The conservation of energy and momentum have been viewed as undermining Cartesian mental causation since the 1690s. Modern discussions of the topic tend to use mid-nineteenth century physics, neglecting both locality and Noether’s theorem and its converse. The relevance of General Relativity (GR) has rarely been considered. But a few authors have proposed that the non-localizability of gravitational energy and consequent lack of physically meaningful local conservation laws answers the conservation objection to mental causation: conservation already fails in GR, so there is nothing for minds to violate. This paper is motivated by two ideas. First, one might take seriously the fact that GR formally has an infinity of rigid symmetries of the action and hence, by Noether’s first theorem, an infinity of conserved energies-momenta . Second, Sean Carroll has asked  how one should modify the Dirac–Maxwell–Einstein equations to describe mental causation. This paper uses the generalized Bianchi identities to show that General Relativity tends to exclude, not facilitate, such Cartesian mental causation. In the simplest case, Cartesian mental influence must be spatio-temporally constant, and hence 0. The difficulty may diminish for more complicated models. Its persuasiveness is also affected by larger world-view considerations. The new general relativistic objection provides some support for realism about gravitational energy-momentum in GR (taking pseudotensor laws seriously). Such realism also might help to answer an objection to theories of causation involving conserved quantities, because energies-momenta would be conserved even in GR. The energy conservation objection to nonphysical mental causation has been made starting from Leibniz in the 1600s Leibniz , p. 172 x,  y,  z,  t,  is also the real mathematical reason for the validity of the momentum-energy-law. ...We assert that for these differential equations, a law, analogous to the energy law , or at any rate not from classical field theories excluding General Relativity. Hence the conservation argument against interactionism degenerates into a mere denial or an incredulous stare. If philosophers of mind aim to respect real physics rather than A-level chemistry  A more interesting question for interactionists is whether their view violates conservation laws badly enough to run afoul of experiment. Unfortunately Butterfield’s insights have not had the deserved effect on the philosophy of mind literature.The failure of the Leibniz-to-Churchland energy conservation objection is not really news to philosophers of physics. As Jeremy Butterfield wrote over two decades ago:positive account or a defense of traditional mind-body interaction (which I do not aim to do) might need to take into account quantum physics somehow. Given that this paper explains how General Relativity implies a less trivial objection than the traditional Leibnizian one, quantum replies could become relevant for that reason also.The failure of the traditional Leibnizian objection occurs in what would seem to be the most conservation-friendly territory available, classical local field theory with the principle of least action Pitts .1 AspectThe mind-body problem was of considerable interest to Herbert Feigl , 2004. FWhat difference does General Relativity make? While General Relativity is by now over a century old, there seems to have been no correct exploration of its bearing on the conservation law issue in the philosophy of mind until now. Typically the energy conservation objection is based on a rather elementary grasp of physics, roughly high-school chemistry level, corresponding perhaps to the physics of the 1860s, so any attempt to address the difference made by General Relativity is welcome.Two better-informed authors have claimed that conservation laws already fail in General Relativity even apart from dualism Mohrhoff , 2011; tGenerally there is something of an anti-realist tendency regarding energy conservation in General Relativity, at least regarding the local conservation laws, the kind that elsewhere modern physics usually employs. An old standard textbook decreed that “[a]nybody who looks for a magic formula for ‘local gravitational energy-momentum’ is looking for the right answer to the wrong question.”  and the difficulty of finding an adequate alternative. When one does the generalized Bianchi identity mathematics (below), one finds that General Relativity makes Cartesian mental causation harder, not easier. Thus one can go beyond interpretive stances and achieve objective results.Fortunately there In the simplest case, when the Cartesian mental influence is a scalar field , that influence must be spatio-temporally constant, as will appear below. Spatio-temporal constancy is obviously absurd for the influence of a human mind unless that influence is zero, so that there is no Cartesian mental causation after all. Unlike the traditional Leibnizian objection, this new objection from General Relativity does not assume something equivalent (given Noether’s theorem and its converse) to non-interaction in order to infer non-interaction. Thus General Relativity resists external influences by trying to force them to vanish. While the simplest toy model of mind-body influence yields a negative result for the ability of the non-physical mind to influence the body, this result weakens as the complexity of the model rises. The complexity of the model for mental causation is also bound up with larger world-view issues, as will appear below. Because the majority  interpretation of gravitational energy has the wrong heuristic force, leading one to think that General Relativity is more lax when in fact it is more rigid, the non-localization interpretation is somewhat undermined by the objective Bianchi identity results. Correspondingly, the minority realist interpretation has the correct heuristic force and so is somewhat confirmed.ies theory of causation), because the mathematics speaks of infinitely many conserved energies and momenta if it speaks of any. One might see the help given to conserved quantity theories of causation as another theoretical virtue that counts somewhat in favor of realism about gravitational energy(s). But there are lingering difficulties not unrelated to those that motivated doubts about the reality of gravitational energy in the first place.Realism about gravitational energy is philosophically interesting for another reason, namely, the relevance to conserved quantity theories of causation Fair . A numbesame status as non-gravitational energy. If one already doubts the existence of non-gravitational energy, or if one comes to doubt its existence by being persuaded that non-gravitational energy is no better than gravitational energy, such views would be perfectly compatible with the views defended here. Given that most people seem content with non-gravitational energy and that I do not object to this view, I will continue to describe my view of gravitational energy as realist despite only arguing for parity between non-gravitational energy and gravitational energy.In arguing for “realism” about gravitational energy, I do not intend to be making novel moves in metaphysics, but rather to be taking for granted the presumably unproblematic (at any rate rarely criticized) status of non-gravitational energy in other theories and arguing that gravitational energy has the The question whether the causal influence of immaterial minds  can be modelled in physics, though not novel, has become the more timely in light of the recent interventions of Sean Carroll, Caltech cosmologist, amateur philosopher, and proponent of “poetic naturalism,” which one can choose as one’s religion at Facebook Carroll . JudgingScience. Where the book discusses the bearing of physics on the philosophy of mind, it continues the earlier program. Carroll’s rhetorical questions can serve to inspire a genuine inquiry into his questions. It turns that whereas the traditional Leibnizian energy conservation objection is question-begging  on the right, representing how the soul interacts with electrons.  So any respectable scientist who took this idea seriously would be asking—what form does that interaction take? Is it local in spacetime? Does the soul respect gauge invariance and Lorentz invariance? Does the soul have a Hamiltonian? Do the interactions preserve unitarity and conservation of information?If you believe in an immaterial soul that interacts with our bodies, you need to believe that this equation Nobody ever asks these questions out loud, possibly because of how silly they sound. Once you start asking them, the choice you are faced with becomes clear: either overthrow everything we think we have learned about modern physics, or distrust the stew of religious accounts/unreliable testimony/wishful thinking that makes people believe in the possibility of life after death. It’s not a difficult decision, as scientific theory-choice goes  is plausible depends entirely on which of two closely related but distinct targets one has in mind: spirits or parapsychology-as-subtle-physics. It is especially easy to conflate these two targets due to the gradual shift  only in particular space-time regions—in living brains, around saints, in prayer meetings, at séances, near witchdoctors  no life after death , not where one finds it convenient to look, has been made before, such as in the eighteenth century by defenders of miracles Gottfried Less, George Campbell and William Paley  failure of interactionist dualism to the denial of an afterlife is a bit quick; one might consider such presently even less fashionable substance dualist options as occasionalism, pre-established harmony, and epiphenomenalism before discarding an afterlife on the basis of troubles with interactionism; perhaps idealism is also worth another look. Given that my purpose here is not to defend ideas of an afterlife but to develop Carroll’s abandoned program of evaluating interactionism physically, I will not pursue such questions further, however.How an immaterial soul might interact with the physical body remains a challenging question for dualists even today, and indeed it has grown enormously more difficult to see how it might be addressed [compared to the days when Elisabeth queried Descartes]....Carroll , pp. 212But in fact a fair number of serious people have suggested that such interaction is in fact made easier rather than harder, due to quantum mechanics  physicalist philosophers of mind who raise the energy conservation issue, but in fact there are key differences. For one, Carroll doesn’t bring up energy conservation philosophical worry about interactionism, such as Princess Elisabeth’s understandable inability to conceive how such disparate entities as mind with no spatial location and matter could interact, already starts to dissipate upon being framed in contemporary physics. While it has sometimes been unclear what this objection is at least in modern philosophical reiterations  What, then, is to stop an immaterial substance from having effects that appear in a Lagrangian? It seems that there is just nothing much else to say in response to “how?” unless one rejects the usual standards of modern physics. The de-materialization of everything including matter into fields, suggested around 1930 by Pascual Jordan and by now generally accepted in physics, has left the contemporary understanding of the physical world far more ethereal (so to speak), ghostly, tenuous, and mathematical than either the seventeenth century mechanical philosophy or tables-and-chairs daily experience would have suggested. Carroll is not worried about spatially non-located souls, because he wants to refute the following view:Very roughly speaking, when most people think about an immaterial soul that persists after death, they have in mind some sort of blob of spirit energy that takes up residence near our brain, and drives around our body like a soccer mom driving an SUV Carroll .Hence the greatest source of difficulty faced by Princess Elisabeth, nonspatiality of souls, does not concern Carroll. After conceiving an interesting research program, the implementation of which might in fact tend to undermine interactionist dualism, Carroll abandoned it. I, however, will take it up, at least in part, thereby finding a new objection to interactionist dualism from General Relativity. Carroll’s foundling research program suggests exploring what could possibly be the “new term (at minimum) on the right, representing how the soul interacts with electrons” to assess the prospects for modeling soul-brain interaction in a fashion congenial to theoretical physicists. Such a term would, if all goes well for the dualist, preserve core physical principles insofar as one could reasonably expect , and unitarity . I aim for something less ambitious, namely to see what bearing General Relativity has on the energy conservation question. Happily for Carroll and unhappily for interactionist dualists, it turns out that there is a difficulty in the vicinity.Carroll performs dualists a service by clearly formulating the issue and sketching a potentially illuminating research program. Indeed much of the ions Kim , formulaions Kim . This faThe big problem for interaction is and remains the utter nonspatiality of Cartesian egos.  My suggestion is that the dualist give up nonspatiality. Descartes had his own seventeenth-century metaphysical reasons for insisting that minds are entirely nonspatial, but we need not accept those. Why not suppose that minds are located where it feels as if they are located, in the head behind the eyes? [footnote suppressed] Lycan Spatial extension also leaves more room for efforts toward detailed dualist neuroscientific proposals, such as Eccles made  follow a very common interpretation in the physics and philosophy of physics communities  doubted the existence of gravitational waves and/or gravitational energy altogether, although this view largely disappeared due to the late 1950s sticky bead argument that gravitational wave energy could be converted to heat Bondi . Recent, a princOne reason that General Relativity makes the mind-body problem harder builds on the mathematical fact that General Relativity not only entails local conservation laws , but also  is entailed by conservation laws Noether , p. 428.My view is distinctive in proposing that this mathematics can be taken seriously, that is, realistically. , Genera Carroll  cannot b Carroll ; his Gen Carroll . HoweverGeneral Relativity proves very different from earlier physical theories in that whereas earlier theories passively tolerate the introduction of external causal influences , General Relativity actively resists them by trying to force them to vanish. One might take the view that laws of nature describe the tendencies of physical entities, while leaving unspecified whether any nonphysical entities influence the physical (von Wachter u (indices suppressed) and influence not have any equations of motion from the principle of least action: one does not postulate the vanishing of Let the action for General Relativity with matter A runs over all the components. Suppose  that under infinitesimal coordinate transformations along the vector field To go further, it is necessary to be a bit more specific about the mental influence Anderson . This exmentclasspt{minimaA. Then the Lie derivative u. Then wherever will impose a novel restriction on the allowed states of matter and gravity like a Lagrange multiplier even without the postulation that , is that must have as a solution etc.—presumably they will be countable and will not fill an interval including . If The terms that survive when the gravitational and material field equations are imposed takes the formfor Pons .] In ordvia the expression An example might help: let What if there are two, three or four scalar fields? If their gradients are linearly independent, then one will have two, three or four copies (respectively) of the same sad story. One can use the scalars with independent gradients as space-time coordinates locally and thus turn the still only four of these identities,no limit on how many field components over which the index A can range. The freedom to choose the form of the transformations of the fields is also relevant, albeit in a less transparent and less important way. In the single scalar u. Thus it could turn out that the general relativistic objection still has force even with some additional field components to employ. But that seems unlikely to be true to any great extent. There is a literature on underdetermined differential equations, which in general outline confirms the expectation that having fewer equations than unknowns leads to having a variety of solutions  divine action (a.k.a. miracles), angelic action, demonic action, genie action (genies/jinn being part of Muslim belief), action by the spirits presumably of the dead . There  Wegener . But at sic], namely to be a means for rational and free beings , much harder than other field theories do. Thus contemplation of spirit-to-matter causation sheds a bit of light on the gravitational energy localization debate in favor of realism.The treatment of the generalized Bianchi identities above shows that the relevance of General Relativity for mental causation does not have to be yoked to the frequently denigrated pseudotensor conservation laws for energy and momentum. Rather, the tendency of General Relativity to restrict immaterial-to-material causation can be explored in a tensorial way, free of conventional taint and hence free of the usual interpretive controversy over gravitational energy. The fact that these calculations do show a tendency to resist immaterial-to-material causation shows that the heuristic force of the widely received anti-realist gloss on the conservation laws is incorrect. That heuristic was the basis for the Mohrhoff–Collins view that General Relativity facilitates immaterial-to-material causation. The conclusion that General Relativity makes immaterial-to-material causation harder rather than easier could have been motivated [and indeed has been Pitts ] by real Noether , p. 428. Noether , that thDoes the use of gravitational and [gravitational wave] energy perhaps enable us to ascertain more easily GR’s empirical content? I fail to see how this could be true Duerr .The question of mental causation suggests, however, that it is true. Realism suggests that immaterial minds would have a harder time acting on general relativistic worlds than in non-general relativistic worlds, whereas anti-realism suggests that it would not be harder and might well be easier. What happens if a soul equipped with at most 4 scalar fields of influence Gravitational energy nonrealist Duerr has mused:sic] global conservation laws do hold in our universe as far as we know. I take it, then, that the conserved quantity theory is not refuted.But that there are general relativistic spacetimes in which global conservation laws do not hold does not entail that global conservation laws fail in our world. Whether they do or not depends on the actual structure of spacetime, and in particular whether certain symmetries hold. As I understand it, our spacetime does exhibit the right symmetry, and that [I suggested that the account holds in all physically possible worlds, that is, in all worlds which have the same laws of nature as ours. Has Rueger shown that this is not so? Not at all. To say, for example, that non-symmetric spacetimes are possible can be misleading. It means simply that it is a solution to the equations of the General Theory of Relativity. But this doesn’t mean that such a world is a physically possible world in the sense given above. If such a world violates other laws that hold in the actual world, then that world is not physically possible. This is exactly what we have in these non-symmetric spacetimes. Symmetries and conservation laws that hold in the actual world break down, so it is not a physically possible world in my sense.Therefore we need not give up on the Conserved Quantity theory, understood as a contingent hypothesis Dowe .Dowe seems not to realize that maintaining such a global conservation law would be revisionary—indeed he is suggesting in effect that the usual cosmological models are not even physically possible—so the cost is greater than he envisaged. Whether a global conservation law is philosophically interesting is difficult to judge. Many philosophers are unaware that global conservation laws are a crude and archaic relative of the conservation laws that are of primary interest in physics, and hence are too easily satisfied with global conservation laws. I might also suggest that the conserved quantity theory need not be quite so contingent—it could potentially hold for all general relativistic worlds, not just those with symmetries of the geometry—if local conservation laws are employed.As various authors have noted, it is rather awkward or perhaps fatal for conserved quantity theories of causation that energy and momentum are no longer conserved quantities given the widespread anti-realism about conservation laws in light of General Relativity Rueger . Dowe haIf the above considerations have shown that realism about gravitational energy localization and consequently about local conservation laws in General Relativity has something going for it, then that is a boon for a conserved quantity theory of causation. If energy and momentum are no less conserved in General Relativity than in other field theories, then Rueger’s objection no longer holds just as stated. One would need to become accustomed to speaking of plural energies and momenta, however.multiplicity of conserved quantities, including energy (1), momentum (3), and angular momentum (3), not to mention (with different origins) charge. Did pre-general relativistic physics have at least 7 causations? If not, I do not see why infinitely many energies should imply infinitely many causations. If so, then either a multiplicity of causations is acceptable—in which case why not infinitely many if seven or eight causations are permitted—or conserved quantity theories of causation face a much broader objection than seems to have been noticed before, because one has energy-causation, x-momentum causation, z-angular-momentum causation, etc. already in pre-general relativistic theories On any of the three possibilities, it is not obvious that any qualitatively new problem of infinitely many causations is generated by accepting infinitely many energies in General Relativity.Does this mean that the general relativistic objection to conserved quantity theories of causation is resolved? That would be too quick.There might, however, be a remnant of a problem from the original motivations for denying the reality of gravitational energy. In pre-general relativistic theories, it is difficult (except in highly symmetric situations) to transfer energy without transferring momentum, or to transfer momentum without transferring angular momentum, or the like; the various conserved quantities as indicators of causation tend to give the same result in most cases. On the other hand, it seems plausible that in General Relativity, one could find a coordinate system in which, e.g., Minkowski space-time in Cartesian coordinates up till should use such coordinates. Such a proposal has been made  and the acceptance of all the infinitely many energies (as I have proposed) suggests that one could readily find coordinates with oscillatory behavior and non-zero energy transport from one place to another, as well as coordinates that reflect the symmetry of the physical situation and no energy transport. Is there a principled way to tell a consistent and physically reasonable story, or is one stuck with intuitively spurious causation due to wavy coordinates in situations in which (by ordinary standards) nothing is happening?Perhaps more seriously, consider a not-quite-symmetric world, such as the actualThis paper has shown using coordinate-covariant calculations that General Relativity makes it harder for immaterial minds to act on the physical world, rather than being like other theories or (as one might have heard) easier than other theories. This result and other considerations might tend to show that gravitational energy is real, objectively located, and infinite in multiplicity. Such conclusions, if accepted, might be of some use in addressing a serious objection to conserved quantity theories of causation.


E. coli lysis by applying an alternating current (AC) electric field and investigated the effects of voltage, frequency, and flow rate on the lysis. The results showed that the lysis efficiency of the bacteria was increased with a higher voltage, lower frequency, and lower flow rate. When the voltage was at 10 Vp-p, the lysis efficiency was close to 100%. The study provided a simple, rapid, reagent-free, and high-efficiency cleavage method for biology and biomedical applications involving bacteria lysis.Cell lysis is a key step for studying the structure and function of proteins in cells and an important intermediate step in drug screening, cancer diagnosis, and genome analysis. The current cell lysis methods still suffer from limitations, such as the need for large instruments, a long and time-consuming process, a large sample volume, chemical reagent contamination, and their unsuitability for the small amount of bacteria lysis required for point-of-care testing (POCT) devices. Therefore, a fast, chemical-free, portable, and non-invasive device needs to be developed. In the present study, we designed an integrated microfluidic chip to achieve  Cell lysis is a basic step in biological research that uses an external force to break the cell membrane and release cellular contents, such as DNA, RNA, and proteins . At presE. coli [Microfluidic chips provide the advantages of miniaturization, integration, high throughput, low consumption, and rapid analysis, which can be meticulous and controllable in cell research conditions. Presently, the microfluidic cell lysis methods , includiE. coli . HoweverIn this paper, we present an electrical microfluidic bacteria lysis method and device, in which an interdigital electrode was employed. By applying low-voltage alternating current (AC) signals, highly effective bacterial lysis was successfully achieved. The parametric studies of electrical and fluidic conditions were conducted as well.F is a factor determined by the shape of the cell , E is the electric field strength, a is the cell radius, α is the electric field direction of the cell pole (α can be 0°–180°), ω is the frequency of the AC electric field, and τ is a coefficient determined by the cell membrane capacitance, cytoplasmic resistance, and cell suspension resistance.Microfluidic electrolysis applies an electric field to the cell membrane, and a strong transmembrane potential will be generated across the cell membrane. When the transmembrane potential is higher than the threshold potential, pores will be produced on the cell membrane and will cause an imbalance of osmotic pressure to lyse the cell . In an AIt can be seen from the equation that the transmembrane potential generated on the bacterial cell membrane is related to the bacteria itself, the fluid properties, and the electric field strength and frequency. In the present study, we employed the interdigitated electrode, which has a 100 μm width with 100 μm spacing for each electrode in it, and the conductive layer was copper plated with gold . Due to The microfluidic chip was composed of three layers , the uppE. coli suspension was injected into the chip channel by a syringe pump . The microfluidic chip, syringes, and hoses were sterilized with alcohol and rinsed with ultrapure water (UPW) before the experiments to ensure that no bacteria remained in the system. A function generator  was used as a power source to supply AC  with different voltages and frequencies to two electrodes on the chip. We changed the voltage in the range of 0–10 Vp-p, the frequency of 1 kHz–50 MHz, and the flow rate of 0.5–10 μL/min. The lysate was collected in an EP tube, and then we counted the growth of colonies on LB solid culture plates. Since our chip was opaque, 10 μL of lysate from different lysis conditions were collected and observed under the microscope directly. A fluorescent microscope  with a CCD camera  was used to visualize the results of bacterial lysis.The experimental setup are shown in E. coli (JM109), and both the liquid and solid medium were LB medium. Cryopreserved E. coli was streaked onto LB solid medium and incubated for 18 h at 37 °C. A single colony was picked and inoculated in 5 mL of LB liquid medium, then placed in a constant temperature shaker at 37 °C and incubated at 180–200 rpm with shaking for 12 h until the OD 600 was approximately 1.0. Then, 1 mL of the bacterial solution was centrifuged at 130,000 rpm for 1 min, and the supernatant was decanted, then resuspended and diluted by UPW.The bacteria strain was n was the number of colonies on culture plates in each 100 μL of lysate, n0 was the number of colonies from the original bacterial solution and η was the ratio of n0 − n to n0. Three experiments were repeated. Using Microsoft Excel  for image rendering, and data processing. The fitting curves were fitted logarithmically using Microsoft Excel, and they show the lysis efficiency of the bacteria under different conditions. Error bars indicated the standard deviation of measurements (n ≥ 3).The lysis efficiency was defined as Equation (2):E. coli at different voltages. As shown in p-p) was applied to the chip , with the increase in the voltage level in the AC electric field, the electric field strength gradually increased, resulting in an increased cell transmembrane potential. Electroporation appeared and the cells became more susceptible to lyse. When the AC frequency and flow rate were kept constant, the lysis efficiency of  voltage . When thE. coli lysis visually under the microscope. When the voltage was increased, the number of E. coli in the field of view decreased, which indicated that a higher voltage was more efficient for E. coli lysis. When the voltage was increased to 10 Vp-p, almost no E. coli existed in the field of view, indicating that the lysis was quite complete.We observed the p-p and the flow rate of 2 μL/min, the lysis results of different frequencies are shown in According to Equation (1), the frequency is another factor that influences the transmembrane potential in an AC electric field; the cell transmembrane potential is inversely proportional to the electric field frequency. We kept the voltage of 6 VE. coli lysis was very high (about 90%). With the increase in frequency, the lysis efficiency decreased significantly. After the frequency reached 50 MHz, the bacteria could not be broken, indicating that the high-frequency condition was not suitable for bacteria lysis. This result is consistent with Equation (1), that is, with the decrease in frequency, the transmembrane potential increases gradually, and the lysis efficiency increases gradually.When the frequency was in the range of 1–500 kHz, the efficiency of ωτ) is much less than 1 at low frequencies, i.e., (ωτ) ≪ 1. Therefore, the equation can be approximated at a low frequency as ΔV = (F · a · cosα) × E, the efficiency is predicted to be independent of frequency, as is shown in ωτ) ≫ 1.0, so Equation (1) can be approximate asTo be more specific, according to Equation (1), , the time that the bacteria spent in the AC field was relatively short, resulting in a large amount of recovered unlysed bacteria. The results showed that the flow rate can affect the lysis efficiency of bacteria by affecting the action time of the applied electric field on the bacteria. To improve the efficiency of the experiment and achieve high-throughput and high-efficiency bacteria lysis, the time required for bacteria lysis was minimized while ensuring lysis efficiency. Therefore, we considered 2 μL/min as the most suitable flow rate and 3 s as the shortest processing time for the present chip.After investigating the effects of the electric field conditions on bacterial lysis, we found that the flow rate was also decisive for bacterial lysis efficiency . The resE. coli under low voltage conditions, we combined the interdigitated electrode with the microfluidic chip, which can achieve a strong electric field strength in a very small space, so that the E. coli cell membrane can generate a larger transmembrane potential and be cleaved more easily. Specifically, the lysis efficiency of E. coli at different voltages, frequencies, and flow rates were studied to achieve rapid, chemical-free, portable, and non-invasive bacterial lysis under low voltage conditions. The results showed that increasing the voltage and decreasing the frequency or flow rate can greatly improve the lysis efficiency of E. coli. Compared with conventional methods, this method is fast (3 s) and particularly suitable for small-volume sample lysis with no mechanical damage or chemical contamination [E. coli lysis efficiency at a lower voltage (10 Vp-p compared with thousands of volts) with an optimized frequency and flow rate. In addition, our microfluidic chip is simpler and less expensive to manufacture, enabling the efficient electrolysis of E. coli, which is suitable for basic research on trace bacteria.In this study, in order to realize the lysis of  is fast  s and pamination ,19, we a


Subjective cognitive decline (SCD) is defined as a self-perception of a progressive cognitive impairment, which is not detected objectively through neuropsychological tests. The Alzheimer's Disease Cooperative Study developed the Cognitive Function Instrument (CFI) to evaluate individuals with SCD. The CFI consists of two versions, namely, a self-report and a partner report.This study aimed to translate CFI into Brazilian Portuguese, perform a cross-cultural adaptation, and validate the Brazilian version.yes” for the question: “Do you feel like your memory is becoming worse?”.The translation and transcultural adaptation process consisted of six stages, and the preliminary version was answered by a sample of individuals recruited among the patients’ caregivers from a cognitive neurology outpatient clinic. Finally, the final Brazilian version of the CFI was applied to a sample of nondemented older adults to validate the instrument, which was divided into with and without SCD, according to the answer “The final version of CFI showed a high level of acceptability as an assessment tool in nondemented older adults. Participants with SCD had higher scores in the CFI self-report compared with those without complaints. In the receiver operating characteristic curve analysis, the area under the curve of the CFI self-report was 0.865 , and the cutoff score of 2.0 was the one that best distinguished the SCD group from the control group, with a sensitivity of 73.3% and a specificity of 81.5%.CFI proved to be an instrument with good accuracy and easy applicability to identify older adults with SCD. Longitudinal epidemiological studies have linked SCD with a higher risk factor for progression to mild cognitive impairment (MCI) and dementia. In a meta-analysis of 29 studies, the annual conversion rate from SCD to MCI and dementia was approximately 6.7 and 2.3%, respectively, compared with the conversion rate of only 1% to dementia among older adults without SCD. Moreover, among those studies with a follow-up of more than 4 years, the progression to MCI and dementia reached 26.7 and 14.1%, respectively. Also, the group of older adults with subjective complaints has a higher prevalence of positive biomarkers for Alzheimer's disease (AD).Subjective cognitive decline (SCD) is defined as a self-perception of a progressive cognitive impairment, which is not detected objectively through neuropsychological tests. However, one of the difficulties pointed out by this task force was the lack of a gold standard instrument for assessment and quantification of SCD. The significant variability and heterogeneity of tools for SCD evaluation have made it difficult to compare research in this area. Some studies have used semi-structured questionnaires, while others have used simple questions like “is your memory getting worse?”. In a nonsystematic review, 19 studies were compared with SCD measures, and 34 self-report questionnaires were identified. Those instruments differed mainly in the mode of administration (by self-administered or interview), in the timeframe by items , and in the assessed cognitive domains .In 2014, an international working group proposed a diagnostic criterion for SCD, focusing on the standardization of the terminology for research in preclinical AD. In that review, four types of questionnaires were used in studies and only two had been properly validated.In Brazil, there are few SCD questionnaires translated and adapted to our language and culture. In a systematic review, 25 Brazilian studies were identified, of which 19 used some type of standardized questionnaire. Initially, it was designed to be applied by email and called Mail-In Cognitive Function Screening Instrument (MCFSI); however, it was also used for a self-report on-site assessment. In a longitudinal study with participants of ADCS, CFI was associated with cognitive decline in 48 months. The CFI consists of two versions, i.e., a self-report and a partner report, with 14 questions each. The patient and his/her companion must read and answer the questionnaire independently, without consulting anyone. The items ask about cognitive  and functional difficulties, and the issues address the present complaints compared with 1 year ago. Possible responses were “yes” (1), “no” (0), or “maybe” (0.5). The range of scores was 0–14. In some questions (such as driving and performance at work), it is possible to answer “does not apply.”The Cognitive Function Instrument (CFI) was developed by the Alzheimer's Disease Cooperative Study (ADCS) for the evaluation of subjective cognitive complaints in a group of older adults without dementiaTherefore, this study aimed to translate the CFI to Brazilian Portuguese, perform a cross-cultural adaptation, and analyze its diagnostic accuracy to identify SCD. During the process of translation and adaptation, the following aspects were observed: semantic equivalence , idiomatic equivalence , experimental or cultural equivalence , and conceptual equivalence . In addition, a concern of the translators was to consider the heterogeneity of Brazilian population schooling.The translation was performed based on the methods proposed by Beaton et al.This transcultural translation and adaptation process consisted of six stages, described below :Initial translation: Two translations of the original instrument were prepared independently by two bilingual specialists in the area of cognitive neurology or neuropsychology.Synthesis of translation: The two translators met to draw up a synthesis of the two translated versions, and a third member of the project resolved divergences.Back translation (or reverse translation): The synthesis of the translation obtained was back-translated into English by two other translators who were also bilingual and specialists in the field. The reverse translations were also developed independently and blind to the original version of the instrument.Review by a committee of experts: At this stage, a specialist committee, composed of two other members who did not participate in the translations, met to review all the available versions. The original instrument, the synthesis of the Portuguese translation, and the backward versions were compared. This comparison evaluated the semantic, idiomatic, experimental or cultural, and conceptual equivalences of the terms used in the different versions. From this analysis, a preliminary version of the instrument was translated, adapted, and drafted.Test of a preliminary version: After elaborating the preliminary version, it was applied in a sample of cognitively normal adults. All participants were asked to comment on the instrument whether they understood each question, what their doubts were, and whether they had any suggestions.Final review by the expert committee: In this last stage, the expert committee again met to prepare the final version. From the comments and suggestions, any changes were applied to obtain the final version. The final Brazilian version of the CFI was used in a group of older adult volunteers without dementia, so that the clinical validity of the instrument could be analyzed.The preliminary version was answered by a sample of individuals recruited among the patients’ relatives from the cognitive neurology outpatient clinic of the Hospital das Clínicas of the Faculdade de Medicina of the Universidade de São Paulo. The inclusion criteria were: 1) to be above 45 years old, 2) to read and write, and 3) to read and understand a text in Portuguese, and 4) to have a next of kin.yes” for the question: “Do you feel like your memory is becoming worse?”. If the participant answered “no,” he/she was included in the control group. The participants were recruited from different centers in the city of São Paulo, Brazil: outpatient clinic of the Geriatrics Department of a university hospital ; Open University Program for Senior Citizens at the School of Arts, Sciences and Humanities from the Universidade de São Paulo; and a Senior Center for the Promotion of Healthy Aging. We also recruited community-dwelling older adults through social media and newspapers.The final version was applied to a sample of cognitively unimpaired older adults. They were divided into two groups: with subjective memory complaint (SCD group) and without complaint (control group). The SCD group was defined by the answer “; 4) clinical dementia rating (CDR) score equal to zero; and 5) 15-question version of the geriatric depression scale (GDS-15)≤5.For the sample who completed the final version, the inclusion criteria were: 1) age ≥60 years; 2) schooling ≥4 years; 3) mini-mental state examination (MMSE) normal for education according to the scores obtained by Brucki et al.; 2) diagnosis of a major psychiatric disorder according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition; 3) history of alcohol or psychoactive drug abuse; 4) current or previous diagnosis of the central nervous system diseases ; and 5) both visual and/or auditory limitations that could impair the performance in cognitive tests.The exclusion criteria were: 1) diagnosis of dementia or MCI according to the criteria of the National Institute on Aging and Alzheimer's Association screening for depression and anxiety symptoms using GDS-15 and the Geriatric Anxiety Inventory (GAI), respectively; and the functional assessment with the Functional Activities Questionnaire (FAQ) and the CDR.The first assessment was carried out by a neurologist with training in cognitive neurology and consisted of a semi-structured interview with a collection of sociodemographic data; cognitive assessment with MMSE, Montreal Cognitive Assessment (MoCA), and the Brief Cognitive Screening Battery (BCSB)In this first assessment, the participant was also asked to read and answer the CFI self-report. The participant was allowed to ask questions to the examiner in case of doubts. When the older adult was unaccompanied, the CFI partner report was given to him, so that a family member could answer and then send it by email.After the first assessment, the participants who met the inclusion criteria were invited to complete the neuropsychological tests. The tests performed were Forward and Backward Digit Span Test, Trail Making A (TMA) and Trail Making B (TMB), Category  and Letter (FAS) Verbal Fluency Tests, Rey-Osterrieth Complex Figure , Logical Memory of the Wechsler Memory Scale, Rey Auditory Verbal Learning Test, and 60-item version of the Boston Naming Test. The estimated intelligence quotient (IQ) was measured with the vocabulary and matrices subtests of the Wechsler Adult Intelligence Scale, Third Edition (WAIS-III). Those who performed at least one test with standard deviation (SD) less than or equal to −1.5 from average normative values adjusted for age and education received a diagnosis of MCI and were excluded from the sample.Categorical variables were expressed as absolute and relative frequencies and compared with Pearson's chi-square test on univariate analysis. Descriptive statistics including mean, SD, median, and interquartile range (IQR) values were generated for continuous numerical variables. Variables were tested for normality with histogram graphs and the Kolmogorov-Smirnov test. All continuous numerical variables assumed a non-normal distribution and were compared with the Mann-Whitney U test.Cronbach's alpha for CFI self-report and partner report was used to analyze the internal consistency. The construct validity was obtained from Spearman's rank correlation coefficient (rS) of the total score of CFI self-report and partner report and its items with the other assessment instruments and the neuropsychological test results.Receiver Operating Characteristic (ROC) curve analysis was used to calculate the area under the curve (AUC) with a 95% confidence interval (95%CI) and the cutoff scores for CFI sensitivity and specificity capable of distinguishing older adults with SCD from those without SCD. Positive and negative predictive values of the questionnaire were also calculated.The analyses were performed using the Statistical Package for the Social Sciences software, version 21.0 . All tests were performed considering bilateral hypotheses, and the two-tailed p<0.05 were considered statistically significant.The study was approved by the Ethics and Research Committee of the Hospital das Clínicas from the Medical School of the Universidade de São Paulo under protocol number 62047616.0.0000.0068. Informed consent was obtained from each participant. The study of human subjects was designed and conducted according to the Declaration of Helsinki.Supplementary Tables 1 and 2 show the final version of the CFI. Eventually, a combination of the two translations was used for the synthetic version , while in other items, one of the translations was chosen .On some questions, equivalent terms replaced the original words, for example, the term “decline” replaced by “piorou” (became worse) and “diminuiu’ (decreased) in questions 1 and 10, respectively. Conversely, words were deleted without prejudice to the comprehensive question, as in items 2 (“tend”) and 12 . Such adaptations were aimed mainly at less educated individuals. The term “tax form” was adapted as “imposto de renda” (income tax) because it was closer to the Brazilian cultural context. In contrast, some items were translated literally, without substitution, elimination, or addition of words or terms (such as questions 11 and 14). In other items, examples were inserted to make the question clearer (as in question 9). In addition to the questions, we also adapted the instructions for the questionnaire to make it clearer to the less educated individuals. Supplementary Tables 3 and 4 show all steps of translation and adaptation until the final version was reached.The preliminary version was applied to 37 individuals. The mean and median age were 63.4 (SD=11.3) and 64.5 (IQR=23) years, respectively. The median schooling was 11.0 (IQR=10) years of schooling. Only eight (21.6%) participants had difficulty in understanding any of the questions or making suggestions.Five questions were changed between the preliminary and final versions . In questions 9 and 12, examples were added to make the questions clearer. Furthermore, words were added and replaced in questions 4 and 10, respectively. Three subjects doubted about the “maybe” option, so we wrote in parenthesis “can be.” Two other subjects had difficulty in understanding “does not apply” option, so we wrote in parenthesis “I do not drive a car” (question 7), “I do not deal with money” (question 8), and “I do not do paid work” (question 10), respectively.The final version was submitted to 72 cognitively normal older adults (48 women) for validation. In only 24 subjects, the CFI partner report was obtained. Forty-five subjects answered “yes” to the question “Do you feel like your memory is becoming worse?” and therefore were classified in the SCD group. The acceptability of the instrument was high because no further adjustments were necessary for the final version during the validation stage.The median age of the control group was higher than that of the SCD group but without statistical significance. Schooling was similar between the two groups. Older adults in the SCD group had more anxiety and depression symptoms. There was no statistically significant difference between the groups in the neuropsychological tests . The SCDApproximately half of older adults in the SCD group answered “yes or maybe” when questioned about the worsening of memory in the last year . QuestioThe reliability, measured by Cronbach's alpha, for CFI self-report and partner report was 0.80 (95%CI 0.73–0.86) and 0.70 (95%CI 0.48–0.85), respectively. Cronbach's alpha varied less if each item was deleted in both versions . CorrectA total sample of CFI self-report score did not correlate with age, education, and gender; there was a significantly positive correlation with GAI  and GDS . Some questions and cognitive tests depicted a weak correlation: question 2 (questions repetition) with MMSE total score  and questions 4 (use of written reminders) and 12 (hobbies) with delayed recall of Logical Memory . In addition, question 12 correlated with Category Verbal Fluency , delayed recall of Rey–Osterrieth Complex Figure , TMB , and IQ .In the SCD group, only GAI  and GDS  also showed significant correlations with the CFI scores. MMSE showed a significant correlation with questions 2  and 4 . In the control group, education  and letter verbal fluency  correlated with CFI.A total sample of CFI partner report did not correlate with CFI self-report  neither with anxiety nor depression measures. Only question 13  correlated with age . Among the cognitive tests, MoCA had a significantly negative correlation with question 2  and IQ with question 13 .In ROC curve analysis, the AUC of the CFI self-report was 0.865  . A CFI sThe final version of both CFI self-report and partner report had a high level of acceptability as an assessment tool among participants with and without SCD. As expected, the individuals with cognitive complaints had higher scores in the CFI self-report than those without memory complaints. Conversely, the SCD and control groups did not show differences in neuropsychological tests, revealing the subjective nature of this syndrome, when cognitive tests are incongruent with the perception that one's memory is getting worse.. However, other hypotheses have been raised in the literature. Some authors discussed whether the first episode of a late-life depression could be a manifestation of prodromal AD, a risk factor for the development of dementia, or both. Thus, the relationship between anxiety symptoms and SCD in older adults is still surrounded by uncertainties, whether anxiety is a consequence of perceived decline or an independent predictor for conversion to dementia.In addition to the CFI self-report score, the two groups differed in their scores on the anxiety (GAI) and depression (GDS) scales, even excluding patients diagnosed with psychiatric disorders , depressive, and anxious symptoms correlated with the CFI self-report score. One explanation is that individuals with depressive and/or anxious symptoms are more attentive and concerned about their negative perceptions, including the sensation of cognitive decline. In the Italian version, the alpha was 0.77 and 0.78 retrospectively, while in the Norwegian version, the values were 0.86 and 0.94, both higher than ours. In turn, Li et al. calculated the interclass coefficient to assess 3-month test–retest reliability, and results were 0.76 in CFI self-report and 0.78 in CFI partner report.Cronbach's alpha values were substantial, indicating an acceptable internal consistency for the instrument. It mirrors the results from the original study for the CFI self-report , but CFI partner report , in the Norwegian version, cutoff points of 4 and 6.5 were indicated to discriminate dementia from MCI and SCD using the CFI self-report and from SCD using the CFI partner report, respectively.In addition, AUC values proved to be entirely satisfactory in the ROC curve, indicating the good accuracy of the CFI self-report to discriminate subjects with SCD from those without, better than several cognitive screening and memory tests. A score above 2.0 showed good sensitivity and high specificity for the diagnosis of SCD. Since it is a nonspecific syndrome and already denotes early cognitive decline stages, more specificity than sensitivity is sought in an SCD questionnaire. Although the original studies did not indicate a cutoff value and the Italian version of the CFI, and these two questions were also the most answered as yes or maybe. Interestingly, in our study, only half of the subjects with SCD answered “yes” or “maybe” to question 1 . In contrast, all the participants in the control group answered “no” to the first CFI question as expected.In the present study, the most frequently reported cognitive complaints in CFI were “to need to use of written reminders” (question 4) and “trouble recalling names and words” (question 6). In line with our results, previous studies validated the MCFSI. In our study, questions 2 (repetition of questions) and 4 (needing notes) are the indicatives of more strictly amnestic complaints correlated with Logical Memory delayed, and with no other memory measure. Moreover, question 12 (difficulty in carrying out hobbies), which denotes more impairment of executive functions, was correlated with tests related to executive functions . Therefore, even if the total CFI score was not associated with an objective cognitive impairment, these results suggest that specific questions can be correlated with the cognitive domain to which they refer, respectively.Only verbal fluency test, TMTB, MMSE total scores, and delayed recall of a story  were weakly correlated with some CFI questions but not with their total score. No neuropsychological tests correlated with CFI in our sample. This finding differed from other studies that showed a correlation between the CFI score and worse performance in objective cognitive tests. In a 48-month longitudinal study, Amariglio et al. showed that both CFI self-report and partner report scores were higher in the group of individuals with CDR progression. The group with progressively worse CDR score exhibited successive increment in CFI scores over the months of follow-up. In another study, also with a 4-year follow-up, both CFI self-report and partner report scores at baseline were higher among those nondemented older adults (CDR: 0 or 0.5) who later evolved with cognitive decline.CFI has already been proven to be a useful tool and it has a good association with the progression of cognitive decline in nondemented older adults. Both the CFI self-report and partner report were associated with cognitive decline in longitudinal studies. However, the two versions showed different outcomes during the follow-up. While CFI self-report score had a higher score in baseline, CFI partner report score became higher after months of follow-up. Noteworthy, the type of partner  can influence the quality of information and, consequently, the prediction of cognitive decline in the long term.Regarding the CFI partner report, there was no difference between SCD and control groups in our study. This lack of difference between groups may be due to a small sample of participants with a filled partner version (only 33.3%). In contrast, this nondifference can be explained by the observation that self-perception of decline precedes that observed by the relatives and friends, differently from what occurs in patients with MCI and dementia who have a lack of awareness (anosognosia) of cognitive deficits. Interestingly, they showed that CFI self-report had a similar effect size between the amyloid groups and neuropsychological tests. However, further studies are needed to establish an association between the CFI scores and the diagnosis of prodromal AD using biomarkers.To the best of our knowledge, there is only one published study correlating CFI scores with AD biomarkers. In a cross-sectional survey with 4,486 pre-MCI older adults, Sperling et al. highlighted that individuals with positive amyloid PET displayed higher scores on both CFI self-report and partner reportDo you feel like your memory is becoming worse?”) as the criterion to define the SCD group. However, as there is no gold standard questionnaire for the diagnosis of SCD, we opted for a question used in other studies that showed a good predictive value for the progression to MCI or dementia.The main limitation of this study is the sample size, especially the number of participants who had the CFI partner report filled out. Another limitation is the high level of education in the sample. As it is a self-administered instrument, it will be necessary to study samples with less schooling. Also, we used a single question (“The main contribution of our study was the translation and clinical validity of an SCD instrument that has been widely used in longitudinal cohorts and studies with AD biomarkers in reference centers to be used in Brazil, since we lack questionnaires adapted to our language and culture to assess SCD. Furthermore, the CFI self-report proved to be an instrument with good accuracy and easy applicability to identify SCD among older adults.CFI proved to be a questionnaire with good sensitivity and specificity for the diagnosis of SCD, with the greatest accuracy among many neuropsychological measures. Future longitudinal studies will be essential to assess the potential of CFI in predicting conversion to MCI or dementia in the Brazilian population. Also, studies with biomarkers should be interesting to explore the role of the CFI questionnaire in subjects with a diagnosis of prodromal AD in our country.


Background: Extensive research on the blood-testis barrier has been undertaken in recent years. However, no systematic bibliometric study has been conducted on this subject. Our research aimed to identify the hotspots and frontiers of blood-testis barrier research and to serve as a guide for future scientific research and decision-making in the field.Methods: Studies on the blood-testis barrier were found in the Web of Science Core Collection. VOSviewer, CiteSpace, and Microsoft Excel were used to conduct the bibliometric and visual analyses.Results: We found 942 blood-testis barrier studies published in English between 1992 and 2022. The number of annual publications and citations increased significantly between 2011 and 2022, notably in the United States. China and the United States, the US Population Council, Endocrinology, and Cheng C. Yan were the most productive countries, institution, journal, and author, respectively. The study keywords indicated that blood-testis barrier research involves a variety of compositional features , cell types , reproductive toxicity , and relevant mechanisms .Conclusion: The composition and molecular processes of the blood-testis barrier as well as the blood-testis barrier in male infertility patients are the primary research hotspots in this field. In addition, future research will likely focus on treatment and the development of novel medications that target signal pathways in oxidative stress and apoptosis to preserve the blood-testis barrier. Further studies must extend to clinical diagnosis and therapy. Blood-tissue barriers prevent large molecules from being exchanged uncontrollably across metabolically distinct compartments . In the Male infertility is hypothesized to be linked to the BTB. Thirty to forty percent of males with aberrant semen parameters have unexplained infertility. Infertile individuals’ spermatogenic abnormalities are caused by a variety of factors. The most common cause of unexplained male infertility is endocrine disturbance of testicular development during the neonatal period due to environmental pollutants and genetic and epigenetic factors . These vBibliometric analysis, which concentrates on the systems and characteristics of the literature, is frequently used to comprehend the knowledge structure and discover emerging trends using qualitative and quantitative study of the scientific literature. The contributions of different authors, institutions, nations, and publications can be compared, and a certain study subject can be summarized, and the future growth of that field can be projected. Developing guidelines, comprehending research hotspots, and assessing research trends all rely heavily on this analytical technique. Health research , environBTB research has progressed in the 30 years since it was initially conceived, but there are still certain challenges to be resolved. How to determine the function and structure of the BTB in patients, how to employ effective medications to treat male infertility caused by BTB damage, and whether BTB-related target drugs are being developed remain to be resolved.In this study, we used the Web of Science Core Collection (WoSCC) to carry out a bibliometric analysis and visually assess the research hotspots of the BTB field. The results revealed the global research trends in this field, which might lead to new design ideas for future study and illuminate fundamental and clinical investigations.On 31 May 2020, the linked publications from the start of the databases until 2022 were collected from the Science Citation Index Expanded (SCI-E) core database via the WoSCC. With the search term “blood-testis barrier” and the literature categories “article” and “review,” a total of 942 items were found that met the search parameters and were analyzed further.The authors worked independently to gather and screen the WoSCC raw data. The data were analyzed using VOSviewer, CiteSpace, and Excel. Dissension was resolved through dialog. We investigated journal associations, evaluated collaborative teams across nations, institutions, and writers, created visualization maps, captured keywords, and discovered cocited authors/references using CiteSpace IV and VOSviewer.There were a total of 942 articles that met the retrieval criteria. A total of 57 regions/countries have published studies on the BTB. These regions/countries had a diverse range of collaborative teams . China cThe BTB papers from 1992 to 2022 were predominantly disseminated in various journals, according to the data analysis, and the top 10 journals are summarized in A total of 4,300 authors were involved in BTB research. The authors’ collaborative network is depicted in The top 10 papers with the most citations are presented in There were 2,853 keywords in all; 292 keywords were presented in a minimum of five documents. The colors in We used bibliometric analysis and network visualization to characterize the current landscape of BTB research, analyzing the contributions of countries, institutions, journals, and authors to this emerging field and predicting hot topics that will continue to be of research interest in the coming years. Since the field’s inception in 1992, yearly publishing output has consistently increased, with particularly significant growth over the last 12 years, accounting for 98 percent of all papers identified. China and the United States are now the world leaders in BTB research, with the most publications and citations as well as the highest ranking for coauthorship analysis by nation. These findings show that China and the US may have a considerable effect on the direction of research in this subject and that their collaboration is among the strongest in the world. Over the last decade, the number of studies undertaken in Italy, Japan, and Germany has also increased significantly. The most prolific institution, the US Population Council, was placed at the top in coauthorship analyses undertaken by the institution, indicating strong collaboration with other institutions.in vitro compound culture model of the interaction between Sertoli cells and spermatogenic cells as well as research into the molecular mechanisms of spermatogenesis, which is now extensively utilized throughout the world  and cryptorchidism, disruption of the BTB and changes in the expression of its proteins are thought to be one of the mechanisms of spermatogenesis dysfunction. The expression of claudin-11 , E-cadheThe direct detection of the BTB in humans has not been accomplished due to technological limitations, but research on its critical protein and gene expression features may be the key to future advances in male infertility. In humans, claudin-11 might be an important component of the BTB. Normal  and aberrant (diffuse expression in Sertoli cells/extremely low or no expression) patterns of claudin-11 protein have been identified. In men with defective spermatogenesis, the claudin-11 pattern is strong, but the fraction of localization is changed in Sertoli cell-only syndrome and primary spermatocyte maturation arrest . The proEscherichia coli affects the BTB by disrupting the mTORC1-mTORC2 balance  may play a role in 30–80% of infertile patients . An imbaTo our knowledge, this is the first bibliometric study of trends in BTB research. Through coauthorship, cocitation, and cooccurrence analyses, we built and visualized bibliometric networks using well-known scientometric tools (VOSviewer and CiteSpace). Research on the composition of the BTB and related damage will be of great help in protecting male fertility and developing related contraceptives in the future. We also see that many drugs and components based on the repair of the BTB have great prospects in the treatment of male infertility. Nonetheless, there are certain limitations to our findings. The searches were initially mostly undertaken in the WoSCC. Second, it appears that we only included WoSCC studies in English. Furthermore, because this is a new and evolving research topic, we may have underestimated the contribution of newly published studies to various analyses due to their low citation frequency, although some of the studies were published in high-quality journals. However, we believe that this study may still be used to convey the overall position and general development in this sector.According to our findings, China and the United States are important contributors to research on the BTB. Cheng C. Yan of the US Population Council is a pioneering scientist who has made substantial contributions to this subject. The bulk of relevant papers have been published in high-impact journals, implying that advancement in this subject is significant. The keywords indicate that a variety of compositional features , cell types , reproductive toxicity , and relevant mechanisms  are areas of interest in BTB research. The research has shifted away from identifying the BTB toward understanding its architecture, activation mechanisms, and male infertility functions.


Firstly, Ni(CH3COO)2/PVP composite nanofibers were prepared by a conventional electrospinning method, and then NiO nanowire-in-nanotube structured nanofibers were successfully synthesized by two-stage calcination procedure of Ni(CH3COO)2/PVP composite nanofibers which was determined to be the key process for preparing NiO nanowire-in-nanotube structured nanofibers. The NiO nanowire-in-nanotube structured nanofibers have pure cubic phase structure with space group of Fm3̄m, and the outer diameter and wall thickness of nanotubes and nanowire diameter are 130 ± 0.99 nm, 30 nm and 40 nm, respectively. Preliminarily, it is satisfactorily found that NiO nanowire-in-nanotube structured nanofibers used as photocatalyst for water splitting exhibit higher H2 evolution rate of 622 μmol h−1 than counterpart NiO hollow nanofibers of 472 μmol h−1 owing to its novel nanostructure. The possible formation mechanism of NiO nanowire-in-nanotube structured nanofibers is proposed. To evaluate the universality of this novel preparative technique, taking Co3O4 as an example, it is found that Co3O4 nanowire-in-nanotube structured nanofibers are also successfully fabricated via this novel method. The special nanowire-in-nanotube structure of the one-dimensional nanomaterials makes them have promising applications in catalysis, lithium-ion battery, drug delivery, etc. This manufacturing strategy has some advantages over other methods to form nanowire-in-nanotube structured nanofibers, such as easy, highly efficient and cost effective. The design idea and synthetic technique provide a novel perspective to create other nanowire-in-nanotube structured nanomaterials.NiO nanowire-in-nanotube structured nanofibers were easily and directly fabricated  via one-pot uniaxial electrospinning followed by designed calcination procedures.NiO nanowire-in-nanotube structured nanofibers were easily and directly fabricated  Many methods, such as hydrothermal method, electrochemical etching/deposition, solid state reaction, microwave synthesis, electrospinning,2–6 have been used to prepare these 1D nanostructured materials. Among these methods, electrospinning is a straightforward and effective method to prepare 1D nanomaterials with diameters ranging from micrometer to nanometer,7 including nanofibers/nanobelts, hollow nanofibers, coaxial nanofibers/nanobelts, Janus nanofibers/nanobelts, nanowire-in-microtube structured core/shell fibers.8–16One-dimensional (1D) nanostructured materials have received increasing attention owing to their special properties, which have wide applications in various fields, such as magnetism, optics, photocatalysis, Li-ion battery, etc17–19. Usually, the preparation process of these specially structured 1D nanocomposites contains three steps. The first step is the synthesis of core materials, and then the other two layers including intermediate layers and shells are gradually coated on the core materials to form triple-layered composite materials. Finally, the intermediate layers are removed by calcination or extraction using appropriate solvent, and the nanocomposites with void structure between the inner and outer substances are obtained. Tingting Wang et al. have prepared uniform yolk–shell architectures by high-temperature calcination of core/shell/shell structured nanomaterials to remove the middle layers.20 Nian Liu et al. have fabricated yolk–shell Si@void@C structure by using HF to remove SiO2 sacrificial layer in the Si@SiO2@C structure.21 In addition to the above three-step method, Zhao Yong et al. have reported the fabrication of nanowire-in-microtube structured core/shell fibers by multifluidic coaxial electrospinning approach. Firstly, three coaxial capillaries were assembled as the spinneret, and a chemically inert middle fluid was introduced to work as a spacer between the outer and inner fluids, and then a three-layered core/shell structure was formed. Subsequently, the middle layer of the as-prepared fibers was selectively removed, thus nanowire-in-microtube structured core/shell fibers were obtained with a hollow cavity between the shell and the core materials.16 However, the aforementioned preparation methods for nanocomposites with hollow cavity are mostly complicated and costly, and usually, the structural uniformity of the products is not satisfactory. Therefore, it is urgent to find a simple and efficient method to form nanocomposites with void structure in order to simplify the productive process and reduce costs.Recently, the nanocomposites with a hollow cavity between the shell and core have aroused widespread interest due to their special structure and large specific surface area, which have potential applications in biological medicine, sensor, lithium-ion batteries, adsorption and catalysis, 22 which has been widely used in catalysis, battery cathode, electrochromic films, etc. Mengzhu Liu et al. reported the formation of multilayer NiO nanostructures by electrospinning and compared the properties of multilayer NiO and NiO powders. The result shows that multilayer NiO exhibits much higher sensing signal than NiO powders due to its higher surface area.23 Xiong Wang et al. reported the formation, improved photocatalytic properties and excellent electrochemical performance of hierarchically structured NiO macroporous microspheres with large surface area.24 Hence, NiO with special structure possesses many excellent performances, which has been reported in the above literatures, especially it has been confirmed that NiO nanotubes have higher photocatalytic property than ordinary NiO solid nanofibers because of the larger specific surface area.25 Nanowire-in-nanotube structured nanofibers theoretically have larger specific surface area than counterpart NiO nanotubes. For this reason, the fabrication of NiO nanowire-in-nanotube structured nanofiber, as a novel and special morphology, is an important and essential subject to research. By now, no reports on the synthesis of NiO nanowire-in-nanotube structured nanofiber are found in the references.NiO is p-typed semiconductor with wide band gap (3.6–4.0 eV),3COO)2/PVP composite nanofibers. The products were characterized systematically, and their photocatalytic water splitting activity was initially investigated, and some meaningful results were achieved.In this work, we design a novel and simple strategy to form NiO nanowire-in-nanotube structured nanofibers by two-stage calcination procedure of electrospinning-made Ni(CH3COO)2·4H2O, AR], polyvinyl pyrrolidone , N,N-dimethylformamide , nickel nitrate  and cobalt acetate tetrahydrate  were used in the experiments. Distilled water was made in our lab.Nickel acetate tetrahydrate [Ni(CH3COO)2·4H2O was dissolved in 7.0000 g of DMF, and then 2.0000 g of PVP was added into the above solution under magnetic stirring for 12 h to form uniform green-transparent spinning solution with a certain viscosity. In the electrospinning solution, the mass ratio of Ni(CH3COO)2·4H2O, PVP and DMF was fixed as 10 : 20 : 70. Subsequently, the electrospinning was carried out at ambient temperature by using a conventional single-spinneret electrospinning setup with the positive direct current (DC) voltage of 13 kV and the spinning distance of 18 cm. Then, Ni(CH3COO)2/PVP composite nanofibers were obtained on the collector through the above process with the volatilization of solvent.1.0000 g of Ni(CH3COO)2/PVP composite nanofibers were heat-treated from ambient temperature (20 °C) to 200 °C with a heating rate of 1 °C min−1 and then remained for 2 h at 200 °C , after that, the temperature was raised to 450 °C with the same heating rate of 1 °C min−1 and remained for 2 h . Thereafter, the temperature was reduced to 200 °C at a cooling rate of 1 °C min−1 followed by natural cooling down to room temperature, and thus NiO nanowire-in-nanotube structured nanofibers were successfully obtained.The as-prepared Ni2/PVP composite nanofibers. S4–S6 were prepared by changing the pre-oxidation duration time via two-stage calcination of Ni(CH3COO)2/PVP composite nanofibers. Samples S7–S9 were obtained in the same conditions except for the different heating rates. S10–S13 were synthesized at different oxidation temperatures by one-stage calcination of Ni(CH3COO)2/PVP composite nanofibers without undergoing pre-oxidation. S14 and S15 were fabricated by using different kinds of inorganic salts via two-stage calcination of corresponding composite nanofibers.Samples S1–S3 were obtained at different pre-oxidation temperatures by two-stage calcination of Ni(CHλ = 0.15418 nm). The scanning electron microscope  and transmission electron microscope  were used to observe the morphologies and sizes of the samples. The elemental analysis was performed by X-MaxN80 energy dispersive X-ray spectrometer (EDS) attached to SEM. Thermogravimetric and differential scanning calorimetry (TG-DSC) analysis was carried out on a Q600 thermal analyzer in air atmosphere. The specific surface area of products was measured by ASAP 2020 instrument.X-ray diffraction (XRD) patterns were collected by using a Rigaku D/max-RA X-ray diffractometer operating at 40 kV and 30 mA with the Cu Kα radiation and Ni filter (λ < 750 nm). Before testing, 0.1 g of the photocatalyst (NiO nanowire-in-nanotube structured nanofibers and NiO hollow nanofibers), 25 mL of methyl alcohol and 75 mL of tap water were successively added into a 200 mL quartz cuvette to ensure uniform dispersion of the sample under vigorous magnetic stirring. Then the suspension was degassed by evacuation. Throughout the experiment, the amount of produced gas was sampled intermittently, and the hydrogen content was measured by gas chromatography .Experiments for photocatalytic water splitting into hydrogen were performed in a Labsolar-IIIAG photocatalytic system device  by external visible light irradiation. The light source was a xenon lamp  equipped with a cut off filter L38 (380 < 3COO)2/PVP composite nanofibers, as seen in 3COO)2/PVP composite nanofibers lose about 12.55% of their initial weight when the temperature arises from 20 °C to 100 °C accompanied by a wide endothermic peak at 50 °C in the DSC curve. With the continuous rise in temperature to 250 °C, Ni(CH3COO)2/PVP composite nanofibers slightly lose their weight due to the oxidation of Ni(CH3COO)2 to form NiO. When the temperature reaches up to 250 °C, Ni(CH3COO)2 is intensively decomposed to form NiO, gaseous H2O and CO2, together with obvious weight loss in TG curve and an exothermic peak at 260 °C in DSC curve. Afterwards, PVP begins to decompose at 290 °C, and the decomposition process is completed at 324 °C. Major weight loss and heat release occur in this process. No weight loss in TG curve and thermal peak in DSC curve are detected when temperature is over 324 °C, meaning that stable inorganic oxide can be obtained above 324 °C, and the total weight loss percentage is 85%.TG and DSC curves of Ni at 150 °C to 250 °C.In order to study the crystalline phases of products undergone the pre-oxidation process, the XRD patterns of samples S10–S12 were also gained, as seen in Furthermore, it can be observed from 3COO)2/PVP composite nanofibers and samples S1–S3 and S13 obtained by different calcination process. One can see that Ni(CH3COO)2/PVP composite nanofibers have smooth surface and uniform dispersity, as indicated in 3COO)2/PVP composite nanofibers without pre-oxidization process. It is observed that hollow structured nanofibers, rather than nanowire-in-nanotube structured nanofibers, are obtained. Therefore, it can be concluded that pre-oxidation process plays an important role in the formation of NiO nanowire-in-nanotube structured nanofibers. Furthermore, SEM observation demonstrates that the diameters of Ni(CH3COO)2/PVP composite nanofibers, S1, S2, S3 and S13 are 293 ± 1.43 nm, 160 ± 3 nm, 130 ± 0.99 nm, 111 ± 1.33 nm and 120 ± 3.17 nm, respectively. It is found that with the increase of the pre-oxidation temperature, the diameters of the samples are gradually decreased. To investigate the influence of other conditions on the morphology of the products, we choose 200 °C as the optimal pre-oxidation temperature in the subsequent work.3COO)2/PVP composite nanofibers. It is easy to find that all these samples are NiO nanowire-in-nanotube structured nanofibers. With the increase of pre-oxidation duration time, the surface of nanowire-in-nanotube structured nanofibers gradually becomes rough. It is also found that the diameters of S4, S5 and S6 respectively are 138 ± 3.36 nm, 98 ± 0.79 nm and 95 ± 0.35 nm, indicating that the diameters of the samples are gradually reduced with the increase of the pre-oxidation duration time. Thus, 2 h is selected as the optimum pre-oxidation duration time in the following study.−1, 1 °C min−1, 3 °C min−1, 5 °C min−1) by two-stage calcination of Ni(CH3COO)2/PVP composite nanofibers, are displayed in −1, NiO solid nanofibers, rather than nanowire-in-nanotube structured nanofibers, are acquired. −1) is beneficial to form nanowire-in-nanotube structure. However, over high heating rate  will lead to the structural damage of the products, as indicated in −1 is the best condition for the preparation of NiO nanowire-in-nanotube structured nanofibers.The SEM images of samples S7, S2, S8, S9 fabricated at different heating rate (0.5 °C min3COO)2/PVP composite nanofibers at 150 °C (a), 200 °C (b) and 250 °C (c) for 2 h. The samples are solid nanofibers regardless of the oxidation temperature of 150 °C, 200 °C and 250 °C, indicating that the PVP in original composite nanofibers does not decomposed and the nanowire-in-nanotube structure is unformed at the ranges of calcination temperatures. Nevertheless, the diameters of these samples are slightly decreased with the increased calcination temperature, which are measured to be 142 ± 4.7 nm (S10), 127 ± 2.22 nm (S11) and 125 ± 1.8 nm (S12), respectively. This is maybe because the Ni(CH3COO)2 on the surface of the nanofibers is decomposed to NiO, gaseous H2O and CO2, which causes slight decrease in diameter, whereas the Ni(CH3COO)2 in the inner nanofibers is barely decomposed due to the non-contact with abundant oxygen.−1 for the pre-oxidation process, and 450 °C for 2 h with the same heating rate of 1 °C min−1 for oxidation process. Based on the above experimental results, it can be concluded that the optimum preparation conditions for NiO nanowire-in-nanotube structured nanofibers are as following: 200 °C for 2 h with a heating rate of 1 °C min3COO)2·4H2O is respectively replaced by Ni(NO3)2·6H2O and Co(CH3COO)2·4H2O, using the identical optimum pre-oxidation and oxidation conditions. 3O4 nanostructures fabricated by two-stage calcination of Ni(NO3)2/PVP and Co(CH3COO)2/PVP composite nanofibers. It can be obviously found that NiO and Co3O4 nanowire-in-nanotube structured nanofibers are obtained, as seen in 3O4 nanowire-in-nanotube structured nanofibers, as seen in 3O4 nanowire-in-nanotube structured nanofibers are 120 ± 3.17 nm and 107 ± 0.56 nm, respectively, as shown in In order to demonstrate the universality of this fabrication method, Ni(CH3COO)2/PVP composite nanofibers are formed by the traditional electrospinning process using the spinning solution containing PVP, DMF and Ni(CH3COO)2. At the moment, the composite nanofiber is a solid nanofiber, and PVP plays the role of fiber framework. Secondly, Ni(CH3COO)2/PVP composite nanofibers are calcined at 200 °C for 2 h (namely pre-oxidation process), and then the temperature is raised to 450 °C and keeps for 2 h (namely oxidation process). In the pre-oxidation process, Ni(CH3COO)2 on the surfaces of Ni(CH3COO)2/PVP composite nanofibers first begins to gradually decompose and oxidize to NiO rather than that in the inside of the composite nanofibers because the Ni(CH3COO)2 on the fiber surfaces could directly contact with oxygen. As a consequence, a NiO shell together with PVP is formed on the surface of each nanofiber. As the pre-oxidation time goes by, the Ni2+ ions near the surface of composite nanofiber are gradually attracted to the NiO shell so that the NiO crystal can grow up. Thus, the concentration of Ni2+ near the surface of composite nanofiber becomes lower and lower, and the NiO shell turns to denser and denser. Afterwards, in the oxidation process, PVP begins to decompose at 290 °C and produce CO2 and H2O, accompanied by the decomposition and oxidization of the residual Ni(CH3COO)2 to NiO. In this process, pre-generated NiO takes place the role of PVP as fiber framework. Moreover, a space between the surface and core of each nanofiber is formed because almost all of the Ni2+ ions near the surface of composite nanofiber move to the fiber surface, leaving only PVP which is eliminated by oxidation process. On the other hand, the Ni2+ ions in the core of each nanofiber are oxidized to form a NiO nanowire in the outer NiO nanotube. Based on the above formation mechanism of NiO nanowire-in-nanotube structured nanofibers, it is rational that the thickness of the nanotube of each NiO nanowire-in-nanotube structured nanofiber is increased with raising pre-oxidation temperature or extending pre-oxidation duration time, as seen in 2+ ions can move to the surface of the composite nanofiber.−1, NiO solid nanofibers are formed. The reason is that the inside and surface of the composite nanofiber can fully contact with oxygen to form NiO because there has been sufficient reaction time before the temperature rises to the decomposition temperature of PVP. By contrast, over high heating rate  causes destruction of the morphology of the nanofibers. That is because when the heating rate is too high, PVP and Ni(CH3COO)2 decompose so fast that lots of gases are rapidly produced, which impedes nanoparticles from mutually connect to form nanofibers.It has been found that heating rate also strongly affect the morphology of the products. When the heating rate is 0.5 °C min3COO)2 on the surface of each nanofiber begins to decompose, and thus a porous NiO shell are generated on the surface of nanofiber. Before the NiO shell becomes dense, PVP starts to decompose due to the absence of pre-oxidation process, which causes the Ni2+ ions inside the nanofiber are transported to the fiber surface by the gases generated from the PVP.26 Finally, Ni2+ ions are enriched in the shell of the nanofiber, and thus NiO hollow nanofibers are obtained after calcination.It has been also discovered that NiO hollow nanofibers are formed when pre-oxidation process is not carried out. The possible formation mechanism of NiO hollow nanofibers is as following: in the process of heating, lots of voids appear in the surface of the composite nanofibers due to the volatilization of residual DMF in the nanofibers. With the increase of temperature, Ni(CHλ > 380 nm) with methanol as a sacrifice. It can be seen that the hydrogen production rate of NiO nanowire-in-nanotube structured nanofibers and NiO hollow nanofibers is respectively 622 μmol h−1 and 472 μmol h−1 under the same mass. The amount of hydrogen produced by NiO nanowire-in-nanotube structured nanofibers is 1.32 times higher than that of NiO hollow nanofibers. 2 g−1, 24 nm) are bigger than those of NiO hollow nanofibers . It has been known that the H2-production activity from water splitting strongly depends on the microstructure of NiO.27,2829 which also causes higher hydrogen production rate of NiO nanowire-in-nanotube structured nanofibers. Nonetheless, at the beginning of the reaction, the hydrogen production rate of the NiO hollow nanofibers is higher than that of NiO nanowire-in-nanotube structured nanofibers. This may be because nanowires in the NiO nanowire-in-nanotube structured nanofibers block water molecules and methanol molecules from getting into the NiO nanowire-in-nanotube structured nanofibers, and thus the inner surfaces of the NiO nanowire-in-nanotube structured nanofibers are rarely used. As the reaction time increases, water molecules and methanol molecules gradually enter into the NiO nanowire-in-nanotube structured nanofibers, the large inner surfaces greatly promote the reaction. Therefore, the H2-production activity is accelerated.2 evolution, which facilitates photocatalytic reaction. For crystalline semiconductors, the band gap energies of the samples can be estimated from a plot of (αhν)2versus photon energy (hν). The indirect band gap energies of the samples are similar to the intercept of the tangent to the plot, and the band gap of the sample can be calculated by the formula:22B is the absorption constant for indirect transitions, absorbance (A) is proportional to the absorption coefficient (α). Here, α is replaced by A. The insets of 2230Eg is the band gap energy of the NiO, EC is the energy of free electrons on the hydrogen scale (ca. 4.5 eV), X is the electronegativity of NiO.31 CB potential of NiO nanowire-in-nanotube structured nanofibers and NiO hollow nanofibers are calculated to be −3.6 eV and −3.79 eV, respectively. The VB potential of NiO can be calculated by the formula:The possible mechanism for photocatalytic hydrogen generation over NiO nanostructures is as following: the CB position of NiO can be expressed empirically by the formula:2 and O2.32 When NiO nanofibers are exposed to visible light, the energy of a photon is absorbed by an electron in the valence band of NiO nanofibers. The photogenerated electron (e−) is excited to the conduction band and simultaneously leaves behind a positive hole (h+) in the valence band. Subsequently, OH− and H2 are produced to reduce a water molecules by a photogenerated electron (e−). At the same time, the separation efficiency of the electron–hole pairs is enhanced, due to the reaction of the CH3OH reagents with the photogenerated hole (h+). It was proposed that the reaction equation for production-H2 from water splitting is as follows:33After calculation, the VB potential of NiO nanowire-in-nanotube structured nanofibers and NiO hollow nanofibers are −0.2 eV and −0.09 eV, respectively, as indicated in Fm3̄m were fabricated by this fabrication method for the first time. The outer diameter and wall thickness of nanotubes and embedded nanowire diameter are 130 ± 0.99 nm, 30 nm and 40 nm, respectively. NiO nanowire-in-nanotube structured nanofibers used as photocatalyst for water splitting exhibit higher H2 evolution rate of 622 μmol h−1 than NiO hollow nanofibers of 472 μmol h−1 under visible light illumination owing to its special nanostructure. This technique we newly designed and proposed possesses universality and guiding significance to fabricate other nanowire-in-nanotube structured materials. The step for removing middle layer of the as-prepared fibers in conventional methods can be omitted by using our method, so that the preparation procedure is simplified. Moreover, for nanowire-in-nanotube structured materials, the spatial characteristics between embedded nanowire and nanotube may be considered as potential applications in the fields of photocatalysis, drug loading and delivery, sensor, and Li-ion battery.We propose a simple and universal technique to synthesize metallic oxide nanowire-in-nanotube structured nanofibers by two-stage calcination of electrospinning-made composite nanofibers. NiO nanowire-in-nanotube structured nanofibers with space group of There are no conflicts of interest to declare.