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Circular RNA (circRNA) is a non-coding RNA with a covalently closed loop structure and usually more stable than messenger RNA (mRNA). However, coding sequences (CDSs) following an internal ribosome entry site (IRES) in circRNAs can be translated, and this property has been recently utilized to produce proteins as novel therapeutic tools. However, it is difficult to produce large proteins from circRNAs because of the low circularization efficiency of lengthy RNAs. In this study, we report that we successfully synthesized circRNAs with the splint DNA ligation method using RNA ligase 1 and the splint DNAs, which contain complementary sequences to both ends of precursor linear RNAs. This method results in more efficient circularization than the conventional enzymatic method that does not use the splint DNAs, easily generating circRNAs that express relatively large proteins, including IgG heavy and light chains. Longer splint DNA (42 nucleotide) is more effective in circularization. Also, the use of splint DNAs with an adenine analog, 2,6-diaminopurine (DAP), increase the circularization efficiency presumably by strengthening the interaction between the splint DNAs and the precursor RNAs. The splint DNA ligation method requires 5 times more splint DNA than the precursor RNA to efficiently produce circRNAs, but our modified splint DNA ligation method can produce circRNAs using the amount of splint DNA which is equal to that of the precursor RNA. Our modified splint DNA ligation method will help develop novel therapeutic tools using circRNAs, to treat various diseases and to develop human and veterinary vaccines. [ABSTRACT FROM AUTHOR]

This article presents a wide-lock-in-range and ultralow-jitter, 12–14.5 GHz subsampling phase-locked loop (SSPLL) using a frequency-disturbance-detecting/correcting (FDC) loop. By detecting and correcting the frequency disturbance, $f_{\mathbf {D}}$ , frequently, the FDC loop can increase the lock-in range of the SSPLL to 3.2 times the reference frequency, $f_{\mathbf {REF}}$. Since the FDC loop only is concerned with correcting an $f_{\mathbf {D}}$ -event at the output and is not concerned with the jitter, there is no design tradeoff between the jitter, and the power consumption as is the case in previous techniques. Due to its logic using frequency information rather than phase, the FDC loop also can reduce the time required for the reacquisition of the frequency. In this work, the prototype SSPLL was fabricated in a 65 nm CMOS, and it used the 50 MHz $f_{\mathbf {REF}}$. In the measurements, the FDC loop that consumed only 150 $\mu \text{W}$ of power made the SSPLL achieve the lock-in range of 160 MHz and the frequency-reacquisition time of less than 800 ns. The measured rms jitter at 13 GHz was 83 fs. The active area was 0.23 mm2, and the total power consumption was 7.7 mW. [ABSTRACT FROM AUTHOR]

This article presents a cascaded architecture of a frequency synthesizer to generate ultra-low-jitter output signals in a millimeter-wave (mmW) frequency band from 28 to 31 GHz. The mmW-band injection-locked frequency multiplier (ILFM) placed at the second stage has a wide bandwidth so that the performance of the jitter of this frequency synthesizer is determined by the GHz-band, digital subsampling phase-locked loop (SSPLL) at the first stage. To suppress the quantization noise of the digital SSPLL while using a small amount of power, the optimally spaced voltage comparators (OSVCs) are presented as a voltage quantizer. This article was designed and fabricated using 65-nm CMOS technology. In measurements, this prototype frequency synthesizer generated output signals in the range of 28–31 GHz, with an rms jitter of less than 80 fs and an integrated phase noise (IPN) of less than −40 dBc. The active silicon area was 0.32 mm2, and the total power consumption was 41.8 mW. [ABSTRACT FROM AUTHOR]

An ultra-low-jitter, ring-LC -hybrid injection-locked clock multiplier (ILCM) is presented to achieve a high multiplication factor of 114. The proposed hybrid ILCM cascades a ring-type voltage-controlled oscillator (VCO)-based ILCM and an LC-type VCO-based ILCM. Using a dual-purpose frequency calibrator (DPFC) that can continuously calibrate the frequency drifts of the two VCOs, concurrently, the proposed ILCM can maintain excellent jitter performance against process-voltage-temperature (PVT) variations. Since the DPFC eliminates the use of an additional calibrator and operates at a very low frequency, it can reduce the expenditures for silicon and power. The proposed ILCM was fabricated in a 65-nm CMOS process. The RMS jitter of the 22.8-GHz output, integrated from 1 kHz to 100 MHz, was 153 fs, and the DPFC restricted its variations due to variations in temperatures and supply voltages to less than 180 fs. The proposed ILCM achieved the power efficiency of 0.32 mW/GHz. The active area was 0.2 mm2. The total power consumption was 7.4 mW, but the DPFC consumed only 400 $\mu \text{W}$. [ABSTRACT FROM AUTHOR]

Herein is presented an external capacitorless low-dropout regulator (LDO) that provides high-power-supply rejection (PSR) at all low-to-high frequencies. The LDO is designed to have the dominant pole at the gate of the pass transistor to secure stability without the use of an external capacitor, even when the load current increases significantly. Using the proposed adaptive supply-ripple cancellation (ASRC) technique, in which the ripples copied from the supply are injected adaptively to the body gate, the PSR hump that appears in conventional gate-pole-dominant LDOs can be suppressed significantly. Since the ASRC circuit continues to adjust the magnitude of the injecting ripples to an optimal value, the LDO presented here can maintain high PSRs, irrespective of the magnitude of the load current $I_{L}$ , or the dropout voltage $V_{\mathrm {DO}}$. The proposed LDO was fabricated in a 65-nm CMOS process, and it had an input voltage of 1.2 V. With a 240-pF load capacitor, the measured PSRs were less than −36 dB at all frequencies from 10 kHz to 1 GHz, despite changes of $I_{L}$ and $V_{\mathrm {DO}}$ as well as process, voltage, temperature (PVT) variations. [ABSTRACT FROM AUTHOR]

This paper presents a 680 MHz–6 GHz $2 \times 2$ multiple-input and multiple-output (MIMO) long-term evolution (LTE) RF transceiver in 65-nm CMOS for low-cost and multi-band capable femtocell base stations. The transceiver integrates two receivers (RXs), two transmitters (TXs), and two frequency synthesizers, for the $2 \times 2$ MIMO operation to support both the frequency division duplex (FDD) and the time division duplex (TDD) modes. Each pair of an RX and a TX features eight single-ended low noise amplifiers (LNAs), and eight TX outputs that extensively share active and passive circuits with minimal performance degradation. In the measurement, each RX illustrates the noise figure (NF) from 2.9 to 5.2 dB, the input-referred third-order intercept point (IIP3) of more than −2 dBm, and the IIP2 of more than 48 dBm, over the entire frequency range at the maximum gain. Each TX achieved the adjacent channel leakage ratio (ACLR) that was less than −54 dBc at −5-dBm output power with −157-dBc/Hz phase noise at the RX band, while achieving an error-vector-magnitude (EVM) of less than 2.8%, over the entire frequency range. The transceiver, packaged in a flip-chip chip-scale package (fcCSP), is mounted on the board of the commercial femtocell of the LTE Band5, along with a commercial duplexer, power amplifier, and modem. The femtocell achieved −100-dBm reference sensitivity without the use of an external LNA. It also achieved −51-dBc TX ACLR and 1.68% TX EVM at 20-dBm output power in the LTE 10-MHz mode with the $2 \times 2$ MIMO configuration, without applying a digital pre-distortion (DPD) technique. [ABSTRACT FROM AUTHOR]

An external capacitor-less ultra low-dropout (LDO) regulator that can continue to provide high power-supply rejection (PSR) over a wide range of the load current is proposed. Using the loop-gain stabilizer (LGS) to fix the dc level of the output voltage of the error amplifier to the optimal value, the LDO can keep maximizing the unity-gain frequency, while the load current changes widely up to 200 mA. Despite the multiple poles in the regulating loop, the stability can easily be obtained due to an intrinsic left-half plane zero, generated by the auxiliary path of the LGS. The proposed LDO was fabricated in a 40-nm CMOS process, and it had an input voltage of 1.1 V. When the dropout voltage was 0.1 V and the load current was 200 mA, the measured PSRs were −60 and −35 dB at 1 and 10 MHz, respectively. Due to the LGS, the dc loop gain was maintained to be high, resulting in good load and line regulations of 19~\mu \textV /mA and 0.75 mV/V, respectively. While the total current consumption of the LDO was 275~\mu \textA , the LGS consumed only 7~\mu \textA . The area was 0.008 mm2 with 4-pF on-chip capacitance for compensation. [ABSTRACT FROM AUTHOR]

A low-jitter, ring-type voltage-controlled oscillator (VCO)-based injection-locked clock multiplier (ILCM) with a continuous frequency-tracking loop (FTL) for process-voltage-temperature (PVT)-calibration is presented. Using a single replica-delay cell of the VCO that provides the intrinsic phase information of the free-running VCO, the proposed FTL can continuously track and correct frequency drifts. Therefore, the proposed ILCM can calibrate real-time frequency drifts due to voltage or temperature variations as well as static frequency deviations due to process variations. Since the FTL provided an additional filtering of in-band VCO noise, the ILCM was able to achieve excellent jitter performance over the PVT variations, while it was based on a ring-VCO. The proposed ILCM was fabricated in a 65 nm CMOS process. When injection locked, the RMS-jitter integrated from 10 kHz to 40 MHz of the 1.20 GHz output signal was 185 fs. The proposed PVT-calibrator regulated the degradations of jitter to less than 5% and 7% over temperatures and supply voltages, respectively. The active area was \text 0.06 mm^2 and total power consumption was 9.5 mW. [ABSTRACT FROM PUBLISHER]

A wideband and low phase noise quadrature local oscillation (LO) signal generator for multistandard cellular transceivers was proposed. Using the new LO-plan consisting of divide-by-6, divide-by-4, and divide-by-12 frequency dividers, the required frequency-tuning range (FTR) of a voltage-controlled oscillator (VCO) was reduced to 39%, which can be easily covered by a single LC-VCO. Due to the reduced FTR, the VCO can retain a high Q-factor and achieve low phase noise. The key building block of the new LO-plan is a quadrature divide-by-6 divider, capable of generating precise I/Q signals. To implement the quadrature divide-by-6 divider, we proposed a fully differential divide-by-3 divider with 50% duty cycle. Using the same idea, a fully differential divide-by-2 circuit was also proposed for divide-by-4 and divide-by-12 dividers. The proposed LO-generator was fabricated in a 40 nm CMOS process, and covered LO-frequencies of 0.56–2.92 GHz for multistandard cellular transceivers. The LO-generator occupied a small silicon area of 0.15\;\textmm^2 and achieved an excellent phase noise performance of - 141.02\;\textdBc/\textHz at a 1 MHz offset from a 709 MHz LO-frequency. [ABSTRACT FROM PUBLISHER]

Background: Elaeocarpus sylvestris (Lour.) Poir. (Elaeocarpaceae) belongs to a genus of tropical and semitropical evergreen trees, which has known biological activities such as antiviral and immunomodulatory activities. However, its antiviral potential against influenza virus infection remains unknown.Purpose: In this study, we investigated the antiviral activity of the 50% aqueous ethanolic extract of E. sylvestris (ESE) against influenza A virus (IAV) infection, which could lead to the development of novel phytomedicine to treat influenza virus infection.Methods: To investigate the in vitro antiviral activity of ESE and its main ingredients, 1,​2,​3,​4,​6-​penta-​O-​galloyl-β-d-glucose (PGG) and geraniin (GE), the levels of viral RNAs, proteins, and infectious viral particles in IAV-infected MDCK cells were analyzed. Molecular docking analysis was performed to determine the binding energy of PGG and GE for IAV proteins. To investigate in vivo antiviral activity, IAV-infected mice were treated intranasally or intragastrically with ESE, PGG, or GE.Results: ESE and its gallate main ingredients (PGG and GE) strongly inhibited the production of viral RNAs, viral proteins, and infectious viral particles in vitro. Also through the viral attachment on cells, polymerase activity, signaling pathway, we revealed the ESE, PGG, and GE inhibit multiple steps of IAV replication. Molecular docking analysis revealed that PGG and GE could interact with 12 key viral proteins (M1, NP, NS1 effector domain (ED), NS1 RNA-binding domain (RBD), HA pocket A, HA receptor-binding domain (RBD), NA, PA, PB1, PB2 C-terminal domain, PB2 middle domain, and PB2 cap-binding domain) of IAV proteins with stable binding energy. Furthermore, intranasal administration of ESE, PGG, or GE protected mice from IAV-induced mortality and morbidity. Importantly, oral administration of ESE suppressed IAV replication and the expression of inflammatory cytokines such as IFN-γ, TNF-α, and IL-6 in the lungs to a large extent.Conclusion: ESE and its major components (PGG and PE) exhibited strong antiviral activity in multiple steps against IAV infection in silico, in vivo, and in vitro. Therefore, ESE could be used as a novel natural product derived therapeutic agent to treat influenza virus infection. [ABSTRACT FROM AUTHOR]

The immune-suppressive effects of omega-3 (n-3) polyunsaturated fatty acids (PUFAs) on T cells have been observed via multiple in vitro and in vivo models. However, the precise mechanism that causes these effects is still undefined. In this study, we investigated whether n-3 PUFAs regulated T cell receptor (TCR) and peptide-major histocompatibility complex (pMHC) interactions. The expansion of anti-viral CD8+ T cells that endogenously synthesize n-3 PUFAs (FAT-1) dramatically decreased upon lymphocytic choriomeningitis virus (LCMV) infection in vivo. This decrease was not caused by the considerable reduction of TCR expression or the impaired chemotactic activity of T cells. Interestingly, a highly inclined and laminated optical sheet (HILO) microscopic analysis revealed that the TCR motility was notably reduced on the surface of the FAT-1 CD8+ T cells compared to the wild type (WT) CD8+ T cells. Importantly, the adhesion strength of the FAT-1 CD8+ T cells to the peptide-MHC was significantly lower than that of the WT CD8+T cells. Consistent with this result, treatment with docosahexaenoic acid (DHA), one type of n-3 PUFA, significantly decreased CD8+ T cell adhesion to the pMHC. Collectively, our results reveal a novel mechanism through which n-3 PUFAs decrease TCR-pMHC interactions by modulating TCR mobility on CD8+ T cell surfaces. [ABSTRACT FROM AUTHOR]

Influenza A virus (IAV) continues to threaten human health. To date, two classes of antiviral drugs have been approved to treat IAV infection, but the continuous emergence of the drug-resistant IAV mutant reinforces the need to develop new antiviral drugs. In this study, we aimed to investigate the anti-IAV activity of an aqueous mixture of Agrimonia pilosa and Galla rhois extracts (APRG64). We demonstrated that APRG64 significantly reduced the IAV-induced cytopathic effect, the transcription/expression of viral proteins, and the production of infectious viral particles. Among nine major components of APRG64, apigenin was identified as the main ingredient responsible for the anti-IAV activity. Interestingly, APRG64 and apigenin inhibited the cell attachment and entry of virus and polymerase activity. Importantly, intranasal administration of APRG64 or apigenin strongly reduced viral loads in the lungs of IAV-infected mice. Furthermore, oral administration of APRG64 significantly reduced the level of viral RNAs and the expression level of pro-inflammatory cytokines in the lungs, which protected mice from IAV-induced mortality. In conclusion, APRG64 could be an attractive antiviral drug to treat IAV infection. [Display omitted] • APRG64 and its compound apigenin inhibit IAV replication. • APRG64 reduces pulmonary viral burden and the level of inflammatory cytokines. • Oral administration of APRG64 protects mice from IAV-induced mortality. [ABSTRACT FROM AUTHOR]

To investigate whether earthworm cellulases contribute to the innate immune system, the responsiveness of cellulase activity and mRNA expression to bacterial challenge was examined by zymography and RNA sequencing. A zymographic analysis revealed that the activity levels of earthworm cellulases were upregulated in response to either a bacterial (Bacillus subtilis or Escherichia coli) or LPS challenge. After the challenge, significant increases in cellulase 1 and cellulase 2 activity levels were observed within 8–16 and 16–24 h, respectively. In the coelomic fluid, both activities were significantly upregulated at 8 h post-injection with B. subtilis. Based on RNA sequencing, cellulase-related mRNAs encoding beta-1,4-endoglucanases were upregulated by 3-fold within 6 h after B. subtilis injection. Our results clearly demonstrated that earthworm cellulases are upregulated by bacterial challenge at the mRNA and protein levels. These results support the view that earthworm cellulases act as inducible humoral effectors of innate immunity against bacterial infection. • Cellulase activity levels were upregulated by a bacterial or LPS challenge. • RNA-seq discovered that cellulase-related mRNAs increased by B. subtilis injection. • Earthworm cellulases could act as immune effectors against bacterial infection. [ABSTRACT FROM AUTHOR]

GATA1, a member of the GATA transcription factor family, is a critical factor in hematopoietic system development. In a previous study, we demonstrated the increased expression of GATA1 in the dorsolateral prefrontal cortex (dlPFC) of patients suffering from depression and described its role as a transcriptional repressor of synapse-related genes. In this study, we investigated how GATA1 globally altered gene expression using multi-omics approaches. Through the combined analyses of ChIPseq, mRNAseq, and small RNAseq, we profiled genes that are potentially affected by GATA1 in cultured cortical neurons, and Gene Ontology (GO) analysis revealed that GATA1 might be associated with immune-related functions. We hypothesized that GATA1 induces immune activation, which has detrimental effects including synapse loss and depressive-like behavior. To test this hypothesis, we first performed a microglial morphometric analysis of a brain having overexpression of GATA1 because microglia are the resident immune cells of the central nervous system. Fractal analysis showed that the ramification and process length of microglia decreased in brains having GATA1 overexpression compared to the control, suggesting that GATA1 overexpression increases the activation of microglia. Through flow cytometry and immunohistochemical analysis, we found that activated microglia showed pro-inflammatory phenotypes characterized by the expression of CD86 and CD68. Finally, we demonstrated that the effects of GATA1 overexpression including synapse loss and depressive-like behavior could be blocked by inhibiting microglial activation using minocycline. These results will elucidate the regulatory mechanisms of GATA1 that affect pathophysiological conditions such as depression and provide a potential target for the treatment of depression., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Choi, Lee, Kim, Lim and Kang.)

Chios mastic gum (CMG), a resin of the mastic tree ( Pistacia lentiscus var. chia), has been used to treat multiple disorders caused by gastrointestinal malfunctions and bacterial infections for more than 2500 years. However, little is known about CMG's antiviral activity. CMG is known to influence multiple cellular processes such as cell proliferation, differentiation and apoptosis. As virus replication is largely dependent on the host cellular metabolism, it is conceivable that CMG regulates virus infectivity. Therefore, in this study, we evaluated CMG's potential as an antiviral drug to treat influenza A virus (IAV) infection. CMG treatment dramatically reduced the cytopathogenic effect and production of RNAs, proteins and infectious particles of IAV. Interestingly, CMG interfered with the early stage of the virus life cycle after viral attachment. Importantly, the administration of CMG greatly ameliorated morbidity and mortality in IAV-infected mice. The results suggest that CMG displays a potent anti-IAV activity by blocking the early stage of viral replication. Thus, mastic gum could be exploited as a novel therapeutic agent against IAV infection.