Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

SN1 Reaction: Stereochemistry

S_N1 Reaction: Stereochemistry

This lesson provides an in-depth discussion of the stereochemical outcomes in an SN1 reaction.
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...

SN1 Reaction: Kinetics

S_N1 Reaction: Kinetics

In an SN2 reaction, the reaction rate depends on both the type of nucleophile and the substrate. A hindered tertiary alkyl halide is practically inert to the SN2 mechanism despite using a strong nucleophile.
However, Sir Christopher Ingold and Edward D. Hughes, who studied the kinetics of various nucleophilic substitution reactions, noticed that a tertiary alkyl halide does undergo a nucleophilic substitution reaction in the presence of a weak nucleophile. While studying the substitution...

SN1 Reaction: Mechanism

S_N1 Reaction: Mechanism

Kinetic studies of ionization of a tertiary halide in a protic solvent suggest that only the substrate participates in the rate-determining step (slow step). The nucleophile is involved only after the slowest step. The SN1 reaction takes place in a multiple-step mechanism.
Firstly, the haloalkane ionizes to generate a carbocation intermediate and a halide ion. This heterolytic cleavage is highly endothermic with large activation energy. The ionization of the substrate, facilitated by a...

Acidity of 1-Alkynes

Acidity of 1-Alkynes

The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.

Predicting Products: SN1 vs. SN2

Predicting Products: S_N1 vs. S_N2

Nucleophilic substitution reactions of alkyl halides can proceed via an SN1 or an SN2 mechanism. While in SN2 reactions, the nucleophile attacks the substrate simultaneously as the leaving group departs, in SN1 reactions, the substrate first dissociates to give the carbocation intermediate. Various factors such as the structure of the substrate, the strength of the nucleophile, and the nature of the solvent promote one mechanism over the other.
With increased substitution on the alkyl halide,...

Preparation of 1° Amines: Gabriel Synthesis

Preparation of 1° Amines: Gabriel Synthesis

Direct alkylation is not a suitable method for synthesizing amines because it produces polyalkylated products. Gabriel synthesis is the most preferred method to exclusively make primary amines. The method uses phthalimide, which contains a protected form of nitrogen that participates in alkylation only once to predominantly give primary amines.
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Temporal Patterns of Allergen Sensitisation in the General Population: The LEAD Study.

Clinical and translational allergy·2026

Same author

Association of triglyceride-glucose index with presence and development of impaired spirometry: results from Austrian LEAD cohort.

BMC pulmonary medicine·2026

Same author

Physiological characteristics and temporal transitions of preserved ratio impaired spirometry.

ERJ open research·2026

Same author

Integration of lung function in allostatic load scoring and its impact on mortality prediction.

Scientific reports·2026

Same author

Real-Time Symptom Ratings Using Ecological Momentary Assessment Versus Traditional Questionnaires in Patients With Chronic Obstructive Pulmonary Disease: Observational Study.

JMIR medical informatics·2026

Same author

Determinants of Fractional Exhaled Nitric Oxide in a Population-Based Cohort: The Role of Lung Volumes and Body Composition.

Respiration; international review of thoracic diseases·2026

Search research articles

Related Experiment Video

Updated: Jan 29, 2026

Lung Fixation under Constant Pressure for Evaluation of Emphysema in Mice

Lung Fixation under Constant Pressure for Evaluation of Emphysema in Mice

Published on: September 26, 2019

Emphysema: looking beyond alpha-1 antitrypsin deficiency.

Rob Janssen¹, Ianthe Piscaer^2,3, Frits M E Franssen^2,3,4

¹a Department of Pulmonary Medicine , Canisius-Wilhelmina Hospital , Nijmegen , The Netherlands.

Expert Review of Respiratory Medicine

|February 15, 2019

Summary

Non-AATD emphysema, a smoking-related lung condition, is underappreciated despite its impact on COPD patients. Recognizing it as a distinct diagnosis is crucial for targeted emphysema treatments.

Keywords:

COPD Emphysema antiproteases centrilobular emphysema elastin degradation elastin repair non-alpha1 antitrypsin emphysema panlobular emphysema paraseptal emphysema proteases

More Related Videos

Generation of Alpha-Synuclein Preformed Fibrils from Monomers and Use In Vivo

Generation of Alpha-Synuclein Preformed Fibrils from Monomers and Use In Vivo

Published on: June 2, 2019

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Published on: June 21, 2017

Related Experiment Videos

Last Updated: Jan 29, 2026

Lung Fixation under Constant Pressure for Evaluation of Emphysema in Mice

Lung Fixation under Constant Pressure for Evaluation of Emphysema in Mice

Published on: September 26, 2019

Generation of Alpha-Synuclein Preformed Fibrils from Monomers and Use In Vivo

Generation of Alpha-Synuclein Preformed Fibrils from Monomers and Use In Vivo

Published on: June 2, 2019

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Published on: June 21, 2017

Area of Science:

Pulmonary Medicine
Genetics
Cell Biology

Background:

Chronic obstructive pulmonary disease (COPD) encompasses various pathologies, including emphysema, characterized by lung tissue destruction.
Alpha-1 antitrypsin deficiency (AATD) is a genetic cause, while smoking is the primary risk factor for non-AATD emphysema.
Non-AATD emphysema is frequently overlooked, hindering research and clinical progress despite its association with significant patient symptoms and outcomes.

Purpose of the Study:

To highlight the clinical relevance of non-AATD emphysema.
To advocate for the acknowledgment of non-AATD emphysema as a distinct clinical diagnosis.
To propose new therapeutic targets for emphysema.

Main Methods:

Review of mechanisms underlying lung tissue destruction in emphysema.
Analysis of current therapeutic options for emphysema.
Discussion of the limitations of current COPD classification.

Main Results:

Key mechanisms of emphysema include protease/antiprotease imbalance, oxidative stress, altered cell death and autophagy, and impaired repair.
Current COPD treatments show less efficacy in emphysematous patients.
Non-AATD emphysema significantly impacts dyspnea, exercise capacity, and patient outcomes.

Conclusions:

Non-AATD emphysema warrants recognition as a distinct clinical diagnosis, separate from the broad COPD classification.
Therapeutic strategies should focus on decelerating proteolysis and promoting tissue repair in emphysema.
Emerging treatments involving Vitamin A/K, hyaluronan, copper, and roflumilast show promise.