLUSION: These studies demonstrate that HER2 specific CD4 T cells can be successfully expanded from HER2-DC1 vaccinated patients. Post HER2 DC1 vaccine can generate a pool of antigen specific CD4 T cells and may offer a promising ACT for HER2 BC. Further studies are warranted to demonstrate the efficacy in the clinical setting. Citation Format: Namrata Gautam, Krithika Kodumudi, Colin Snyder, Amber Beyer, Ricardo Costa, Heather Han, Brian Czerniecki. Adoptive T cell therapy using IL-7 and IL-15 expanded HER2-specific CD4 T cells for metastatic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3197.

Abstract 4056: Intratumoral delivery of autologous tumor antigen specific CD4 Th1 cells combined with dendritic cells eradicates HER2 mammary carcinoma

Abstract Human epidermal growth factor receptor 2 (HER2) overexpression accounts for 30% of invasive breast cancer (BC) and is critically associated with aggressive disease, recurrence and metastasis. Adoptive cell therapy approaches using cytotoxic CD8 T cells and natural killer cells have been shown to trigger anti-tumor immunity in BC. However, the immunosuppressive tumor microenvironment (TME) can inhibit response to these therapies and diminish the presence and function of tumor-infiltrating lymphocytes. Recently, we have shown a critical role for anti-tumor CD4 Th1 cells in dendritic cells (DC) intratumoral (i.t.) delivery in combination with anti-HER2 therapy. This combination therapy enhanced systemic and local anti-tumor immunity and eradicated tumors in HER2 positive BC with a requirement for CD4 Th1 cells. Here we investigated the efficacy of i.t. delivery of both autologous anti-tumor CD4 Th1 cells and tumor antigen pulsed type 1 polarized dendritic cells (HER2-DC1) in a HER2 mammary carcinoma model. CD4 T cells were isolated from BALB/c mice that had completely regressed (pCR) from orthotopic TUBO tumors following HER2-DC1 i.t. or combination therapy with anti-HER2 antibody. CD4 Th1 cells were then expanded by co-culturing with HER2-DC1 in the presence of interleukin (IL)-2 and IL-7 cytokines. BALB/c mice bearing orthotopic TUBO tumors were treated weekly for six weeks with anti-tumor CD4 Th1 cells i.t., non-specific CD4 Th1 cells i.t., HER2-DC1 i.t. or combination therapy. The i.t. delivery of anti-tumor CD4 Th1 cells combined with HER2-DC1 induced a strong anti-tumor response with survival benefit and complete tumor eradication in 50% of treated mice. Importantly, the i.t. delivery of anti-tumor CD4 Th1 cells were critical for providing priming signals to HER2-DC1 within the TME via CD40/CD40L engagement (licensing). This was supported by a strong anti-tumor response and complete tumor regression in 60% of orthotopic TUBO tumor bearing mice treated with CD40/CD40L licensed HER2-DC1 i.t. therapy compared to un-licensed HER2-DC1 i.t. therapy. Additionally, enhanced survival and functionality of human and mouse HER2-DC1 was observed following activation of CD40/CD40L signaling using anti-CD40 agonistic antibody in vitro. Collectively, these results suggest a new promising therapeutic strategy using DC1-anti-tumor CD4 Th1 adoptive cell therapy intratumoral delivery to induce DC1 priming and create robust anti-tumor immunity within the TME in BC. Citation Format: Ganesan Ramamoorthi, Amy Aldrich, Colin Snyder, Brian Czerniecki. Intratumoral delivery of autologous tumor antigen specific CD4 Th1 cells combined with dendritic cells eradicates HER2 mammary carcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4056.

Numerical and experimental investigations of mechanical properties of AW 6005-T6 Aluminium alloy butt weld joint using GMAW process

This study aimed to investigate the effect of the welding heat input on the heat affected zone (HAZ) of AW 6005-T6 aluminium alloy for a butt-welded joint using gas metal arc welding. The determination of the thermal cycles, metallography, and the resulting mechanical properties in the zone makes its possible. The study involved using a welding experiment, numerical simulation, physical simulation, and mechanical tests. The welding was carried out using the pulsed gas metal arc welding (GMAW) transfer and type J thermocouples were used to develop the thermal cycles in the HAZ. Simufact® Welding was utilized for the numerical simulation. Optical microscope was used to evaluate the microstructures and Vickers microhardness test was done along the weld cross-section. The HAZ was located on the weld cross-section with a mean hardness of 63.7 HV0.1, which is considerably lower when compared with the base metal (BM) which has a hardness of 100 HV0.1. This indicates thermal softening occurred due to the heat input to the material. There is a match in the hardness values of the Gleeble samples and the locations on the weld cross section suggested by the model showing validity of the simulation. It is important to note the fact that there is an influence of heat input into aluminum AW 6005-T6 weld joints and its mechanical properties in the design of welding process parameters for automotive parts. The welding parameters can be optimized to decrease the heat input into the weld, as this can directly affects the mechanical properties in the HAZ.

Comparison of Raw and Excess Steam Jet-Cooked/Drum-Dried Pinto Bean Flours and Their Effects on Ground Beef Patties

Many types of plant-based materials have been investigated as fat replacers or meat extenders in beef patties and meatballs, including cereal and pulse flours as well as isolated plant proteins. Previously, excess steam jet cooking and drum drying of pulse flours were shown to impart potentially useful properties as food ingredients. In this study, pinto bean flour was jet-cooked and drum-dried (JC-DD) and compared with raw pinto bean flour when added to ground beef patties. The finely milled flours were mixed with ground beef at levels of 6, 12, and 18% along with equal amounts of water. The effects of jet cooking and drum drying on the flour included complete breakdown of starch granules, greatly reduced viscosity upon heating in water, and substantial reduction of several volatile beany flavor components. The highest level of JC-DD flour resulted in the highest cooked patty weight, moisture content, and diameter and the lowest cooking time, springiness, and fat content. There were significant color changes in both raw and cooked beef patties to which pinto bean flour was added, but they were not large due to the native color of bean seed coats. Texture analysis revealed that addition of JC-DD flour to the meat resulted in a greater degree of tenderizing compared to the raw flour. The experiments indicate that further investigation of different flour/water ratios and different pulse types might lead to higher substitution levels. Novelty Impact Statement. The use of pulse flour as a meat extender was investigated with the novel approach of processing the pulse flour by excess steam jet cooking and drum drying. Comparison of the effects of raw and jet-cooked flour on the properties of cooked ground beef patties revealed advantages of jet cooking the flour including higher cooked patty weight, moisture content, and diameter and a greater degree of tenderizing.

Nonlinear Diffusion for Bacterial Traveling Wave Phenomenon.

The bacterial traveling waves observed in experiments are of pulse type which is different from the monotone traveling waves of the Fisher-KPP equation. For this reason, the Keller-Segel equations are widely used for bacterial waves. Note that the Keller-Segel equations do not contain the population dynamics of bacteria, but the population of bacteria multiplies and plays a crucial role in wave propagation. In this paper, we consider the singular limits of a linear system with active and inactive cells together with bacterial population dynamics. Eventually, we see that if there are no chemotactic dynamics in the system, we only obtain a monotone traveling wave. This is evidence that chemotaxis dynamics are needed even if population growth is included in the system.

Analysis of laser-induced transient population gratings by different types of exciting pulse

Motivated by atomic response to different initial coherent optical fields, we comparatively studied transient population grating (TPG) induced by successive pulse train. Time delay and pump pulse duration dependence of TPG is achieved by numerically solving the density matrix equations. Results reveal that the creation and erasure of TPG is possible by choosing the appropriate pulse parameters, which is illustrated by Bloch sphere model and quantitative validation. To obtain desired large grating amplitude for rectangular pulse, the allowed pulse duration can be extended to one order wider than that of Gaussian pulse. Population grating can be erased to near zero by a third pulse with time delay by an odd multiple of half the pulse width, and it also can be erased further to recover atom assembly back to the initial state by a fourth pulse with time delay equal to an integer multiple of pulse width. Atomic behaviors excited by different types of pulse presented here may be significant to manipulate TPG during coherent light-matter interaction.

Supercontinuum generation in NALM fiber laser with pulse type switchable

We report a supercontinuum (SC) generation based on pulse type switchable nonlinear amplification loop mirror (NALM) mode-locked fiber laser. In the experiment, we obtained a dissipative soliton (DS) mode-locked pulse with a spectral width of 20.04 nm and a pulse duration of 1.68 ps, which is used as a SC generation. The spectrum width of SC generated by DS is up to 940 nm (1460–2400 nm), and the unflatness of SC in 1580.2–2177.6 nm is less than 0.9 dB. By adjusting the polarization controller (PC) and pump power, the switching between DS and bound state soliton (BSS) is realized. The spectral width of SC generated by BSS is up to 962 nm (1438–2400 nm), and the 10 dB bandwidth is 689.2 nm. In addition, we carried out temperature sensing experiments and proved that our SC system has good smoothness and fineness. Our results demonstrate the SC generation with two switchable pulse type, which provides the possibility for different application requirements.

Effect of soaking conditions on glyphosate absorption in selected pulses: understanding solvent behaviour and morphological changes

ABSTRACT Pesticides are being used in agriculture in an unregulated and imprecise way, resulting in food grains having varying amounts of pesticide residues after harvest. Using farm samples to develop a new technique to determine the pesticide residue levels might result in inconsistent results. There is currently no specific technique for preparing the standard pulse samples with appropriate levels of glyphosate residual levels. The objective of this study was to develop a standard method for glyphosate spiking by evaluating the absorption of glyphosate in six types of pulses (chickpea, yellow pea, red lentil, large green lentil, French green lentil, and black beluga lentil) at four different concentrations (5 mg/kg, 10 mg/kg, 15 mg/kg and 20 mg/kg) using two different solvents (water and water + ethanol (50:50)). Both the type of pulse and nature of solvent significantly affected the glyphosate absorption. The highest glyphosate absorption as determined by ELISA was observed when water was used as solvent in all pulses and at all concentration levels. The values ranged from 3.45–17.46, 4.13–18.31, 4.08–17.09, 4.11–18.40, 4.99–18.43 and 4.56–18.04 mg/kg for yellow pea, chickpea, large green lentil, French green lentil, red lentil, and black beluga lentil, respectively. Among the pulses, the absorption was highest in red lentil and lowest in large green lentil, which can be attributed to their maximum moisture absorption capacity. Further, the colour changes were lower in water + ethanol solvent than water only probably due to the colour retention properties of ethanol. The results obtained with this technique showed the potential of preparing standard pulse samples with known glyphosate levels.