Methodological advances for studying gamma motor neurons

The muscle spindle is an important sense organ for motor control and proprioception. Specialized intrafusal fibers are innervated by both stretch sensitive afferents and γ motor neurons that control the length of the spindle and tune the sensitivity of the muscle spindle afferents to both dynamic movement and static length. γ motor neurons share many similarities with other skeletal motor neurons, making it challenging to identify and specifically record or stimulate them. This short review will discuss recent advances in genetic and molecular biology techniques, electrophysiological recording, optical imaging, computer modelling, and stem cell culture techniques that have the potential to help answer important questions about fusimotor function in motor control and disease

Molecular determinants of mechanosensation in the muscle spindle

The muscle spindle (MS) provides essential sensory information for motor control and proprioception. The Group Ia and II MS afferents are low threshold slowly-adapting mechanoreceptors and report both static muscle length and dynamic muscle movement information. The exact molecular mechanism by which MS afferents transduce muscle movement into action potentials is incompletely understood. This short review will discuss recent evidence suggesting that PIEZO2 is an essential mechanically sensitive ion channel in MS afferents and that vesicle-released glutamate contributes to maintaining afferent excitability during the static phase of stretch. Other mechanically gated ion channels, voltage-gated sodium channels, other ion channels, regulatory proteins, and interactions with the intrafusal fibers are also important for MS afferent mechanosensation. Future studies are needed to fully understand mechanosensation in the MS and whether different complements of molecular mediators contribute to the different response properties of Group Ia and II afferents

Bioethanol Production from Brewers Spent Grains Using a Fungal Consolidated Bioprocessing (CBP) Approach.

Production of bioethanol from brewers spent grains (BSG) using consolidated bioprocessing (CBP) is reported. Each CBP system consists of a primary filamentous fungal species, which secretes the enzymes required to deconstruct biomass, paired with a secondary yeast species to ferment liberated sugars to ethanol. Interestingly, although several pairings of fungi were investigated, the sake fermentation system (A. oryzae and S. cerevisiae NCYC479) was found to yield the highest concentrations of ethanol (37 g/L of ethanol within 10 days). On this basis, 1 t of BSG (dry weight) would yield 94 kg of ethanol using 36 hL of water in the process. QRT-PCR analysis of selected carbohydrate degrading (CAZy) genes expressed by A. oryzae in the BSG sake system showed that hemicellulose was deconstructed first, followed by cellulose. One drawback of the CBP approach is lower ethanol productivity rates; however, it requires low energy and water inputs, and hence is worthy of further investigation and optimisation

Occupational Transitions of Family Caregivers of Loved Ones with Dementia

Purpose: The primary purpose of this study was to explore how family caregivers of people with dementia experience transitions in occupations as they assume the caregiver role. Because unpaid family caregivers play a vital part in the scheme of health care, it is important to understand their supports, their perceptions of themselves as caregivers, and the impact of caregiving on relationships, identity, and physical and mental health. Many researchers have studied the effects of caregiver burden, yet minimal attention has been given to the lived experiences of caregiving on their daily roles and routines. Methods: A qualitative descriptive design was used to obtain data from eight caregivers through semi-structured interviews. Content analysis was then applied to all data. Results: The following categories were identified: 1) Benefits, which consisted of the positive experiences gained as a result of caregiving; 2) Consequences, which included the physical, mental, and emotional burdens attached to being a caregiver; and 3) Supports, which were positive resources utilized by caregivers to be both better prepared to care for their loved ones and more capable within their caregiving role. Conclusion: Findings confirm that unpaid caregivers of loved ones with dementia experience dramatic changes in many aspects of their lives. Caregivers felt a strong responsibility as a family member to provide care for their loved ones. It has been found that caregivers spend most of their time engaged in caregiver related tasks, consequently impacting their occupational balance and ability to engage in what they would like to do. Health care providers must be mindful of the changes that caregivers experience, by assisting them to increase supports, anticipate the consequences, and recognize and value the benefits

Rapid analysis of formic acid, acetic acid, and furfural in pretreated wheat straw hydrolysates and ethanol in a bioethanol fermentation using atmospheric pressure chemical ionisation mass spectrometry.

Atmospheric pressure chemical ionisation mass spectrometry (APCI-MS) offers advantages as a rapid analytical technique for the quantification of three biomass degradation products (acetic acid, formic acid and furfural) within pretreated wheat straw hydrolysates and the analysis of ethanol during fermentation. The data we obtained using APCI-MS correlated significantly with high-performance liquid chromatography analysis whilst offering the analyst minimal sample preparation and faster sample throughput

Maximising high solid loading enzymatic saccharification yield from acid-catalysed hydrothermally-pretreated brewers spent grain

Enzyme saccharification of pretreated brewers spent grains (BSG) was investigated, aiming at maximising glucose production. Factors investigated were; variation of the solids loadings at different cellulolytic enzyme doses, reaction time, higher energy mixing methods, supplementation of the cellulolytic enzymes with additional enzymes (and cofactors) and use of fed-batch methods. Improved slurry agitation through aerated high-torque mixing offered small but significant enhancements in glucose yields (to 53 ± 2.9 g/L and 45% of theoretical yield) compared to only 41 ± 4.0 g/L and 39% of theoretical yield for standard shaking methods (at 15% w/v solids loading). Supplementation of the cellulolytic enzymes with additional enzymes (acetyl xylan esterases, ferulic acid esterases and α-L- arabinofuranosidases) also boosted achieved glucose yields to 58 – 69 ± 0.8 - 6.2 g/L which equated to 52 - 58% of theoretical yield. Fed-batch methods also enhanced glucose yields (to 58 ± 2.2 g/L and 35% of theoretical yield at 25% w/v solids loading) compared to non-fed-batch methods. From these investigations a novel enzymatic saccharification method was developed (using enhanced mixing, a fed-batch approach and additional carbohydrate degrading enzymes) which further increased glucose yields to 78 ± 4.1 g/L and 43% of theoretical yield when operating at high solids loading (25% w/v)

Family Connect: Keeping families informed during the COVID-19 pandemic

Family Connect programs to enhance communication with families and care partners who were unable to visit their inpatient loved ones during the COVID-19 crisis. While they differed in composition, the Family Connect programs at both institutions leveraged providers who had decreased clinical activity during the pandemic. The Family Connect team became integrated with the team. At both institutions, Family Connect teams perform virtual chart review, discuss patient status and care plan with the primary provider and communicate with the patient’s designated family member or care partner daily. Conversations are documented in the electronic medical record (EMR), which allows for metric tracking and clear communication to all team members. All Family Connect providers undergo a comprehensive training program focused on workflow, communication, and EMR training. Family Connect can be tailored to the needs of specific health systems based on patient volume and staffing. The NYULH Family Connect model incorporated medical student mentorship, on-site nurse liaisons to assist patients with virtual visits with families, and a 24/7 call center for family support. The YNHHS model was separate from the YNHHS COVID-19 call center and utilized attending and trainee physicians. The program is highly portable and can be easily reinitiated if needed. Experience Framework This article is associated with the Patient, Family & Community Engagement lens of The Beryl Institute Experience Framework. (http://bit.ly/ExperienceFramework) Access other PXJ articles related to this lens. Access other resources related to this lens

NaV1.1 is essential for proprioceptive signaling and motor behaviors

The voltage-gated sodium channel (NaV), NaV1.1, is well-studied in the central nervous system; conversely, its contribution to peripheral sensory neuron function is more enigmatic. Here, we identify a new role for NaV1.1 in mammalian proprioception. RNAscope analysis and in vitro patch-clamp recordings in genetically identified mouse proprioceptors show ubiquitous channel expression and significant contributions to intrinsic excitability. Notably, genetic deletion of NaV1.1 in sensory neurons caused profound and visible motor coordination deficits in conditional knockout mice of both sexes, similar to conditional Piezo2-knockout animals, suggesting that this channel is a major contributor to sensory proprioceptive transmission. Ex vivo muscle afferent recordings from conditional knockout mice found that loss of NaV1.1 leads to inconsistent and unreliable proprioceptor firing characterized by action potential failures during static muscle stretch; conversely, afferent responses to dynamic vibrations were unaffected. This suggests that while a combination of Piezo2 and other NaV isoforms is sufficient to elicit activity in response to transient stimuli, NaV1.1 is required for transmission of receptor potentials generated during sustained muscle stretch. Impressively, recordings from afferents of heterozygous conditional knockout animals were similarly impaired, and heterozygous conditional knockout mice also exhibited motor behavioral deficits. Thus, NaV1.1 haploinsufficiency in sensory neurons impairs both proprioceptor function and motor behaviors. Importantly, human patients harboring NaV1.1 loss-of-function mutations often present with motor delays and ataxia; therefore, our data suggest that sensory neuron dysfunction contributes to the clinical manifestations of neurological disorders in which NaV1.1 function is compromised. Collectively, we present the first evidence that NaV1.1 is essential for mammalian proprioceptive signaling and behaviors

Advancing the decadal plan for the science of nutrition: Progressing a framework for implementation

Aims: In 2019, the Australian Academy of Science in collaboration with the nutrition community published the decadal plan for the science of nutrition. This article aims to review progress towards each of its pillar goals (societal determinants, nutrition mechanisms, precision and personalised nutrition, and education and training) and two enabling platforms (a national data capability and a trusted voice for nutrition science), prioritise actions, and conceptualise program logic implementation models. This process also brought together public health nutrition researchers to reflect on societal determinants of health, and advise how the next 5 years of the decadal plan could reflect contemporary issues. Methods: Two engagement events, in 2023, brought together experienced and mid- and early-career nutrition professionals for co-creation of implementation logic models. Results: One hundred and nine early and mid-career professionals were involved. A revised model for the decadal plan pillars emerged from synthesis of all logic models. This new model integrated the precision and personalised nutrition pillar with nutrition mechanisms pillar. These combined pillars build towards the national data capability enabling platform and created new cross-cutting themes for education and training. The need arose for greater focus on respectful engagement with Aboriginal and Torres Strait Islander communities and sustained effort to build cross-disciplinary collaboration to realise the plan\u27s societal determinants goals. A new alliance for nutrition science is proposed to become a unified advocacy voice and build trust in nutrition professionals. Conclusions: A programmatic approach provides a road map for implementing the decadal plan for the final 5 years

Double Field Inflation

We present an inflationary universe model which utilizes two coupled real scalar fields. The inflation field $\phi$ experiences a first order phase transition and its potential dominates the energy density of the Universe during the inflationary epoch. This field $\phi$ is initially trapped in its metastable minimum and must tunnel through a potential barrier to reach the true vacuum. The second auxiliary field $\psi$ couples to the inflaton field and serves as a catalyst to provide an abrupt end to the inflationary epoch; i.e., the $\psi$ field produces a time-dependent nucleation rate for bubbles of true $\phi$ vacuum. In this model, we find that bubbles of true vacuum can indeed percolate and we argue that thermalization of the interiors can more easily take place. The required degree of flatness (i.e., the fine tuning) in the potential of the $\psi$ field is comparable to that of other models which invoke slowly rolling fields. Pseudo Nambu-Goldstone bosons may naturally provide the flat potential for the rolling field.Comment: 18 pages, 2 figures, This early paper is being placed on the archive to make it more easily accessible in light of recent interest in reviving tunneling inflationary models and as its results are used in an accompanying submissio