Understanding the human brain is one of the most significant challenges of the 21st century. As theoretical studies continue to improve the description of the complex mechanisms that regulate biological processes, in parallel numerous experiments are conducted to enrich or verify these theoretical predictions also with the aim of extrapolating more accurate models. In the fields of magnetometry and thermometry, among the various sensors proposed for biological application, nitrogen-vacancy (NV) centers are emerging as a promising solution due to their perfect biocompatibility and the possibility of being positioned in close proximity to the cell membrane, thus allowing a nanometric spatial resolution down to the nano-scale. Still many issues must be overcome to obtain either a sensitivity capable of revealing the very weak electromagnetic fields generated by neurons (or other excitable cells) during their firing activity or a spatial resolution sufficient to measure intracellular thermal gradient due to biological processes. However, over the last few years, significant improvements have been achieved in this direction, thanks to the use of innovative techniques. In this review, the new results regarding the application of NV centers will be analyzed and the main challenges that must be afforded for leading to practical applications will be discussed.
Temperature is one of the most relevant parameters for the regulation of intracellular processes. Measuring localized subcellular temperature gradients is fundamental for a deeper understanding of cell function, such as the genesis of action potentials, and cell metabolism. Notwithstanding several proposed techniques, at the moment detection of temperature fluctuations at the subcellular level still represents an ongoing challenge. Here, for the first time, temperature variations (1 °C) associated with potentiation and inhibition of neuronal firing is detected, by exploiting a nanoscale thermometer based on optically detected magnetic resonance in nanodiamonds. The results demonstrate that nitrogen-vacancy centers in nanodiamonds provide a tool for assessing various levels of neuronal spiking activity, since they are suitable for monitoring different temperature variations, respectively, associated with the spontaneous firing of hippocampal neurons, the disinhibition of GABAergic transmission and the silencing of the network. Conjugated with the high sensitivity of this technique (in perspective sensitive to < 0.1 °C variations), nanodiamonds pave the way to a systematic study of the generation of localized temperature gradients under physiological and pathological conditions. Furthermore, they prompt further studies explaining in detail the physiological mechanism originating this effect.
Objectives:
The present study was designed to compare outcomes in patients undergoing thoracic surgery using the VivaSight double-lumen tube (VDLT) or the conventional double-lumen tube (cDLT).
Design:
A retrospective analysis of 100 patients scheduled for lung resection recruited over 21 consecutive months (January 2018–September 2019).
Setting:
Single-center university teaching hospital investigation.
Participants:
A randomized sample of 100 patients who underwent lung resection during this period were selected for the purpose to compare 50 patients in the VDLT group and 50 in the cDLT group.
Interventions:
After institutional review board approval, patients were chosen according to inclusion and exclusion criteria and we created a general database. The 100 patients have been chosen through a random process with the Microsoft Excel program (Microsoft 2018, Version 16.16.16).
Measurements and Main Results:
The primary endpoint of the study was to analyze the need to use fiberoptic bronchoscopy to confirm the correct positioning of VDLT or the cDLT used for lung isolation. Secondary endpoints were respiratory parameters, admission to the intensive care unit, length of hospitalization, postoperative complications, readmission, and 30-day mortality rate. The use of fiberoptic bronchoscopy was lower in the VDLT group, and the size of the tube was smaller. The intraoperative respiratory and hemodynamics parameters were optimal. There were no other preoperative, intraoperative, or postoperative differences between both groups.
Conclusions:
The VDLT reduces the need for fiberoptic bronchoscopy, and it seems that a smaller size is needed. Finally, VDLT is cost-effective using disposable fiberscopes.
We present an innovative experimental set-up that uses Nitrogen-Vacancy centres in diamonds to measure magnetic fields with the sensitivity of $\eta =68\pm 3~\mathrm{nT}/\sqrt{\mathrm{Hz}}$
η
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68
±
3
nT
/
Hz
at demonstrated (sub)cellular scale. The presented method of magnetic sensing, utilizing a lock-in based ODMR technique for the optical detection of microwave-driven spin resonances induced in NV centers, is characterized by the excellent magnetic sensitivity at such small scale and the full biocompatibility. The cellular scale is obtained using a NV-rich sensing layer of 15 nm thickness along z axis and a focused laser spot of $(10 \times 10)~\mu\mathrm{m}^{2}$
(
10
×
10
)
μ
m
2
in x-y plane. The biocompatibility derives from an accurate choice of the applied optical power. For this regard, we also report how the magnetic sensitivity changes for different applied laser power and discuss the limits of the sensitivity sustainable with biosystem at such small volume scale. As such, this method offers a whole range of research possibilities for biosciences.
The combined use of a double-lumen tube and a bronchial blocker can be very helpful in two different clinical scenarios: (1) in isolating not only the contralateral lung, but also the lobe/s of the same lung in which the infected lobe must be resected, (2) in preventing/treating hypoxemia because of the presence of a contralateral lobectomy. A cardiothoracic anesthesiologist must expertise this technique to avoid complications during surgery.
A novel technique is introduced for the reconstruction of multimode optical fields, based on simultaneously exploiting both the generalized Glauber's Kth‐order correlation function and a recently proposed anti‐correlation function (dubbed ) which is resilient to Poissonian noise. It is experimentally demonstrated that this method yields mode reconstructions with higher fidelity with respect to those obtained with reconstruction methods based only on 's, even requiring less “a priori” information. The reliability and versatility of this technique make it suitable for a widespread use in real applications of optical quantum measurement, from quantum information to quantum metrology, especially when one needs to characterize ensembles of single‐photon emitters in the presence of background noise (due, for example, to residual excitation laser, stray light or unwanted fluorescence).
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