Ramping Dynamics in the Frontal Cortex Unfold Over Multiple Timescales During Motor Planning.

Plans are formulated and refined over the period leading to their execution, ensuring that the appropriate behavior is enacted at just the right time. While existing evidence suggests that memory circuits convey the passage of time through diverse neuronal responses, it remains unclear whether the neural circuits involved in planning behavior exhibit analogous temporal dynamics. Using publicly available data, we analyzed how activity in the frontal motor cortex evolves during motor planning. Individual neurons exhibited diverse ramping activity throughout a delay interval that preceded a planned movement. The collective activity of these neurons was useful for making temporal predictions that became increasingly precise as the movement time approached. This temporal diversity gave rise to a spectrum of encoding patterns, ranging from stable to dynamic representations of the upcoming movement. Our results indicate that neural activity unfolds over multiple timescales during motor planning, suggesting a shared mechanism in the brain for processing temporal information related to both past memories and future plans.

Efficacy of detergent-based cleaning and wiping against SARS-CoV-2 on high-touch surfaces.

Efficacy of cleaning methods against SARS-CoV-2 suspended in either 5% soil load (SARS-soil) or simulated saliva (SARS-SS) was evaluated immediately (hydrated virus, T0) or 2 hours post-contamination (dried virus, T2). Hard water dampened wiping (DW) of surfaces, resulted in 1.77-3.91 log reduction (T0) or 0.93-2.41 log reduction (T2). Incorporating surface pre-wetting by spraying with a detergent solution (D + DW) or hard water (W + DW) just prior to dampened wiping did not unilaterally increase efficacy against infectious SARS-CoV-2, however, the effect was nuanced with respect to surface, viral matrix, and time. Cleaning efficacy on porous surfaces (seat fabric, SF) was low. W + DW on stainless steel (SS) was as effective as D + DW for all conditions except SARS-soil at T2 on SS. DW was the only method that consistently resulted in > 3-log reduction of hydrated (T0) SARS-CoV-2 on SS and ABS plastic. These results suggest that wiping with a hard water dampened wipe can reduce infectious virus on hard non-porous surfaces. Pre-wetting surfaces with surfactants did not significantly increase efficacy for the conditions tested. Surface material, presence or absence of pre-wetting, and time post-contamination affect efficacy of cleaning methods.

Evaluation of surface disinfection methods to inactivate the beta coronavirus Murine Hepatitis Virus.

The list of EPA-approved disinfectants for coronavirus features many products for use on hard, non-porous materials. There are significantly fewer products registered for use on porous materials. Further, many common, high-touch surfaces fall in between non-porous materials such as glass and porous materials such as soft fabrics. The objective of this study was to assess the efficacy of selected commercially available disinfectant products against coronaviruses on common, high-touch surfaces. Four disinfectants (Clorox Total 360, Bleach solution, Vital Oxide, and Peroxide Multi-Surface Cleaner) were evaluated against Murine Hepatitis Virus A59 (MHV) as a surrogate coronavirus for SARS-CoV-2. MHV in cell culture medium was inoculated onto four materials: stainless steel, latex-painted drywall tape, Styrene Butadiene rubber (rubber), and bus seat fabric. Immediately (T0) or 2-hr (T2) post-inoculation, disinfectants were applied by trigger-pull or electrostatic sprayer and either held for recommended contact times (Spray only) or immediately wiped (Spray and Wipe). Recovered infectious MHV was quantified by median tissue culture infectious dose assay. Bleach solution, Clorox Total 360, and Vital Oxide were all effective (>3-log10 reduction or complete kill of infectious virus) with both the Spray Only and Spray and Wipe methods on stainless steel, rubber, and painted drywall tape when used at recommended contact times at both T0 and T2 hr. Multi-Surface Cleaner unexpectedly showed limited efficacy against MHV on stainless steel within the recommended contact time; however, it showed increased (2.3 times greater efficacy) when used in the Spray and Wipe method compared to Spray Only. The only products to achieve a 3-log10 reduction on fabric were Vital Oxide and Clorox Total 360; however, the efficacy of Vital Oxide against MHV on fabric was reduced to below 3-log10 when applied by an electrostatic sprayer compared to a trigger-pull sprayer. This study highlights the importance of considering the material, product, and application method when developing a disinfection strategy for coronaviruses on high-touch surfaces.

Decontamination of SARS-CoV-2 contaminated N95 filtering facepiece respirators using artificial sun lamps.

AIMS: Assess the feasibility of using light from artificial sun lamps to decontaminate N95 filtering facepiece respirators (FFRs) contaminated with SARS-CoV-2. METHODS AND RESULTS: FFR coupons or whole FFRs contaminated with 5 log10 TCID50 (target concentration) SARS-CoV-2 in culture media, simulated saliva, or simulated lung fluid were dried for 1-2 h, then exposed to light from tanning and horticulture lamps to assess decontamination. Exposed coupons and whole FFRs showed SARS-CoV-2 inactivation for all matrices tested. Furthermore, FFRs still met performance specifications after five decontamination cycles. CONCLUSIONS: It is feasible that artificial sunlight from these sun lamps can be used to decontaminate FFRs provided the UV dose is sufficient and the light is unobstructed. Furthermore, decontamination can be performed up to five times without degrading FFR performance. SIGNIFICANCE AND IMPACT OF THE STUDY: This research shows a proof of principle that artificial sun lamps may be an option to decontaminate SARS-CoV-2 on N95 FFRs. UV doses required for inactivation to levels below detection ranged from 4 to 37·8 J cm-2 depending on the light source, virus matrix and FFR type.

Contextual variability and serial position effects in free recall.

In immediate free recall, words recalled successively tend to come from nearby serial positions. M. J. Kahana (1996) documented this effect and showed that this tendency, which the authors refer to as the lag recency effect, is well described by a variant of the search of associative memory (SAM) model (J. G. W. Raaijmakers & R. M. Shiffrin, 1980, 1981). In 2 experiments, participants performed immediate, delayed, and continuous distractor free recall under conditions designed to minimize rehearsal. The lag recency effect, previously observed in immediate free recall, was also observed in delayed and continuous distractor free recall. Although two-store memory models, such as SAM, readily account for the end-of-list recency effect in immediate free recall, and its attenuation in delayed free recall, these models fail to account for the long-term recency effect. By means of analytic simulations, the authors show that both the end of list recency effect and the lag recency effect, across all distractor conditions, can be explained by a single-store model in which context, retrieved with each recalled item, serves as a cue for subsequent recalls.

The ability of pressure-controlled discography to predict surgical and nonsurgical outcomes.

STUDY DESIGN: A multicenter, retrospective study of long-term surgical and nonsurgical patient outcomes, after lumbar discography. OBJECTIVES: To investigate the efficacy and surgical outcome predictive value of categorizing positive discography findings, using a pressure x pain provocation categorization system. BACKGROUND: With the use of pressure-controlled manometric discography, improved and more specific diagnostic categorization is possible. The literature suggests that more specific categorization of positive discographic findings may predict surgical and nonsurgical outcomes. Studies have shown that intertransverse fusions may not fully protect the disc from anterior loading. Consequently, in patients who have low-pressure-sensitive discs, surgery that includes interbody fusion should provide a more favorable long-term outcome than intertransverse fusion only. METHODS: Long-term outcome was ascertained in 96 patients who had lumbar discography and subsequently underwent interbody fusion alone, combined fusion, intertransverse fusion or no surgery. Patients were retrospectively placed into specific diagnostic categories, according to a four-point scale. Progressively restrictive subgroups, beginning with the entire sample and ending with the most sensitive group (chemically sensitive), were examined for long-term surgical outcome differentiation. RESULTS: There were no significant differences in long-term surgical outcome across the entire sample. However, significant outcome differences existed across the subgroup of patients with chemically sensitive discs. In this group, patients undergoing interbody/combined fusion had a significantly better outcome than patients who had intertransverse fusion. Nonsurgical patients had the worst outcome overall. CONCLUSIONS: Patients with highly (chemically) sensitive discs appear to achieve significantly better long-term outcomes with interbody/combined fusion than with intertransverse fusion. Patients without disc surgery have the least favorable outcome. Precise prospective categorization of positive discographic diagnoses may predict outcomes from treatment, surgical or otherwise, thereby greatly facilitating therapeutic decision-making.

Percutaneous lumbar discectomy. Preoperative and postoperative magnetic resonance imaging.

We evaluated magnetic resonance imaging studies of thirty patients before and after a contained herniation of a lumbar disc was treated with a percutaneous lumbar discectomy. The imaging studies were evaluated to determine whether the preoperative appearance of the herniated disc was predictive of the outcome of percutaneous discectomy and also to determine a possible mechanism of action of the procedure in the relief of symptoms. The index operation was successful in seventeen (57 per cent) of the thirty patients. The preoperative imaging studies showed no differences in the appearance of the discs that went on to have a successful result and those that went on to have an unsuccessful result. Imaging studies made four to six weeks after the operation showed no measurable changes in the morphology of the disc. Imaging studies made a mean of fourteen months after the operation showed no changes in the morphology of the disc in twenty-four (80 per cent) of the patients, irrespective of the clinical outcome. Only three of the seventeen patients who had a successful result had a reduction of more than two millimeters in the size of the herniated segment, and two of the thirteen patients who had an unsuccessful result had an increase of more than one millimeter in the size of the herniated segment. We found that preoperative imaging studies cannot predict the clinical outcome of percutaneous lumbar discectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Intrapartum amnioinfusion in twin gestation. A preliminary report of three cases.

Amnioinfusion is an intrapartum technique that is not usually attempted in twin gestations. This report describes infusion of normal saline into the amniotic sacs of three twin gestations with oligohydramnios. All the twins were safely delivered vaginally. No untoward effects were noted. Ultrasound is advised following amnioinfusion to assess the increase in the amniotic fluid volume.

The use of the Lottes nail in the treatment of closed and open tibial shaft fractures.

During the years 1979 through 1987, 98 patients with 101 acute tibial fractures were initially treated with Lottes' nails at the authors' institution. Ninety-one percent of the fractures healed uneventfully. The average healing times were 15.7 weeks for the 40 closed fractures and 20.5 weeks for the 61 open fractures. Infection occurred in one of the 40 closed fractures (2.5%) and in eight of the 61 open fractures (13.1%). By Gustilo grade, infection occurred in none of the 22 Grade I fractures (0%); one of the 22 Grade II fractures (4.5%); and seven of the 17 Grade III open fractures (41.2%). Seven of the eight malunions resulted from preventable technical errors. Five of the six nonunions healed after a secondary procedure. Lottes nailing is recommended in closed fractures and Grade I and II open fractures when internal fixation is required. Grade III open fractures, treated with the Lottes nail, had a high rate of infection.

Carpal tunnel syndrome secondary to wrist and finger flexor spasticity.

Ten patients with spastic wrist flexion deformities secondary to traumatic brain injury were evaluated for carpal tunnel syndrome. The angle of wrist flexion deformity averaged 75 degrees (range, 58 to 115 degrees). Nerve conduction studies demonstrated prolonged median motor and/or sensory latencies in all patients. Preoperative wick catheter measurements of carpal tunnel pressures in eight patients averaged 11 mm Hg in the resting position, 21 mm Hg in maximal wrist flexion, and 15 mm Hg in maximal extension. Each patient had carpal tunnel release with simultaneous wrist and finger flexor tendon releases or lengthenings. At surgery nine of the median nerves were constricted at the proximal edge of the transverse carpal ligament. The presence of normal carpal tunnel pressures and impingement of the median nerve at the proximal edge of the transverse carpal ligament indicates that the chronically flexed posture of the wrist resulted in median nerve compression, and this condition may be aggravated by underlying pressure from the spastic finger flexors.

Infections in patients with neutropenia.

We review published reports and our experience in regard to the causative organisms of infections in patients with neutropenia. The organisms isolated from infected patients were almost exclusively pyogenic and enteric bacteria, and our patients had no history of serious viral or fungal infections, documenting the importance of the neutrophil in normal host defense against extracellular but not intracellular pathogens. Staphylococcus aureus was the single most commonly cultured organism; however, Pseudomonas and Escherichia coli were almost as commonly isolated. Positive cultures were obtained primarily from the blood or cutaneous, subcutaneous, or deep tissue abscesses. In patients with congenital neutropenia, pneumonia, otitis media, and abscesses were the most frequent infections diagnosed clinically. There is a suggestion that recent antibiotic therapy shifted the spectrum of infecting organisms toward enteric bacteria.