Construction and characterization of Aeromonas hydrophila crp and fur deletion mutants and evaluation of its potential as live-attenuated vaccines in crucian carp.

Aeromonas hydrophila (A. hydrophila) is a typical zoonotic pathogenic bacterium that infects humans, animals, and fish. It has been reported that the Fur, a Fe2+ regulatory protein, and the Crp, a cAMP receptor protein, play important roles in bacterial virulence in many bacteria, but no research has been investigated on A. hydrophila. In this study, the Δfur and Δcrp mutant strains were constructed by the suicide plasmid method. These two mutant strains exhibited a slightly diminished bacterial growth and also were observed some alterations in the number of outer membrane proteins, and the disappearance of hemolysis in the Δcrp strain. Animal experiments of crucian carp showed that the Δfur and Δcrp mutant strains significantly decreased virulence compared to the wild-type strain, and both mutant strains were able to induce good immune responses by two kinds of administration routes of intraperitoneal immunization (i.p) and immersion immunization, and the protection rates through intraperitoneal injection of Δfur and Δcrp to crucian carp were as high as 83.3 % and 73.3 %, respectively, and immersion immunization route of Δfur and Δcrp to crucian carp provided protection as high as 40 % and 20 %, respectively. These two mutant strains showed abilities to induce changes in enzymatic activities of the non-specific enzymes SOD, LZM, AKP, and ACP in crucian carp. Together, these results indicated the Δfur and Δcrp mutants were safe and effective candidate vaccine strains, showing good protection against the wild-type A. hydrophila challenge.

Light-Reinforced Key Intermediate for Anticoking To Boost Highly Durable Methane Dry Reforming over Single Atom Ni Active Sites on CeO2.

Dry reforming of methane (DRM) has been investigated for more than a century; the paramount stumbling block in its industrial application is the inevitable sintering of catalysts and excessive carbon emissions at high temperatures. However, the low-temperature DRM process still suffered from poor reactivity and severe catalyst deactivation from coking. Herein, we proposed a concept that highly durable DRM could be achieved at low temperatures via fabricating the active site integration with light irradiation. The active sites with Ni-O coordination (NiSA/CeO2) and Ni-Ni coordination (NiNP/CeO2) on CeO2, respectively, were successfully constructed to obtain two targeted reaction paths that produced the key intermediate (CH3O*) for anticoking during DRM. In particular, the operando diffuse reflectance infrared Fourier transform spectroscopy coupling with steady-state isotopic transient kinetic analysis (operando DRIFTS-SSITKA) was utilized and successfully tracked the anticoking paths during the DRM process. It was found that the path from CH3* to CH3O* over NiSA/CeO2 was the key path for anticoking. Furthermore, the targeted reaction path from CH3* to CH3O* was reinforced by light irradiation during the DRM process. Hence, the NiSA/CeO2 catalyst exhibits excellent stability with negligible carbon deposition for 230 h under thermo-photo catalytic DRM at a low temperature of 472 °C, while NiNP/CeO2 shows apparent coke deposition behavior after 0.5 h in solely thermal-driven DRM. The findings are vital as they provide critical insights into the simultaneous achievement of low-temperature and anticoking DRM process through distinguishing and directionally regulating the key intermediate species.

High performance self-powered photodetector based on van der Waals heterojunction.

Self-powered photodetectors that do not require external power support are expected to play a key role in future photodetectors due to their low power characteristics, but achieving high responsivity remains a challenge. 2D van der Waals heterojunctions are a promising technology for high-performance self-powered photodetectors due to their excellent optical and electrical properties. Here, we fabricate a self-powered photodetector based on In2Se3/WSe2/ReS2van der Waals heterojunction self-powered photodetector. Due to the presence of ReS2layer, photocurrent is enhanced as a result of the increase in light absorption efficiency and the effective region for generating photogenerated carriers. The built-in electric field is enhanced by a negative 'back-gate voltage' along the p-n junction vertical direction generated by the electrons in the photo-generated electrons accumulation layer. Accordingly, the optical responsivity and the photoresponse speed of this heterojunction self-powered photodetector are greatly boosted. The proposed self-powered photodetector based on the In2Se3/WSe2/ReS2heterojunction exhibits a high responsivity of 438 mA W-1, which is 17 times higher compared to the In2Se3/WSe2photodetector, a self-powered current (1.1 nA) that is an order of magnitude higher than that of the In2Se3/WSe2photodetector, and a fast response time that is 250% faster. Thus the self-powered photodetector with a stronger built-in electric field and a wider depletion zone can provide a new technological support for the fabrication of high responsivity, low power consumption and high speed self-powered photodetectors based on van der Waals heterojunctions.

Nivolumab plus ipilimumab versus nivolumab in individuals with treatment-naive programmed death-ligand 1 positive metastatic soft tissue sarcomas: a multicentre retrospective study.

BACKGROUND: Currently, the choice of treatment for individuals with metastatic soft tissue sarcomas (MSTS) presents a significant challenge to clinicians. The aim of this retrospective study was to assess the efficacy and safety of nivolumab plus ipilimumab (NPI) versus nivolumab alone (NIV) in individuals with treatment-naive programmed death-ligand 1 (PD-L1) positive MSTS. METHODS: Prospectively maintained databases were reviewed from 2013 to 2018 to assess individuals with treatment-naive PD-L1 MSTS who received NPI (nivolumab 3 mg/kg and ipilimumab 1 mg/kg every 3 weeks for 4 doses followed by nivolumab 3 mg/kg every 2 weeks) or NIV (3 mg/kg every 2 weeks) until disease progression, withdrawal, unendurable [AEs], or death. The co-primary endpoints were overall survival (OS) and progression-free survival (PFS). RESULTS: The median follow-up was 16.0 months (IQR 14.4-18.5) after targeted intervention. The median OS was 12.2 months (95% confidence interval [CI], 6.1-13.7) and 9.2 months (95% CI, 4.2-11.5) for the NPI and NIV groups, respectively (hazard ratio [HR] 0.49, 95% CI, 0.33-0.73; p=0.0002); the median PFS was 4.1 months (95% CI, 3.2-4.5) and 2.2 months (95% CI, 1.1-3.4) for the NPI and NIV groups, respectively (HR 0.51, 95% CI, 0.36-0.71; p< 0.0001). Key grade 3-5 AEs occurred more frequently in the NPI group than in the NIV group (94 [72.9%] for NPI vs. 35 [27.1%], p< 0.001). CONCLUSIONS: For treatment-naive PD-L1 positive MSTS, NPI seems to be less tolerated but has a greater survival advantage than NIV as the primary therapy.

Outcomes of rotational atherectomy for severely calcified coronary lesions: A single center 5-year experience.

OBJECTIVES: The aim of this study was to investigate the influences of accumulated experience on rotational atherectomy (RA) operation regarding to in-hospital outcomes in the drug-eluting stent (DES) era. METHODS: Between 2015 and 2019, 540 de novo lesions with calcified coronary lesions treated by RA and DES implantation at our center were retrospectively assessed. In-hospital major adverse cardiac events (MACE) were defined as all cause death, cardiac death, target vessel revascularization, and stroke. RESULTS: From 2015 to 2019, RA operations were 22, 60, 102, 157, and 199 cases, respectively. Rates of procedural complications were 4.5, 3.3, 11.8, 8.3, and 7.5%, respectively. Rates of in-hospital MACE were 0, 0, 3.9, 2.5, and 2.0%, respectively. Compared with planned RA, bailout RA was associated with more contrast use (207.5 ± 82.8 ml vs. 189.2 ± 70.0 ml, p = .008). As for procedural complications and in-hospital outcomes, no differences were observed between two strategies. Logistic regression revealed that hypertension was independently associated with complications (OR 5.830, 95% CI 1.382-24.591, p = .016). For MACE, independent risk factors were heart failure (OR 17.593, 95% CI 1.475-209.816, p = .023) and procedural complications (OR 127.629, 95% CI 15.135-1,076.258, p < .001). CONCLUSIONS: Along with the rapid increase of RA use and accumulated experience, rates of complications and MACE went up first and then dropped down. Hypertension was found to be an independent risk factor of procedural complications. For in-hospital MACE, independent risk factors were heart failure and procedural complications.

Treating Intimal Injury to the Graft Hepatic Artery by Intraoperative Fluorescence Vascular Stenting.

BACKGROUND: Early hepatic artery (HA) thrombosis and primary graft failure contribute greatly to the mortality of patients after liver transplantation. Herein, we present the treatment of intimal injury of HA by intraoperative fluorescence vascular stenting. METHODS: A sample of 471 patients receiving liver transplantations underwent arterial anastomosis. Six patients (1.3%) were found to have early HA thrombosis. Two patients had thrombi that were impenetrable with a guide wire. Intimal injury on both the graft and the donor sides of the HA was found after thrombectomy. We performed anastomosis between unhealthy graft vessels and healthy recipient vessels. Intraoperative angiography was done immediately because of the guide wire being easier to insert through a fresh thrombus, and a long endovascular stent was inserted to bypass the injured vessels. RESULTS: The proper HA was reconstructed under microscopy. Three days after reconstruction, an angioplasty showed no dissection, stenosis, or pseudoaneurysm of the HA. Unexpectedly, these 2 patients survived well with acceptable graft functionality, one based on a 32-month follow-up and the other based on a 2-month follow-up. CONCLUSION: Anastomosis of the intimally injured graft artery followed by immediate endovascular angioplasty with stenting to bypass the injury zone is an efficacious and tolerable procedure.

Negative regulation of filamentous growth in Candida albicans by Dig1p.

Transcriptional regulation involves both positive and negative regulatory elements. The Dig1 negative regulators are part of a fungal-specific module that includes a transcription factor (a Ste12 family member) and a Dig1 family member. In Saccharomyces cerevisiae, the post-genome-duplication Dig1/Dig2 proteins regulate MAP kinase controlled signalling pathways involved in mating and filamentous growth. We have identified the single Dig1 orthologue in the fungal pathogen Candida albicans. Genetic studies and transcriptional profiling experiments show that this single protein is implicated in the regulation of MAP kinase-controlled processes involved in mating, filamentous growth and biofilm formation, and also influences cAMP-regulated processes. This suggests that the multiple cellular roles of the Dig1 protein are ancestral and predate the sub-functionalization apparent in S. cerevisiae after the genome duplication. Intriguingly, even though loss of Dig1 function in C. albicans enhances filamentous growth and biofilm formation, colonization of the murine gastrointestinal tract is reduced in the mutant. The complexity of the processes influenced by Dig1 in C. albicans, and the observation that Dig1 is one of the few regulatory proteins that were retained in the duplicated state after the whole genome duplication event in yeast, emphasizes the important role of these negative regulators in fungal transcriptional control.

Chemogenomic Profiling of the Fungal Pathogen Candida albicans.

There is currently a small number of classes of antifungal drugs, and these drugs are known to target a very limited set of cellular functions. We derived a set of approximately 900 nonessential, transactivator-defective disruption strains from the tetracycline-regulated GRACE collection of strains of the fungal pathogen Candida albicans This strain set was screened against classic antifungal drugs to identify gene inactivations that conferred either enhanced sensitivity or increased resistance to the compounds. We examined two azoles, fluconazole and posaconazole; two echinocandins, caspofungin and anidulafungin; and a polyene, amphotericin B. Overall, the chemogenomic profiles within drug classes were highly similar, but there was little overlap between classes, suggesting that the different drug classes interacted with discrete networks of genes in C. albicans We also tested two pyridine amides, designated GPI-LY7 and GPI-C107; these drugs gave very similar profiles that were distinct from those of the echinocandins, azoles, or polyenes, supporting the idea that they target a distinct cellular function. Intriguingly, in cases where these gene sets can be compared to genetic disruptions conferring drug sensitivity in other fungi, we find very little correspondence in genes. Thus, even though the drug targets are the same in the different species, the specific genetic profiles that can lead to drug sensitivity are distinct. This implies that chemogenomic screens of one organism may be poorly predictive of the profiles found in other organisms and that drug sensitivity and resistance profiles can differ significantly among organisms even when the apparent target of the drug is the same.

A functional portrait of Med7 and the mediator complex in Candida albicans.

Mediator is a multi-subunit protein complex that regulates gene expression in eukaryotes by integrating physiological and developmental signals and transmitting them to the general RNA polymerase II machinery. We examined, in the fungal pathogen Candida albicans, a set of conditional alleles of genes encoding Mediator subunits of the head, middle, and tail modules that were found to be essential in the related ascomycete Saccharomyces cerevisiae. Intriguingly, while the Med4, 8, 10, 11, 14, 17, 21 and 22 subunits were essential in both fungi, the structurally highly conserved Med7 subunit was apparently non-essential in C. albicans. While loss of CaMed7 did not lead to loss of viability under normal growth conditions, it dramatically influenced the pathogen's ability to grow in different carbon sources, to form hyphae and biofilms, and to colonize the gastrointestinal tracts of mice. We used epitope tagging and location profiling of the Med7 subunit to examine the distribution of the DNA sites bound by Mediator during growth in either the yeast or the hyphal form, two distinct morphologies characterized by different transcription profiles. We observed a core set of 200 genes bound by Med7 under both conditions; this core set is expanded moderately during yeast growth, but is expanded considerably during hyphal growth, supporting the idea that Mediator binding correlates with changes in transcriptional activity and that this binding is condition specific. Med7 bound not only in the promoter regions of active genes but also within coding regions and at the 3' ends of genes. By combining genome-wide location profiling, expression analyses and phenotyping, we have identified different Med7p-influenced regulons including genes related to glycolysis and the Filamentous Growth Regulator family. In the absence of Med7, the ribosomal regulon is de-repressed, suggesting Med7 is involved in central aspects of growth control.

Influence of ocular features and incision width on surgically induced astigmatism after cataract surgery.

PURPOSE: To identify factors associated with surgically induced astigmatism (SIA) following phacoemulsification. METHODS: Six hundred five eyes underwent phacoemulsification with a 2.2-mm (the 2.2-mm group, n = 248) or 2.75-mm (the 2.75-mm group, n = 357) superior limbal incision. Preoperative axial length, anterior chamber depth, corneal curvature, and intra-ocular pressure were measured. Corneal curvature and intraocular pressure were measured at 1 day, 1 week, and 1, 2, and 3 months postoperatively. SIA, corneal flattening, and torque were calculated using the Alpins method. The effect of preoperative corneal astigmatism meridian on SIA was also examined. Differences in SIA between the 2.2- and 2.75-mm groups were explored, and correlations between SIA and preoperative corneal astigmatism, anterior chamber depth, axial length, age, and intraocular pressure were analyzed. RESULTS: SIA, corneal flattening, and torque were smaller in the 2.2-mm group than in the 2.75-mm group at 1 week (P = .003, .006, and .014, respectively), but not statistically different thereafter. Higher preoperative corneal astigmatism, older age, and shallower anterior chamber depth were associated with greater SIA in both groups. The effect of astigmatism meridian on SIA was more noticeable in the 2.75-mm group. Shorter axial length and lower intraocular pressures were associated with greater SIA in the 2.75-mm group but not in the 2.2-mm group. CONCLUSIONS: Reducing limbal incision width and considering patient age, the meridian and magnitude of corneal astigmatism, anterior chamber depth, axial length, and intraocular pressure, and adjusting the flattening component of SIA input for toric intraocular lens power calculation could potentially improve the astigmatism control in refractive lens surgery.

Research on the Coupling Effect of NBTI and TID for FDSOI pMOSFETs.

The coupling effect of negative bias temperature instability (NBTI) and total ionizing dose (TID) was investigated by simulation based on the fully depleted silicon on insulator (FDSOI) PMOS. After simulating the situation of irradiation after NBT stress, it was found that the NBTI effect weakens the threshold degradation of FDSOI PMOS under irradiation. Afterward, NBT stress was decomposed into high gate voltage stress and high-temperature stress, which was applied to the device simultaneously with irradiation. The devices under high gate voltage exhibited more severe threshold voltage degradation after irradiation compared to those under low gate voltage. Devices at high temperatures also exhibit more severe threshold degradation after irradiation compared to devices under low temperatures. Finally, the simultaneous effect of high gate voltage, high temperature, and irradiation on the device was investigated, which fully demonstrated the impact of the NBT stress on the TID effect, resulting in far more severe threshold voltage degradation.

Simulation of the Irradiation Cascade Effect of 6H-SiC Based on Molecular Dynamics Principles.

When semiconductor materials are exposed to radiation fields, cascade collision effects may form between the radiation particles in the radiation field and the lattice atoms in the target material, creating irradiation defects that can lead to degradation or failure of the performance of the device. In fact, 6H-SiC is one of the typical materials for third-generation broadband semiconductors and has been widely used in many areas of intense radiation, such as deep space exploration. In this paper, the irradiation cascade effect between irradiated particles of different energies in the radiation and lattice atoms in 6H-SiC target materials is simulated based on the molecular dynamics analysis method, and images of the microscopic trajectory evolution of PKA and SKA are obtained. The recombination rates of the Frenkel pairs were calculated at PKA energies of 1 keV, 2 keV, 5 keV, and 10 keV. The relationship between the number of defects, the spatial distribution pattern of defects, and the clustering of defects in the irradiation cascade effect of 6H-SiC materials with time and the energy of PKA are investigated. The results show that the clusters are dominated by vacant clusters and are mainly distributed near the trajectories of the SKA. The number and size of vacant clusters, the number of Frenkel pairs, and the intensity of cascade collisions of SKAs are positively correlated with the magnitude of the energy of the PKA. The recombination rate of Frenkel pairs is negatively correlated with the magnitude of the energy of PKA.

Influence of Temperature and Incidence Angle on the Irradiation Cascade Effect of 6H-SiC: Molecular Dynamics Simulations.

SiC devices have been typically subjected to extreme environments and complex stresses during operation, such as intense radiation and large diurnal amplitude differences on the lunar surface. Radiation displacement damage may lead to degradation or failure of the performance of semiconductor devices. In this paper, the effects of temperature and incidence angle on the irradiation cascade effect of 6H-SiC were investigated separately using the principles of molecular dynamics. Temperatures were set to 100 K, 150 K, 200 K, 250 K, 300 K, 350 K, 400 K and 450 K. The incidence direction was parallel to the specified crystal plane, with angles of 8°, 15°, 30°, 45°, 60° and 75° to the negative direction of the Z-axis. In this paper, the six types of defects were counted, and the microscopic distribution images and trajectories of each type of defect were extracted. The results show a linear relationship between the peak of the Frenkel pair and temperature. The recombination rate of Frenkel pairs depends on the local temperature and degree of aggregation at the center of the cascade collision. Increasing the angle of incidence first inhibits and then promotes the production of total defects and Frenkel pairs. The lowest number of total defects, Frenkel pairs and antisite defects are produced at a 45° incident angle. At an incidence angle of 75°, larger size hollow clusters and anti-clusters are more likely to appear in the 6H-SiC.

Single Event Upset Study of 22 nm Fully Depleted Silicon-on-Insulator Static Random Access Memory with Charge Sharing Effect.

In this paper, the single event effect of 6T-SRAM is simulated at circuit level and device level based on a 22 nm fully depleted silicon-on-insulator (FDSOI) process, and the effects of charge sharing and bipolar amplification are considered in device-level simulation. The results demonstrate that, under the combined influence of these two effects, the circuit's upset threshold and critical charge decreased by 15.4% and 23.5%, respectively. This indicates that the charge sharing effect exacerbates the single event effects. By analyzing the incident conditions of two different incident radius particles, it is concluded that the particles with a smaller incident radius have a worse impact on the SRAM circuit, and are more likely to cause the single event upset in the circuit, indicating that the ionization distribution generated by the incident particle affects the charge collection.

Simulation of Total Ionizing Dose Effects Technique for CMOS Inverter Circuit.

The total ionizing dose (TID) effect significantly impacts the electrical parameters of fully depleted silicon on insulator (FDSOI) devices and even invalidates the on-off function of devices. At present, most of the irradiation research on the circuit level is focused on the single event effect, and there is very little research on the total ionizing dose effect. Therefore, this study mainly analyzes the influence of TID effects on a CMOS inverter circuit based on 22 nm FDSOI transistors. First, we constructed and calibrated an N-type FDSOI metal-oxide semiconductor (NMOS) structure and P-type FDSOI metal-oxide semiconductor (PMOS) structure. The transfer characteristics and trapped charge distribution of these devices were studied under different irradiation doses. Next, we studied the TID effect on an inverter circuit composed of these two MOS transistors. The simulation results show that when the radiation dose was 400 krad (Si), the logic threshold drift of the inverter was approximately 0.052 V. These results help further investigate the impact on integrated circuits in an irradiation environment.

A novel tapered guide extension catheter facilitated successful completion of complex percutaneous coronary intervention.

BACKGROUND: Guide extension catheters (GEC) are widely applied to cope with insufficient backup support in complex percutaneous coronary intervention (PCI). In the study, we aim to evaluate the feasibility and safety with a novel 5-4F tapered GEC used in complex lesion. METHODS: The single-center retrospective study enrolled a total of 615 patients, in whom the 5F or 5-4F Expressman GEC was used to facilitate PCI procedure. Demographic and procedural data were collected. RESULTS: 5F GEC was used in 295 patients and 5-4F tapered GEC in 320 patients. The average age was 63.6 ± 11.0 years and 81.6% of the patients were male. Severe calcification and chronic total occlusion (CTO) were the commonest indication for the GEC use. The 5-4F tapered GEC was frequently used in active greeting technique (AGT) during CTO intervention procedure than 5F GEC (6.1% vs. 13.1%, p < 0.001). The average depth of intubation was 41.5 ± 19.6 mm for the 5-4F tapered GEC and 24.4 ± 15.1 mm for 5F GEC (p < 0.001). The rate of successful device delivery with 5-4F GEC was higher than 5F GEC (95.6% vs. 98.4%, p = 0.037). Pressure damping with 5F GEC occurred frequently than 5-4F GEC (7.4% vs. 2.5%, p < 0.05). Similarly, the incidence of intraoperative hypotension was higher in 5F GEC than 5-4F GEC (4.7% vs.1.9%, p < 0.05). CONCLUSIONS: The novel 5-4F tapered GEC was superior to the 5F GEC in facilitating successful completion of PCI in the majority of patients with complex lesions via transradial approach.

A Nomogram Combining Neutrophil-to-Lymphocyte Ratio and D-Dimer Predicts Chemosensitivity of Oxaliplatin-Based First-Line Chemotherapy in Patients with Unresectable Advanced Gastric Cancer.

Introduction: No effective peripheral blood predictors have been establoshed for first-line chemotherapy in patients with advanced gastric cancer. In this study, a nomogram combining the neutrophil-to-lymphocyte ratio/D-dimer with gender, number of metastases, and histological grade was established to predict progression-free survival in patients with unresectable advanced gastric cancer. Methods: We retrospectively collected baseline clinical characteristics and blood parameters from 153 patients diagnosed with advanced gastric cancer that underwent oxaliplatin-based first-line chemotherapy. Kaplan-Meier analysis and Cox regression analysis were used to determine the factors associated with progression-free survival. The concordance index (C-index) and calibration curve were used to determine the prediction accuracy and discriminative ability of the nomogram as a visual complement to the prognostic score system. Results: Determined by the X-tile software, the optimal cut-off points for the neutrophil-to-lymphocyte ratio and D-dimer were 3.18 and 0.56 mg/L, respectively. Multivariate analysis identified four independent prognostic factors: two or more metastatic organs (HR: 1.562, 95% CI: 1.009-2.418, P = .046), poor differentiation (HR: 0.308, 95% CI: 0.194-0.487, P < .001), neutrophil-to-lymphocyte ratio >3.18 (HR: 1.427, 95% CI: 1.024-1.989, P = .036), and D-dimer >0.56 mg/L (HR: 1.811, 95% CI: 1.183-2.773, P = .006). Receiver operating characteristic curves showed that the combination of the neutrophil-to-lymphocyte ratio and D-dimer in the prediction model exhibited the highest predictive performance (area under the curve, 0.800). The prognostic nomogram yielded a C-index of 0.800. Decision curve analysis demonstrated that the prognostic nomogram was clinically useful. A nomogram-based risk classification system was also constructed to facilitate risk stratification of advanced gastric cancer for optimal clinical management. Conclusion: We identified the neutrophil-to-lymphocyte ratio and D-dimer level as independent prognostic factors for advanced gastric cancer. The prognostic nomogram combining the neutrophil-to-lymphocyte ratio and D-dimer level can be applied in the individualized prediction of treatment outcome in patients with advanced gastric cancer.

Ultra-Low-Voltage-Triggered Silicon Controlled Rectifier ESD Protection Device for 2.5 V Nano Integrated Circuit.

In this paper, an improved low-voltage-triggered silicon-controlled rectifier (LVTSCR) called an ultra-low-voltage-triggered SCR (ULVTSCR) is proposed and fabricated in a 40-nm CMOS process. By adding an external NMOSs-chain triggering component to the conventional LVTSCR, the proposed ULVTSCR can realize ~2 V lower trigger voltage. Meanwhile, the trigger voltage of the ULVTSCR is adjustable with the number of its incorporated NMOS transistors. Compared with the existing Diodes-chain Triggered SCR (DTSCR) scheme, the NMOSs-chain triggered ULVTSCR possesses a 25% lowered overshoot voltage in the same area consumption, and thus it is more suitable for 2.5 V circuits ESD protections considering the CDM protection applications.

A Novel L-Gate InGaAs/GaAsSb TFET with Improved Performance and Suppressed Ambipolar Effect.

A heterojunction tunneling field effect transistor with an L-shaped gate (HJ-LTFET), which is very applicable to operate at low voltage, is proposed and studied by TCAD tools in this paper. InGaAs/GaAsSb heterojunction is applied in HJ-LTFET to enhance the ON-state current (ION). Owing to the quasi-broken gap energy band alignment of InGaAs/GaAsSb heterojunction, height and thickness of tunneling barrier are greatly reduced. However, the OFF-state leakage current (IOFF) also increases significantly due to the reduced barrier height and thickness and results in an obvious source-to-drain tunneling (SDT). In order to solve this problem, an HfO2 barrier layer is inserted between source and drain. Result shows that the insertion layer can greatly suppress the horizontal tunneling leakage appears at the source and drain interface. Other optimization studies such as work function modulation, doping concentration optimization, scaling capability, and analog/RF performance analysis are carried out, too. Finally, the HJ-LTFET with a large ION of 213 µA/µm, a steep average SS of 8.9 mV/dec, and a suppressed IOFF of 10-12 µA/µm can be obtained. Not only that, but the fT and GBP reached the maximum values of 68.3 GHz and 7.3 GHz under the condition of Vd = 0.5 V, respectively.