Erratum: Prediction for a Four-Neutron Resonance [Phys. Rev. Lett. 117, 182502 (2016)].

This corrects the article DOI: 10.1103/PhysRevLett.117.182502.

Prediction for a Four-Neutron Resonance.

We utilize various ab initio approaches to search for a low-lying resonance in the four-neutron (4n) system using the JISP16 realistic NN interaction. Our most accurate prediction is obtained using a J-matrix extension of the no-core shell model and suggests a 4n resonant state at an energy near E_{r}=0.8 MeV with a width of approximately Γ=1.4 MeV.

Collective modes in light nuclei from first principles.

Results for ab initio no-core shell model calculations in a symmetry-adapted SU(3)-based coupling scheme demonstrate that collective modes in light nuclei emerge from first principles. The low-lying states of 6Li, 8Be, and 6He are shown to exhibit orderly patterns that favor spatial configurations with strong quadrupole deformation and complementary low intrinsic spin values, a picture that is consistent with the nuclear symplectic model. The results also suggest a pragmatic path forward to accommodate deformation-driven collective features in ab initio analyses when they dominate the nuclear landscape.

α-Clustering in atomic nuclei from first principles with statistical learning and the Hoyle state character.

A long-standing crucial question with atomic nuclei is whether or not α clustering occurs there. An α particle (helium-4 nucleus) comprises two protons and two neutrons, and may be the building block of some nuclei. This is a very beautiful and fascinating idea, and is indeed plausible because the α particle is particularly stable with a large binding energy. However, direct experimental evidence has never been provided. Here, we show whether and how α(-like) objects emerge in atomic nuclei, by means of state-of-the-art quantum many-body simulations formulated from first principles, utilizing supercomputers including K/Fugaku. The obtained physical quantities exhibit agreement with experimental data. The appearance and variation of the α clustering are shown by utilizing density profiles for the nuclei beryllium-8, -10 and carbon-12. With additional insight by statistical learning, an unexpected crossover picture is presented for the Hoyle state, a critical gateway to the birth of life.

Electron in a transverse harmonic cavity.

Recent experiments with heavy ions and planned experiments with ultraintense lasers require nonperturbative solutions to quantum field theory for predicting and interpreting the results. To propel this theoretical direction, we solve the nonperturbative problem of an electron in a strong transverse confining potential using Hamiltonian light-front quantum field theory. We evaluate both the invariant mass spectra and the anomalous magnetic moment of the lowest state for this two-scale system. The weak external field limit of the anomalous magnetic moment agrees with the result of QED perturbation theory within the anticipated accuracy.

Origin of the anomalous long lifetime of ¹4C.

We report the microscopic origins of the anomalously suppressed beta decay of ¹4C to ¹4N using the ab initio no-core shell model with the Hamiltonian from the chiral effective field theory including three-nucleon force terms. The three-nucleon force induces unexpectedly large cancellations within the p shell between contributions to beta decay, which reduce the traditionally large contributions from the nucleon-nucleon interactions by an order of magnitude, leading to the long lifetime of ¹4C.

Structure of A=10-13 nuclei with two- plus three-nucleon interactions from chiral effective field theory.

Properties of finite nuclei are evaluated with two-nucleon (NN) and three-nucleon (NNN) interactions derived within chiral effective field theory. The nuclear Hamiltonian is fixed by properties of the A=2 system, except for two low-energy constants (LECs) that parametrize the short range NNN interaction, which we constrain with the A=3 binding energies. We investigate the sensitivity of 4He, 6Li, 10,11B, and 12,13C properties to the variation of the constrained LECs. We identify observables that are sensitive to this variation and find preferred values that give the best overall description. We demonstrate that the NNN interaction terms significantly improve the binding energies and spectra of mid-p-shell nuclei not just with the preferred choice of the LECs but even within a wide range of the constrained LECs. We find that a very high quality description of these nuclei requires further improvements to the chiral Hamiltonian.

Biochemical studies on glucose initiated germination in Bacillus megaterium.

Bacillus megaterium QM B1551 spores contained the enzymes for the Embden-Meyerhof pathway and the initial reactions in the hexose monophosphate pathway but not the Entner-Doudoroff pathway. With [U-14C]glucose no metabolism was detected until after about 30% of the spores had lost heat resistance. Mutants that lacked either phosphofructokinase or 6-phosphogluconate dehydrogenase were able to initiate germination on glucose like wild type. Purified methyl alpha-D-glucopyranoside, 6-deoxyglucose and 6-deoxy-methyl alpha-D-glucopyranoside were not substrates for spore enzymes yet these compounds still initiated germination. Therefore, metabolism of exogenously added glucose is probably not the primary stimulatory effect in germination.

An evaluation of respiration chain-associated functions during initiation of germination of Bacillus megaterium spores.

In Bacillus megaterium QM B1551, spore germination could be initiated by glucose in the absence of detectable oxygen consumption, ATP synthesis or a pH decrease in the external media, suggesting that none of those reactions were mandatory. In addition, initiation of germination was insensitive to a variety of inhibitors of energy production or protonmotive force uncouplers. Therefore the respiratory chain-associated functions are not prerequisites for initiation of germination but these functions may be necessary to drive energy-dependent transport systems and other biosynthetic reactions during outgrowth.

Changes in the lipid content of boar sperm plasma membranes during epididymal maturation.

Plasma membranes of boar sperm from caput, corpus and cauda of the epididymis were purified by differential- and sucrose-density equilibrium centrifugation and were found to yield a single band at a density of 1.13 g/cm3. This fraction was enriched in acid and alkaline phosphatase, 5'-nucleotidase and (Na+ + K+)-ATPase activities, whereas it contained minimal amounts of hyaluronidase and N-acetylglucosaminidase and no succinic acid dehydrogenase activities. The plasma membrane of caput, corpus and cauda sperm had the same phospholipid/protein and cholesterol/phospholipid ratios but yielded different amounts of protein and individual lipid classes. Several changes in the plasma membrane were observed during transit of sperm through the epididymis. Within the phospholipid class a decrease in the percentage of phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol was detected accompanied by an increase in amount of phosphatidylcholine, sphingomyelin and polyphosphoinositides. In the other lipid classes there was a decrease in the amount of free fatty acid and the major glycolipid. The amount of cholesterol decreased, while the amount of desmosterol and cholesterol sulfate increased. There was an increase in the amount of diacylglycerol. In addition, the changes in the fatty acid composition of the total membrane lipid and each phospholipid were determined. The above changes in the lipid composition of the plasma membrane during epididymal maturation may help to explain the decreased resistance to cold shock and changes in membrane fluidity of sperm during transit in the epididymis.

Biological membranes are rich in low-frequency motion.

Using 13C cross-polarization NMR techniques, we have found that the effect of protein on the dynamics of the hydrocarbon interior of a series of biological membranes is to depress the intensity of motion on the nanosecond timescale (i.e., T1 becomes longer) and to enhance the intensity of motion on the timescale of tens of microseconds (i.e., T1p becomes shorter.)

Mechanism by which hydralazine increases propranolol bioavailability.

Five healthy subjects were given oral 14C-propranolol (10 microCi, 40 mg) alone and in combination with hydralazine, 25 and 50 mg. Hydralazine increased propranolol peak concentrations from 25 +/- 7 ng/ml to 61 +/- 10 and 85 +/- 11 ng/ml, reduced time to peak concentrations from 2.2 +/- 0.2 hr to 0.7 +/- 0.1 and 0.8 +/- 0.1 hr, and increased area under the propranolol concentration: time curves from 153 +/- 38 ng X ml-1 X hr to 246 +/- 64 and 324 ng X ml-1 X hr (in all cases P less than 0.05). Hydralazine did not change the fraction of the 14C-propranolol dose recovered in the urine as basic, acidic, and polar metabolites: 0.28 +/- 0.2, 0.27 +/- 0.03, and 0.44 +/- 0.03. The urinary excretion rate of radioactive metabolites of propranolol in acid, basic, and residue fractions increased in the 0 = to = 2-hr time interval after hydralazine but there was no change in the relative proportion of each metabolite fraction at any time. Similar results were obtained by HPLC. Studies with radioactive propranolol indicate that a major acid and basic metabolite remains to be defined in addition to unextracted polar metabolites. Our data indicate that hydralazine increases propranolol bioavailability by its hemodynamic actions rather than by inhibition of its metabolism.

Effects of nadolol and propranolol on plasma lidocaine clearance.

Nadolol and propranolol effects on lidocaine elimination were followed in six healthy men and women. Each received three separate 30-hr infusions of lidocaine (2 mg/min): one alone, one after 3 days pretreatment with nadolol (160 mg daily), and one after 3 days pretreatment with propranolol (80 mg every 8 hr). Liver blood flow was determined by the systemic clearance of indocyanine green. Steady-state plasma lidocaine levels were increased by nadolol (2.1 +/- 0.2 to 2.7 +/- 0.3 micrograms/ml) and by propranolol (2.1 +/- 0.2 to 2.5 +/- 0.3 micrograms/ml). Lidocaine plasma clearance was decreased by nadolol (1030 +/- 81 to 850 +/- 82 ml/min) and by propranolol (1030 +/- 81 to 866 +/- 75 ml/min). Hepatic blood flow was decreased by nadolol (1275 +/- 77 to 902 +/- 102 ml/min) and propranolol (1275 +/- 77 to 957 +/- 119 ml/min). The hepatic extraction ratio for lidocaine was increased by nadolol (0.86 +/- 0.06 to 0.91 +/- 0.05) and by propranolol (0.86 +/- 0.06 to 0.90 +/- 0.06). Lidocaine intrinsic clearance was not changed by nadolol (8.19 +/- 1.87 to 9.52 +/- 2.36 l/min) or propranolol (8.19 +/- 1.87 to 9.50 +/- 3.13 l/min). Our data indicate that both nadolol and propranolol reduce lidocaine clearance by their effects on hepatic blood flow and not by inhibition of lidocaine metabolism.

Novel multivalent effects of pyrazinoylguanidine in patients with azotemia.

In patients with azotemia, urea excretion, urea clearance, and urea/creatinine clearance ratio were increased by pyrazinoylguanidine in a dose-related manner. Urine volume and excretion of sodium greater than chloride greater than potassium tended to increase during administration of pyrazinoylguanidine. Systemic arterial pressure declined while pyrazinoylguanidine was given at 300 or 600 mg b.i.d. for 3 days. At both doses pyrazinoylguanidine reduced plasma renin activity during the first 2 hours. Between days 1 and 3 only the high dose of pyrazinoylguanidine decreased plasma renin activity and plasma aldosterone levels. These findings with pyrazinoylguanidine are consistent with those of secretion of urea in human subjects across the renal tubules and indicate that this process is susceptible to pharmacologic alteration, even in the presence of severe renal insufficiency.

Effect of dose and uremia on plasma and urine profiles of propranolol metabolites.

The relationship between plasma levels of 4 propranolol metabolites--naphthoxylactic acid (NLA), 4-hydroxypropranolol (4-OH), naphthoxyacetic acid (NAA), and propranolol glycol (PG)--and propranolol plasma levels was determined in healthy, adult male subjects after increasing single oral doses of propranolol. NLA was present at plasma levels 6 to 25 times that of propranolol. More than 90% of circulating NLA was in the plasma fraction, where it was 95% protein bound. The ratio of plasma concentrations of the pharmacologically active metabolite 4-OH to propranolol approached unity 0.5 hr after propranolol, 160 mg or 320 mg orally, but fell rapidly. Plasma levels of NAA were in the same range as propranolol, especially as time progressed. PG circulated at plasma levels less than 12% of propranolol. As oral doses of propranolol were increased from 20 to 320 mg, there was a decrease in intrinsic plasma clearance (Cli) from 425 to 200 1/hr. Half-life rose from 3 to 5 hr. Urinary recovery of 4-OH fell as Cli rose. Urinary recovery of propranolol conjugates, NLA, and N-desisopropylpropranolol (NDIPP) rose as Cli fell. Our results suggest that naphthalene ring oxidation of propranolol represents a high-affinity low-capacity enzymatic pathway(s) that plays an important role in the extensive hepatic extraction of propranolol after small doses orally. Plasma NLA and plasma NAA were determined before and after hemodialysis in 14 uremic patients receiving long-term propranolol therapy. Mean plasma NLA was 4.372 ng/ml, and mean plasma NAA level was 238 ng/ml when mean plasma propranolol level was 15 ng/ml.

Dazoxiben, a thromboxane synthetase inhibitor, in Raynaud's phenomenon.

Dazoxiben, a specific thromboxane synthetase inhibitor, was evaluated in 21 patients with Raynaud's phenomenon in a double-blind, placebo-controlled crossover experiment. Total fingertip blood flows were measured by plethysmography and capillary blood flows were measured by 133Xe disappearance rate. Subjects were studied in both a warm (28 degrees) and a cold (20 degrees) room. Arteriovenous (AV) shunt flow was estimated by subtraction of capillary flow from total flow. Ex vivo production of thromboxane B2 (TXB2) and 6-keto PGF1 alpha was determined by specific radioimmunoassay in serum from venous blood incubated for 1 hr (37 degrees). Plasma concentrations of TXB2 and 6-keto PGF1 alpha were also monitored. Dazoxiben (100 mg 4 times a day for 14 days) inhibited ex vivo TXB2 production (from 463.1 +/- 69.9 to 101.8 +/- 13.4 ng/ml/hr; (means +/- SE], enhanced ex vivo 6-keto PGF1 alpha production (from 1.38 +/- 0.05 to 3.76 +/- 0.18 ng/ml/hr), reduced plasma TXB2 concentration (from 88.1 +/- 13.9 to 38.8 +/- 5.9 pg/ml). There were no changes in plasma concentration of 6-keto PGF1 alpha. Dazoxiben did not improve total digital blood flow, capillary flow, AV shunt flow, or forearm blood flow at 28 degrees or 20 degrees. There was no subjective improvement in frequency or severity of Raynaud's attacks (assessed by patient diaries). It is concluded that dazoxiben is a potent and specific thromboxane synthetase inhibitor capable of altering arachidonic acid metabolism, but is of little or no benefit in the treatment of Raynaud's phenomenon.

Contrasting effects of pyrazinoylguanidine and hydrochlorothiazide in patients with renal insufficiency.

A single blind crossover study with washout phases showed that pyrazinoylguanidine (PZG) reduced elevated serum concentrations of urea, triglycerides, and cholesterol in patients with renal insufficiency. Pyrazinoylguanidine was saluretic, without affecting serum potassium or glucose concentrations. The onset of PZG's antihypertensive effect occurred within 4 hours. In contrast, hydrochlorothiazide (HCTZ) increased serum concentrations of urea, triglycerides, and glucose, without affecting cholesterol.

Fatty acid and phospholipid composition ofBacillus megaterium spores with altered germination properties.

The ability of spores to trigger germination was altered by growing spores at either a suboptimal temperature or in a rich medium modified by substituting L-isoleucine for D-glucose. Compared to the control, spores grown in the presence of isoleucine germinated more readily between 20 and 28 C, while spores grown at 20 C germinated slower than the control at any temperature tested. Analysis of the composition of these spores indicated that spores grown in the presence of isoleucine had much higher levels of anteiso-C15 fatty acids than the control, while the phospholipid composition and the phospholipid to protein ratio were unchanged. The fatty acid composition for spores grown at 20 C was comparable to that of the control spores, but the levels of diphosphatidylglycerol and phosphatidylglycerol were altered as well as the ratio of phospholipid to protein. Steady-state fluorescent anisotropy measurements were made with 1,6-diphenyl-1,3,5-hexatriene incorporated into membrane isolated from these spores. The membranes from spores grown in the presence of isoleucine were more "fluid" between 10 and 20 C than membranes from the control spores. Membranes from 20 C grown spores were less "fluid" between 10 and 38 C than membranes from the control spores. These results show that triggering of spore germination was altered by growing spores under conditions that altered the composition of spore membranes.

Lipid composition of Bacillus megaterium spores and spore membranes.

Bacillus megaterium QM B1551 spore lipids were extracted by an improved technique, and the phospholipid and fatty acid compositions were determined. Phospholipids accounted for 65% of the total fatty acids; the neutral lipid fraction contained 15% and the remaining fatty acids were in the interphase, aqueous phase and pellet from the lipid extraction. Each phospholipid had similar fatty acid compositions as did the delipidated pellet. However, the aqueous phase and, to some extent, the interphase had unique fatty acid compositions. Also, fatty acids were found acylated to proteins, which was observed by electrophoresis of delipidated proteins from spores grown in [1-14C]palmitate. Therefore, spores contain unique non-phosphatide fatty acid components that can now be analyzed.

Lipid composition of the membrane released after an in vitro acrosome reaction of epididymal boar sperm.

Prior to fertilization, mammalian sperm must undergo the acrosome reaction, which involves modifications of the plasma and outer acrosomal membranes followed by vesiculation and release of the membranes. The membrane fraction that was released from caudal boar sperm undergoing an in vitro acrosome-like reaction was isolated and characterized with respect to density, marker enzymes and lipid composition. This membrane had a lower phospholipid/protein ratio (mg/mg) than the sperm plasma membrane, whereas both membranes had similar molar sterol/phospholipid ratios. The major phospholipid was sphingomyelin, followed by phosphatidylethanolamine and phosphatidylcholine, whereas in the plasma membrane the order was reversed; the two major phosphoglycerides contained alkylacyl and alkenylacyl species in addition to the diacyl species. The released membrane also contained lower amounts of cholesterol sulfate and unsaturated fatty acids than the plasma membranes. These results, in combination with our studies on the changes of the sperm membranes during maturation and acrosome reaction, will allow a better understanding of the mechanism of the sperm acrosome reaction.