A Preliminary Study of Vallecular Bolus Aggregation in Healthy Swallowing of Solid Food Boluses.

OBJECTIVE: The pharyngeal swallow typically begins within 400 ms following the arrival of a liquid bolus in the pharynx. By contrast, processed food particles aggregate in the valleculae prior to swallow initiation. With solid foods, swallow reaction time (SRT), the interval between bolus passing the ramus of mandible and hyoid burst onset (HYB) can be subdivided into components of vallecular aggregation time (VAT) and the subsequent end of aggregation to hyoid burst interval (EOA-to-HYB). However, expected durations of these timing measures remain unclear. We aimed to study bolus aggregation in healthy swallowing for International Dysphagia Diet Standardisation Initiative Food Levels 5 (minced and moist [MM5]), 6 (soft and bite-sized [SB6]), and 7 (regular [RG7]). Understanding typical patterns and durations of vallecular aggregation with solids in healthy swallowing will inform the identification of impaired swallow timing in patient populations. DESIGN: Twenty healthy adults (10 males, Mage = 28 years, range: 23-55 years) swallowed two boluses each of MM5, SB6, and RG7 foods in videofluoroscopy. Blinded duplicate ratings determined bolus location at swallow onset, SRT, VAT, and EOA-to-HYB. Texture-based differences were measured using Friedman's tests. Bolus location was at/above the valleculae at swallow onset for 85% of boluses, with no differences by texture. SRT, VAT, and EOA-to-HYB did not vary by texture, with overall median values (interquartile range) of 99 ms (-66 to 743 ms) for SRT, 347 ms (66 to 891 ms) for VAT, and -132 ms (-231 to -83 ms) for EOA-to-HYB. CONCLUSIONS: These data corroborate prior evidence that it is not unusual for food particles to aggregate in the valleculae prior to swallow initiation in healthy swallowing. However, durations of vallecular aggregation are typically < 1 s in healthy adults.

Meta-analysis of single-case design research: Application of multilevel modeling.

This study describes the benefits and challenges of meta-analyses of single-case design research using multilevel modeling. The researchers illustrate procedures for conducting meta-analyses using four-level multilevel modeling through open-source R code. The demonstration uses data from multiple-baseline or multiple-probe across-participant single-case design studies (n = 21) on word problem instruction for students with learning disabilities published between 1975 and 2023. Researchers explore changes in levels and trends between adjacent phases (baseline vs. intervention and intervention vs. maintenance) using the sample data. The researchers conclude that word problem solving of students with learning disabilities varies based on the complexity of the word problem measures involving single-word problem, mixed-word problem, and generalization questions. These moderating effects differed across adjacent phases. These findings extend previous literature on meta-analyses methodology by describing how multilevel modeling can be used to compare the impacts of time-varying predictors within and across cases when analyzing single-case design studies. Future researchers may want to use this methodology to explore the roles of time-varying predictors as well as case or study-level moderators. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Investigating midwives and nurses reporting of 'infant feeding at hospital discharge': an online survey across NSW Australia.

BACKGROUND: The collection of data on 'infant feeding at hospital discharge' is used to monitor breastfeeding outcomes, health service benchmarking, and research. While some Australian states have clear definitions of this data collection point, there is no operational definition of 'infant feeding at hospital discharge' in the Australian state of New South Wales. Little is known about how midwives interpret the term 'infant feeding at hospital discharge', in particular, the timeframe used to calculate these important indicators. The purpose of this study was to explore midwives' and nurses' practices of reporting 'infant feeding at hospital discharge' in the Australian state of New South Wales. METHODS: An online survey was distributed across public and private maternity hospitals in New South Wales, Australia. The survey asked midwives and nurses their practice of reporting 'infant feeding at discharge' from categories offered by the state Mothers and Babies report of either "full breastfeeding", "any breastfeeding", and "infant formula only". The Qualtrics survey was available from December 2021 to May 2022. RESULTS: There were 319 completed surveys for analysis and all 15 NSW Health Districts were represented. Some participants reported using the timeframe 'since birth' as a reference (39%), however, the majority (54%, n = 173) referenced one of the feeding timeframes within the previous 24 h. Most midwives and nurses (83%, n = 265) recommended 24 h before discharge as the most relevant reference timeframe, and 65% (n = 207) were in favour of recording data on 'exclusive breastfeeding' since birth. CONCLUSION: This study identified multiple practice inconsistencies within New South Wales reporting of 'infant feeding at hospital discharge'. This has ramifications for key health statistics, state reporting, and national benchmarking. While the Baby Friendly Hospital Initiative accreditation requires hospitals to demonstrate and continuously monitor at least a 75% exclusive breastfeeding rate on discharge, only 11 New South Wales facilities have achieved this accreditation. We recommend introducing an option to collect 'exclusive breastfeeding' on discharge' which is in line with participant recommendations and the Baby Friendly Hospital accreditation. Other important considerations are the updated World Health Organization indicators such as, "Ever breastfed"; "Early initiation of breastfeeding" (first hour); "Exclusively breastfed for the first two days after birth".

Engineering Spin-Orbit Interactions in Silicon Qubits at the Atomic-Scale.

Spin-orbit interactions arise whenever the bulk inversion symmetry and/or structural inversion symmetry of a crystal is broken providing a bridge between a qubit's spin and orbital degree of freedom. While strong interactions can facilitate fast qubit operations by all-electrical control, they also provide a mechanism to couple charge noise thereby limiting qubit lifetimes. Previously believed to be negligible in bulk silicon, recent silicon nano-electronic devices have shown larger than bulk spin-orbit coupling strengths from Dresselhaus and Rashba couplings. Here, it is shown that with precision placement of phosphorus atoms in silicon along the [110] direction (without inversion symmetry) or [111] direction (with inversion symmetry), a wide range of Dresselhaus and Rashba coupling strength can be achieved from zero to 1113 × 10-13eV-cm. It is shown that with precision placement of phosphorus atoms, the local symmetry (C2v, D2d, and D3d) can be changed to engineer spin-orbit interactions. Since spin-orbit interactions affect both qubit operation and lifetimes, understanding their impact is essential for quantum processor design.

Atomic Engineering of Molecular Qubits for High-Speed, High-Fidelity Single Qubit Gates.

Universal quantum computing requires fast single- and two-qubit gates with individual qubit addressability to minimize decoherence errors during processor operation. Electron spin qubits using individual phosphorus donor atoms in silicon have demonstrated long coherence times with high fidelities, providing an attractive platform for scalable quantum computing. While individual qubit addressability has been demonstrated by controlling the hyperfine interaction between the electron and nuclear wave function in a global magnetic field, the small hyperfine Stark coefficient of 0.34 MHz/MV m-1 achieved to date has limited the speed of single quantum gates to ∼42 µs to avoid rotating neighboring qubits due to power broadening from the antenna. The use of molecular 2P qubits with more than one donor atom has not only demonstrated fast (0.8 ns) two-qubit SWAP gates and long spin relaxation times of ∼30 s but provides an alternate way to achieve high selectivity of the qubit resonance frequency. Here, we show in two different devices that by placing the donors with comparable interatomic spacings (∼0.8 nm) but along different crystallographic axes, either the [110] or [310] orientations using STM lithography, we can engineer the hyperfine Stark shift from 1 MHz/MV m-1 to 11.2 MHz/MV m-1, respectively, a factor of 10 difference. NEMO atomistic calculations show that larger hyperfine Stark coefficients of up to ∼70 MHz/MV m-1 can be achieved within 2P molecules by placing the donors ≥5 nm apart. When combined with Gaussian pulse shaping, we show that fast single qubit gates with 2π rotation times of 10 ns and ∼99% fidelity single qubit operations are feasible without affecting neighboring qubits. By increasing the single qubit gate time to ∼550 ns, two orders of magnitude faster than previously measured, our simulations confirm that >99.99% single qubit control fidelities are achievable.

Exploring the Efficacy of the Effortful Swallow Maneuver for Improving Swallowing in People With Parkinson Disease-A Pilot Study.

Objectives: To determine the immediate (compensatory) and longer term (rehabilitative) effect of the effortful swallow (ES) maneuver on physiological swallowing parameters in Parkinson disease. Design: Virtual intervention protocol via Microsoft Teams with pre- and post-videofluoroscopic swallowing studies. Setting: Outpatient hospital setting, with intervention performed virtually. Participants: Eight participants (median age 74 years [63-82])with Parkinson disease (years post onset 3-20) with a Hoehn and Yahr scale score between 2 and 4 (N=8). Interventions: ES maneuver, initiated using a maximum effort isometric tongue-to-palate press, with biofeedback provided using the Iowa Oral Performance Instrument. The protocol included 30 minute sessions twice daily, 5 days/week for 4 weeks. Main Outcome Measures: Penetration-Aspiration Scale scores, time-to-laryngeal-vestibule-closure, total pharyngeal residue, and pharyngeal area at maximum constriction as seen on lateral view videofluoroscopy. Results: No consistent, systematic trends were identified in the direction of improvement or deterioration across Penetration-Aspiration Scale scores, time-to-laryngeal-vestibule-closure, pharyngeal area at maximum constriction, or total pharyngeal residue. Conclusions: Heterogeneous response to the ES as both a compensatory and rehabilitative technique. Positive response on the compensatory probe was predictive of positive response after rehabilitation.

The Influence of Sex, Age, and Repeated Measurement on Pixel-Based Measures of Pharyngeal Area at Rest.

PURPOSE: Videofluoroscopic (VFSS) measurements of pharyngeal swallow mechanics can differentiate age- and disease-related changes in swallowing. Pharyngeal area at rest (PhAR) may differ in people with dysphagia, although its impact is not clear. Before the role of PhAR in dysphagia can be explored, it is important to establish whether PhAR remains stable across repeated measures in healthy adults, and varies as a function of sex or age. We hypothesized that healthy adults would show stable PhAR across repeated measures, but that larger PhAR would be seen in men versus women and in older versus younger adults. METHOD: We collected VFSS data from 87 healthy adults (44 men, M age = 46 years, range: 21-82). Trained raters identified the swallow rest frame after the initial swallow of each bolus and measured unobliterated pharyngeal area on these frames, in %(C2-4)2 units. Repeated-measures analyses of variance with a factor of sex, a covariate of age, and a repeated factor of task repetition were performed across the first 12 available measures per participant (N = 1,044 swallows). RESULTS: There were no significant variations in PhAR across repeated measures. A significant Sex × Age interaction was seen (p = .04): Males had significantly larger PhAR than females (p = .001), but females showed larger PhAR with advancing age (R = .47). CONCLUSIONS: These data confirm stability in PhAR across repeated measurements in healthy individuals. However, significant sex and age differences should be taken into consideration in future studies exploring the role of PhAR in people with dysphagia. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.22043543.

The Use of Exchange Coupled Atom Qubits as Atomic-Scale Magnetic Field Sensors.

Phosphorus atoms in silicon offer a rich quantum computing platform where both nuclear and electron spins can be used to store and process quantum information. While individual control of electron and nuclear spins has been demonstrated, the interplay between them during qubit operations has been largely unexplored. This study investigates the use of exchange-based operation between donor bound electron spins to probe the local magnetic fields experienced by the qubits with exquisite precision at the atomic scale. To achieve this, coherent exchange oscillations are performed between two electron spin qubits, where the left and right qubits are hosted by three and two phosphorus donors, respectively. The frequency spectrum of exchange oscillations shows quantized changes in the local magnetic fields at the qubit sites, corresponding to the different hyperfine coupling between the electron and each of the qubit-hosting nuclear spins. This ability to sense the hyperfine fields of individual nuclear spins using the exchange interaction constitutes a unique metrology technique, which reveals the exact crystallographic arrangements of the phosphorus atoms in the silicon crystal for each qubit. The detailed knowledge obtained of the local magnetic environment can then be used to engineer hyperfine fields in multi-donor qubits for high-fidelity two-qubit gates.

Ramped measurement technique for robust high-fidelity spin qubit readout.

State preparation and measurement of single-electron spin qubits typically rely on spin-to-charge conversion where a spin-dependent charge transition of the electron is detected by a coupled charge sensor. For high-fidelity, fast readout, this process requires that the qubit energy is much larger than the temperature of the system limiting the temperature range for measurements. Here, we demonstrate an initialization and measurement technique that involves voltage ramps rather than static voltages allowing us to achieve state-to-charge readout fidelities above 99% for qubit energies almost half that required by traditional methods. This previously unidentified measurement technique is highly relevant for achieving high-fidelity electron spin readout at higher temperature operation and offers a number of pragmatic benefits compared to traditional energy-selective readout such as real-time dynamic feedback and minimal alignment procedures.

The BLIiNG study - Breastfeeding length and intensity in gestational diabetes and metabolic effects in a subsequent pregnancy: A cohort study.

BACKGROUND: Gestational diabetes mellitus is associated with higher risk for developing type 2 diabetes. Breastfeeding is protective against the development of type 2 diabetes after gestational diabetes. There are no data regarding the effect of breastfeeding on the development of recurrent gestational diabetes. OBJECTIVE: Investigate the relationship of previous breastfeeding duration and intensity with the recurrence of gestational diabetes, and second pregnancy glucose tolerance test results. METHODS: We conducted a questionnaire-based pilot cohort study, enrolling 210 women during a subsequent second pregnancy, after a gestational diabetes-affected first pregnancy. Models for length and intensity of breastfeeding as predictors of the oral glucose tolerance test and for diagnosis of gestational diabetes in second pregnancy were fitted and then adjusted for possible confounders. RESULTS: Recurrent gestational diabetes rate in the study cohort was 70% (n = 146). In a fully adjusted model high intensity breastfeeding was associated with a lower 2-hour glucose level on the oral glucose tolerance test (by 0.66 mmol/L, 95% CI [0.15-1.17]; p = 0.01) and breastfeeding greater than six months with a lower 1-hour glucose on the oral glucose tolerance test (by 0.67 mmol/L, 95% CI [0.16-1.19]; p = 0.01), compared to women who breastfed less intensively or for a shorter duration respectively. There was an 18% reduction in the risk of gestational diabetes if a woman breastfed for more than six months (RR 0.82, 95% CI [0.69-0.98]; p = 0.03). The association was attenuated in the fully adjusted model (RR 0.89, 95% CI [0.78-1.02]; p = 0.09). CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: We found the risk of recurrent gestational diabetes was reduced by both increased duration and intensity of breastfeeding. Antenatal lactation education should be embedded into care pathways for women diagnosed with gestational diabetes.

Monolithic Three-Dimensional Tuning of an Atomically Defined Silicon Tunnel Junction.

A requirement for quantum information processors is the in situ tunability of the tunnel rates and the exchange interaction energy within the device. The large energy level separation for atom qubits in silicon is well suited for qubit operation but limits device tunability using in-plane gate architectures, requiring vertically separated top-gates to control tunnelling within the device. In this paper, we address control of the simplest tunnelling device in Si:P, the tunnel junction. Here we demonstrate that we can tune its conductance by using a vertically separated top-gate aligned with ±5 nm precision to the junction. We show that a monolithic 3D epitaxial top-gate increases the capacitive coupling by a factor of 3 compared to in-plane gates, resulting in a tunnel barrier height tunability of 0-186 meV. By combining multiple gated junctions in series we extend our monolithic 3D gating technology to implement nanoscale logic circuits including AND and OR gates.

Coherent control of a donor-molecule electron spin qubit in silicon.

Donor spins in silicon provide a promising material platform for large scale quantum computing. Excellent electron spin coherence times of [Formula: see text] µs with fidelities of 99.9% have been demonstrated for isolated phosphorus donors in isotopically pure 28Si, where donors are local-area-implanted in a nanoscale MOS device. Despite robust single qubit gates, realising two-qubit exchange gates using this technique is challenging due to the statistical nature of the dopant implant and placement process. In parallel a precision scanning probe lithography route has been developed to place single donors and donor molecules on one atomic plane of silicon with high accuracy aligned to heavily phosphorus doped silicon in-plane gates. Recent results using this technique have demonstrated a fast (0.8 ns) two-qubit gate with two P donor molecules placed 13 nm apart in natSi. In this paper we demonstrate a single qubit gate with coherent oscillations of the electron spin on a P donor molecule in natSi patterned by scanning tunneling microscope (STM) lithography. The electron spin exhibits excellent coherence properties, with a [Formula: see text] decoherence time of 298 ± 30 µs, and [Formula: see text] dephasing time of 295 ± 23 ns.

Engineering long spin coherence times of spin-orbit qubits in silicon.

Electron-spin qubits have long coherence times suitable for quantum technologies. Spin-orbit coupling promises to greatly improve spin qubit scalability and functionality, allowing qubit coupling via photons, phonons or mutual capacitances, and enabling the realization of engineered hybrid and topological quantum systems. However, despite much recent interest, results to date have yielded short coherence times (from 0.1 to 1 µs). Here we demonstrate ultra-long coherence times of 10 ms for holes where spin-orbit coupling yields quantized total angular momentum. We focus on holes bound to boron acceptors in bulk silicon 28, whose wavefunction symmetry can be controlled through crystal strain, allowing direct control over the longitudinal electric dipole that causes decoherence. The results rival the best electron-spin qubits and are 104 to 105 longer than previous spin-orbit qubits. These results open a pathway to develop new artificial quantum systems and to improve the functionality and scalability of spin-based quantum technologies.

Exploiting a Single-Crystal Environment to Minimize the Charge Noise on Qubits in Silicon.

Electron spins in silicon offer a competitive, scalable quantum-computing platform with excellent single-qubit properties. However, the two-qubit gate fidelities achieved so far have fallen short of the 99% threshold required for large-scale error-corrected quantum computing architectures. In the past few years, there has been a growing realization that the critical obstacle in meeting this threshold in semiconductor qubits is charge noise arising from the qubit environment. In this work, a notably low level of charge noise of S0  = 0.0088 ± 0.0004 µeV2 Hz-1 is demonstrated using atom qubits in crystalline silicon, achieved by separating the qubits from surfaces and interface states. The charge noise is measured using both a single electron transistor and an exchange-coupled qubit pair that collectively provide a consistent charge noise spectrum over four frequency decades, with the noise level S0 being an order of magnitude lower than previously reported. Low-frequency detuning noise, set by the total measurement time, is shown to be the dominant dephasing source of two-qubit exchange oscillations. With recent advances in fast (≈µs) single-shot readout, it is shown that by reducing the total measurement time to ≈1 s, 99.99% two-qubit S W A P gate fidelities can be achieved in single-crystal atom qubits in silicon.

Hypertension Self-management in Socially Disadvantaged African Americans: the Achieving Blood Pressure Control Together (ACT) Randomized Comparative Effectiveness Trial.

BACKGROUND: Effective hypertension self-management interventions are needed for socially disadvantaged African Americans, who have poorer blood pressure (BP) control compared to others. OBJECTIVE: We studied the incremental effectiveness of contextually adapted hypertension self-management interventions among socially disadvantaged African Americans. DESIGN: Randomized comparative effectiveness trial. PARTICIPANTS: One hundred fifty-nine African Americans at an urban primary care clinic. INTERVENTIONS: Participants were randomly assigned to receive (1) a community health worker ("CHW") intervention, including the provision of a home BP monitor; (2) the CHW plus additional training in shared decision-making skills ("DoMyPART"); or (3) the CHW plus additional training in self-management problem-solving ("Problem Solving"). MAIN MEASURES: We assessed group differences in BP control (systolic BP (SBP) < 140 mm Hg and diastolic BP (DBP) < 90 mmHg), over 12 months using generalized linear mixed models. We also assessed changes in SBP and DBP and participants' BP self-monitoring frequency, clinic visit patient-centeredness (i.e., extent of patient-physician discussions focused on patient emotional and psychosocial concerns), hypertension self-management behaviors, and self-efficacy. KEY RESULTS: BP control improved in all groups from baseline (36%) to 12 months (52%) with significant declines in SBP (estimated mean [95% CI] - 9.1 [- 15.1, - 3.1], - 7.4 [- 13.4, - 1.4], and - 11.3 [- 17.2, - 5.3] mmHg) and DBP (- 4.8 [- 8.3, - 1.3], - 4.0 [- 7.5, - 0.5], and - 5.4 [- 8.8, - 1.9] mmHg) for CHW, DoMyPART, and Problem Solving, respectively). There were no group differences in BP outcomes, BP self-monitor use, or clinic visit patient-centeredness. The Problem Solving group had higher odds of high hypertension self-care behaviors (OR [95% CI] 18.7 [4.0, 87.3]) and self-efficacy scores (OR [95% CI] 4.7 [1.5, 14.9]) at 12 months compared to baseline, while other groups did not. Compared to DoMyPART, the Problem Solving group had higher odds of high hypertension self-care behaviors (OR [95% CI] 5.7 [1.3, 25.5]) at 12 months. CONCLUSION: A context-adapted CHW intervention was correlated with improvements in BP control among socially disadvantaged African Americans. However, it is not clear whether improvements were the result of this intervention. Neither the addition of shared decision-making nor problem-solving self-management training to the CHW intervention further improved BP control. TRIAL REGISTRY: ClinicalTrials.gov Identifier: NCT01902719.

Spin read-out in atomic qubits in an all-epitaxial three-dimensional transistor.

The realization of the surface code for topological error correction is an essential step towards a universal quantum computer1-3. For single-atom qubits in silicon4-7, the need to control and read out qubits synchronously and in parallel requires the formation of a two-dimensional array of qubits with control electrodes patterned above and below this qubit layer. This vertical three-dimensional device architecture8 requires the ability to pattern dopants in multiple, vertically separated planes of the silicon crystal with nanometre precision interlayer alignment. Additionally, the dopants must not diffuse or segregate during the silicon encapsulation. Critical components of this architecture-such as nanowires9, single-atom transistors4 and single-electron transistors10-have been realized on one atomic plane by patterning phosphorus dopants in silicon using scanning tunnelling microscope hydrogen resist lithography11,12. Here, we extend this to three dimensions and demonstrate single-shot spin read-out with 97.9% measurement fidelity of a phosphorus dopant qubit within a vertically gated single-electron transistor with <5 nm interlayer alignment accuracy. Our strategy ensures the formation of a fully crystalline transistor using just two atomic species: phosphorus and silicon.

Readout and control of the spin-orbit states of two coupled acceptor atoms in a silicon transistor.

Coupling spin qubits to electric fields is attractive to simplify qubit manipulation and couple qubits over long distances. Electron spins in silicon offer long lifetimes, but their weak spin-orbit interaction makes electrical coupling challenging. Hole spins bound to acceptor dopants, spin-orbit-coupled J = 3/2 systems similar to Si vacancies in SiC and single Co dopants, are an electrically active spin system in silicon. However, J = 3/2 systems are much less studied than S = 1/2 electrons, and spin readout has not yet been demonstrated for acceptors in silicon. Here, we study acceptor hole spin dynamics by dispersive readout of single-hole tunneling between two coupled acceptors in a nanowire transistor. We identify m J = ±1/2 and m J = ±3/2 levels, and we use a magnetic field to overcome the initial heavy-light hole splitting and to tune the J = 3/2 energy spectrum. We find regimes of spin-like (+3/2 to -3/2) and charge-like (±1/2 to ±3/2) relaxations, separated by a regime of enhanced relaxation induced by mixing of light and heavy holes. The demonstrated control over the energy level ordering and hybridization are new tools in the J = 3/2 system that are crucial to optimize single-atom spin lifetime and electrical coupling.

Addressable electron spin resonance using donors and donor molecules in silicon.

Phosphorus donor impurities in silicon are a promising candidate for solid-state quantum computing due to their exceptionally long coherence times and high fidelities. However, individual addressability of exchange coupled donors with separations ~15 nm is challenging. We show that by using atomic precision lithography, we can place a single P donor next to a 2P molecule 16 ± 1 nm apart and use their distinctive hyperfine coupling strengths to address qubits at vastly different resonance frequencies. In particular, the single donor yields two hyperfine peaks separated by 97 ± 2.5 MHz, in contrast to the donor molecule that exhibits three peaks separated by 262 ± 10 MHz. Atomistic tight-binding simulations confirm the large hyperfine interaction strength in the 2P molecule with an interdonor separation of ~0.7 nm, consistent with lithographic scanning tunneling microscopy images of the 2P site during device fabrication. We discuss the viability of using donor molecules for built-in addressability of electron spin qubits in silicon.

Characterization of a Scalable Donor-Based Singlet-Triplet Qubit Architecture in Silicon.

We present a donor-based quadruple-quantum-dot device, designed to host two singlet-triplet qubits fabricated by scanning tunnelling microscope lithography, with just two leads per qubit. The design is geometrically compact, with each pair of dots independently controlled via one gate and one reservoir. The reservoirs both supply electrons for the dots and measure the singlet-triplet state of each qubit via dispersive sensing. We verify the locations of the four phosphorus donor dots via an electrostatic model of the device. We study one of the observed singlet-triplet states with a tunnel coupling of 39 GHz and a S0-to- T- decay of 2 ms at zero detuning. We measure a 5 GHz electrostatic interaction between two pairs of dots separated by 65 nm. The results outline a low-gate-density pathway to a scalable 1D building block of atomic-precision singlet-triplet qubits using donors with dispersive readout.