Public health infection prevention: An analysis of existing training during the COVID-19 pandemic

OBJECTIVES

In response to the COVID-19 pandemic, agencies and organizations required trainings to support the needs of the public health workforce. To better understand the training resources available, this study identified, organized, and classified infection prevention and control (IPC) training and educational opportunities.

STUDY DESIGN

Environmental scan.

METHODS

A total of 306 IPC training resources were compiled between January and April 2021. Key themes and topics were identified and compared to the Healthcare Infection Control Practices Advisory Committee's (HICPAC) core IPC practices.

RESULTS

Three hundred and six training resources, including webinars, fact sheets, module-based learning activities, infographics, and professional practice guidance materials, were identified. Common themes included proper use of personal protective equipment (e.g., masks, gloves), community reopening guidance, and mass vaccination resources. A large proportion (74.9%) of trainings were under 60 min. Using the HICPAC framework, the most frequently addressed content included standard precautions (40%), leadership support (31.6%), and transmission-based precautions (25.8%). Few trainings addressed performance monitoring and feedback (17.1%).

CONCLUSIONS

A wide range of organizations developed IPC-specific content during the pandemic. However, these resources did not address the breadth of knowledge required to implement IPC concepts effectively. The creation of universally applicable IPC core competencies and the development of high-quality IPC education and trainings for public health and the overall responder workforces should be prioritized. Accessible high-quality online and just-in-time trainings are critical for future pandemic and disaster preparedness.

Beam power scale-up in micro-electromechanical systems based multi-beam ion accelerators

We report on the development of multi-beam radio frequency (RF) linear ion accelerators that are formed from stacks of low cost wafers and describe the status of beam power scale-up using an array of 112 beams. The total argon ion current extracted from the 112-beamlet extraction column was 0.5 mA. The measured energy gain in each RF gap reached as high as 7.25 keV. We present a path toward using this technology to achieve ion currents >1 mA and ion energies >100 keV for applications in material processing.

Absolute calibration of GafChromic film for very high flux laser driven ion beams

We report on the calibration of GafChromic HD-v2 radiochromic film in the extremely high dose regime up to 100 kGy together with very high dose rates up to 7 × 10¹¹ Gy/s. The absolute calibration was done with nanosecond ion bunches at the Neutralized Drift Compression Experiment II particle accelerator at Lawrence Berkeley National Laboratory (LBNL) and covers a broad dose dynamic range over three orders of magnitude. We then applied the resulting calibration curve to calibrate a laser driven ion experiment performed on the BELLA petawatt laser facility at LBNL. Here, we reconstructed the spatial and energy resolved distributions of the laser-accelerated proton beams. The resulting proton distribution is in fair agreement with the spectrum that was measured with a Thomson spectrometer in combination with a microchannel plate detector.

Design and implementation of a Thomson parabola for fluence dependent energy-loss measurements at the Neutralized Drift Compression eXperiment

The interaction of ion beams with matter includes the investigation of the basic principles of ion stopping in heated materials. An unsolved question is the effect of different, especially higher, ion beam fluences on ion stopping in solid targets. This is relevant in applications such as in fusion sciences. To address this question, a Thomson parabola was built for the Neutralized Drift Compression eXperiment (NDCX-II) for ion energy-loss measurements at different ion beam fluences. The linear induction accelerator NDCX-II delivers 2 ns short, intense ion pulses, up to several tens of nC/pulse, or 10¹⁰-10¹¹ ions, with a peak kinetic energy of ∼1.1 MeV and a minimal spot size of 2 mm FWHM. For this particular accelerator, the energy determination with conventional beam diagnostics, for example, time of flight measurements, is imprecise due to the non-trivial longitudinal phase space of the beam. In contrast, a Thomson parabola is well suited to reliably determine the beam energy distribution. The Thomson parabola differentiates charged particles by energy and charge-to-mass ratio, through deflection of charged particles by electric and magnetic fields. During first proof-of-principle experiments, we achieved to reproduce the average initial helium beam energy as predicted by computer simulations with a deviation of only 1.4%. Successful energy-loss measurements with 1 μm thick silicon nitride foils show the suitability of the accelerator for such experiments. The initial ion energy was determined during a primary measurement without a target, while a second measurement, incorporating the target, was used to determine the transmitted energy. The energy-loss was then determined as the difference between the two energies.

Source-to-accelerator quadrupole matching section for a compact linear accelerator

Recently, we presented a new approach for a compact radio-frequency (RF) accelerator structure and demonstrated the functionality of the individual components: acceleration units and focusing elements. In this paper, we combine these units to form a working accelerator structure: a matching section between the ion source extraction grids and the RF-acceleration unit and electrostatic focusing quadrupoles between successive acceleration units. The matching section consists of six electrostatic quadrupoles (ESQs) fabricated using 3D-printing techniques. The matching section enables us to capture more beam current and to match the beam envelope to conditions for stable transport in an acceleration lattice. We present data from an integrated accelerator consisting of the source, matching section, and an ESQ doublet sandwiched between two RF-acceleration units.

A compact linear accelerator based on a scalable microelectromechanical-system RF-structure

A new approach for a compact radio-frequency (RF) accelerator structure is presented. The new accelerator architecture is based on the Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) structure that was first developed in the 1980s. The MEQALAC utilized RF resonators producing the accelerating fields and providing for higher beam currents through parallel beamlets focused using arrays of electrostatic quadrupoles (ESQs). While the early work obtained ESQs with lateral dimensions on the order of a few centimeters, using a printed circuit board (PCB), we reduce the characteristic dimension to the millimeter regime, while massively scaling up the potential number of parallel beamlets. Using Microelectromechanical systems scalable fabrication approaches, we are working on further reducing the characteristic dimension to the sub-millimeter regime. The technology is based on RF-acceleration components and ESQs implemented in the PCB or silicon wafers where each beamlet passes through beam apertures in the wafer. The complete accelerator is then assembled by stacking these wafers. This approach has the potential for fast and inexpensive batch fabrication of the components and flexibility in system design for application specific beam energies and currents. For prototyping the accelerator architecture, the components have been fabricated using the PCB. In this paper, we present proof of concept results of the principal components using the PCB: RF acceleration and ESQ focusing. Ongoing developments on implementing components in silicon and scaling of the accelerator technology to high currents and beam energies are discussed.

Development and testing of a pulsed helium ion source for probing materials and warm dense matter studies

The neutralized drift compression experiment was designed and commissioned as a pulsed, linear induction accelerator to drive thin targets to warm dense matter (WDM) states with peak temperatures of ∼1 eV using intense, short pulses (∼1 ns) of 1.2 MeV lithium ions. At that kinetic energy, heating a thin target foil near the Bragg peak energy using He(+) ions leads to more uniform energy deposition of the target material than Li(+) ions. Experiments show that a higher current density of helium ions can be delivered from a plasma source compared to Li(+) ions from a hot plate type ion source. He(+) beam pulses as high as 200 mA at the peak and 4 μs long were measured from a multi-aperture 7-cm-diameter emission area. Within ±5% variation, the uniform beam area is approximately 6 cm across. The accelerated and compressed pulsed ion beams can be used for materials studies and isochoric heating of target materials for high energy density physics experiments and WDM studies.

Vascular depression: overrepresented among African Americans?

OBJECTIVE

Our primary aim was to compare the rate of vascular depression among a clinical sample of African American and Caucasian depressed older adults. Secondary aims included characterizing the clinical and neuropsychological profile of vascular depression and comparing antidepressant response rates between patients with vascular and nonvascular depression.

METHODS

This was a two-site, multi-ethnic, open 8-week trial of antidepressant medication in older adults with depression. Men and women 50 years or older meeting DSM-IV criteria for nonpsychotic unipolar depression participated in this trial. Each participant underwent a comprehensive psychiatric and neuropsychological evaluation and a brain MRI, which were performed at baseline.

RESULTS

Forty-six patients met inclusion and exclusion criteria. Forty-two of those patients received an MRI at baseline. Sixteen patients met criteria for vascular depression. Patients with vascular depression were significantly more likely to be African American and have a higher likelihood of being female, a higher rate of hypertension and psychomotor retardation, a lower rate of family history of affective illness, and frontal systems dysfunction on neuropsychological testing. The difference in response rates between patients with vascular and nonvascular depression did not reach statistical significance.

CONCLUSIONS

This is the first study to document high rates of vascular depression in a clinical sample of African Americans and Caucasians. Our findings suggest that vascular depression may be overrepresented among African Americans, which is consistent with the high rates of cardiovascular disease, hypertension, and stroke in this population.

Less is more in antidepressant clinical trials: a meta-analysis of the effect of visit frequency on treatment response and dropout

OBJECTIVE

We investigated how the number of follow-up visits affects response rates and dropout among patients in antidepressant trials for major depressive disorder (MDD).

DATA SOURCES

MEDLINE, PsycINFO, and PubMed were searched to identify trials contrasting antidepressants to placebo or active comparator in adults with depression. The index terms depression-drug therapy, depressive disorder-drug therapy, and antidepressant agents, in addition to the classes and individual generic names of all antidepressants, were combined using the "or" operator. Results were limited to (1) English-language articles, (2) publication year 1985 or later, (3) age group ≥ 18 years, and (4) publication types including clinical trials, controlled clinical trials, meta-analysis, multicenter study, randomized controlled trial, or review.

STUDY SELECTION

Included articles reported trials of approved antidepressant medications for MDD in outpatients aged 18-65 years, were 6-12 weeks in duration, and had response rates specified using a standardized measure. Trials were excluded for enrolling inpatients, pregnant women, psychotic subjects, or those with treatment-resistant depression. These criteria allowed 9,189 articles identified in the literature review to be narrowed to 111 reports.

DATA EXTRACTION

Demographic characteristics, the number of study visits planned in each treatment cell, duration of active treatment, attrition rates, and response rates to medication and placebo were entered into a database.

RESULTS

In a multilevel meta-analysis, active medication versus placebo (OR = 1.96, P < .001), active comparator versus placebo-controlled study design (OR = 1.82, P < .001), and longer versus shorter duration (OR = 1.87, P < .001) were associated with significantly increased odds of treatment response. After controlling for these variables, the number of study visits did not significantly influence response rates (OR = 0.97, P = .877). The odds of dropout were significantly decreased for active comparator versus placebo-controlled trials (OR = 0.67, P = .002) and longer versus shorter duration trials (OR = 0.54, P = .035), while increasing numbers of study visits significantly increased the odds of participant dropout (OR = 2.77, P < .001).

CONCLUSIONS

Visit schedules that are much more frequent than are commonly practiced in the community treatment of depression may increase the expense of clinical trials and make them less generalizable to standard clinical treatment.

Novel methods for improvement of a Penning ion source for neutron generator applications

Penning ion source performance for neutron generator applications is characterized by the atomic ion fraction and beam current density, providing two paths by which source performance can be improved for increased neutron yields. We have fabricated a Penning ion source to investigate novel methods for improving source performance, including optimization of wall materials and electrode geometry, advanced magnetic confinement, and integration of field emitter arrays for electron injection. Effects of several electrode geometries on discharge characteristics and extracted ion current were studied. Additional magnetic confinement resulted in a factor of two increase in beam current density. First results indicate unchanged proton fraction and increased beam current density due to electron injection from carbon nanofiber arrays.

A tandem-based compact dual-energy gamma generator

A dual-energy tandem-type gamma generator has been developed at E. O. Lawrence Berkeley National Laboratory and Sandia National Laboratories. The tandem accelerator geometry allows higher energy nuclear reactions to be reached, thereby allowing more flexible generation of MeV-energy gammas for active interrogation applications. Both positively charged ions and atoms of hydrogen are created from negative ions via a gas stripper. In this paper, we show first results of the working tandem-based gamma generator and that a gas stripper can be utilized in a compact source design. Preliminary results of monoenergetic gamma production are shown.

Integration of scanning probes and ion beams

We report the integration of a scanning force microscope with ion beams. The scanning probe images surface structures non-invasively and aligns the ion beam to regions of interest. The ion beam is transported through a hole in the scanning probe tip. Piezoresistive force sensors allow placement of micromachined cantilevers close to the ion beam lens. Scanning probe imaging and alignment is demonstrated in a vacuum chamber coupled to the ion beam line. Dot arrays are formed by ion implantation in resist layers on silicon samples with dot diameters limited by the hole size in the probe tips of a few hundred nm.

European Convention on Human Rights: effects on psychiatric care

The introduction of the European Convention on Human Rights into UK law will have a direct effect on practice in mental health care. The authors discuss developments associated with the Convention, examine different articles and suggest the changes they could bring. They suggest that, rather than reacting to the development of convention rights, healthcare professionals should take the opportunity to influence new standards for psychiatric care.

Biochemical and morphologic characterization of acrylamide peripheral neuropathy

To determine whether reduced Na+/K+-ATPase activity might be involved in acrylamide (ACR)-induced peripheral axon swelling and degeneration, rubidium (Rb+) transport was measured as an index of enzyme function. x-ray microanalysis was used to quantify elemental Rb uptake and accumulation in internodal myelinated axons, mitochondria, Schwann cells, and myelin of rat tibial nerve cryosections. Results demonstrated impairment of Rb uptake in tibial axons from orally intoxicated (2.8 mM ACR for 34 days), moderately affected rats. In severely affected oral rats (49 days), complete inhibition of Rb transport and frank axon degeneration were evident. However, in moderate-to-severely affected rats exposed to ACR via ip injection (50 mg/kg/day for 11 days), neither structural nor enzymatic changes were present in tibial fibers. These findings in nerve cryosections suggested inhibition of axolemmal Na+ pump activity and degeneration were dependent upon route of ACR administration. This possibility was substantiated by a quantitative longitudinal morphometric study of conventionally fixed tibial nerve. Oral ACR treatment (2.8 mM ACR for 15-49 days) was associated with progressive axon degeneration, which was preceded by atrophy. Axonal swellings were rarely (<1%) observed. In contrast, ip ACR injection (50 mg/kg/day for 5-11 days) produced classic behavioral neurotoxicity but did not alter axon morphology in tibial nerve. Thus, fiber degeneration and decreased Na+ pump activity were consequences of subchronic oral ACR administration. This parallel expression suggests a mechanistic relationship. However, the corresponding general neurotoxicological significance is unclear since, behavioral toxicity induced by ip ACR develops without structural and enzymatic changes in tibial nerve.

Cost-effectiveness analysis of extended conservative therapy versus surgical intervention in the management of herniated lumbar intervertebral disc

The management of herniated lumbar intervertebral disc for patients not responding to an initial trial of conservative therapy is generally surgical. Little is known about the effect of continued conservative therapy on patients who have not improved or have deteriorated within the first 3 months. This study assessed which form of treatment, surgical or continued conservative therapy, is more cost-effective once an adequate trial of conservative therapy has failed. The study is a retrospective chart review of 55 white male truck drivers who presented with acutely herniated nucleus pulposus between 1985 and 1989. Twenty-five patients underwent surgery, and 30 underwent continued conservative therapy after initial rehabilitation. No significant difference was found in outcome (80% good or fair in both the surgical and conservative groups) or costs ($55,000 +/- $1,000/case during a 5-year period), hence no difference in the cost-effectiveness between the two treatment modalities (each $63,000 +/- $2,000/adjusted outcome). Conservatively treated patients, however, missed significantly more work. It was concluded that, for a patient not responding to the initial trial of conservative therapy, the option to undergo continued conservative treatment should be made available.