Microwave vacuum drying as compared to conventional vacuum drying has evinced advantages regarding drying time, while comparable product characteristics were achieved when drying sensitive biological ...material. Due to the volumetric microwave input, a time reduction of up to 90% is possible. When drying viscous liquids, a foamed structure that remains stable during drying exhibits further advantages as the diffusion‐limited third drying step is enhanced by the porous structure. As foams not only have to be thermally resistant during microwave vacuum processing, but also withstand the vacuum, a specific process for foam drying by microwaves under low pressure conditions was developed. Foam formation and stabilization was achieved by using a synergistic mixture of proteins and carbohydrates; Lactobacillus paracasei ssp. paracasei F19 (L. paracasei) served as a model sensitive substance. Investigation of surface activity and foaming properties as a function of L. paracasei concentration revealed a significant positive contribution of the bacterial cells. It was shown that L. paracasei directly adsorbed at the air–water interface. Besides, a structuring of the liquid lamellae was assumed. Moreover, drying time was reduced to at least 50% compared to microwave vacuum drying without foaming. It was further observed that the slight loss in survival was mainly due to the relatively high moisture content and high vacuum levels at the beginning of the process. However, foaming, vacuum application, and final drying, respectively, did not affect viability of the bacterial cells. Thus, by incorporation of lactic acid bacteria into foam structures, drying can be carried out in a fraction of time, and further results in high‐product quality.
Practical Application
The application of continuous foam drying offers an efficient and energy‐saving alternative to the currently applied techniques for the processing of sensitive material. The process could be applied for the preservation of starter cultures and probiotics as well as in the pharmaceutical industry, when sensitive material such as therapeutic proteins is dried. This process is especially suitable for freezing‐sensitive and thermolabile substances.
We report an improved measurement of the cosmic microwave background B-mode polarization power spectrum with the Polarbear experiment at 150 GHz. By adding new data collected during the second season ...of observations (2013-2014) to re-analyzed data from the first season (2012-2013), we have reduced twofold the band-power uncertainties. The band powers are reported over angular multipoles , where the dominant B-mode signal is expected to be due to the gravitational lensing of E-modes. We reject the null hypothesis of no B-mode polarization at a confidence of 3.1 including both statistical and systematic uncertainties. We test the consistency of the measured B-modes with the Λ Cold Dark Matter (ΛCDM) framework by fitting for a single lensing amplitude parameter AL relative to the Planck 2015 best-fit model prediction. We obtain 0.14(foreground) 0.04(multi), where is the fiducial ΛCDM value.
We present a measurement of the B-mode polarization power spectrum of the cosmic microwave background (CMB) using data taken from 2014 July to 2016 December with the Polarbear experiment. The CMB ...power spectra are measured using observations at 150 GHz with an instantaneous array sensitivity of on a 670 square degree patch of sky centered at (R.A., decl.) = (+0h12m0s, −59°18′). A continuously rotating half-wave plate is used to modulate polarization and to suppress low-frequency noise. We achieve 32 K arcmin effective polarization map noise with a knee in sensitivity of = 90, where the inflationary gravitational-wave signal is expected to peak. The measured B-mode power spectrum is consistent with a ΛCDM lensing and single dust component foreground model over a range of multipoles 50 ≤ ≤ 600. The data disfavor zero at 2.2 using this range of Polarbear data alone. We cross-correlate our data with Planck full mission 143, 217, and 353 GHz frequency maps and find the low- B-mode power in the combined data set to be consistent with thermal dust emission. We place an upper limit on the tensor-to-scalar ratio r < 0.90 at the 95% confidence level after marginalizing over foregrounds.
We present an overview of the design and status of the
Polarbear
-2 and the Simons Array experiments.
Polarbear
-2 is a cosmic microwave background polarimetry experiment which aims to characterize ...the arc-minute angular scale B-mode signal from weak gravitational lensing and search for the degree angular scale B-mode signal from inflationary gravitational waves. The receiver has a 365 mm diameter focal plane cooled to 270 mK. The focal plane is filled with 7588 dichroic lenslet–antenna-coupled polarization sensitive transition edge sensor (TES) bolometric pixels that are sensitive to 95 and 150 GHz bands simultaneously. The TES bolometers are read-out by SQUIDs with 40 channel frequency domain multiplexing. Refractive optical elements are made with high-purity alumina to achieve high optical throughput. The receiver is designed to achieve noise equivalent temperature of 5.8
μ
K
CMB
s
in each frequency band.
Polarbear
-2 will deploy in 2016 in the Atacama desert in Chile. The Simons Array is a project to further increase sensitivity by deploying three
Polarbear
-2 type receivers. The Simons Array will cover 95, 150, and 220 GHz frequency bands for foreground control. The Simons Array will be able to constrain tensor-to-scalar ratio and sum of neutrino masses to
σ
(
r
)
=
6
×
10
-
3
at
r
=
0.1
and
∑
m
ν
(
σ
=
1
)
to 40 meV.
Gravitational lensing due to the large-scale distribution of matter in the cosmos distorts the primordial cosmic microwave background (CMB) and thereby induces new, small-scale B-mode polarization. ...This signal carries detailed information about the distribution of all the gravitating matter between the observer and CMB last scattering surface. We report the first direct evidence for polarization lensing based on purely CMB information, from using the four-point correlations of even- and odd-parity E- and B-mode polarization mapped over ∼30 square degrees of the sky measured by the POLARBEAR experiment. These data were analyzed using a blind analysis framework and checked for spurious systematic contamination using null tests and simulations. Evidence for the signal of polarization lensing and lensing B modes is found at 4.2σ (stat+sys) significance. The amplitude of matter fluctuations is measured with a precision of 27%, and is found to be consistent with the Lambda cold dark matter cosmological model. This measurement demonstrates a new technique, capable of mapping all gravitating matter in the Universe, sensitive to the sum of neutrino masses, and essential for cleaning the lensing B-mode signal in searches for primordial gravitational waves.
We present the first measurement of cross-correlation between the lensing potential, reconstructed from cosmic microwave background (CMB) polarization data, and the cosmic shear field from galaxy ...shapes. This measurement is made using data from the Polarbear CMB experiment and the Subaru Hyper Suprime-Cam (HSC) survey. By analyzing an 11 deg2 overlapping region, we reject the null hypothesis at 3.5 and constrain the amplitude of the cross-spectrum to , where is the amplitude normalized with respect to the Planck 2018 prediction, based on the flat Λ cold dark matter cosmology. The first measurement of this cross-spectrum without relying on CMB temperature measurements is possible owing to the deep Polarbear map with a noise level of ∼6 K arcmin, as well as the deep HSC data with a high galaxy number density of . We present a detailed study of the systematics budget to show that residual systematics in our results are negligibly small, which demonstrates the future potential of this cross-correlation technique.
The salt-induced peptide formation (SIPF) reaction is a prebiotically plausible mechanism for the spontaneous polymerization of amino acids into peptides on early Earth. Experimental investigations ...of the SIPF reaction have found that in certain conditions, the l enantiomer is more reactive than the d enantiomer, indicating its potential role in the rise of biohomochirality. Previous work hypothesized that the distortion of the CuCl active complex toward a tetrahedral-like structure increases the central chirality on the Cu ion, which amplifies the inherent parity-violating energy differences between l- and d-amino acid enantiomers, leading to stereoselectivity. Computational evaluations of this theory have been limited to the protonated–neutral l + l forms of the CuCl active complex. Here, density functional theory methods were used to compare the energies and geometries of the homochiral (l + l and d + d) and heterochiral (l + d) CuCl–amino acid complexes for both the positive–neutral and neutral–neutral forms for alanine, valine, and proline. Significant energy differences were not observed between different chiral active complexes (i.e., d + d, l + l vs. l + d), and the distortions of active complexes between stereoselective systems and non-selective systems were not consistent, indicating that the geometry of the active complex is not the primary driver of the observed stereoselectivity of the SIPF reaction.
We reconstruct the gravitational lensing convergence signal from cosmic microwave background (CMB) polarization data taken by the Polarbear experiment and cross-correlate it with cosmic infrared ...background maps from the Herschel satellite. From the cross spectra, we obtain evidence for gravitational lensing of the CMB polarization at a statistical significance of 4.0σ and indication of the presence of a lensing B-mode signal at a significance of 2.3σ. We demonstrate that our results are not biased by instrumental and astrophysical systematic errors by performing null tests, checks with simulated and real data, and analytical calculations. This measurement of polarization lensing, made via the robust cross-correlation channel, not only reinforces POLARBEAR auto-correlation measurements, but also represents one of the early steps towards establishing CMB polarization lensing as a powerful new probe of cosmology and astrophysics.
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