Sam Holtzen, PhD
@samholtzen.bsky.social
780 followers 530 following 180 posts
postdoc at caltech he/they opinions are my own 💻 https://samholtzen.github.io/ 🏺 sellish.ghost.io
Posts Media Videos Starter Packs
Pinned
samholtzen.bsky.social
Hi everyone! My name is Sam and I'm a postdoc at Caltech working on developing high throughput screening methods for metabolite biosensors! 🧪

I'll be posting some post threads soon on fundamentals of fluorescence, FRET, and biosensors! ✨
samholtzen.bsky.social
whaaaaat how unexpected!
lgbtqnation.com
Gavin Newsom vetoes gender education bill, declines to sign other trans protections - buff.ly/MTUAV85
Reposted by Sam Holtzen, PhD
damiandn.bsky.social
This analysis remains undefeated.
samholtzen.bsky.social
hi science bluesky 🧪 i have a question. has anyone shown if sgRNAs are susceptible to degradation by RNases when they're bound to the Cas9 protein? I know they're very unstable when unbound, but I can't seem to find evidence of their stability in the RNP complex. any help is appreciated!!
Reposted by Sam Holtzen, PhD
rahaeli.bsky.social
Hey remember when the CDC dropped 6 of the 8 foodborne illnesses from the nationwide monitoring system in July and one of them was listeria? Mentioning for no particular reason www.nbcnews.com/health/healt...
Reposted by Sam Holtzen, PhD
brendannyhan.bsky.social
An unprecedented violation of our civic and Constitutional traditions. Calling every military leader in the world back to the U.S. to hear a wildly inappropriate partisan campaign speech followed by a fascist call to use the military against Americans.
Reposted by Sam Holtzen, PhD
boghuma.bsky.social
This is the official communication from the FDA to physicians on acetaminophen use in pregnancy.
- They acknowledge the lack of a causal link with autism
- Essentially tell physicians to keep doing what we've been doing anyway
It's very different from the press conference.
Pass it on.
Official communication from FDA to physicians on acetaminophen use in pregnancy acknowledges there is no causal link between its use in pregnancy and autism. Also states clearly that this is the safest over the counter treatment for fever and pain in pregnancy. It is very different from what was communicated at the press conference.
Reposted by Sam Holtzen, PhD
joshuasweitz.bsky.social
Reminder: a large (2.5M+) sibling control study found "no evidence of increased risk of autism, ADHD, or intellectual disability associated with acetaminophen use". Precisely the kind of data that requires serious consideration before declaring mission accomplished.

jamanetwork.com/journals/jam...
Acetaminophen Use During Pregnancy and Children’s Risk of Autism, ADHD, and Intellectual Disability
This nationwide cohort study with sibling control analysis examines the association of acetaminophen use during pregnancy with children’s risk of autism, ADHD, and intellectual disability.
jamanetwork.com
Reposted by Sam Holtzen, PhD
katestarbird.bsky.social
Universities. Rural hospitals. Tech companies. Several sectors are going to be profoundly hurt by this. Not to mention the chaos of the moment as current H1-B owners scramble to get back to the U.S., cancel travel, etc. due to the uncertainty. An absolute mess. As intended.
samholtzen.bsky.social
"arise against the backdrop of documented performance concerns" is crazy lmfao
Reposted by Sam Holtzen, PhD
freya.bsky.social
the epistemic breakdown of factual reality in this political media environment has been so harmful

when facts genuinely favor the left, the right will simply deny the facts or call the messenger biased, without any refutation

reality will always be biased against a movement detached from reality
bencollins.bsky.social
Political violence is evil, killing people is evil, a country with more guns in it than people is broken, and what the government is saying about political violence right now being a primarily leftwing phenomenon is factually, statistically untrue. They are using this moment to rewrite history.
Reposted by Sam Holtzen, PhD
radleybalko.bsky.social
We're witnessing the most aggressive, fanatical crackdown on free speech in my lifetime. The speed and breadth of government censorship and private sector and nonprofit capitulation has been astonishing. As has the lack of urgency/silence from people who've long claimed to care about this stuff.
Reposted by Sam Holtzen, PhD
erininthemorning.com
Political violence is abhorrent. I have not celebrated Kirk's death.

But Newsom calling for his followers to "continue Charlie Kirk's work," someone who praised stoning gay people as "god's perfect law," who called for men to "take care of" trans people like they did in the 50s and 60s, is not it.
Reposted by Sam Holtzen, PhD
brendelbored.bsky.social
Glenn Beck’s media outlet The Blaze just gave an interview last month to the person who killed the politicians in Minnesota
Blaze Media
https://www.theblaze.com
Exclusive: Assassination suspect Vance
Boelter tells STUNNING inside ...
Aug 12, 2025 - Vance Luther Boelter told Blaze News he shot at Sen. John Hoffman and his wife only after they laid hands on him and his shooting arm.
Reposted by Sam Holtzen, PhD
samd.bsky.social
political violence is a terrible scourge that has claimed victims from both parties

the way some people are just itching to treat this as a reichstag fire moment to enable a dictatorship is extremely scary and a good reminder that political violence is a threat to the very core of liberal democracy
zackbeauchamp.bsky.social
Very, very bad stuff coming from leading right-wingers
Reposted by Sam Holtzen, PhD
soniaseneviratne.bsky.social
Hot off the press: We can provide for the first time a systematic attribution of recent #heatwaves to the emissions of #carbon_majors. Essential new #Nature article coordinated by @yannquilcaille.bsky.social at @ethz.ch, with numerous contributors @usyseth.bsky.social:
www.nature.com/articles/s41...
www.nature.com
Reposted by Sam Holtzen, PhD
jeremymberg.bsky.social
Here is a word cloud of the words that were missing from the noncompetitive renewal awards but had been present in the parent award.

3/4
A word cloud with dominant words "equity", "disparity", "diverse", and similar words.
samholtzen.bsky.social
another note but this is so clearly biased towards the center because it is presented as an upside down parabola, leading viewers to automatically assume the local maximum is the most reliable and accurate news source. this was DIRECTLY taught to us in high school when shown this chart.
samholtzen.bsky.social
screaming at the top of my lungs that reporting facts requires you to select the facts to report based on a conscious or unconscious bias!!!! only trust facts when put in the direct context!!!!!!
samholtzen.bsky.social
i remember seeing this chart in high school as a fun lesson"both sides are extreme, trust the center" and looking back now i grow weary
Reposted by Sam Holtzen, PhD
notalawyer.bsky.social
one of the great conservative moves over the past decade has been to make themselves so unpleasant that their own family members are forced to cut them off, and then use that fact to argue that *liberals* are too uncivil
lakshya.splitticket.org
Sharing this finding: Harris voters are the only group of people remotely likely to say it's OK to cut off friends/family for political views.

I don't think they're *wrong* — again, it's a question of identity. But we're very different from most of America. www.theargumentmag.com/p/when-ameri...
Reposted by Sam Holtzen, PhD
aaronradney.bsky.social
I will remind folks those images of Nazi book burnings aren't burning just any books. They're burning the library of Magnus Hirschfeld; a gay, Jewish doctor who created an institute dedicated to LGBTQ sex education and healthcare. And a man who pioneered gender affirming care surgeries.
samholtzen.bsky.social
i don't think gavin newsom is our only choice in resisting fascism. he's just the one making the biggest spectacle of gesturing in that direction