1,4-Bis(imidazol-1-yl)benzene–terephthalic acid (1/1)

In the title compound, C12H10N4·C8H6O4, 1,4-bis­(imidazol-1-yl)benzene and terephthalic acid mol­ecules are joined via strong O—H⋯N hydrogen bonds to form infinite zigzag chains. Both mol­ecules are located on crystallographic inversion centers. The O—H⋯N hydrogen-bonded chains are assembled into two-dimensional layers through weak C—H⋯O and strong π–π stacking inter­actions [centroid–centroid distance = 3.818 (2) Å], leading to the formation of a three-dimensional supra­molecular structure

Active inductor shunt peaking in high-speed VCSEL driver design

An all transistor active inductor shunt peaking structure has been used in a prototype of 8-Gbps high-speed VCSEL driver which is designed for the optical link in ATLAS liquid Argon calorimeter upgrade. The VCSEL driver is fabricated in a commercial 0.25-um Silicon-on-Sapphire (SoS) CMOS process for radiation tolerant purpose. The all transistor active inductor shunt peaking is used to overcome the bandwidth limitation from the CMOS process. The peaking structure has the same peaking effect as the passive one, but takes a small area, does not need linear resistors and can overcome the process variation by adjust the peaking strength via an external control. The design has been tapped out, and the prototype has been proofed by the preliminary electrical test results and bit error ratio test results. The driver achieves 8-Gbps data rate as simulated with the peaking. We present the all transistor active inductor shunt peaking structure, simulation and test results in this paper.Comment: 4 pages, 6 figures and 1 table, Submitted to 'Chinese Physics C

Acid Dissociation of 3-Mercaptopropionic Acid Coated CdSe–CdS/Cd0.5Zn0.5S/ZnS Core–Multishell Quantum Dot and Strong Ionic Interaction with Ca2+ Ion

By devising careful electrophoresis, it was shown that at pH below 7.0, the electrophoretic mobility of 3-mercaptopropionic acid (3MPA) coated CdSe–ZnS core–shell quantum dots (denoted as QD-3MPA) was very small. At pH above 7.0, QD-3MPA migrated toward the anode, implying acid dissociation, and the degree of which was proportional to the pH value. QD-3MPA’s electrophoretic mobility was impaired after adding sufficient Ca2+ ions to the QD solution and revived when a similar amount of Ca2+ chelators (ethylene glycol tetraacetic acid, EGTA) was added. This demonstrated that acid dissociation and its pH dependence of 3MPA on the QD surface are critical factors in understanding the electric and optical properties of QDs. The acid dissociated QD-3MPA interacted strongly with Ca2+, forming a charge neutral QD-3MPA–Ca2+ complex in the absence of EGTA. First-principles study confirmed the observed experimental evidence. The strong ionic interaction between acid dissociated QD-3MPA and Ca2+ is critical for developing reliable QD-based biosensing assays. Moreover, the strategy and techniques reported in this work are easily applicable to other fluorescent biomarkers and therefore can be important for advancing in vivo and in vitro imaging, sensing, and labeling

Development of A 16:1 serializer for data transmission at 5 Gbps

Radiation tolerant, high speed and low power serializer ASIC is critical for optical link systems in particle physics experiments. Based on a commercial 0.25 μm silicon-onsapphire CMOS technology, we design a 16:1 serializer with 5 Gbps serial data rate. This ASIC has been submitted for fabrication. The post-layout simulation indicates the deterministic jitter is 54 ps (pk-pk) and random jitter is 3 ps (rms). The power consumption of the serializer is 500 mW. The design details and post layout simulation results are presented in this paper

High-Speed Serial Optical Link Test Bench Using FPGA with Embedded Transceivers

We develop a custom Bit Error Rate test bench based on Altera’s Stratix II GX transceiver signal integrity development kit, demonstrate it on point-to-point serial optical link with data rate up to 5 Gbps, and compare it with commercial stand alone tester. The 8B/10B protocol is implemented and its effects studied. A variable optical attenuator is inserted in the fibre loop to induce transmission degradation and to measure receiver sensitivity. We report comparable receiver sensitivity results using the FPGA based tester and commercial tester. The results of the FPGA also shows that there are more one-tozero bit flips than zero-to-one bit flips at lower error rate. In 8B/10B coded transmission, there are more word errors than bit flips, and the total error rate is less than two times that of non-coded transmission. Total error rate measured complies with simulation results, according to the protocol setup

The Design of a High Speed Low Power Phase Locked Loop

The upgrade of the ATLAS Liquid Argon Calorimeter readout system calls for the development of radiation tolerant, high speed and low power serializer ASIC. We have designed a phase locked loop using a commercial 0.25-μm Silicon-on- Sapphire (SoS) CMOS technology. Post-layout simulation indicates that tuning range is 3.79 – 5.01 GHz and power consumption is 104 mW. The PLL has been submitted for fabrication. The design and simulation results are presented

Real-world observations and impacts of Chinese herbal medicine for migraine: results of a registry-based cohort study

Background: Migraine is a prevalent, recurrent condition with substantial disease burden. Chinese herbal medicine (CHM) has been used frequently for migraine in controlled clinical settings. This study is to summarise the characteristics of patients who seek clinical care in a tertiary Chinese medicine hospital in China; to gather their preferences and values of using CHM; to explore the effect of CHM for migraine and its comorbidities in a real-world setting, and to collect first-hand expertise of clinicians’ practice pattern in prescribing CHM for migraine.Methods: This registry-based cohort study was prospectively conducted at Guangdong Provincial Hospital of Chinese Medicine from December 2020 to May 2022. Adult migraine patients seeking their initial anti-migraine clinical care at the hospital were consecutively recruited and followed up for 12 weeks. Practitioners specialised in headache management prescribed individualised treatments without research interference. Standardised case report forms were employed to gather information on patients’ preferences and perspective of seeking clinical care, as well as to assess participants’ migraine severity, comorbidities, and quality of life, at 4-weeks intervals. Various analytical methods were utilised based on the computed data.Results: In this study, we observed 248 participants. Of these, 73 received CHM treatment for 28 days or longer. Notably, these participants exhibited a greater disease severity, compared to those treated with CHM for less than 28 days. Of the 248 participants, 83.47% of them expected CHM would effectively reduce the severity of their migraine, around 50% expected effects for migraine-associated comorbidities, while 51.61% expressing concerns about potential side effects. CHM appeared to be effective in reducing monthly migraine days and pain intensity, improving patients’ quality of life, and potentially reducing comorbid anxiety, with a minimum of 28 days CHM treatment. Herbs such as gan cao, gui zhi, chuan xiong, fu ling, bai zhu, yan hu suo, etc. were frequently prescribed for migraine, based on patients’ specific symptoms.Conclusion: CHM appeared to be beneficial for migraine and comorbid anxiety in real-world clinical practice when used continuously for 28 days or more.Clinical Trial Registration:clinicaltrials.gov, identifier ChiCTR2000041003

Analysis of the first gigantic jet recorded over continental North America

[1] Two low-light cameras near Marfa, Texas, recorded a gigantic jet over northern Mexico on 13 May 2005 at approximately 0423:50 UTC. Assuming that the farthest of two candidate storm systems was its source, the bright lower channel ended in a fork at around 50–59 km height with the very dim upper branches extended to 69–80 km altitude. During the time window containing the jet, extremely low frequency magnetic field recordings show that there was no fast charge moment change larger than 50 coulomb times kilometers (C km) but there was a larger and slower charge moment change of 520 C km over 70 ms. The likely parent thunderstorm was a high-precipitation supercell cluster containing a persistent mesocyclone, with radar echo tops of at least 17 km. However, photogrammetric analysis suggests that the gigantic jet occurred over the forward flank downdraft region with echo tops of 14 km. This part of the supercell may have had an inverted-polarity charge configuration as evidenced by positive cloud-to-ground lightning flashes (+CG) dominating over negative flashes (-CG), while -CGs occurred under the downwind anvil. Four minutes before the gigantic jet, -CG activity practically ceased in this area, while +CG rates increased, culminating during the 20 s leading up to the gigantic jet with four National Lightning Detection Network–detected +CGs. A relative lull in lightning activity of both polarities was observed for up to 1.5 min after the gigantic jet. The maturing storm subsequently produced 30 sprites between 0454 and 0820 UTC, some associated with extremely large impulse charge moment change values.Peer ReviewedPostprint (published version

Dielectric functions and electronic band structure of lead zirconate titanate thin films

We measure pseudodielectric functions in the visible-deep ultraviolet spectral range of Pb(ZrxTi1−x)O3 (x=0.2,0.56,0.82) (PZT), Pb0.98Nb0.04 (Zr0.2Ti0.8)0.96O3, Pb0.91La0.09 (Zr0.65Ti0.35)0.98O3, and Pb0.85La0.15Ti0.96O3 films grown on platinized silicon substrates using a sol-gel method and on (0001) sapphire using a radio-frequency sputtering method. Using a parametric optical constant model, we estimate the dielectric functions(ϵ) of the perovskite oxide thin films. Taking the second derivative of the fitted layer dielectric functions and using the standard critical-point model, we determine the parameters of the critical points. In the second derivative spectra, the lowest band-gapenergy peak near 4 eVis fitted as a double peak for annealed PZTs due to the perovskite phase. As-grown PZTs have mainly pyrochlore phase and the lowest band-gap peak is fitted as a single peak. We also examine the effect of dopants La and Nb, which substitute at Pb and Zr (Ti) sites, respectively. We found three band gaps Ea(∼3.9eV), Eb (∼4.5eV), and Ec (∼6.5eV) in the order of increasing energy. The Ea and Eb band-gap energies were not sensitive to Zr composition. We discuss the change of critical-point parameters for PZTs in comparison to the band-structure calculations based on local-density approximation. The near constancy of the lowest band-gap energy independent of Zr composition is consistent with the band-structure calculations