Abundant hydrocarbons in the disk around a very-low-mass star.

Very-low-mass stars (those less than 0.3 solar masses) host orbiting terrestrial planets more frequently than other types of stars. The compositions of those planets are largely unknown but are expected to relate to the protoplanetary disk in which they form. We used James Webb Space Telescope mid-infrared spectroscopy to investigate the chemical composition of the planet-forming disk around ISO-ChaI 147, a 0.11-solar-mass star. The inner disk has a carbon-rich chemistry; we identified emission from 13 carbon-bearing molecules, including ethane and benzene. The high column densities of hydrocarbons indicate that the observations probe deep into the disk. The high carbon-to-oxygen ratio indicates radial transport of material within the disk, which we predict would affect the bulk composition of any planets forming in the disk.

Outflows from the youngest stars are mostly molecular.

The formation of stars and planets is accompanied not only by the build-up of matter, namely accretion, but also by its expulsion in the form of highly supersonic jets that can stretch for several parsecs1,2. As accretion and jet activity are correlated and because young stars acquire most of their mass rapidly early on, the most powerful jets are associated with the youngest protostars3. This period, however, coincides with the time when the protostar and its surroundings are hidden behind many magnitudes of visual extinction. Millimetre interferometers can probe this stage but only for the coolest components3. No information is provided on the hottest (greater than 1,000 K) constituents of the jet, that is, the atomic, ionized and high-temperature molecular gases that are thought to make up the jet's backbone. Detecting such a spine relies on observing in the infrared that can penetrate through the shroud of dust. Here we report near-infrared observations of Herbig-Haro 211 from the James Webb Space Telescope, an outflow from an analogue of our Sun when it was, at most, a few times 104 years old. These observations reveal copious emission from hot molecules, explaining the origin of the 'green fuzzies'4-7 discovered nearly two decades ago by the Spitzer Space Telescope8. This outflow is found to be propagating slowly in comparison to its more evolved counterparts and, surprisingly, almost no trace of atomic or ionized emission is seen, suggesting its spine is almost purely molecular.

Water in the terrestrial planet-forming zone of the PDS 70 disk.

Terrestrial and sub-Neptune planets are expected to form in the inner (less than 10 AU) regions of protoplanetary disks1. Water plays a key role in their formation2-4, although it is yet unclear whether water molecules are formed in situ or transported from the outer disk5,6. So far Spitzer Space Telescope observations have only provided water luminosity upper limits for dust-depleted inner disks7, similar to PDS 70, the first system with direct confirmation of protoplanet presence8,9. Here we report JWST observations of PDS 70, a benchmark target to search for water in a disk hosting a large (approximately 54 AU) planet-carved gap separating an inner and outer disk10,11. Our findings show water in the inner disk of PDS 70. This implies that potential terrestrial planets forming therein have access to a water reservoir. The column densities of water vapour suggest in-situ formation via a reaction sequence involving O, H2 and/or OH, and survival through water self-shielding5. This is also supported by the presence of CO2 emission, another molecule sensitive to ultraviolet photodissociation. Dust shielding, and replenishment of both gas and small dust from the outer disk, may also play a role in sustaining the water reservoir12. Our observations also reveal a strong variability of the mid-infrared spectral energy distribution, pointing to a change of inner disk geometry.

Publisher Correction: Measuring the ionisation fraction in a jet from a massive protostar.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Measuring the ionisation fraction in a jet from a massive protostar.

It is important to determine if massive stars form via disc accretion, like their low-mass counterparts. Theory and observation indicate that protostellar jets are a natural consequence of accretion discs and are likely to be crucial for removing angular momentum during the collapse. However, massive protostars are typically rarer, more distant and more dust enshrouded, making observational studies of their jets more challenging. A fundamental question is whether the degree of ionisation in jets is similar across the mass spectrum. Here we determine an ionisation fraction of ~5-12% in the jet from the massive protostar G35.20-0.74N, based on spatially coincident infrared and radio emission. This is similar to the values found in jets from lower-mass young stars, implying a unified mechanism of shock ionisation applies in jets across most of the protostellar mass spectrum, up to at least ~10 solar masses.

Cell reprogramming: a new chemical approach to stem cell biology and tissue regeneration.

Generation of pluripotent stem cells (iPSCs) from adult fibroblasts starts a "new era" in stem cell biology, as it overcomes several key issues associated with previous approaches, including the ethical concerns associated with human embryonic stem cells. However, as the genetic approach for cell reprogramming has already shown potential safety issues, a chemical approach may be a safer and easier alternative. Moreover, a chemical approach could be advantageous not only for the de-differentiation phase, but also for inducing reprogrammed cells into the desired cell type with higher efficiency than current methodologies. Finally, a chemical approach may be envisioned to activate resident adult stem cells to proliferate and regenerate damaged tissues in situ, without the need for exogenous cell injections.

Mechanical circulatory support in severe heart failure: single-center experience.

Ventricular assist devices (VADs) have become important therapeutic tools to treat patients with end-stage cardiac failure. VADs are an essential component of transplantation programs as they successfully bridge individuals who would otherwise die. Recently left ventricular VAD (LVAD) therapy has been proposed as alternative to heart transplantation (HTx) for patients who are not transplant candidates. Other indications have now expanded into areas such as postcardiotomy failure, acute myocarditis, and acute massive myocardial infarction. From 1988 to May 2003, 80 patients received left or biventricular mechanical circulatory support including 78 as a bridge to and two as an alternative to HT. All patients survived the operation. Mean duration of VAD support was 77 +/- 150 days. Fifty-one points (63.8%) underwent heart transplantation; 3 (3.8%) recovered and were weaned from VADs. Major bleeding episodes occurred in 11 patients (13.8%) and major neurologic events occurred in 8 (10%). Sixteen patients (20%) were discharged home while waiting for HTx. Twenty-two patients (27.5%) died on VAD. In conclusion, VAD therapy proved effective in bridging patients with end-stage heart failure to HTx. While on LVAD support patients who were assisted with implantable wearable devices could be discharged at home, improving their quality of life.

Impella recover 100 microaxial left ventricular assist device: the Niguarda experience.

BACKGROUND: The Impella Recover 100 (IR100) is an intravascular microaxial blood pump used to support blood circulation for a maximum of 7 days in cases of reduced left ventricular function, for example in postcardiotomy low output syndrome or in cardiogenic shock after acute myocardial infarction. MATERIALS AND METHODS: We supported five patients with the IR100. The mean age, cardiac index (CI), and ejection fraction (EF) of our population were 42 years, 1.83 L/min/m(2), and 20%, respectively. Two patients (group A) with ischemic dilated cardiomyopathy were bridged to heart transplant. Two patients (group B) with fulminan myocarditis and septic shock were bridged to recovery. One patient, with severe valvular cardiomyopathy who underwent aortic valve replacement and mitral valve annuloplasty, was supported to weaning from ECC. RESULTS: Mean support time was 9.8 +/- 2.3 days. Only one acute myocarditis patient died from a severe vasoplegic syndrome despite maximal inotropic and vasoactive support. Both group A patients were successfully transplanted. Among group B, the second patient resolved the septic status and was slowly weaned from the device and discharged home with moderate improvement of LV function (EF = 40%). Patient C was weaned from the IR100 and electively placed on the heart transplant recipient list. CONCLUSIONS: IR100 is a device that in our experience can be utilized for various indications for short-term support. In compromised patients where a traditional LVAD is contraindicated, the IR100 showed good results, for it is minimally invasive and does not need ECC or systemic anticoagulation.