Quantum computing for atomic and molecular resonances.

The complex-scaling method can be used to calculate molecular resonances within the Born-Oppenheimer approximation, assuming that the electronic coordinates are dilated independently of the nuclear coordinates. With this method, one will calculate the complex energy of a non-Hermitian Hamiltonian, whose real part is associated with the resonance position and imaginary part is the inverse of the lifetime. In this study, we propose techniques to simulate resonances on a quantum computer. First, we transformed the scaled molecular Hamiltonian to second quantization and then used the Jordan-Wigner transformation to transform the scaled Hamiltonian to the qubit space. To obtain the complex eigenvalues, we introduce the direct measurement method, which is applied to obtain the resonances of a simple one-dimensional model potential that exhibits pre-dissociating resonances analogous to those found in diatomic molecules. Finally, we applied the method to simulate the resonances of the H2 - molecule. The numerical results from the IBM Qiskit simulators and IBM quantum computers verify our techniques.

Highly Polyvalent DNA Motors Generate 100+ pN of Force via Autochemophoresis.

Motor proteins such as myosin, kinesin, and dynein are essential to eukaryotic life and power countless processes including muscle contraction, wound closure, cargo transport, and cell division. The design of synthetic nanomachines that can reproduce the functions of these motors is a longstanding goal in the field of nanotechnology. DNA walkers, which are programmed to "walk" along defined tracks via the burnt bridge Brownian ratchet mechanism, are among the most promising synthetic mimics of these motor proteins. While these DNA-based motors can perform useful tasks such as cargo transport, they have not been shown to be capable of cooperating to generate large collective forces for tasks akin to muscle contraction. In this work, we demonstrate that highly polyvalent DNA motors (HPDMs), which can be viewed as cooperative teams of thousands of DNA walkers attached to a microsphere, can generate and sustain substantial forces in the 100+ pN regime. Specifically, we show that HPDMs can generate forces that can unzip and shear DNA duplexes (∼12 and ∼50 pN, respectively) and rupture biotin-streptavidin bonds (∼100-150 pN). To help explain these results, we present a variant of the burnt-bridge Brownian ratchet mechanism that we term autochemophoresis, wherein many individual force generating units generate a self-propagating chemomechanical gradient that produces large collective forces. In addition, we demonstrate the potential of this work to impact future engineering applications by harnessing HPDM autochemophoresis to deposit "molecular ink" via mechanical bond rupture. This work expands the capabilities of synthetic DNA motors to mimic the force-generating functions of biological motors. Our work also builds upon previous observations of autochemophoresis in bacterial transport processes, indicating that autochemophoresis may be a fundamental mechanism of pN-scale force generation in living systems.

Electronic Structure Calculations and the Ising Hamiltonian.

Obtaining exact solutions to the Schrödinger equation for atoms, molecules, and extended systems continues to be a "Holy Grail" problem which the fields of theoretical chemistry and physics have been striving to solve since inception. Recent breakthroughs have been made in the development of hardware-efficient quantum optimizers and coherent Ising machines capable of simulating hundreds of interacting spins with an Ising-type Hamiltonian. One of the most vital questions pertaining to these new devices is, "Can these machines be used to perform electronic structure calculations?" Within this work, we review the general procedure used by these devices and prove that there is an exact mapping between the electronic structure Hamiltonian and the Ising Hamiltonian. Additionally, we provide simulation results of the transformed Ising Hamiltonian for H2 , He2 , HeH+, and LiH molecules, which match the exact numerical calculations. This demonstrates that one can map the molecular Hamiltonian to an Ising-type Hamiltonian which could easily be implemented on currently available quantum hardware. This is an early step in developing generalized methods on such devices for chemical physics.

pH-sensitive microemulsion-based gels for removal of colonic ammonia: a novel preventative oral preparation for hepatic encephalopathy in rats.

Microemulsions with limited stability in mimetic gastrointestinal environments have previously demonstrated potential for the effective removal of ammonia from artificial colonic fluid. Specialized pH­sensitive microemulsion­based gels for the removal of colonic ammonia (MBG­RCA), however, possess relative stability in the gastrointestinal (GI) tract of normal rats, indicating potential use in in vivo applications. An investigation of the effects of oral MBG­RCA was conducted in order to evaluate the reduction of intestinal ammonia and the prevention of hepatic encephalopathy (HE) in rat models. Eighty rats were allocated into eight 4­day treatment groups: The HE model (intraperitoneal injection of thioacetamide) group; the high­, medium­ and low­dose MBG­RCA therapeutic groups (15, 10 and 5 ml/kg MBG­RCA, respectively); and the normal, blank, lactulose and acetic acid control groups, each of which received daily treatment administration. Oral MBG­RCA effects were identified using behavioral monitoring observed by an infrared night vision supervisory control system, electroencephalograms, blood ammonia levels, intestinal ammonia levels, liver functionality and pathological observation. High­ and medium­dose oral administrations of MBG­RCA significantly decreased the blood and intestinal ammonia levels (P<0.05), improved liver functionality and reduced the clinical manifestations of HE in rats. MBG­RCA demonstrated high clearance of rat colonic ammonia while maintaining sufficient stability in the GI tract, indicating the potential for the development of new clinically relevant oral preparations for the prevention of HE. Additionally, such preparations are advantageous in that ammonia is eliminated without the production of potentially harmful metabolic byproducts.

Isolation and partial characterization of a novel pollen-specific cDNA with multiple polyadenylation sites from wheat.

A novel pollen-specific full-length cDNA clone PSG076 was isolated using suppression subtractive hybridization and 5'/3' RACE techniques. PSG076 was shown to exhibit multi-site polyadenylation by sequencing the 3' ends of the cDNAs. At least six transcripts with different length were produced from the single gene based on different poly(A) tail attachment sites. However, polyadenylation consensus sequence AAUAAA was not seen at the 3'-untranslated sequence. PSG076 contained a 299 bp 5' untranslated region and an open reading frame of 663 bp encoding a 221 amino acid peptide with pI of 4.31. A blast search revealed that this sequence did not show a significant similarity to any genes deposited in the public database. Southern blot indicated that PSG076 was a single copy gene. Northern blot and RT-PCR analysis indicated that PSG076 transcripts showed specific expression in mature pollen, and weak or undetectable signals in uninucleate microspore, immature seed, stem, young leave, root and ovary. Further analysis of the expression pattern in gametophyte showed that PSG076 transcripts were undetectable in uninucleate, binucleate microspore and pollen at early stage, and were first detectable and increased rapidly at middle and late stages of pollen development with the maximum level in mature pollen and also expressed in germinating pollen in vivo, suggesting that PSG076 might play a role in pollen germination and pollen tube growth in addition to its function in maturation. The evidences gathered in this work indicated that the six different transcripts from the single gene were differentially expressed during pollen development.